Drill and blast

The pattern a bench is drilled and fired to — drafted from the rules, adjusted by the people who drill and load it, and taken from approval to the muckpile.

Mining → Blasts

What a blast is

A blast is a block of a bench, the holes drilled into it, and what each hole is loaded with. Trackapt drafts the holes from a handful of rules, drills every one to the grade from the ground it actually stands on, and works out the explosives, the powder factor and the rest from the holes as they stand.

Nothing is set in stone

The drafted pattern is a starting point. Move a hole round a boulder, drop one on soft ground, add filler holes where the face is ragged, bring in the pattern the surveyor marked out or the collars they picked up after drilling, record what the charging crew really loaded. Every figure follows the holes you end up with — never the pattern the page first drew.

Designing a blast

Open Blasts, then New blast (the plus).

The page gives the pattern the room. Everything the blast is set up from sits in seven tiles along the top — The block, Ground and rock, Pattern rules, Timing and checks, Top of ore, Tie-up and Front row — each saying in a line or two what is set, with a warning stripe where something needs you. Click a tile and its section opens as a window over the page. What you change there applies as you type — the pattern behind the window moves with it — so closing the window, by Done, Esc or a click outside it, loses nothing.

The tiles sit under a The set-up heading that folds. While there is no pattern it stays open, because the tiles are then the whole of the work; once a pattern is drawn it folds away, so the picture of the pattern is the first thing on the page. Folded, the heading still counts what needs you — 2 need attention — so a warning is never out of sight. Open or fold it yourself and that choice stands while you stay on the page. The checks and the front row, with its table, are never inside it: they stay on the page either way.

The block

Field	What to choose
Pit	The pit the blast is on. Fixed once the blast is saved.
The block comes from	A bench of a pit design — pick the design and the bench; the block is the bench floor. A boundary I pick or draw — one of the pit's boundaries; its levels are read off the survey. In the Mining workspace, Add new boundary in the list draws a new one (see Drawing a new boundary as you design). Corners I type — one east, north per line.
Pit bench height, Bench reference RL	The pit's planned benches: how tall they are, and any RL one of them breaks at. Set once for the pit with Save for the pit — every blast and mine plan on the pit starts from them.
Which bench this shot takes	Shown where the ground under the block is surveyed: every bench that ground holds, from one level down to the next below it, and — where the ground spans more than one of the pit's planned benches — each of those benches, with All … benches together beside them. Pick one and the floor and the crest are set from it. Levels I type hands them back to you. Where the floor under the bench is not flat, Where its floor is taken chooses its lower edge or its mean.
Expect small benches	Off by default. On, flat platforms less than a bench apart — a capping over the ore, a thin ore bench on the basement — are asked about before any bench is taken: separate small benches, or one floor that is not flat.
Floor RL	The level the bench is taken down to. Filled in from the survey; type over it to override.
Crest RL	Rock above this belongs to the bench above. Blank: the surveyed ground decides.
The holes are drilled to	One level — the floor RL, the usual flat floor; or A grade surface — a designed floor each hole reads under its own toe, for a ramp, a drainage fall or any floor that is not flat. Where the surface does not reach, the floor RL stands.

Ground and rock

Field	What to choose
Surface, As of	The surveyed ground each collar is read off — what finds the free face, measures the front row, and is drawn in 3D.
Block model	Optional. Name the fields for density, rock factor and free-dig rock, and each hole reads its own.

Then the pattern rules: hole diameter, bench height, rock density, the product (and a product for wet holes, with the water level), and how the burden is decided:

Burden from	What it does
From the hole and the rock	Konya and Walter's rule from the diameter and the two densities. The usual starting point.
To a powder factor	Type the kg/m³ this rock is blasted at; the burden that gives it is found.
To a fragment size	Type the mean fragment wanted and the rock factor; the burden that gives it is found.
As I type it	Type the burden and spacing yourself.

Spacing, sub-drill and stemming follow from the burden unless you type them. Press Draft the pattern: rows are laid one burden apart from the free face, holes one spacing apart, staggered.

Drawing a new boundary as you design

In the Mining workspace, Design blast opens Design a blast beside the picture. With A boundary I pick or draw chosen, the Boundary list starts with Add new boundary, and ends with it too once the pit has boundaries. Choose it and click the corners on the picture: each sits on the current surface, and a double-click, Enter or a click on the first corner closes it. It is checked as any boundary is: one that crosses itself is drawn again, and one over ground already measured is offered a trim. Name it as you draw; a name such as Boundary 5 is filled in for you. Then press Save boundary. It is filed with the pit's survey boundaries and becomes the block at once: its levels are read and the pattern is laid on it. It stays filed whether or not you save the blast. Cancel puts it away and keeps the block you had. Where a pattern is already laid, you are asked first, and asked again on saving if you changed that pattern while drawing. While you draw, the blast's own picture tools, Undo and Redo wait until the boundary is saved or cancelled.

The edit button beside the list renames the boundary chosen. The new name shows on the form and the picture as you type; Save renames it on the Survey screen and on every blast taken from it, because a blast keeps the boundary itself rather than its name. Volume readings already filed keep the name they were filed under. Cancel or Esc puts the old name back. Adding and renaming a boundary need access level 3, but Design blast itself, and every other way into designing a blast, needs access level 4, so drawing a boundary from it does too. At level 3 a boundary is drawn on its own with Draw boundary on the workspace's Survey tab.

On the blast screen (Blasts → New blast), the Boundary list offers the pit's boundaries; a new one is drawn in the Mining workspace, under Design blast.

The pit's planned benches

A pit is mined in benches of a planned height, breaking at the same RLs everywhere — every 10 m from RL 670, say. Set both once, under The block: Pit bench height and Bench reference RL (any RL a bench breaks at), then Save for the pit. The mine plan reads the same figures, so its boundary slices start on the same height.

The survey can only show a bench where the ground has a flat to show it. A boundary that falls from RL 710 to RL 670 with no terrace between reads as one 40 m "bench"; with the pit's benches planned, the page says what it found and offers it as the benches it spans:

RL 710.0 down to RL 670.0 is 40.0 m — 4 of the pit's 10 m benches, and the survey holds no level between. It is offered as 4 benches, broken at the pit's planned RL 700, RL 690, RL 680, each drilled to the floor of the one below.

Each is offered on its own — RL 710 → RL 700, RL 700 → RL 690 and so on — and the top one a rig can take today is taken for you: the highest bench with at least 15 % of the block still standing above its floor. A high corner of the block reaching into the bench above is still offered, but is not taken for you — nearly all of its holes would design to nothing. All 4 benches together takes the whole span in one blast, where that is really meant: every hole is that much deeper, and the rig has to reach.

Ground that rises above the top level with no flat of its own — a slope up to the bench above, rock the last blast left standing — is offered the same way, as the pit's benches, ahead of the rest: the rig takes the highest ground first. It is read to the 98th percentile of the ground inside the block, so a survey spike does not make a bench. All … benches together is offered for any benches that stand one on another, whether the survey found their levels or the pit's plan did.

Only a bench that can be drafted is offered. Before listing a bench, or All … benches together, the app lays the pattern on it as it stands, inside the final wall at that bench's own floor. Where no hole fits, it is left out of the list and the level note says why: for example, The bench RL 685.1 → RL 680.3 is not offered: no hole of this blast's pattern fits it. Every hole fell off the top of the bench. Where no bench can be drafted there is no list, and the note stands on its own. That is typical of a rise with no flat on it, where every collar would stand on the face. It is also typical of a bench below ground the block still stands above, or of a bench the final wall leaves no room on. All … benches together is tried as one blast, not bench by bench, so it can be offered even where each of its benches alone is not; the note then says so. Levels I type stays available, and those levels are still checked against the ground.

The benches are tried again whenever anything the draft is laid with changes, and only then. That is everything: the pattern (burden, spacing, layout, hole diameter and the other rules), the bench height, the final wall's pit design and its benches, the pit's wall control (where the blast has none of its own), the free face you picked, your answers about berms and the bench below, your answers about small benches (a platform you said is a bench of its own is drilled as one), the ore (where it is read from, its cut-off and stand-off), the grade surface, the block model and its rock fields, and the explosives catalogue. Where the app picks the bench for you and that bench sets the bench height, the benches are tried again at that height straight away, so the list you see already matches it. Renaming the blast, editing its notes or typing its own floor leaves the list as it is: each bench is tried at its own floor. The app waits until the change has stood for a moment (while you type, until you pause), then reads and tries the benches once, so the list can change just after you stop. Where the ore is read off a surface, the benches are tried again as soon as that surface has loaded, so a bench whose every hole falls within the ore stand-off drops off the list then, not only the next time you change something. The same goes for the grade surface and the block model: choosing another one tries the benches again once it has loaded, not merely once one has.

Where every bench alone is held back and only All … benches together is left, a new blast does not keep the bench the app first chose for it: nothing is picked, and the floor and crest are left empty until you choose the benches together or type levels of your own.

A blast whose floor and crest are a bench that is held back keeps its levels as levels you type. The level note says so, and why that bench is not offered.

A span only up to a fifth taller than a planned bench — 12 m on a 10 m bench — is still one bench, and nothing is said. A top or bottom sliver thinner than a fifth of a bench joins the bench next to it rather than becoming a bench of its own. Where the ground stands at one level and no floor could be read under it, the floor is taken at the pit's planned RL a bench below, and the page says so. Levels you type that span more than one planned bench are warned about unless they are a span you chose to take together (typing exactly a span's crest and floor counts as choosing it). On a pit that plans its benches, a bench shorter than planned — the partial top of a span — is not warned about.

The Bench height under Pattern rules starts at the pit's. Change it there for this blast only: the ground is then broken at that height, still from the pit's reference RL, and the page says the blast works on its own height with Use the pit's to go back. Picking a bench never changes the bench height on a pit that plans its benches. Until the pit's benches are set, the levels are read off the ground alone.

The levels a boundary stands at

A boundary drawn on a pit survey does not need its levels typed: the ground under it already stands at them. Choose the boundary (or type the corners) and, as soon as a surveyed Surface is set under Ground and rock, the page reads the ground inside the boundary and out to 30 m around it, and says what it found:

The surveyed ground here stands at RL 1100, RL 1090. A bench is taken from one level down to the next below it.

Each such pair is offered as a bench of its own — RL 1100 → RL 1090 · 10.0 m · 4,210 m² — with the area of the block that stands at or above that crest. The one standing on most of the block is taken for you; pick another and the floor and the crest move to it. Where the boundary sits wholly on one flat, the level its face drops to is read off the ground just outside it, and the bench says so: floor beside the block.

A floor that is not flat. A surveyed floor is seldom dead flat. Where a floor humps and hollows over a metre or more — from RL 1089.2 to RL 1091.6, say — so that no one level holds enough of it, it is still found, but it is not one RL. (A floor that mostly stands at one level is taken at that level, however rough. Ground that lies on one plane is read as a slope and is not offered as a floor — a ramp, but also a floor graded to an even fall of about a metre or more across the block; type such a floor, or drill it to a grade surface.) The bench is offered down to its lower edge, and under the bench a second choice appears, Where its floor is taken: Its lower edge or Its mean. Holes on ground already at or below the floor design to nothing, so the page says beside the choice what each one leaves out of play:

The floor is not flat: the ground read there runs from RL 1089.2 to RL 1091.6. Taken at its lower edge, RL 1089.2, under 1% of the block stands at or below it, and those holes are out of play. Taken at its mean, RL 1090.2, 4% of the block would stand at or below it, and those holes would be out of play.

The lower edge keeps nearly every hole in play; the holes on the floor's higher ground are drilled that much deeper. To take neither, type a floor of your own. A saved blast keeps which of the two it was taken at, and opens on it again.

The bench's own ground, not the whole boundary. A survey boundary is not the extent of a blast. One boundary can hold two or three benches at different levels, and the bench you blast is usually only part of it. So once the bench is chosen, the block is that bench's own footprint inside the boundary: the ground standing at the bench's level — within a quarter of the bench below its crest, and no more than half a bench above it. Its edges are the bench's own: the crest, where the ground drops to the bench below, and the foot of the wall rising to the bench above. The holes are laid only inside it, and The free face (Read it off the ground and Pick the edges myself) and the back line are read off those edges, not the boundary's. The boundary only bounds the search. A note under the levels says what the block is:

The block is the bench's own ground inside Pit 3 east, read off the survey at RL 110: about 1,180 m² of the boundary's 3,200 m². …

Where the bench fills the boundary, the block is simply the boundary. Where no ground stands at the bench's level inside it — a level typed wrongly, say — the block stays the whole boundary, and the note says so. Where the bench stands in two separate pieces inside the boundary, the larger is taken and the note says that too.

Adjusting the outline. The footprint is a starting suggestion. Open Corners to type over a corner's east or north, add a corner half-way along the side after it, or take one out — asked first, and Undo puts it back. In the Mining workspace, Adjust on the picture lets you drag a corner, press on a side to put a corner there, or click a corner and press Delete to take it out. The outline always stays inside the boundary, and its sides may not cross. Once adjusted, Read the outline again puts back the footprint the survey gives (asked first). Picking another bench reads that bench's footprint afresh.

A saved blast keeps its outline — read or adjusted — and opens on it again.

Small benches. A thin bench is ordinary work: a capping of a metre left over the ore, or an ore bench of a metre that truncates on the basement, under benches of ten metres or more — over a seam, and over a massive orebody too. On the survey, two such platforms a metre apart look like one floor that is not flat. Turn on Expect small benches in The block and the page looks for them. Where the ground steps between well-defined flat platforms — each an area of the block, together most of the floor, half a metre or more apart — it asks:

The ground here stands on 2 distinct flat platforms, RL 1092.0 and RL 1091.0, 1.0 m apart. They may be 2 small benches — a capping over the ore, or a thin ore bench on the basement — or one floor that is not flat.

No bench is taken until you answer — a bench already picked off the survey is let go — the block tile says so, and the blast cannot be saved until you do. Separate small benches makes each platform a level of its own and offers the bench between them however thin, marked small bench. One floor that is not flat reads them as one uneven floor, taken at its lower edge or its mean. Until you answer, the levels offered are exactly what they would be with the switch off. Ground whose heights differ haphazardly, a ramp, and a floor graded for drainage are read as described above and are not asked about. The switch is off unless you turn it on; a saved blast keeps it and its answers, and an answer stays with its question when a resurvey moves the platforms by a few centimetres.

What the page can see is limited by how finely it samples the ground: platforms less than half a metre apart, or narrower than two sampling steps across, are not found — type those levels; on finely sampled, noisy ground a half-metre step can be missed too. Two flat areas joined by a slope steeper than about 8 % between neighbouring samples, and a flat-bottomed sump a metre or two deep, are asked about, since the ground alone cannot tell them from a step: answer One floor that is not flat. Where many plateaus stand close together, only the most distinct are asked about. An answer names its platforms by RL, not by place, so changing the outline or the design bench lets the answers go and asks again. A bench of a metre is still judged by the pattern rules, so expect the stiffness warning on it.

Nothing here takes the levels away from you. Levels I type — or simply typing in Floor RL or Crest RL — settles them, and the page stops offering its own. What it does not stop doing is checking them against the same ground:

What it says	What it means
The floor RL 1105 is at or above the ground everywhere inside this boundary — the highest ground is RL 1103.4. There is nothing here to drill.	The bench has already been taken, or a digit slipped. Drilling here is drilling air.
The crest RL 1090 is below all of the ground here (lowest RL 1097): the bench above this one has not been taken yet.	The collars would start below ground. Blast the bench above first, or raise the crest.
The floor RL 1050 is 45.0 m below the lowest ground in this boundary (RL 1095) — more than one bench.	Take the benches one at a time.
The crest RL 1085 is not above the floor RL 1090.	A bench is drilled from its crest down to its floor. Refused when the blast is saved, too.
37% of this boundary already stands at or below RL 1090: those holes design to nothing.	Part of the block is dug out. Often deliberate — a boundary that spans two benches — so it is a warning, not a refusal.
Nothing here stands at RL 1092. The nearest level the survey holds is RL 1090.	Usually a mistyped level; the bench the ground really holds is offered beside the message.
RL 1090.2 is inside a floor that is not flat: the survey holds it from RL 1089.2 to RL 1091.6. 4% of this boundary already stands at or below RL 1090.2, and those holes are out of play. Its lower edge is RL 1089.2.	The floor sits above the lowest the floor runs. Often meant; type the lower edge, or take it under Where its floor is taken, to bring those holes back into play.

The first four cannot be drilled on this ground, so they are also said on the page itself, under the plan, with Take RL 1100 down to RL 1090 beside them. The rest are warnings: the block tile reads Check the levels against the survey and the words are in the window.

A block with no surveyed ground is checked for one thing only — a crest at or below its own floor, which is no bench whatever the ground says. Nothing else is checked, and nothing else is refused: the levels are then yours alone.

How long each hole is

You never type a hole's length; it is worked from the ground and the grade. A hole goes from the surveyed ground at its collar down to the grade under its toe, plus the sub-drill — and, where it leans, along the lean:

length = (collar RL − grade RL + sub-drill) ÷ cos(lean)

A hole on a high spot is longer and holds more, which is what stops the humps a flat design leaves on the floor. A leaning hole's toe lands towards the face, and on a grade surface the toe is read where it lands. The Holes table and the charge sheet give each hole's Lean and Toe RL, and What it takes gives the shortest and longest hole.

Where a hole can be collared

A rig drills from the top of the bench and nowhere else, so the collar is always the surveyed ground itself — never the crest level under it — and a drafted hole is only laid where a rig can stand. A hole the draft would put in any of these places is left out, and What it takes says how many:

Left out where	Read as
On the face	The lie of the ground round the collar is steeper than 20° read two ways: across a 2.5 m footing, and across the pattern's own footing — 0.6 of the burden, never less than 1.5 m. Only ground steep both ways is the face, so a hump or a rough top is not taken for one at any burden, and a small pattern keeps its first row against a steep face.
Below the crest	The ground is more than 30 % of the bench height under the crest, and never less than 1 m: 3 m on a 10 m bench, 1.5 m on a 5 m one.
On the bench above	The ground stands more than half a bench over the crest: that bench has to be taken first.
On a berm	A flat terrace about the pit's berm width, a bench step from the ground either side — see Berms.
Behind a berm's crest	Ground joined to a berm and no more than 1 m below it — never more than 0.4 of the berm's height over the crest — on its wall side: its ragged ledge and the wall behind. Firing it would cast the berm into the blast — see Berms.
On the crest of the bench below	A lip at or under this blast's crest with the wall rising close behind it and the ground falling away in front to the floor — the top of the next bench down, drilled with that bench, not this one. See The crest of the bench below.

How near the crest a collar can come depends on the pattern, because a smaller pattern is drilled by a smaller rig. On a face leaning back 2:1, the nearest collar is about 0.7 m behind the crest at a 2 m burden, 0.85 m at 3 m and 1.15 m at 4 m or more; behind a vertical wall, 1.5 m, 1.8 m and 2.4 m. If your site keeps rigs further back than that, move those holes back by hand or raise the burden.

A hole you add by hand in one of those places is kept — it is yours to judge — and its warning says why a rig cannot stand there. If every hole would be left out, Draft leaves the pattern as it was and says why — usually the crest or floor level does not match the ground.

The rock the blast breaks is measured from that same ground, up to half a bench over the crest, so the powder factor divides the charge by the rock it is drilled into. Higher than that is the bench above, measured from the crest; if you keep charged holes up there, the checks warn that the powder factor reads high until you take the bench above first or remove them.

Apply the rules to every hole, charging the holes again and taking a stand-off all read the ground again: a collar not on the surveyed ground moves onto it, lengths and charges change, and a hole off the top of the bench gains a warning. Draft again leaves such holes out.

A mine plan costs the benches it has not reached as though the benches above were already taken: collars at the crest, and no hole judged by where a rig could stand today.

Berms

A berm is the catch ledge left on a pit wall where one bench steps back from the next. It keeps falling rock off the floor below, so it stays — even a temporary one. Mining a seam-like body along its dip — chrome, diamonds in a conglomerate — starts again at the top bench each time and works down, leaving a berm below each bench, and those berms move on as mining advances. Until they do, no hole is drafted on one as if it were the top of a bench.

The page finds berms on the surveyed ground itself. A flat terrace is a berm when all of these hold:

Test	Figure
Above the blast	It stands at least a fifth of the bench (2 m on a 10 m bench, never less than 1 m) above the blast's own crest. With no crest level set, no berm is looked for at all — the pattern card says so — because a crest guessed from the floor would make a berm of the top being blasted. Ground at the level being blasted — a narrow top against the wall, a haul road along the crest, a platform of a stepped floor — is the production bench, never a berm. Platforms you said are separate small benches are never berms either.
Flat	The ground across it, averaged over 1.5 m so a survey's roughness is not read as slope, slopes no more than 8°. Rougher ground leaves gaps in a flat; they are filled before it is measured, so a rough production top still reads as broad as it is.
About the berm width	Its typical width along its length is at least 2 m and no more than the berm width and half again — 15 m on a 10 m berm. A corner, a ramp through it or a wider stretch does not change that; a terrace wider all along is ground to mine.
A ledge on a wall	It covers at least a berm width's square, and looking out from its edge the ground falls at least a fifth of the bench (2 m on a 10 m bench) along one side and rises as much along the other, the two facing opposite ways. A trench has the ground rising on both sides; a flat at the rim of the pit, or on a bund, has no wall rising behind it.

The step is a fifth of a bench, not half of one, because that is what the berms look like on the ground: on the ROMBE highwall, where benches are taken in parts as mining moves along dip, the berms step only 2–3 m apart.

A ledge that sags along its length is still one ledge. A catch berm is rarely one contour. In hilly ground it sags along its length and comes back up, and the sag is far steeper than a flat, so each stretch either side of it reads as a terrace of its own and the dip between them as neither, though the eye reads it as plainly part of the berm. The two stretches are read as one berm on one card, the dip with them, when: the berm stands either side of the dip, the two stretches within a step of each other; the dip is at least half a metre below the ledge either side; and the ledge's own step is in front of the dip — ground falling away below it to the bench, as it does in front of the rest of the berm. That last is what keeps the top of the bench out of it: a top standing a metre or two above the crest you typed, between two remnants of a ledge or in a bay a ledge wraps round, has no step under it, and it is drafted as the top.

What this does not join: a ledge that dips and stays down is two berms, each with its own card, and the slope between them is wall side; two berms stacked one above the other keep their own cards; and ground below this blast's crest is never a berm, however much it looks like a ledge on the picture — a strip along the foot of a wall with the ground in front of it falling away to the bench below is left off as the crest of the bench below (see below) — the top of the next bench down. If a berm you answered Leave it or Drill it on is read joined to another, check its card: the answer is kept only where the joined berm still stands where the answered one did, so it may need giving again.

A ramp cut down through a berm is a dip of this kind: the ledge carries on past it, and the road belongs to the berm. Hole positions on the road are left off with the berm, and the berm's card counts them.

The berm width is set once for the pit, under The block beside the pit's bench height — Pit berm width, then Save for the pit — and every blast on the pit starts from it: 10 m where the pit has none. Pattern rules has Berm width for this blast only. 0 looks for no berms at all, for a pit that leaves none; otherwise it is 2 to 100 m. Clearing the pit's field puts it back to 10 m. A berm wider than the berm width and half again is not found — at 6 m, a 9 m berm is missed — so set the width to the berms your walls have.

Not the pit design's berm width

A pit design has a Berm width of its own — the berm it builds each bench back by, 6 m unless the design says — and the mine plan reads that one. The berm width here is a separate setting: the width of the berms drill and blast finds on the ground and keeps holes off. Set both if your pit design and your walls differ.

What the page does with one:

• The draft leaves it out. No hole is collared on a berm; What it takes counts the holes left out, and a card on the pattern names each berm in the block — its width and level, and that it is left as a berm.
• Nothing behind its crest is drilled either. A real berm is seldom a smooth ledge: faults, joints and weathering leave its crest ragged and its surface rising and falling, so the flat the page finds is narrower than the ledge. A hole on the wall side would blast the berm and cast it into the main blast, so the draft leaves out every position on ground joined to the berm and no more than 1 m below it — never more than 0.4 of the berm's height over the crest, 0.48 m on a berm 1.2 m up, so the top being blasted is never reached — all the way up the wall behind. The berm card counts the positions on the ledge itself — its ragged edge, no higher over the berm than that margin below it — not those up the batter or on the benches above, which no pattern drills; the checks list them, and the berm's window shades all of that ground as Behind the berm's crest. Ground joined to a berm that is closed all round by lower ground — a ledge across a remnant standing on the bench — is not the pit wall, and nothing behind it is left out. Where the block has a final wall, a position past it is counted there, never twice. A hole you place there is kept, with a warning.
• Ground that is not fired is not in the volume. What it takes measures the rock over the block less every berm left in place and the ground behind its crest, so the rock, the tonnes, the powder factor and the drill yield are worked on the rock the charge is fired into. The card and the charge sheet say how much was left out: The volume leaves out 1,240 m² of the block on a berm or behind its crest, which is not fired. A berm you answer Drill it is production ground, and its rock is counted.
• You decide what the ground cannot. A flat can look exactly like a berm — a platform of this bench stepping up 2 m, say, that you have not answered as a small bench. Each berm card asks: Leave it — it is a berm, which is what happens until you say, or Drill it — it is production ground. The card counts the hole positions left off the berm and behind its crest; Drill it drafts them as ordinary production holes, and Leave it takes them out again — only those still as drafted: a hole on it you moved or gave figures of its own stays, and the card names it as standing on the berm. The answer is kept with the blast, and holds while the berm reads within 0.2 m of the same level: if a new survey moves it further, the answer is dropped and the berm is left again. Platforms you answered as separate small benches are never asked about.
• See where it is. The card says a width and a level, not which flat is meant, so each berm card carries an eye — View this berm on the pattern — that opens the pattern as a window with the berm's ground shaded blue-green and the ground behind its crest violet — the card's width is the berm's alone, so the violet wall behind it can be far wider than the figure — the hole positions it kept off as hollow marks, and any hole standing on it ringed — each mark a pale ring on a dark rim, so it stands out on brown ground, on the shading and on either theme. Island and strip cards carry the same. The window opens in the view the pattern card shows, and has its own Plan, 3D and Pictorial buttons inside the picture, so you can see the berm on the plan, on the ground in three dimensions, or as a person on the bench would. It stays shaded in all three, and switching there leaves the card's own view as it was. It is a picture only: Esc or a click outside closes it, and nothing on the blast changes.
• Nothing on it is an island or a strip. A run of positions on a berm is never taken for one, and no hole reaching an island is collared on a berm.
• An island or a strip beside a berm is never dropped silently. Its card — and the draft's warnings — name the berm it runs up to. The toe of a berm's own step, within one batter run of it, is left with the berm: anything there more than half a metre above the crest stays, so no hole undercuts the catch ledge, and the card says how many positions that is. No hole reaching an island is collared there either. Everything else in it is this blast's rock and is reached as any island is, however high it stands: a mound on the top at the foot of the step is drilled, not left as a toe. Where nothing is left to reach, no hole is added, the card says so, and it is not counted as a toe.
• A hole you place on one is kept — it is yours to judge — and says it is on a berm; the berm's card names it until it is taken out.
• A saved blast shows its berm cards when reopened, and warns about any hole standing on a berm. Nothing moves, and nothing is saved or marked changed on its own: draft again, or take the holes out, when you are ready.
• Mine it from the top. A berm is taken only once the benches above it are: widen the pit from its top bench and work down, or, on a body that strikes along the pit, open a new cut along strike from the outcrop.

The crest of the bench below

A block's outline can run past the top of this bench onto the top of the next bench down — along the foot of a wall, or where a bay of the pit wraps round. The ground there is a lip: it sits at or a little under the crest you are blasting, the wall rises close behind it, and in front of it the ground falls away to below this blast's floor. That lip is the top of the bench below. A hole drilled on it is drilled on the wrong bench: it belongs to the shot that takes the bench below, drilled from there, working down from the top.

So the pattern leaves a designed hole off the crest of the bench below, counts it, and cards it. A hole you put there — by hand, or brought in from survey — is kept, and warned, because it is yours to judge.

This is read off the surveyed ground, not off the outline: round each point the steepest fall and the steepest rise are looked for, out to about a burden and a half. The point is on the crest of the bench below only when the ground falls at least a berm's step and keeps falling toward a lower bench, the ground behind rises at least a berm's step and stays up — a wall climbing to the bench above, not something standing on this bench's top — and the two are roughly opposite: the wall behind, the pit in front. That tells it apart from the ground it must not touch:

• an ordinary free face has open ground falling away in front but the bench top flat behind it — nothing rising — so its front row is drilled as always;
• a mound, windrow or boulder pile behind the front row rises and comes back down to the bench top, so it is no wall, and that front row is drilled as always;
• a berm stands above this crest, not under it;
• the rim of the pit has the ground falling away behind, not rising to a wall.

A hole is left off on its own only where the wall is plain: the steepest thing behind the lip, standing up across its width, with the survey running well past it. A narrow bund running back from the lip, higher ground off to one side, or a pickup that stops a few metres behind puts the lip to you instead — Leave it off — the bench below or Drill it — this bench — with the hole standing until you say.

What it takes lists the crest of the bench below as its own card — how many holes were left off and the RL range of the ground — and its eye opens the pattern as a window with that ground shaded, in Plan, 3D and Pictorial, the left-off positions marked on it. The checks name it too. The shading is a green, drawn apart from a berm's ground and from an island, so a reader takes it for the different bench it marks.

The final wall

A block drawn from a boundary or typed corners can stay inside a pit design's final wall: under The block, Final wall from names the design. No hole is drafted past that design's bench toe at the blast's floor — the toe of the bench the floor lies on — and a hole placed past it says so. That is the narrower outline, so it errs on the side of the wall: where the floor falls between two of the design's bench floors, up to a batter run and a berm is left unblasted against the wall. A block taken from a design's own bench already is that bench. Blasts drafted from a plan stay inside the toe of the whole bench they are cut from.

Wall control

Beside a wall, the pattern's full charge breaks back into rock that has to stay. A wall here is the final wall (from Final wall from, on a boundary or typed-corners block) and the toe of every berm the page finds — the foot of the berm's step, on this blast's side. Against a wall the draft lays rows of its own:

Row	Where	Holes
Stand-off	Half a burden from the wall — 2 m at a 4 m burden.	No hole stands nearer: the pattern's positions there are left out.
Keep-out band	From the stand-off out to half a burden and 0.8 of one more — 5.2 m at a 4 m burden.	The pattern's own holes stay where they are and carry the buffer charge, leaning away from the wall: charged lighter, not removed.
Buffer row (on unless you say)	On the stand-off line, 0.8 of a spacing apart — only in place of a hole of the pattern left out inside the stand-off, within 0.8 of a spacing of it, and never within 0.8 of a spacing of another hole along the wall.	The pattern's diameter and sub-drill, carrying 60 % of the column below the stemming; the rest is stemmed.
Trim row (off unless you say)	On the stand-off line, in place of the pattern's holes left out there; the buffer row moves one buffer burden further in.	89 mm, 15 diameters apart, no sub-drill, loaded in two decks 1 m apart, stemming in proportion to the smaller hole.

• Holes lean away from the wall at the pattern's own angle. A vertical pattern stays vertical: the page never invents a lean.
• Never more explosive against the wall. Holes in the keep-out band are charged lighter where the pattern put them. A row hole is laid only in place of a hole of the pattern the stand-off left out, and the row and any holes added behind it never carry more explosive between them than the holes they replace. So near a wall there is never more explosive, more holes than the row's own, or holes closer than 0.8 of a burden than the pattern alone would have — however deep the block and however far behind it the wall stands. Where the pattern left no hole out, no row is laid: its own holes beside the wall carry the buffer charge. No hole with a full charge has its collar or its toe inside the band: a hole whose lean or whose front-row fix would carry it there is charged lighter, or the fix is not made, and a hole leaned in under an island from beside a wall carries the buffer charge too.
• No strip is left unblasted. Where the stand-off left ground the pattern reached and no hole now reaches — farther from a collar than the pattern's own widest gap, 2.8 m on a staggered 4 × 5 pattern — a buffer hole (BUF-…) is added there: only inside the band, at the buffer charge, never more of them than the positions the stand-off left out, and never more explosive than those positions carried.
• Where no buffer hole stands along a wall that needs one — the row's line falls off the block, on ground no rig stands on, or the pattern left no hole out there — the pattern's hole nearest that stretch of wall carries the buffer charge instead: the one nearest the wall itself, beside the stretch and no farther from the wall than the keep-out band and half a spacing, never a hole off to one side. A stretch longer than a spacing that no such hole stands beside is said, with its metres. A trim row switched on that is not laid along a wall says so too, with its metres and why.
• Rock no hole can reach is said. Where no hole can be designed behind the buffer row — a hump no rig stands on, say — the draft warns how many places are left and names the holes nearest them: 2 places behind the buffer row could not be reached (near F2, F4). Ground already down at the floor is not counted.
• The charges count. A buffer hole's lighter charge and a trim hole's decks are in its kilograms, so the totals, powder factor, most per delay, flyrock, vibration and the magazine take them like any hole's. Re-charging a buffer or trim hole charges it the same way again.
• Fix the front row leaves the wall rows alone. A buffer or trim hole stands at a wall, not at the free face: the front row is judged and fixed without them, and a hole in a wall row keeps its charge and its decks however it is charged again.
• The free face is not a wall. Ground at or above the crest all the way out past the final wall is a wall: that is what a final wall at a pit limit is, the rock beyond it unmined and level with the bench top or higher. Only ground that falls away more than a fifth of a bench below the crest (at least a metre) within a burden and a half of the wall is a free face — even with the crest a few metres past the wall, or a face that starts at the wall itself — and a windrow that rises then falls is a free face too.
• A berm you drill is not a wall. Choosing Drill it on a berm's card takes away the wall rows along its toe, and the pattern takes their ground.
• A card on the pattern names the walls in reach — metres of final wall and of berm toe — the rows along them, and warns of a hole with a full charge whose collar or toe is inside the keep-out band (a hole placed by hand, from survey, drilled or loaded is never changed, only named), or of a stretch of wall longer than two spacings with no buffer hole beside it where the pattern would otherwise stand within reach of that wall.

Set the Buffer row, Buffer charge and Trim row once for the pit under The block, beside its benches, then Save for the pit. Under Pattern rules, Wall control shows what this blast uses — the pit's, or the defaults — and changing any figure there (buffer burden and spacing, stand-off, trim diameter too) gives this blast its own.

Rows are laid by a draft

Rows are laid when the pattern is drafted. A saved blast whose pattern has no wall rows shows its walls and warnings when reopened; nothing on it moves, and nothing is saved or marked changed. Draft again when you want the rows.

Where mining goes next

On a seam-like body that outcrops and dips gently — chrome, or diamonds in a conglomerate — mining advances along dip and along strike in phases, and berms are left on the walls as it goes. Once a blast is on the pit's floor — the toe of the pit design's lowest bench, or where there is no design, the lowest bench the ground under the block offers — and only berms are left beside it, a card on the pattern says what comes next:

• Widen from the top. Mining goes on from the top bench, bench by bench down, each bench leaving its berm for the one below. The card names the top bench.
• Or a new cut along strike. Where the ground runs along strike — the block at least two and a half times as long as it is wide, or the pit's own Strike bearing (under The block), with the ground rising at least a bench towards one end — the high end is the outcrop, and the card says a new cut opens from it, naming the direction (north-east, say).

Start at the top bench opens a new blast on the same pit at its top bench — from the same boundary, or the same pit design. It is not saved, and nothing is drafted until you do.

The pattern in plan and in 3D

The pattern card switches between Plan — the holes as the surveyor marks them out, each named with its depth and, where it is not drilled straight down, its inclination — 3D and Pictorial. Once the shot is tied up, a Firing switch sits beside them, in the card's header and in each picture's corner: turned on, the same three pictures play the shot; see Watching it fire. On a phone the switch shows without its word.

A designed hole is named for where it stands: the row as a letter from the free face back — A the front row, B the row behind it, and past the twenty-sixth row AA, as a spreadsheet letters its columns — then its number along the row. A1, A7, B12. A hole brought in from survey or added by hand keeps the name it came with.

The rows that are not the pattern's take a three-letter token, so nothing can be read as a row: BUF-01 a buffer hole, TRM-01 a trim hole, ISL1-01 a hole covering the first island (ISL2- the second), FIL-01 a filler you add, and SUR-A1 a collar brought in from a pickup that no design hole stood at. The tokens are three letters because one letter is a row: row 2 is B, row 6 F, row 20 T.

An easer takes its name from the front hole it stands behind — the first of the two, by row and number — with an E: A4E, and A4E2 should a second easer come off the same hole. It is built from that hole's own name, so it follows the blast's naming like every other hole, and on the charge sheet A4, A4E, A4E2 read in that order.

In 3D every hole is a rod: grey for the stemming, orange for the charge (blue where the hole is wet), with a white collar, red where the hole has a warning. It stands in the surveyed ground of the blast's surface, so you see the real ground profile — the crest, the face, any toe left in front — over the grade it is drilled to and, where there is ore beneath, the top of the ore. Each collar sits on the surveyed ground where the hole is drilled. The ground is drawn see-through, so the length of each hole below it still shows through it.

The same Plan, 3D and Pictorial buttons also sit inside the picture, beside its legend — icons only on a phone — so you can change view without scrolling back up to the card, and a picture taken full screen stays full screen when you do.

The eye at the picture's top-right corner takes the legend and those buttons off the picture when they cover the holes you are looking at, and brings them back on the next click; the choice is kept as you switch between Plan, 3D and Pictorial. The expand control beside it fills the screen.

The 3D picture draws ground only where the survey walked; ground the surveyor never picked up shows as a gap, the same rule the volume engine uses. A ramp, the far side of a highwall or a sump the pickup did not reach is a hole in the picture, not a fault in it — the page is showing you ground it has no survey for rather than inventing a flat bench across it. The ground is cut to a straight edge 20 m round the block, and further out where a berm or island card's window takes in ground beyond the block.

Rest the pointer on a hole in Plan and its name, position, depth and inclination are written along the bottom of the drawing. A hole with something wrong also shows a tooltip beside its collar saying what: its warning, and what the front row found for it — a hard toe, no free face at the toe, too little rock in front of the charge — and why a fix could bring it no further forward. A sound hole shows no tooltip.

A hole with an error is drawn red: it cannot fire as designed — nothing to charge, a collar past the final wall, a wet hole loaded with a product water spoils, a hard toe or no free face at the toe or too little rock in front of the charge, or the gap a removed hole leaves on either side of it. A hole with only a warning is drawn amber: something to know while it still fires as designed — an unsurveyed collar at the nominal crest, a stand-off note, why a fix could bring it no further forward. The legend says Has an error and Has a warning, each only when a hole on the plan has one; the tooltip says which it is in words. The 3D picture still marks both as Hole with a warning.

Every line of the legend that names a layer is also its switch. Click Drill holes to take every hole out of the picture and look at the ground on its own — the camera stays where it is, so switching them back on shows where each one stands. Click Ground, Grade or Top of ore to switch that layer off and see the holes inside it. Drag to turn, scroll or pinch to zoom; the expand control fills the screen.

A blast on no surface still draws in 3D, with its collars on the nominal crest; the page reminds you to choose the surface to see the ground.

Hide … with warnings, beside the view buttons, takes every hole that carries a warning or an error — its own, what the front row found for it, or a gap beside a removed hole — off the plan, the 3D pictures and the plan sheet, so you can see the pattern that stands without them. Nothing is removed from the blast: the Holes table still lists them, and the figures still count them. The switch only appears when some hole has a warning.

Pictorial shows what a person standing on the bench would see: the surveyed ground, solid, with a collar where each hole is marked out, and nothing below the surface — no rods, no grade, no top of ore. It is the same picture as 3D drawn another way, so switching between the two keeps where you turned and zoomed to.

The plan sheet

Plan sheet, on the pattern card, draws the pattern on the same sheet a survey plan prints on: the paper, orientation and scale you choose, the four corner blocks, and a print at true size, so a spacing measured off the paper with a rule is the spacing on the ground. Every hole is marked where it is collared, with a line to its toe where it leans, and named with its depth and any inclination. The block's outline and the ground's contours are drawn under them, and the title block says how the holes are labelled.

The sheet starts at the smallest listed scale that holds the holes — not the whole survey — and every hole is always named. Where a scale leaves labels running into each other, or puts a hole off the map or under a corner block, the sheet says so under the preview and names a larger scale to try.

The free face

The free face is the open side the rock is thrown towards. Every row is laid from it, and the tie-up starts the shot at an end of the row nearest it, so a face read wrong turns the whole shot round.

How it is found. Trackapt walks out from each edge of the block, square to it, at a quarter, a half and three quarters of the way along. Where the surveyed ground falls to half the bench within two burdens of the outline, at two of those three places, the edge is face. Half the bench is measured from the bench's own levels — its crest and floor — not from the ground at the line, so an outline digitised down the batter or at the toe still finds the face in front of it.

A face standing off the outline. Where the crest of the face stands out past the outline — more than half a burden — the rows are laid from the crest, where the rock really ends, and the pattern card says how far out it stands. Past a whole burden, the first row falls outside the outline and the front holes inside it carry that rock as well as their own burden. Extend the blast to the face pushes the outline out to the crest and drafts the pattern again, so the rock between is drilled with the rest of the blast. The block then becomes drawn corners; a survey boundary it came from is not changed. A block that is a bench of the pit design keeps the design's outline, and the card says so.

A crest inside the outline. An outline drawn down the batter or along the toe puts the crest inside the block. Trackapt walks back up the slope to the crest — where the ground first stands a tenth of the bench below the top — and lays the rows from there, so the front row stands a full burden behind the rock's edge rather than a burden from a line on the batter, which would leave thin rock over the charge at the top of the face. Rows are straight and a crest is not, so the rows move only as far as the whole edge agrees — to where the crest stands nearest the outline. Where it steps back further, or steps out on part of the edge and in on the rest, each front hole is read for the rock it actually has and leaned, brought forward or stemmed deeper as the front row always is. The pattern card says how far in the crest stands.

A box cut. A block with no face within reach is a box cut. Its rows run along the edge with the lowest ground beyond it — the side most likely to open — and it should be fired as a V from the centre. The Front row tile and the pattern card both say when a blast reads as a box cut.

Picking the face yourself. Under Front row, The free face says what was found and lists the block's edges. Choose Pick the edges myself and tick the edges that stand over open ground: they are the face whatever the survey shows, and the choice is saved with the blast. Ticked edges must meet end to end — a face is one stretch of the outline — and until they do, the face is read off the ground. A picked face is dropped if the outline changes, because its edges are no longer the block's. View shades the face on the pattern. Each edge in the list has its own View, which opens the plan with that edge picked out in violet. On the plan, click on or beside any edge to tick it as part of the face, or click a ticked edge to clear it; the window stays open, so a face of several edges is picked in one go. The plan picks; the 3D pictures only show.

The back line: designing from the back

The back line is the back of the blast: the crest of the berm or wall it stands in front of. Laid from the back line, the pattern starts there and works toward the front, so the back of the dig is a clean, straight line that keeps off the berm, and the front row takes whatever is left between the rows behind it and the free face. Rows and holes are still named from the front: row A is the front row, nearest the face, and the tie-up still starts the shot there.

A new blast is laid from the back line. A blast laid from its free face stays that way until you change it.

Where it is. Under Front row, below The free face, The back line offers From the back line or From the free face. Laid from the back line, it says which line it is using:

• Read it off the outline (the default) takes the edges of the outline that face away from the free face — each within 45° of facing straight away from it. It must be one stretch of the outline. Where it cannot be read — a box cut, which has no free face to stand opposite; a back notched into more than one stretch; or no edge facing away — the page says Mark the back line to design from it, and the rows are laid from the free face meanwhile.
• Mark the edges myself lists the outline's edges: tick the ones along the back of the blast. Ticked edges must meet end to end; until they do, the back line is read off the outline. Each ticked edge must also face away from the free face, within the same 45°: tick the free face itself, or a side of the block, and the page warns you, leaves the tick showing with the reason under it, and does not take it — laid from it, row A would stand at the back or the side. Clear it and tick the back edges instead. A marked back line is saved with the blast and dropped if the outline changes, because its edges are no longer the block's. View opens the plan with the back line drawn; click on or beside any edge there to tick it or clear it. The window stays open, so a back line of several edges is marked in one go.

Back row from back line (m) is how far in front of the back line the back row stands. Left empty, it is the edge stand-off from Pattern rules — half a spacing unless you set one — the distance holes already keep from the block's other edges.

How the rows are laid. The rows run parallel to the back line, from its first point to its last. The back row stands the offset in front of the back line, a whole row on a staggered pattern; every second row from it is shifted half a spacing. Each further row stands one burden toward the face, and a hole position is kept only while it stands at least half a burden inside the free face. The holes keep the edge stand-off from the block's side edges. Wall control, berms, the crest of the bench below and islands are read just as they are for a pattern laid from the face.

The front row takes the remainder. Laid from the back line, every row is a full burden apart except the front one: the front row gets whatever distance is left between the row behind it and the free face, never less than half a burden. So on a new blast the front row's burden is seldom the design burden, and is often less — on a 30 m deep block with 165 mm holes it is about 2.2 m, roughly half a burden, where a blast laid from the face would have exactly one. The pattern card shows it beside the burden and spacing — front row 2.23 m to the face — and the front-row checks judge it as they judge any front row. If it is too little, lay from the free face instead, or change the back row offset.

Where the back line is not parallel to the face, the front row's burden changes along it, and the card shows the least and the most. The figure is always row A's own.

Rows behind running out to the face. Where the back line is not parallel to the face, row A can give out part of the way along it, and a row behind can run on past it toward the face. Where a hole of a row behind ends up nearer the face than every hole of row A, the card says so under the front row's figure, naming the holes — 1 hole in row B stands nearer the free face than any hole of row A (B1). Check the front. Those holes break to the face with less burden than the front row's figure shows. A hole only as near as row A's nearest hole, or farther, is never named. With the back line parallel to the face nothing is ever warned of, square or staggered, however the block widens or narrows behind.

A blast laid from the free face shows the front row's own burden, row A.

Design from the back line lays the pattern again from the back line — the one you marked, or the one read off the outline. Over holes already drafted it asks first: the designed holes are replaced, so any you moved or recharged by hand lose those changes, and holes placed by hand or from survey are kept. Not now leaves the holes, and where the rows are laid from, as they were.

On the pictures. The plan draws the block's outline, the free face and — where the pattern is laid from it — the back line, labelled Back line, or Back line (inferred) and dashed where it was read off the outline. Each has its own line in the legend, which switches it off. In 3D and the pictorial the back line is a blue band on the ground, with its own legend line.

The mine plan's draft blasts and its drill-and-blast rates are worked from the free face.

What it takes

The page shows burden × spacing, holes, metres drilled, kilograms by product, primers and detonators, the rock in the block (from the ground to the floor), the powder factor in kg/m³ and kg/t, and the drill yield — tonnes broken per metre drilled.

Checks

Check	What it tells you
Mean fragment	Kuz-Ram's prediction of X50 and X80, and the share over your oversize. A design with no rock factor of its own is worked on 9, a medium-hard rock, and the Mean fragment line says so: on rock factor 9 (assumed — set the design's own). See The rock factor.
Most within 8 ms	The heaviest charge that goes off together — what vibration depends on.
Flyrock clearance	Richards and Moore's range, times a safety factor.
Front row flyrock	The same for the front row as it is loaded, where it has a bottom charge or an easer row. Each hole is read over the burden it actually has, so an easer's reduced burden is not flattered. See An easer row and a bottom charge.
Thin-cover flyrock	The same again for the front hole with the least rock in front of its charge, read off the surveyed ground rather than the design burden — the bottom charge's kilograms a metre where the thin rock is in front of it. The blast is cleared to the furthest of the three, and a warning says so when this one sets it. A charge with under 0.1 m of rock in front of it stands in the open: no clearance can be worked for it, the checks and the sheet say so, and the hole must be stemmed down, moved back or left uncharged before firing.
Front row	How many holes stand at the face, and how many carry too much rock at the toe or too little in front of the charge. See The front row.
Top of ore	How many holes stop above the ore, drill into it, or start in it. See Waste over ore.
Places to protect	The predicted vibration at each place with a vibration limit, against that limit; and for each place protected from fly-rock, how far it stands from the nearest charge (the line from a hole's collar to its toe, since a leaned front hole throws from near its toe) — shown in red, with a warning, when that is inside the fly-rock clearance. A place with no East and North is not known: its vibration is never read as 0 mm/s or as a pass — the card, the warnings and the charge sheet say not known and count it as failed until both are given — and a fly-rock place with no position is taken as inside the clearance, never measured from the grid's origin.

Places to protect are kept in one register under Pattern rules. Each has a name and its mine-grid position, and either or both of:

• a vibration limit (mm/s), from 0.1 to 1000 — leave it blank for a place that only needs keeping fly-rock off, such as a workshop or a haul road. A limit outside that range is refused, whether or not the place is protected from fly-rock;
• Protect from fly-rock — ticked by default. Untick it for a place that only needs its vibration kept down. A place with neither is refused.

Fly-rock or a hard toe. A draft fixes a hard toe by leaning the hole and bringing it forward, and bringing it forward thins the rock in front of its charge. Where the register has no place protected from fly-rock in reach, the draft goes on fixing the toe until half a burden is left in front of the charge — the cover an easer is laid under by design — rather than stopping at the 70 % the front row is judged by: some fly-rock is better than a toe left standing. The thin cover is still named on the front row, a draft stems it deeper where it can, and the clearance widens to cover what is left (Thin-cover flyrock above). Where a protected place is in reach, the draft leaves only as little cover as keeps its throw — Richards and Moore's face burst, safety factor in, for the densest product a front hole can carry (the pattern's, the wet holes' and the front row's bottom charge) — short of the nearest one, and never less than the 70 % it is judged by. The distance is measured from the outline less how far a fixed front hole's charge can stand past it — its lean down the hole at the most the rules allow, and a burden more — so it errs on the safe side. Adding, moving, ticking or removing a place works this out again before the next draft. A front hole leaned for its toe and left between the two covers is named as traded for the toe, never told to move back, which would give the toe up again. Setting your own least in front of the charge under Front row takes this out of the draft's hands: it then fixes to exactly that.

The rock factor

The rock factor says how hard the ground is to break: about 6 for weak rock, 12 for hard, and up to 22 for the very hardest. Type it under Rock factor in Pattern rules, or have each hole read its own from a block model. A reconciled blast suggests a better one from the fragment size the loader actually dug.

A design with no rock factor anywhere — not typed, and no hole reading one — is worked on an assumed 9, so the mean fragment and the rock drawn on the predicted muckpile are never simply missing. The checks say so every time, on the Mean fragment line: on rock factor 9 (assumed — set the design's own); and the charge sheet says the same beside the fragment size. The assumption is only ever used for that prediction:

• a design's or a hole's own rock factor always wins;
• where some holes read one and others do not, the mean is of the ones that do, and 9 is not mixed in;
• To a fragment size still needs a rock factor typed: on the assumed one it keeps Konya's burden and says why;
• an assumed fragment size is not saved with the blast, and nothing is written into the design.

Where Kuz-Ram cannot predict a fragment size at all, the Mean fragment line says why in place of the figure, one reason at a time, first that applies:

The line reads	What to do
charge the holes to predict it	Nothing in the blast is charged. Draft the pattern, or check the product and that the stemming leaves a column to charge.
no rock under the charge to work a powder factor on	The holes are charged, but the block holds no rock between its crest and floor, so there is no powder factor. Check the outline, the floor and crest levels, and that the ground under the block is surveyed.
the design’s rock factor and some holes’ own are 0 or less — type one above 0 in Pattern rules, then re-draft the pattern on it	Both of the two below at once: some holes read the design's rock factor of 0 or less, and the rest were drafted on one. Type one above 0 under Rock factor in Pattern rules and draft the pattern again.
a rock factor of 0 or less predicts nothing — type one above 0 in Pattern rules	The design's own rock factor is 0 or less, and the holes carry none of their own, so they read it. Type one above 0 under Rock factor in Pattern rules, or clear the field to work on the assumed 9.
the holes were drafted on a rock factor of 0 or less — re-draft the pattern on one above 0 in Pattern rules	Each hole keeps the rock factor it was drafted on, and these were drafted while the design's was 0 or less. Type one above 0 under Rock factor in Pattern rules and draft the pattern again.
the product’s strength (RWS) is 0 or less — set one above 0 under Explosives	The holes have a rock factor to work on, but the product's strength is 0 or less. Set its Strength (ANFO = 100) above 0 under Explosives.

The reason is worked in the same pass as the figure, from the rock factor each charged hole actually reads — its own where it carries one, the design's where it does not. So a design's rock factor typed as 0 is only named where a hole falls back on it; over holes that all carry their own it played no part. A cleared Rock factor field is no rock factor, never a 0: with none anywhere the fragment size is worked on the assumed 9.

Holes left out. A rock factor of 0 or less says nothing about how the ground breaks. Where only some charged holes read one, they are left out of the rock factor the fragment size is worked on, rather than averaged in — averaged in, a 0 would pull the predicted fragment size down in proportion to the charge those holes carry, a blast predicted finer than it will break. Their charge still counts in the powder factor. The Mean fragment line says so under the figure: worked without 3 of 40 charged holes — their rock factor is 0 or less (its for one hole), and the charge sheet carries the count as Charged holes left out of the rock factor (0 or less). To bring them back in, type a rock factor above 0 in Pattern rules and re-draft the pattern.

A charged hole with no rock factor of its own, where Pattern rules has none either, is left out too while other holes have one — a block model sampled over only part of the blast leaves holes like this. The line names them with their own reason: worked without 4 of 40 charged holes — they have no rock factor of their own and Pattern rules has none (it has … of its own for one hole). Where both kinds are left out, one line gives both: worked without 7 of 40 charged holes — 3 on a rock factor of 0 or less, 4 with none of their own and none in Pattern rules. The charge sheet gives the second kind its own row, Charged holes left out of the rock factor (none of their own, none in Pattern rules). These need no re-draft: type a rock factor in Pattern rules and they read it at once.

A fragment size worked without some holes is still saved with the blast, as the design's own prediction, and the Mean fragment line's words are saved with it among the blast's warnings — Mean fragment worked without 3 of 40 charged holes — their rock factor is 0 or less. — so the figure is never read back later without them.

These are worked from the hole delay and the row delay in the design, which is a rule of thumb about the pattern rather than a statement about any hole. Cut-offs, relief off the real firing times, and what the delays' own scatter does to the charge in one window need the shot tied up first: see What the checks make of the tie-up.

Going to the holes a check names

Every check that names holes carries links to them — including a check that only counts them (12 front holes …): the links name every hole it counts, not just the first few. Plan, 3D and Pictorial open the pattern as a window on those holes, ringed and framed close in among their neighbours, with the switch to the other two views inside it. The window says which check sent you there. Where a check names one or two holes, Open beside each opens that hole in the hole editor. A check about an empty position — a hole gone from the pattern — shows the position instead. The same links are under the wall checks, what the muckpile predicts, the tie-up checks and each change listed under What the draft put right. With Hide those with warnings on, the window still draws the holes it was opened to show.

The hole editor has the same three pictures in its header: they show the hole over the form, and for a new hole they show where the position typed would put it, before it is added. Looking changes nothing on the blast.

Checks, not the law

These are predictions from published rules, calibrated to your ground only once you enter your own site constants and reconcile your own blasts. Your statutory exclusion zone and your own monitoring always govern.

The front row

The first row is laid one burden behind the face line. But a real face is not a wall: it leans back, bellies out, and keeps a toe where the last blast did not break to the floor. A vertical front hole one burden behind the crest can have far more than a burden of rock in front of it at the bottom — a hard toe that will not dig — and far less halfway up where the face bellies, which is where flyrock comes from.

So Trackapt reads the rock really in front of every hole next to the face, off the surveyed ground: walking out from the hole, level by level, to where the ground falls away.

Reading	What it is	Flagged when
Toe burden	The rock in front of the hole just above the grade, to the foot of the face.	It is more than the burden by more than the extra toe burden allowed — 20 % unless you set it.
No face in reach	No open face within four burdens of the toe: the ground in front stands as high as the toe — muck left from the last blast, a ramp, or ground not taken down to grade.	Always. No lean, move or easer gives the toe anywhere to break to, so the draft cannot fix it: clear the face in front before firing, or check the face picked for the blast.
Least in front of the charge	The least rock between the charge and the face, and the RL it is least at.	It is less than the least in front of the charge — 70 % of the burden unless you set it.

The two are read separately, and not always the same way. The toe is read the way the hole breaks — the face, or open ground right beside the hole such as a step down inside the outline — and the charge the way its cover is thinnest, since flyrock goes to the nearest open ground. Each finding says which way it was read. So one hole can be flagged for both: too much rock at its toe and too little halfway up. That is not a contradiction. It is a face that kept its toe and bellies above it, or a step beside the hole that stops short of the floor. Where the thin cover is on the side the toe breaks to, bringing the hole forward for the toe would thin the cover further, and moving it back would add to the toe — so the findings say not to: stem the hole down past the thin level, and handle the toe with a toe hole or a heavier bottom charge. Fix the front row does the same with such a hole: it never brings it forward, leans it only as far as the cover does not thin, and says the collar was not brought forward because the charge's cover would thin. Cover that is thin on another side — square to the way the toe breaks, or behind it — does not stop the fix: the hole is still brought forward, as long as no step thins the cover any way.

The Front row card lists every front hole with its readings, the ones that need you first; click a hole to change it yourself. Fix the front row does what a driller does for each hard toe:

1. Leans the hole towards the face — the toe moves out, the top of the charge stays where it was — up to the most lean (30° unless you set it).
2. If leaning is not enough, brings the collar forward — as far as it can while the rig still stands on the top of the bench, and only as far as the charge keeps its least allowed burden in front. It is never moved onto the face.
3. Whatever neither can reach is named: that toe needs a toe hole or a heavier bottom charge — the blaster's call. Where it was the ground that stopped the collar — a bund along the crest, a hump, the crest's edge — the message and the Front row card say the hole could not come further forward because a rig cannot stand there. So a rough top or a bund leaves more toes for the blaster than a clean bench does. Where the top of the bench falls away towards the crest, bringing the collar forward brings it down, and the top of the charge comes down with it under the same stemming. Once the charge would sit no higher than the toe — half a metre over the grade — there is no charge above the toe to break it, so the collar goes no further. The message and the Front row card then say the hole could not come further forward because the charge would not rise above the toe there, and the hole's note gives the collar's RL, the stemming and the level the toe is judged at. That toe too needs a toe hole or a heavier bottom charge.

A hard-toe hole already leaned the most the rules allow is not told to lean further: its finding tells it to come forward, or to take a toe hole or a heavier bottom charge.

A hole already drilled is never touched, and a hole the surveyor marked out is only leaned, never moved off its mark. Under the Front row tile you can change the three figures and choose to bring holes forward only.

The front row is whichever holes have nothing of the pattern ahead of them and open ground falling away in front. Where the rows a draft would have laid on the face or on a bund along the crest are left out, the row behind them is the front row, however far back it stands, and it is judged and fixed as one. A single hole left out of a row — out of free-dig rock or off a hump, with its neighbours ahead still drilled — does not make the hole behind it a front hole, and neither does a missing row with another row still standing ahead. A wider strip does: where two or more neighbouring holes of the row ahead are left out — a band of free-dig rock, say, or the whole of that row — the holes behind the strip are judged as front holes, the same as behind a bund.

Every draft fixes its front row as it is drafted, unless you say otherwise: each hard toe is leaned and brought forward before you see the pattern. Turn Fix the front row as the pattern is drafted off under the same tile to have the hard toes only flagged, and fix them yourself from the Front row card. The front row needs the surveyed ground; a box cut has no face to read.

What a draft solves by itself

A draft answers every check a design can answer before you see the pattern, rather than laying it and leaving you a list to correct:

• A hard toe is leaned and brought forward, as above.

• Two leaned toes meeting — two front holes either side of a step in the crest, each leaned towards its own face — would put two charges on one burden. The draft leans one of them less, a quarter of the lean at a time, until the two stand clear. Where no lean clears it, the hole is left as the pattern laid it. Fix the front row refuses such a fix too.

• Thin rock high on the face in front of a front hole's charge is answered by stemming the hole deeper, half a metre at a time, taking the column and its kilograms down with it, until the charge starts below the thin rock. A hole keeps at least half its column charged, and its bottom charge whole. Where that is not enough, the thin rock is too low on the face for stemming to reach, and the hole is left for you.

• Firing order. The page times each hole by where it stands along the face, not by its number in its own row. So a row that starts further along the face than the row ahead of it still fires each hole after the hole straight ahead of it. A hole that would still fire with or before the hole ahead — a front hole leaned past its neighbour's line, a hole behind a gap — is carried a hole delay later, and the rows behind follow. The same goes for a hole beside an easer that would fire too soon after it for the ground between them. These times are worked out each time from the holes and the rules, and never stored. A delay you type on a hole is never moved: if it leaves the hole without relief, the check says so. On a rectangle the times are exactly those of the rows' numbering.

  Three limits hold the timing back rather than let it buy relief with something worse. Each is said in Checks, naming the holes:

  • Ground vibration. A hole is never moved later if that would put more charge into one 8 ms window than the rows' own numbering does. Cannot be given the time it needs … without raising the most charge fired within 8 ms means the hole was left where it stands: type a delay, or split the charge.
  • A ceiling. No hole is carried more than two row delays past the rest of the blast. Could not be timed after the hole ahead within 2 row delays usually follows a delay typed very late on a front hole: check the order there by eye.
  • Wall rows. Buffer and trim holes keep the time their rows give them; the app sets no rule for when a wall row fires.

  Most within 8 ms shows the heavier of two figures: the face's times and the rows' own. So the charge per delay on the page never looks lighter because of a timing no tie-up has fired yet.

Only holes the draft laid are touched: a hole placed by hand, marked by the surveyor or already drilled keeps what it has, and a decked hole keeps its decks. With Fix the front row as the pattern is drafted off, the draft leans nothing and stems nothing.

What the draft put right lists each change, hole by hole: what was done, with the pictures of the hole, and an Undo that puts that one hole back as it was before the draft. Undo works only while the hole is still exactly as the draft left it. Once you have changed the hole yourself, Undo is greyed out and says why, so it can never overwrite your change. The holes the timing moved are listed too, with the time each fires at; type a delay in the hole editor to fire a hole when you choose. Undo the draft asks first, then takes the drafted pattern off and puts back the holes the blast had before the draft. The list is for the visit and is not stored: the next draft replaces it.

What is left in Checks after a draft is what no design can answer, and each says so:

• … extra burden at the toe that no design can reach — the hole is leaned as far as the rules allow (or as far as it can without crowding its neighbour), brought as far forward as the rig can stand, or already drilled. It needs a toe hole, a heavier bottom charge, or the rock in front of it dug out.
• … no free face at the toe — the ground in front stands as high as the toe. Clear the muck or take the ground down to grade before firing.
• … too low on the face for stemming to reach — deck the charge across the thin rock, or load the hole lighter.

A check that says a fix is within reach (… that a fix within the rules takes, … high enough on the face that stemming deeper clears it) appears only where the draft was told not to fix, or after a hole was changed by hand. Draft again, or use Fix the front row or the hole editor. Where the mine turned Fix the front row as the pattern is drafted off, the check says so: solvable, but not fixed: this mine turned automatic front-row fixing off. The setting is kept for mines that fire toe holes or buffer rows instead, or whose rigs cannot angle.

An easer row and a bottom charge

A front hole leaned to a battered face puts its toe out towards the face. The row behind is collared one burden back and drilled plumb, so at the toe it stands that much more than a burden behind the front row — nearly 3 m more on a 10 m bench with a 15° lean. Leaning every row to match takes that away, but leaves a slanting wall behind the blast: a toe the next cut makes for itself. Under the Front row tile you choose how the front row is laid; a new blast is laid with an easer row unless you choose otherwise:

The front row is laid	What it does
One hole a spacing apart, each leaned on its own	Each hard-toe front hole is leaned, and brought forward, as far as its own toe needs. The rows behind carry the extra toe the lean leaves them.
A leaned front row with an easer row behind it (the default)	The same, and between each two front holes where either is leaned, an easer hole half a spacing across from each and set back half a burden, in a row of its own. The leaned holes take the toe at the face; the easers break what they leave. The rows behind, and the wall the blast leaves, stay plumb.

Why a row of its own, and not a hole in the front row. Every row is then a row of one angle. On the bench the crew sees the leaned row along the crest and the easer row behind it, and ties each up for what it is. Holes of two angles alternating along a single line of collars are one row to look at, and a surface connector tied to the wrong one of them is a hole fired with nothing broken in front of it.

Only the holes that need it lean. A front hole leans only as far as its own toe asks; one on a face that stands true is drilled at the pattern's angle, and where neither of two neighbours leaned, no easer goes between them. On easy ground an easer row therefore adds nothing at all.

An easer is named after the first of the two holes it stands between with an E — A4E — and fires half way from the later of the two to the row behind it, whichever way the row fires, rounded up to the whole millisecond an electronic detonator is programmed in. The later of the two, not the earlier: it stands behind both, and the ground in front of it is opened by both. Half of that window rather than half a row delay, because an easer is a row of its own between two rows and has to leave the row behind as much time as it took — on 25 ms holes and a 67 ms row, half a row delay would put it 8 ms ahead of the hole two metres behind it. Tied in with shock tube, it takes the nearest surface connector not less than that. It takes no place of its own along the row: the leaned holes fire one hole delay apart, as every row behind does, so the front row keeps pace with the rows behind it and no hole behind fires before the hole ahead of it.

The easer leans too, half as far. Set back and left plumb, an easer would carry half a burden at its collar and far more at its toe, where the leaned row's toe has gone out to the face. Its toe is put half way between the front row's and the pattern's instead, so the rock it has to break is the same depth in front of it and behind it. A front row brought forward as well as leaned has carried its toe further still, and asks the easer for more lean, not less. The rows behind are not touched.

No easer is added where neither neighbour was leaned or brought forward for its toe (there is no extra toe to take), where it would stand too close to another hole — one placed by hand included — or where no rig can stand. Wherever a leaned front hole is left with no easer behind it — skipped for any of those reasons, or deleted by hand — the pattern card says so, naming the pair, the extra rock the row behind then carries at its toe (up to H × tan θ), and the hole standing in the easer's place where one does: expect a hard toe there. Two charges that close would fire as one, so the easer is not forced in; move or take out the hole in the way and draft again. A hole brought forward plumb is not read here: where it was laid is not kept once the draft is saved. The Front pair column of the holes table says which part each hole plays. Easers are shown on the Front row card with their readings, but their toe is never flagged — judged against the face the blast started with, an easer reads as a hard toe every time, and the face it really fires to is the one the leaned holes make. The cover over its charge still is flagged. Fix the front row leaves an easer at its own lean, and so does a reset to the rules.

An easer row only adds holes beside front holes fixed for their toe, so it needs drafts to fix the front row; with that turned off the tile says so.

Figure	Default	What it does
Easer row set-back	0.5 × burden	How far the easer row stands behind the front row. Half a burden leaves each easer the same depth of rock in front of it and behind it, which is what its lean is worked to. Set it back further and it becomes another row of the pattern; less, and it crowds the face.
Longest stemming	1.5 × burden	How far a stemming lengthened for thin cover may go. See below.

A bottom charge. Choose a denser bottom charge product and every front hole is loaded with it at the bottom, where the burden is heaviest, with the pattern's product above it, under a longer stemming. Heavy at the toe, not heavy the whole length: an easer row already puts more explosive behind each metre of face, and the top of the face is where the cover is thinnest and rock flies from. The two proportions are worked from the burden:

Figure	Default	Where it comes from
Bottom charge length	1.3 × burden, from the bottom of the hole	Langefors and Kihlström's bench-blast bottom charge
Front row stemming	1.0 × burden, never shorter than the pattern's	Langefors and Kihlström's stemming

Both can be changed for the blast, and the tile shows what they come to in metres.

An easer is charged for the burden an easer has. Its bottom charge is worked over its set-back rather than the pattern's burden — half a burden back, half the bottom charge — because a bottom charge is sized to the rock it has to lift, and given the front row's a hole with half the rock in front of it would carry the same kilograms as one with all of it.

Stemming is varied with the cover each hole has. A hole standing less than a burden from the face it fires to carries thin rock over the top of its charge, and that is where flyrock leaves a bench: the gas takes the short way out. Its stemming is lengthened in proportion — the front row's stemming × burden ÷ cover — up to Longest stemming, so the top of the charge sits back where the burden has come back. An easer set back half a burden asks for twice the stemming and is held to the cap; a front hole brought forward for its toe, or one on a crest that has back-broken, is lengthened by what it lost. A hole with a full burden in front of it is not changed, and no stemming is ever shortened. Where the cap bites, the flyrock figure says what is left. The tile shows the easer row's own stemming and bottom charge in metres beside the front row's.

A wet front hole whose bottom product water would spoil takes its column's water-resistant product at the bottom instead. The bottom charge is its own product in the totals, on the charge sheet and on the magazine when the blast is fired — as designed, and as loaded: Record loads as designed keeps it apart, and a loaded kg you type for a hole keeps its bottom charge (never more than the kg typed). The Bottom product and Bottom charge (kg) columns show it hole by hole. The charge sheet gives each hole its Charge length (m) — the whole charged length, bottom charge included — and its Total charge (kg); its Column length (m) and Column charge (kg), the column above the bottom charge (the total less the bottom charge, in metres and in kilograms, so each kg stands beside its own length); and its Bottom product, Bottom charge (kg) and Bottom length (m) — the length the recorded kilograms reach, where the crew recorded a load. When the blast is fired, a product with no magazine item — or not under Explosives at all, or renamed there since the blast was drafted — is named in what was not filed, with its kilograms.

The heavier front throws further

Checks work Richards and Moore's range for the front row as it is loaded — the bottom charge over the burden, and its column over its stemming — and show it as Front row flyrock beside the pattern's. Where it throws further, the warnings say the front row is charged heavy and how far to clear the blast, and the blast's flyrock clearance is the front row's. Each hole is read over the burden it actually has: where the worst is an easer, the warning says how far that hole stands from the face it fires to, so the figure is not read as the front row's.

With an easer row, the warnings also ask you to check how far the easers stand from the holes around them — across to the leaned holes in front, and back to the row behind — against the least distance your explosive's supplier gives between charged holes. They name any hole beside an easer that is too close for the delay between them: less than 8 ms for each metre between the two, or the pattern's own hole delay per metre of spacing where that is less, where the first can dead-press the second. An easer's nearest charged neighbour is as often the row behind it as the row in front, and both are judged. Where two front holes fire less than 8 ms apart — a hole delay under 16 ms, or the two easers either side of a V's apex — the warnings say the ground takes them as one charge, and the charge per delay counts it so. Your statutory exclusion zone always governs.

A hole that fires with or before the hole ahead of it

Checks name any hole that fires at the same moment as, or before, the hole ahead of it towards the face — typically a delay typed by hand, since the page's own timing carries every other hole behind the hole ahead of it (see What a draft solves by itself). With nothing broken in front of it, its burden has nowhere to go: it chokes, craters and throws. Each hole is judged against the nearest row of charged holes ahead of it — within three quarters of a spacing of its own line, whichever row they are numbered — and against the earliest of them to fire, so a hole three rows back is compared with the row in front of it, not only with the front row. On a staggered pattern, one diagonal gone first is relief. For rows laid square to the face, as drafts lay them, a hole beside it in its own row is no measure of its relief, and is not used. A hole firing a millisecond after the hole ahead passes; firing together with it does not. Whether that lead is long enough for the burden is not judged. An uncharged hole relieves nothing and is not counted.

The front is the front row along the face (a side face is not read) and every charged hole of the first row. An easer is not part of it: it stands half a burden behind the leaned row, so it has a row ahead of it like any other hole and is judged against it — fired before the holes it was laid between, it has nothing to move into, and saying so is the whole use of the check. Where nothing charged stands straight ahead of a hole, the nearest front hole ahead of it stands in; where there is none either, the warnings name the holes that could not be judged — check their delays by eye. A blast with no charged first row and no free face found says relief was not judged at all, and why. The check never passes a hole it did not look at. Wall and island holes stand at their own face and are not judged.

A box cut — surveyed ground with no side falling away — fires from the centre out to make its own face, so judging it row 1 first would name sound holes. It is not judged by the face; the warnings say once that relief was not judged because the blast reads as a box cut, so check by eye that every hole fires after the hole that opens ground for it. A blast with no ground survey is not a box cut: its relief is judged from its numbered rows, row 1 at the front, and where there is no charged first row the warnings say there was no survey to find the face from.

Islands in the pattern

A draft leaves a hole out wherever a rig cannot stand to drill it — a hump standing over the crest, a mound too steep to set up on, a hollow still above the floor, a slanting step between two terraces. Where that ground runs down to the floor, as it does off a face, its rock has open ground to go to. Where holes stand all round it, it has none: the holes break their own share and the patch stands up out of the muckpile as a toe. The page calls such a patch an island.

A strip is the same patch reaching the edge of the pattern instead: the positions left out along a step between two terraces, say, with holes along both sides of it and ground below it that never comes down to the floor — it settles on a terrace or in a hollow. Its rock has nowhere to go either, so the page treats a strip exactly as an island, and its card calls it a strip. It needs holes along both sides: a run left out at the edge with holes along one side only — the back row against the face of the bench above, a row along a bund at the side — is the edge of the pattern, and is left as it is. So is one position left out on its own at the edge — the end of a row against ground rising past the side of the block: the holes beside it break it. And neither an island nor a strip is taken against the final wall: rock left there is for the wall's own holes, and no hole added to reach an island is collared past the wall. Nor is anything on a berm: a terrace of about the berm width a bench step from the ground either side is left as a berm, not reached as a strip, and no hole reaching an island is collared on one.

Every island is addressed by default. The draft collars holes on the nearest ground a rig can stand on round the island and leans each one back into it where it has to, so its toe lands under the island — one collared within reach of the island stands straight — leaned no further than the front row's most lean (30° unless you set it), and collared no nearer another hole than 1 m or three tenths of the burden, whichever is more (1.2 m on a 4 m burden). They are named ISL1-01, ISL1-02 and so on, lean their own way rather than towards the face, and fire with the row of the hole nearest their collar. A hole leaned under a hollow is stemmed longer where it has to be, so there is never less ground over its charge than the pattern's stemming; one left no charge by that is not added. It keeps that cover when the rules are applied to every hole again, when the holes are charged again, and when a stand-off is taken. The added holes are not front holes, and do not change which holes are.

The cover is kept however the hole's stemming is changed:

• A shorter stemming typed on an island hole is lengthened back to what its cover needs, and the message after the change says so — for example ISL1-02 keeps a 3.40 m stemming, not the 1.00 m asked for. Apply the rules and charging the holes again say the same where it happens.
• Where no stemming can keep the charge covered — the ground over the hole was dug out since it was added — the hole keeps its place and carries a warning in the hole table: Too little ground over its charge … Take this hole out, or treat the ground over it first.
• Before the ground has loaded, an island hole keeps the longer stemming it already has rather than falling back to the pattern's. A stemming typed in that time is measured once the ground arrives: a hole left with too little ground over its charge is charged again with a longer stemming, and the page says which. A hole already drilled, charged, or with a load or as-drilled survey recorded is left exactly as it is. A hole not yet drilled is checked even on an approved blast, so an approved blast opened with such a hole shows as changed until it is saved again.
• A stand-off over the ore says the same when it leaves an island hole a longer stemming. A hole the stand-off leaves with no charge at all is not flagged for its cover — its own warning says why it has no charge.

A card on the pattern says what was found and whether that was enough:

An island of about 140 m² inside the pattern could not be collared — the ground stands above the crest and it is too steep for a rig to set up on — and holes stand all round it, so left alone it would stay behind as a toe. 3 holes were added from the ground round it, and they reach 5 of its 7 hole positions. The rest cannot be reached from where a rig can stand: treat the area first — doze it down or level it — then draft the blast again. If it is meant to be left, choose Leave it.

A position counts as reached where some hole's toe lies within that hole's own share of the pattern — one burden by one spacing, as a circle. Holes reach under an island: the part of a hump standing above the crest is above every collar, is not drilled, and the card says so — it belongs to the bench above.

Where holes do not reach all of an island, the card says why the rest is not reached:

• Out of a rig's reach — no ground a rig stands on is near enough, at the most lean. Doze a hump down, or level the area.
• Under too little ground — a hole could reach it, but its charge would pass so close under a hollow that no stemming keeps it covered. Fill the hollow, or level it.

Working that out on a large block takes a moment, so the page opens first and each card reads Working out whether holes can reach it… until its answer is in — an island at a time, without holding up the page.

Answer on the card. Where holes were added, Address it already shows picked — that is what the draft did — so only choose Leave it if the island is meant. Where no holes were added yet, neither is picked and the card asks Is it meant to be left?:

Choice	What happens
Address it	The holes added to reach it stay, or are added again.
Leave it — it is meant	A ramp, a bund, ground kept back for later: the holes added to reach it are taken out, and its rock is not drilled. Drafting again leaves it alone.

The answer is saved with the blast and found again by the island's centre, so a resurvey that nudges the island keeps it; where two saved answers are both that close, the nearer one stands. A hole already drilled stays whatever the answer. Where the ground reaches the edge of the pattern, or the holes were left out for another reason — free-dig rock, ore, ground already at the floor — it is not an island, and nothing is added.

Waste over ore: the stand-off

Where a waste bench sits on ore, a hole drilled to the grade blasts the top of the ore into the waste — dilution one way, ore lost the other. Under the Top of ore tile, say where the ore is:

The top of the ore comes from	What it reads
A surface of the top of the ore	A surface the geologist or surveyor made; ore lies below it.
The block model	The blast's block model: a block is ore where the field you choose is at or above the cut-off.

and the stand-off — how much waste each hole leaves over the ore. Every hole is then cut short at the stand-off above the first ore its line meets, and charged from what is left. A designed hole with no room left to drill is left out of the draft; one you placed is kept and says so.

Trackapt asks for the stand-off rather than assume one. Until you give it, holes that reach the ore are only flagged, and the checks ask how far above the ore should the holes stop? — type it there and every hole is stopped above the ore at once. The rock is measured down to the top of the ore where it rises above the grade; what lies beneath is left for the ore blast. A hole collared in ore is counted as such and stood off nothing.

Adjusting the pattern

The Holes table lists every hole: its row, where it came from (Designed, From survey, Added by hand), its stage, collar, lean, toe RL, depth, stemming, column, charge and firing time.

• Add a hole — a filler or a spare. Type where it is; leave any figure blank to use the pattern's, or type the hole's own.
• Place a hole — point at the plan instead of typing a coordinate. The control sits beside Draft the pattern and works on the Plan view: press it, the pointer takes a crosshair, and a click on the ground opens Add a hole with the collar where you clicked. A click that lands near a position the pattern laid and no hole stands at takes that position exactly — within three-tenths of the smaller of burden and spacing — so a hole put back in a gap stands where the pattern wanted it rather than a metre off it. A position a hole already stands at is never taken, and a click on open ground stands where it fell. Clicking a hole still opens that hole. Press the control again, or leave the Plan view, to stop placing.
• Click a hole (in the table, on the plan or in the front row) — move it, rename it, give it its own diameter, sub-drill, stemming, lean or product, set its firing time, mark it wet, record what was loaded, or mark it abandoned. Clear the lean and the hole follows the pattern's again.
• Remove — takes the hole out of the pattern, after you confirm. A drilled hole is better marked abandoned: it stays on the record but out of every total.
• The gap a removed hole leaves is measured. A hole comes out because the collar hit a bootleg, a crack, water or a service — and its two row neighbours now carry two spacings with the same charge, while the hole behind faces unbroken ground: that is where coarse rock and a hard toe come from. The checks judge every hole the design laid against the holes now standing, with the pattern's own reach — its worst cover from burden, spacing and layout, plus a twentieth of a burden, the same reach wall control fills to. Where a laid hole is gone and ground it was to break is out of every standing hole's reach, the checks card says so: D3 is gone: D2 and D4 now stand 10.0 m apart against 5.0 m spacing, and the ground between them is out of reach — add a hole near E … N … or expect coarse rock and a hard toe there. Both neighbours carry the warning in the Holes table and in the tooltip on the plan. Add a hole here on the warning opens Add a hole with the collar at that point; a filler put back near the gap closes it. A blast opened with a hole already missing says the same, without a click. Only cells the design meant to hold a hole count — a berm left undrilled, a wall's stand-off or an island is no gap, and a front hole the front-row fix brought forward still stands for its position, whether the draft fixed it or you asked for the fix later. Gaps are only judged for a pattern that still follows the layout: where fewer than four in five of the laid positions have a hole — a pattern brought in from survey, or drafted under rules since changed, or with many holes pulled — the checks card says so instead, The pattern no longer follows the rules laid on this block (N of M positions have a hole), so gaps are not judged. Re-draft the pattern or check it by eye.
• Two holes standing too close are measured too — the reverse of a gap. A hole put in by hand goes where you point, and that can be too near a hole already standing: two holes half a spacing apart share one burden between two full charges, so the powder factor in that ground is twice what the design chose — overbreak behind the face, flyrock off the collar, and a hole that can cut off its neighbour. Where two holes stand closer than half the smaller of burden and spacing — at the collar, or at the toe where the holes converge below — the checks card says so: FIL-01 stands 1.8 m from C4, less than half the 4.0 m the pattern leaves between neighbours — two charges on one burden, which over-breaks the ground between them and throws off the collar. Move it or take it out. Open FIL-01 on the warning opens the hole to move it, lean it off its neighbour or take it out. Both holes carry the warning in the Holes table and in the tooltip on the plan, in amber: crowding is advice, not a fault — both holes still fire. A wall row and the holes added to reach an island keep their own spacing against the pattern — both are drilled tight on purpose, and a trim row stands deliberately close to the first production row — but a hole you place by hand is judged against them like any other: nothing reserves that ground, and a filler half a metre from a trim hole puts a full production charge inside the buffer zone against the final wall.
• Apply the rules to every hole — every hole keeps its place and takes the pattern's figures again.

Change a rule after drafting and the page says so: Draft the pattern again replaces the designed holes and keeps every hole placed by hand or survey; Charge the holes again keeps every hole where it is.

Holes from survey

Pattern from survey and As drilled from survey both read a pickup the surveyor filed under Mining → Pickups. Only the shots inside the blast's outline (or a few metres beyond it) are read.

These points are	What happens
The pattern to drill	Each point becomes a hole, drilled to the floor from its surveyed height. Choose whether the designed holes give way to it.
Where the holes were drilled	Each point is matched to the nearest designed hole within the distance you give, and the hole is charged again from where it was really drilled. A point near no hole becomes a hole the driller added; a designed hole nobody drilled is named.

Only the shots coded as the pattern

A pickup often walks more than the collars: the crest, the floor, a peg. Every one of those inside the outline would become a hole. Under Shots coded, choose the codes the surveyor booked the collars under (such as PTTN), and only those shots are read. Each code is listed with how many shots carry it and what your site said it stands for when the file was imported. Choose none to take every shot. The codes you chose are offered again on the next blast.

A pickup with no codes has none to choose by, and says so. Every shot inside the outline is taken from it.

Tying the shot up

A hole delay and a row delay typed against the pattern are enough to charge the blast. They are not enough to say when any one hole fires. On a shock tube shot the signal starts at one collar and runs from there — connector to connector across the bench, and down each hole's own downline — so a hole's time is the shortest path the signal can take to reach its collar plus whatever holds it back in the hole. Two holes a row apart can be half a second apart or go off together, depending which way the tie runs. Nothing about cut-offs, relief or the charge in one window can be judged until the shot is tied up, because until then there is no path to judge.

Open the Tie-up tile. Until the pattern is drafted it says so — a tie-up is a network between holes, and there are none yet — and it says so too where the Explosives catalogue holds no surface connector to tie with. See The delays a shot is tied with.

Field	What to choose
How it runs	Echelon — the shot runs diagonally across the pattern, so every hole breaks at an angle to the face. It is the usual bench tie, and a shot not yet tied up opens on it. Row by row — each row fires end to end and the row behind follows it, square to the face. V from the centre — each row opens from its middle to both ends at once, for a cut with no face of its own.
Started at	The hole the lead-in reaches. Left to the app it starts at the end of the front row, so every hole after the first breaks towards ground already moved. Pick any hole to start it where the blaster wants it — from the list, or with the eye beside it, which opens the plan with that firing point ringed: click a hole there and it becomes that firing point.
Downline in each hole	What holds each hole back behind the signal that passed its collar — 400 to 500 ms as a rule. Without one a hole fires the moment the signal arrives, and every connector clipped beside it is cut. A shot not yet tied up opens on the stocked downline nearest 500 ms.
Lead-in	What starts the shot from the firing point. A shot not yet tied up opens on the stocked lead-in nearest 0 ms, so the shot begins the instant it is fired.
Tie each row twice	Ties a second way into each row, so cutting one connector does not take the row with it.

Tie the shot up draws the network: a surface connector between each pair of holes — taken from the Explosives catalogue, nearest to the hole-to-hole and row-to-row milliseconds set under Timing and checks — a downline in every charged hole, and the lead-in at the starting point. Change anything about the pattern and Tie it up again. Untie puts the blast back to firing off the two delays in its design, and asks before it does.

The app drafts it; the blaster owns it. Any hole given a firing time by hand keeps it — the table marks it timed by hand and the network is worked round it — and the starting point, the shape, the downline and the lead-in are all yours to set.

Editing the tie-up by hand

Every connector is listed under Connectors in the Tie-up window: the hole it is clipped at, the hole it fires, the product, its delay, and whether it was tied by hand. Pick one to change its product — the delay changes with it, and nothing is asked — or Remove it. Removing asks first, names both holes and the delay, and says which holes nothing would then reach.

Add a connector takes the hole the signal comes from, then the hole it fires, and a surface connector from the catalogue. The app suggests the one nearest the hole-to-hole delay for two holes of one row, the row-to-row delay between rows, and for an easer the delay the draft itself would give it; the blaster's pick stands. A hole cannot be tied to itself, nor a pair tied twice the same way, and an abandoned hole or one not in the blast is refused. On the firing picture, tap a connector to pick it, or press the add-connector button and tap the two holes — it works the same on a phone.

Every edit is checked at once: cut-offs, holes nothing reaches, one connector carrying the shot, relief, the heaviest 8 ms and the firing times. An edit that leaves a charged hole unreached is allowed — the check shows it as the error it is. A hole a hand-tied connector reaches is marked tied by hand in the table.

Tie it up again over hand edits asks first. Keep your changes lays them over the new draft; Start clean takes the draft alone. A change naming a hole that has since gone or been abandoned cannot be kept, and the notice names it. A fired blast's tie-up is a record and cannot be edited.

An abandoned, uncharged hole still stands in the bench. Its connectors are left out when the blast is saved, and the notice says which. If the chain ran through it, the blaster must tie across it, and the holes nothing reaches check will show them where.

An easer is tied off the holes it stands between, not along their row. It carries their row number but is a row of its own, so the draft chains the front row without it and then clips each easer off the later of its two leaned holes. The connector is chosen by the window it must land in: long enough after that hole that it cannot dead-press it — the same least milliseconds per metre the warnings judge by — and short enough to leave the hole behind it in the next row the same margin. Of the connectors that land it there, the one nearest half its window (the row delay less the hole delay) is taken. On a 3.0 × 3.5 m pattern with holes 25 ms apart, rows 65 ms apart and the easer set back 1.5 m, it must fire at least 16.4 ms after its leaned hole and 10.7 ms before the row behind: a 17 ms connector. Two easers in one gap go in name order, at least 8 ms apart. Where no connector the mine holds fits, the easer is still tied, with the nearest, and the draft says which easer, what it needed and why.

Once it is tied, the tile carries the figures:

It says	What it means
The shot takes	From the lead-in to the last hole to go off.
Heaviest 8 ms	The most explosive inside any 8 ms window — what vibration depends on. Where the delays carry a scatter figure, it also says what the worst run in twenty puts there, which is the figure to hold a vibration limit against.
The timing works to	The burden and spacing the timing makes of the pattern, and the ratio between them. Rock breaks towards whatever was open when it fired, not square to the row it was drilled in, so the burden that matters is measured along the way the firing times fall away and the spacing across it. A 3.0 × 3.5 m pattern tied in echelon can work as 2.4 × 4.4 m — which is how a blaster buys fragmentation without moving a drill.
Relief wanted	How long this rock wants between holes, in milliseconds per metre of burden. Derived from the rock's strength and density, not ruled: published bench practice runs from about 4 ms per metre in strong dense rock to about 16 in weak or weathered ground. Rest the pointer on it and it says what it was derived from.

When each hole fires lists every hole with the moment the signal reaches its collar, the moment it goes off, and what it holds. An easer is marked easer, as it is when the pointer rests on it in the firing picture.

The delays a shot is tied with

A tie-up is made of products, and the products are the mine's. Under Explosives (on the Blasts register), a product of kind Detonator can say what it does in the tie-up:

In the tie-up	What it is
Starter / lead-in	What starts the shot from the firing point.
Surface connector	Clipped between collars on top of the ground — the delay from one hole to the next.
In-hole downline	Goes down the hole with the primer and holds that hole back behind the signal that passed its collar.
No delay	Counted and issued like any detonator, but cannot be timed.

Each one carries its delay off the data sheet, its scatter as a percentage of that delay — a share, not milliseconds, because a long delay scatters wider than a short one; usually 1 to 3 — and, for the bench, its colour and the supplier's series.

The lightning bolt at the top of the Explosives window adds the shock-tube delays in common use in one press: a starter, surface connectors at 9, 17, 25, 33, 42, 65, 67, 100, 109 and 176 ms, and downlines at 400, 425, 450, 475 and 500 ms. They arrive marked as what they are — these figures are the ones in common use across the industry, not your supplier's — and the note goes the moment you change one, because from then on it is yours. A product your supplier makes and nobody else does is added the same way any product is.

Where a delay has no scatter figure against it, the run uses the typical figure for what the delay does and the tile says so. Type your supplier's and the run becomes your mine's.

What the checks make of the tie-up

These are the checks a network makes possible, and none of them can be made without one:

Check	What it tells you
Cut-offs	A connector whose signal has not passed before a hole beside it moves the ground. The line is cut there and everything behind it never fires. Ground is taken to start moving 10 ms after a hole goes off — deliberately the pessimistic end of what is published, so a tie-up that survives the check survives a slower face. A connector with the signal through it but little to spare is said too: any scatter at all closes that.
Relief	A hole that fires with, or before, the hole ahead of it towards the face. The judgement is the same one the design already makes — see Checks — driven here off the tie-up's own times instead of the two delays in the design. Holes it could not judge are named, never passed over.
Holes nothing reaches	A hole the signal never gets to. It would be left charged and unfired.
One connector carrying the shot	Where eight or more charged holes are reached only through a single connector. Cut it — by ground, by a truck, by a crimped tube — and all of them stay charged. Tie a second way in, or switch Tie each row twice on.
The timing against the rock	Row to row and hole to hole, in milliseconds per metre, against what the rock wants. Too little and the burden has not moved before the next hole fires; too much and the face has already relieved itself, so the extra only spreads the muckpile.
The charge in one window	Where scatter in the delays puts appreciably more in one 8 ms window than the nominal timing does, so the vibration limit is held against the higher figure.

Nothing to answer reads as exactly that: every hole is tied in, every connector passes its signal before the ground beside it moves, and every hole has somewhere to break.

Still checks, not the law

A tie-up check is a prediction about a signal running across ground that is already moving. It uses your delays where you have typed them and typical figures where you have not, and it assumes the ground starts moving at one figure everywhere. Your statutory exclusion zone, your own monitoring and the blaster on the bench always govern.

Watching it fire

Watch it fire, on the Tie-up window, plays the shot on the pattern; so does the Firing switch beside Plan, 3D and Pictorial once the shot is tied up. Firing is not a fourth picture: with the switch on, each of the three plays the shot in its own way, and the shot waits at 0 ms for you to press Play. While the switch is on, Plan is the firing plan; turning the switch off shows the blast standing still.

With Firing on	What it plays
Plan	The firing plan: every hole coloured by when it goes off, the signal running along each connector, and an arrow the way each hole's rock leaves.
3D	The shot in three dimensions: holes fire as tied, rock flies as the muckpile model throws it, craters open and the predicted heap forms.
Pictorial	The shot as a person standing off the bench would see it: the ground solid, the rock thrown, the dust, and the heap it leaves.

On the firing plan, every hole is drawn where it is collared, in metres of ground, and coloured by when it goes off — the key runs from 0 ms to the last hole. The signal runs visibly along each connector as it burns, a hole flashes as it detonates and holds its colour after, and an arrow on each fired hole points the way its rock leaves: towards what fired before it, weighted by how much earlier and how much nearer. Connectors the cut-off check found are drawn cut, and holes nothing reaches are left hollow. The shot is played as it would run: a hole behind a connector that moving ground cuts never fires in the picture either, and pointing at it says which connector — the same holes the muckpile card says never fire. Once the blast is fired, the misfires named on the firing are the holes left hollow.

The controls under each picture are the same:

Control	What it does
Play / Pause	Plays the shot; at the end, it plays it again from the start.
Back to the start	Puts the shot back to 0 ms.
Go to the end of the shot	Jumps to the end: the last hole on the plan, the settled heap with the dust cleared in 3D and Pictorial.
The scrubber	Drag it to any moment in the shot.
The speed	Very slow (a fortieth of real time, slow enough to follow every connector by eye), Slow (a tenth, the usual way to read a tie-up, and where it starts) or Real time — over in about two seconds, and worth watching once to see why the other two exist.

On the firing plan, the running count sits under the picture: the moment, how many holes have gone, the kilograms gone so far, and the kilograms inside the last 8 ms. In 3D and Pictorial the clock shows the moment in milliseconds; the holes fire in a few hundred, and the rock flies for seconds after, so Slow shows the firing and Real time the flight. There, the question mark beside the controls opens The shot, played, which says what the playback shows and what in it is illustration.

While a shot plays in 3D or Pictorial, the picture's key gains three lines, each pressed to hide or show what it draws: Connectors (the connectors as tied, the signal running along them, and the broken tube left on the heap), Hole states (a disc on each collar in its hole's colour: waiting, fired, its rock moving, settled, or never firing) and Flyrock (predicted). Two buttons beside the controls change the look and nothing else: the dust button shows or hides the tumble, dust and fume, which are illustration and start shown; the palette button draws the muck in a colour of its own so it stands out, or in the ground's own shade as it would look on the bench, which is where it starts.

Recording a video. The record button beside the controls records the shot as a video file: a 3 s countdown, the shot at the speed chosen, then 3 s of the settled shot, and it saves itself at the end. Change the speed first for a longer or shorter clip. In 3D it records from where you have turned the camera, so turning the view while recording turns the clip, and the clip carries the line Predicted from the design model, not a recording of the blast. While it records the button reads REC with how far it has got; press it again to stop and save the video as it stands. The play controls, the dust and the muck colour are held while it records, and switching picture throws the recording away. A browser that cannot record video does not show the button.

Rest the pointer on a hole on the firing plan for its own line. The expand control fills the screen with the picture and its controls together.

The muckpile it is predicted to leave

On 3D and Pictorial, the Muckpile (predicted) line in the picture's key draws the heap the blast is predicted to leave. It is offered once the shot is tied up. With the blast standing still it starts switched off — press the line to have the heap drawn, and press it again to take it off the picture. With Firing on, the heap is what the shot builds, so its line comes on by itself, and it goes off again when you leave firing mode. An untied shot has no line, and the picture says the shot is not tied up yet. Every hole's rock is thrown the way its timing sends it — the same direction the firing arrows point — as far as its charge per metre of burden carries it, landed on the ground, swollen, and slumped to the angle of repose. Rows behind the front throw less, because there is more broken rock in the way.

The heap is drawn as broken rock, not a smooth mound. The rock lying on it is drawn at its true size, from the fragmentation this design is predicted to give (the mean fragment size and how evenly the rock breaks), coarsest first — so a design that breaks coarse shows its boulders, and one that breaks fine reads as a gravel pile. Where each rock lies on the heap is illustration; the sizes and the heap are the model's. A design with no rock factor of its own is drawn on the assumed 9 (see The rock factor); where the blast has no fragmentation figure at all, the heap is drawn bare rather than with rock of a made-up size.

The heap thins into an apron, not a scatter of little heaps. A hole's charge column is thrown in six slices, the top ones furthest, and each slice is laid over the ground it lands across — along the throw, from where the next shorter slice lands to where the next further one does, deepest at its own landing and thinning to nothing at theirs; across it, the width of ground the hole broke — so the slices of every hole add up to one heap that thins steadily out to the furthest throw, with no ridge across it. The furthest slice has no spot of its own: its rock is shared over where the others land, so nothing is drawn beyond the furthest throw the figures state. The shot played in 3D lays the rock the same way as it comes down, so the heap forms as that apron from the first rock landed, not as little heaps that turn into it at the end. Where the apron is thinner than half a metre it is no longer a heap a loader digs but rock lying scattered on the ground, and it is drawn that way: single rocks lying on the ground, from the coarse end of the same sizes, since it is the big rock that flies furthest, as many as the volume there makes, one deep. Flyrock is drawn the same way — one rock at the coarse end of the sizes, flying out along its arc to land on the ground at its range — but in red, so it is not mistaken for the heap: one off each front-row hole in the way its rock goes (face burst), and three round the collar of each hole the muckpile says craters. It lies where it landed once the shot is down. Its line in the key, Flyrock (predicted), is there only while a shot is played, and switches it off without stopping the shot or moving the camera. The red lumps are not misfires: a hole that never fires keeps its column. Only the drawing is illustration: the volumes, the throw and the volume beyond the face are the model's. Laying the rock out this way puts the heap's highest point a little lower than landing each slice on one spot would, and the height given below is that lower figure.

The figures beneath it say the loose volume and the solid it came from, the swell between them, how far the rock is thrown on average and at the furthest, how high the heap stands, and how much of it lands beyond the face. A shot that is not tied up has no firing times to throw it by, so no heap — and no crater — is predicted for it at all; tie it up and the heap is drawn the way its timing sends it.

What these distances are worth

Under the figures is a line saying whether they are calibrated. Until the mine has surveyed muckpiles of its own they are drawn with typical constants, and the line says so in as many words: the shape and the way it changes are worth reading; the distances are not measurements. Move the start, change the tie, add a row of holes, and watching the heap move is honest work. Reading 23 m off it as the throw is not. See Reconciling for how a mine makes them its own.

When the shot does not go as designed

The heap is not only drawn for a perfect shot. Where something fails, the card says what, and names the holes — in the blast's own names, a run along a row as a range such as C4–C7 — under What does not go as designed. The rock that does not break is drawn in 3D and Pictorial in its own slate colour, Rock left standing (predicted), apart from the loose muck, and switches off from its own line of the key.

• Holes that never fire. Before the blast is fired, a tied-up shot is run the way the tie-up would run it: where a hole's moving ground cuts a surface connector before its signal has passed, every hole behind that connector with no other way in never fires — C4–C7 never fire (the connector from C3 to C4 is cut by the ground B4 moves): 1,240 m³ left standing. A hole that nothing ties in is said the same way. Their rock stands where it stood, unbroken and unswollen, over each hole's own share of the pattern, and the loose volume drops by exactly that much.
• Once the blast is fired, what did not go is what was recorded, not what was predicted. On Record the firing, name the holes that misfired under Which holes misfired where you know them; the heap leaves their rock standing. Misfires counted but not named are said on the card — 2 misfires were recorded without their holes being named — and drawn as fired: the app never guesses which holes they were.
• A toe the bottom charge cannot break. Each front hole's toe is judged against the most its bottom charge can break — Langefors and Kihlström's maximum burden, worked from the hole's diameter, its charge per metre at the bottom, the product's strength, its lean and the pattern's spacing. The rock in front of the toe is read off the surveyed face along the hole's own lean and laid line, as the front row check reads it. Where it is more than the charge can break, the excess stays as a hump at the floor, up to where the face comes back within reach, and less rock is thrown in front of it. An easer is not judged this way: it breaks to the ground its leaned partners open. A toe that cannot be judged — no survey in front of it, or no charge to work from — is said on the card, never left out.
• A hole with no open ground when it fires. A tied-up shot knows when each hole goes. A hole behind the front breaks to the nearest ground already open at that moment — the face, or a hole that fired far enough ahead for its rock to be moving. Where that is further away than its burden, it throws less; where nothing open is within what its charge can break, its rock heaves: it swells where it stood and is not thrown. A hole behind one that never fired is confined the same way.
• Rock cannot fly through rock. Thrown rock that meets rock left standing stops against it and piles there, and the card says how much.

On a shot that is not tied up there are no firing times, so relief — whether the holes fired before a hole behind the front had emptied the ground beside its charge — cannot be judged. The card says so under What does not go as designed, even when the list above it is empty, so an empty list is never read as a clean bill on the one question nobody looked at. Tie the shot up and it is worked out in full.

What each hole's rock does

Under the figures, What each hole's rock does names every hole whose rock does anything other than throw cleanly to the face. Each line is marked Warning where a blaster should act on it, or Note where it is only worth knowing, so a crest left out of reach never reads like a hole about to break out through its collar. One hole gets its own words; several holes doing the same thing share a line, with the range of their figures and the largest of them.

What it says	What it means
Throws to the face	Went as designed. Not listed.
Craters through the collar	No face within the charge's reach, so the rock breaks out upwards and leaves a hollow. The line gives how much rock, how wide the crater is and how deep.
Heaves in place	Nowhere to go, so the rock breaks where it stands and lifts the ground. Not thrown.
Breaks nothing at the surface	The charge reaches neither a face nor the collar: the rock breaks underground and nothing shows.
Toe left	The bottom charge cannot break its burden at the floor.
Part standing	More stemming than burden: a short charge, with most of the bench left standing.
Crest beyond the charge's reach	The top of the bench is further from the charge than it can break. A note, not a warning.

A crater is drawn as well as said: in 3D and Pictorial it is a hollow below the ground the hole was drilled from, and the collar of every hole that craters, heaves or breaks nothing is coloured for what it does, with its own line in the key.

What a short charge really does

Put 0.5 m of charge under 9.5 m of stemming and the heap does not simply get smaller: that charge cannot reach the surface at all, so nothing is thrown, the rock breaks where it stands, and the bench above it is left standing. The card says so hole by hole rather than drawing a tidy little muckpile that could never happen.

Below that, what the figures take as given lists the assumptions this particular shot rests on — for example that rock broken in place swells by the free swell because its rock domain states no confined bulking of its own, or that stemming is judged on its length alone and not on whether it is crushed aggregate or drill cuttings. They are listed because they change what the numbers mean.

The toe judgement uses the Rock constant c under Ground and rock — how much explosive it takes to break a cubic metre of this rock. Left empty it is 0.4 kg/m³, Langefors' figure for most hard crystalline rock; weak ground takes less, massive ground more. Set it for the mine's own rock. Like every figure on this card, what fails is indicative until the mine has calibrated its muckpiles: read it as where to look, not as a survey.

From approval to the muckpile

Stage	What moves it on
Designed	Send for approval. A group with no approval chain approves at once.
Awaiting approval	The desks of the chain sign in order, or Send back with a reason. The requester can Withdraw.
Approved	Mark drilled. Reopen the design takes it back before anything is drilled.
Drilled	Mark charged — record any load that differs from the design first, or Record loads as designed.
Charged	Record the firing: the day, the shotfirer, misfires.
Fired	Reconcile: the rock the survey found, the dig rate, the fragment size, and — where the mine surveys its heaps — the muckpile.

Holes can be changed at every stage until the blast is fired, except while it awaits approval: the pattern is held exactly as it was sent, and Withdraw frees it. After approval, each save writes a line in the blast's change log — which holes were added, removed or moved, by whom, and why (type it in Why the pattern changed).

An approved blast whose pattern changes — holes added, removed or moved, a charge changed, the design rules or the tie-up — goes back for approval where its group has an approval chain, because the approval was of another pattern. Why the pattern changed must be filled in before Save is offered, and the page says Saving sends it back for approval. On saving, the blast returns to Designed with its sign-offs dropped; Send for approval sends it again, from the first stage. A group with no chain asks nobody, so the blast stays approved and the change is logged. Changes to a Drilled or Charged blast are field records: they are logged only.

Approvers hear of it as it happens: sending a blast tells the first stage's approvers; a signature that completes a stage tells the next stage, or the person who asked once the chain is done, while one that leaves its stage waiting on another signature tells nobody; Send back tells the person who asked, with the reason; and Withdraw tells the stage it was waiting on. Nobody is told of their own act, and only people who can open the blast are told. On sending, the toast says the blast was sent for approval — or, in a group with no chain, that it is approved: its group asks nobody to approve blasts.

The chain of desks is set per mine under the shield on the Blasts register, and covers every pit in it. The Mine list offers the Tracker Groups ticked Designs under Used by — the same groups the Pit picker reads — and any group a listed blast is filed in. While no group is ticked it offers every group, and says so under the list.

Two people can act on one blast in the same moment. Trackapt writes a change only onto the blast as you last saw it, so where a colleague got there first you are told "Someone else changed this blast a moment ago. Reload it, then try again." and nothing of yours is written — reload, and do it again if it still applies. Two approvers signing the same desk together both sign. One press of Approve is one decision at one desk: where the blast moves to the next desk while your approval is on its way, it is not carried on to that desk even if you sit there too. You are told either that your approval was recorded at the desk it was made at, or that the desk was completed by another approver as you approved and yours was not needed; open the blast again to approve at the next desk.

Approve and Send back are held to the request that was on your screen. Where the blaster withdrew it, changed the holes and asked again while you were still reading, you get the same "Someone else changed this blast…" and nothing is signed or sent back: reload, read the holes as they are now, and decide again.

Nobody signs a blast twice: someone who signed an earlier stage is turned away from a later one, so no one person clears the whole chain. On a small mine where one person holds two desks — the blaster in charge is also the pit superintendent — turn on Earlier signer may sign for the later stage.

The magazine

Under Explosives (on the Blasts register) each product can be linked to the magazine item and the parameter that counts its issues. Firing a blast then adds each product's kilograms there as a reading on the firing day: the item's daily issues figure. If that day already has a reading someone typed, it is left alone and the firing tells you how many kilograms to add by hand.

The firing is recorded first and filed second, product by product, so the blast says afterwards how the filing went — under Magazine on its page, and in the Magazine column of the Blasts register, which can be filtered on:

It says	What it means	What to do
Filed	Every product came off the magazine.	Nothing.
Partly filed	Some products came off; some did not.	Add the listed kilograms to the magazine by hand.
Not filed	Nothing came off, and kilograms are owed.	Add the listed kilograms to the magazine by hand.
Nothing to file	Filing was switched off for this firing, or no product fired is linked to a magazine item.	Nothing.
Filing cut short	The firing was recorded but its filing never finished, so the blast cannot say what reached the magazine.	Check the magazine's reading for the firing day, and add only what is missing.
Filing unconfirmed	The filing was started moments ago and is not marked finished. A blast does not keep when its filing started, so one still running cannot be told from one cut short.	Reload in a minute. If it then reads Filing cut short, treat it as that.
Not recorded	The blast holds no record of how its filing went, and nothing is shown as taken off the magazine.	Nothing, as a rule: filing may simply not have been asked for. If in doubt, check the magazine's reading for the firing day.

Not recorded is not a failure, and is not worded like one. Filtering the register for Not filed leaves such blasts out — so the filter finds only what somebody has to put right.

What was not filed is listed in amber, a sentence per product — it has no magazine item, its item is no longer under Explosives or was renamed, the magazine no longer keeps the figure it was filed onto, you have no access to the magazine, or the day's reading was typed or corrected by hand — each with the kilograms to add by hand.

Reconciling

Type the rock the blast broke (from the survey before and after digging), the dig rate, and the measured mean fragment. The actual powder factor follows from the explosives fired, and the mean fragment gives back the rock factor this ground behaved as — type it into the next design to make the prediction your own.

What the muck survey found is the second half, and it is optional in the fullest sense: most mines survey no muckpile at all, the blast reconciles perfectly well without it, and leaving every field blank changes nothing. Where a mine does fly or walk its heaps, this is what turns the predicted muckpile from a shape into its own figures.

Field	What it is
Muckpile, loose (m³)	The volume of the heap as it stands, off the after-blast survey.
Rock it came from (m³)	The in-situ volume that heap was broken from. Filled in from the design; type over it. The two together give the swell this ground actually has.
Furthest throw (m)	How far the muck reached from where it stood — the toe of the heap, not one flyrock.
Stood (m high)	The highest the heap stood above the floor.

Type any of them and the dialog works out what this one blast says the constants would be — the swell, and how fast rock leaves this face — beside what the prediction was made with.

One shot is not a calibration

That comparison is shown, and nothing else happens to it. Saving it applies nothing to any design. A muckpile is one reading of ground that varies enormously from blast to blast — structure, the state of the face, a burden that was never quite the design's, scatter in the delays — so a single fit is a reading to put beside the others, not a figure to design on. It takes five surveyed blasts before these become the mine's own, and even then they are shown with the spread they were fitted over, with the odd shot named and set aside rather than averaged away, and with the blasts, the benches and the period they came from written beside them. Until that point the muckpile keeps saying it is not calibrated.

What the crater survey found is the third part, and it is how a mine measures the rock itself. Where a blast broke out through its collars — a confined shot, a single-hole crater test, a hole that vented — survey the hollow and type it here.

Field	What it is
Depth (m)	From the ground as it stood before the blast to the deepest point of the hollow.
Diameter (m)	Across the crater, rim to rim.
Volume (m³)	The rock that left the crater, as solid ground, where the survey measured it. Optional, and the better figure to fit from where it was taken.
Ground rose (m)	The most the ground lifted around it. This is what confined bulking is fitted from.
Over hole	The blast's own hole name, where the crater was one hole's.
Surveyed on	The day it was measured. Never before the firing.

A survey that found nothing broke out is worth filing as depth 0 and diameter 0: that a crater did not form is evidence about the rock too.

Why a crater is worth surveying

A crater is the plainest measurement a blast gives of how far a charge breaks. With no face to go to, the charge breaks out up through its collar as far as it reaches and no further. So the crater the rock actually made, set against the crater that was predicted for it, says what this rock's rock constant really is — and the rise of the ground around it says how much the rock bulks when it is broken with nowhere to go. Both are fitted per rock domain, because how hard rock is to break is a property of the rock and not of the mine: a weathered cap and fresh rock below it are two different constants, and one figure fitted across both describes neither.

What was predicted is saved with the survey, exactly as it was predicted — the muckpile's figures, the crater, and the rock constant the prediction was drawn with, so a fit worked out later, against constants that have since moved, never rewrites the evidence it was fitted from. For the same reason, opening a survey again on a shot that has nothing predicted now — one fired without a tie-up in the app — and saving it keeps the prediction that was saved with it before.

As soon as the survey is whole, the dialog reads it back and says what this crater implies: the rock constant it gives, and how far its charge actually reached against the reach the design was drawn at. A crater bigger than the one predicted is rock that breaks more easily than it was taken to be, so it reads a lower constant; a smaller one reads a higher. Where it can read nothing it says which — no crater was predicted for that hole, the hole is not in the design, the survey found no crater at all, or a figure in it is one the page would not send.

That line is a reading, not a calibration, and says so where it stands. It is one collar, in one piece of ground, under whatever stemming actually went in: a joint through the collar or a wet hole moves it as much as the rock does. The rock's own constant is worked from five or more surveyed blasts in the same rock, under From your own blasts on that rock domain, where it comes with the spread it was fitted over. Saving a crater survey changes no design and no rock domain.

The same five-blast rule holds here. One crater is one shot in one piece of ground, so nothing is called this rock's own figure until five blasts in that domain have been surveyed, the proposal always carries the range the blasts gave and how far they wander, a blast that disagrees badly is named and set aside rather than averaged away, and nothing is ever applied to a design without a person accepting it.

From a plan

A plan can charge its drilling and explosives from the blast pattern instead of one typed rate. See Drill and blast in a plan. Once the plan is computed, Draft this period's blasts cuts each bench's share of the period into blasts from the face — none bigger than the plan's Largest blast — and files each here, ready to adjust and send for approval.

Printing and sharing

The export menu on the blast page gives the charge sheet — the pattern, the totals, every hole with its lean, toe RL, charge and firing time, the front row, and the checks — as a reading preview, Excel, PDF, print or share. The firing time against each hole on that sheet is the one the design's hole and row delays give it, and any time typed by hand. The times the tie-up works out — the signal's own path across the bench — are on the Tie-up window, under When each hole fires; they do not reach the charge sheet. The holes table exports on its own too.