Mine designs

Pits, waste dumps, haul roads and ramps, and underground drill rings.

Mining → Mine designs

What is stored, and what is not

The parameters are the record. The geometry is generated.

A pit's benches are not stored. They come from its floor outline and its three slope rules, and regenerating them takes milliseconds. Opening a design runs it, in the browser, against the same kernel the server would use — so what you see is always what the stored parameters currently produce.

Why it works this way

Storing the drawn shape would let a design drift from the rules it claims to honour. That matters because a geotechnical report gets revised, and every pit designed to the old one has to be visibly out of date rather than quietly still drawn the old way.

Use Showing to narrow the register to one kind of design.

Warnings are outcomes, not errors

A pit that closes on itself at RL 1180, and a ramp too steep for the trucks, are both designs telling you something true.

They are reported in the words a designer can act on — "the floor is too narrow for a 65 degree batter", "this needs 1200 m of centreline against the 600 available" — rather than as a failure to generate. The remedy is a decision: a switchback, a flatter grade, a different floor. The design does not make it for you.

Pits

A pit is designed upward and outward from its floor, because that is what a mining engineer actually decides: the pit bottom is placed on the ore, and the walls are then whatever the rock demands on the way up.

Parameter	What it is
Floor outline	The pit bottom, in plan
Floor level	The level that outline sits at
Bench height	The vertical rise of each bench
Batter angle	The face angle, degrees
Berm width	The catch berm left at each bench crest
Sump depth, Sump area	The sump dug below the floor — see Water in the pit
Diversion drain	How far beyond the top crest the cut-off drain runs

You also set where it has to stop: a maximum number of benches, and either a topography surface — design stops at the bench whose crest reaches ground — or a maximum level where there is no topography yet.

The result says why it ended:

Ended because	Meaning
Surface	It reached the topography. The normal outcome.
Closed	The offset ran out — the floor is too narrow for the slope rules asked of it.
Benches	It hit the bench limit before either of the above.

A pit as drawn elsewhere

A pit designed in another package arrives as its strings: a closed ring per toe and per crest, each at its level, as a Surpac string file or a DXF. On the pit's editor, under As drawn elsewhere, read the file in and the pit is those benches. The slope rules above describe it — the floor outline follows the lowest toe and the bench height the lowest bench — but they are never run; the 3D view, the export and every plan for the pit take exactly the benches that were drawn.

Strings named TOE and CREST are read by name and paired by level. Unnamed rings are read by their level and size: of two rings at one level, the smaller is the crest of the bench below and the larger the toe of the bench above. The editor says how many benches it read and from which level to which; a file holding fewer than a toe and a crest is refused and the reason shown.

Back to the rules drops the drawn benches, after asking, and the pit is designed from its floor and slope rules again. The file can be read in again at any time.

A drawn pit is stored, a designed pit is not

This is the one place a pit's geometry is kept rather than generated, because it was decided elsewhere and nothing here can regenerate it. Re-import when the other package revises it.

Reference elsewhere, near the top of every design, block model and wireframe, is the name the record goes by in that other package. It rides along in every file the record leaves in.

Water in the pit

The slope rules say how the walls stand up; three more numbers say where the water goes, and they are generated from the way the benches are.

Parameter	What it is
Sump depth, Sump area	The sump: a box dug below the floor where the water collects and the pumps stand. It is drawn as a square of that area at the floor's centre, dug that deep, and holds depth times area. A sump larger than the floor is taken as the whole floor, and the design says so.
Diversion drain	The cut-off drain run round the pit beyond the top crest, in metres out from it. Ground beyond the drain sheds away from the pit; the strip between the crest and the drain still drains in, and its area is reported.

Both are drawn in the 3D view — the sump as a box below the floor, the drain strip as a band at the crest — and reported under Water beside the benches: the opening at the crest, the sump's capacity and the level of its bottom, and the area inside the drain. A design that names neither carries no water and says nothing.

A plan for the pit reads the sump's capacity and the drain strip from here where the planner types neither, so the pit is dewatered as it was designed, not as somebody remembered it. Leave all three blank for a design with no water on it.

What the design does not know

Where the water table is, and how much the pit takes from it, is the hydrogeology report's to say; it is typed on the plan, not the design. A design's sump is sized for the storm; the plan is where the storm and the groundwater are read against it.

Stages

A pit with none of these is mined bench by bench, top-down, exactly as drawn. A stage records a pushback or a cutback the mine wants taken before or after another part of the same pit — the sequencing decision the schedule optimiser is built to use, put on the design itself rather than left for a planner to remember.

A stage is drawn like the pit's own floor: an outline, typed or pasted, plan only. Its level is ignored, because a stage's levels are its own From level and To level instead.

Field	What it is
Label	What a planner calls the stage
Outline	The stage's own ring, in plan
From level, To level	The bench levels this stage cuts through
After	The other stages that must be finished first

After is the whole of the ordering: leaving it empty lets a stage start whenever; naming others holds it back until they are done. The list order is display only — it is not what precedence follows.

Two problems block a save

A loop of After references that names no order at all, and two stages that cross the same bench levels and overlap in plan — the same ground claimed twice. Both are named so the conflicting stages are clear.

Add a stage only where a real sequencing decision needs to be seen.

Waste dumps

A dump is the pit turned inside out. Where a pit is designed upward and outward from its floor, a dump is designed upward and inward from its footprint — the toe outline at the ground — lift by lift, until the top closes on itself, the lift limit is reached, or the top level is.

Parameter	What it is
Footprint	The toe outline in plan. Take a boundary already set out in Survey, draw it on a survey of the dump's item, or paste the corners.
Lift height	The vertical rise of each lift
Face angle	The material's angle of repose — what tipped rock settles to on its own, about 35 to 38 degrees for blasted waste — or a flatter angle the stability report asks for
Berm width	The setback between one lift's crest and the next lift's toe. Zero is a single continuous face.
Most lifts	Where to stop, whatever else happens
Base level	Where the lowest toe sits. Leave it empty to stand the dump on the lowest surveyed ground inside its footprint; it is needed where there is no survey.
Top level	A level no crest may pass. Empty, the dump rises until it closes or reaches the lift limit.
Least top width	How far the top must still measure across — the tipping pad. See A dump has to be worked.
Ramp width, Ramp grade	The haul road up to each tipping level. Both empty, no ramp is designed.
Surveyed surface	The ground it stands on. Named, the capacity is measured against the real ground — on a hillside the uphill side of a lift holds nothing.

Take the boundary rather than type it

The ground a dump may occupy is usually agreed long before anyone designs a dump on it: it is walked, drawn and named in Volumes and plans as a boundary. Take a surveyed boundary on the design's editor lists the boundaries drawn on that item and takes the one picked as the footprint. A boundary's corners are already on the mine grid — the frame a design is stored in — so nothing is converted and nothing is retyped, and the area the dump is designed for is provably the area that was granted. It applies to a pit floor too, for the same reason.

A boundary carries no levels, which is why this is offered for a footprint and a floor but not for a road's centreline. Where the plan is already open the ring is drawn on the ground, so what was taken can be seen rather than only read as numbers.

Running it gives the lifts with toe and crest levels, crest area, what each lift holds and what the dump holds to that lift, the overall slope the lift rules produce, and the capacity of the whole dump as placed. A dump whose footprint is too small for another lift says so, and at which level.

Measured, not assumed

The capacity is the space between the designed top and the ground, inside the footprint — measured exactly, piece by piece, against the survey. On flat ground it is the frustum arithmetic a planner does on paper. It is in placed cubic metres: rock swells when it is blasted, and a plan turns its waste tonnes into loose cubic metres through the pit's swell factor before it asks whether they fit.

The result says why it ended:

Ended because	Meaning
Lifts	It reached the lift limit.
Closed	The footprint is too small for another lift at that face angle.
Level	It reached the top level.
Top	The next lift would leave a top too narrow to tip on.
Ground	The survey does not reach the footprint, or there is no ground and no base level.

A dump has to be worked

A stack of lifts is a shape. Two more things make it a dump the mine can actually use, and without them the drawing is wrong in a way no capacity figure would show.

The top is where the trucks tip. Stepping inward lift after lift closes the outline to a point, and nothing tips on an apex: a rear-dump truck has to reverse to the edge, tip, and turn round. Least top width is the room that takes — about 40 m for a rear-dump fleet, more for the largest trucks — and the design stands at the last lift whose crest is still that wide, reporting Top as the reason. The top's width and area are reported beside the lifts, so the pad is a figure rather than an assumption.

A width, not an area

A top of 4,000 m² that is 300 m long and 13 m wide is a road, not a pad. The figure reported is the widest strip that fits inside the top outline, which is what decides whether a truck can turn.

The trucks have to get up there. Give the dump a ramp width and a ramp grade and the design spirals a haul road up the outside of the faces, climbing each lift at that grade and crossing each berm still climbing, so it arrives at every lift's toe exactly at that lift's level. Every crest it passes is a landing — the level tipped at while that lift is being built. The report gives its length, the grade it achieves, how many times it goes round the dump, and the levels it lands on; the 3D view draws it; and it leaves with the design as DUMP-RAMP and DUMP-RAMP-EDGE, and as a body named DUMP RAMP.

The ramp is laid on the faces the lift rules produced — it never moves the dump — so where it does not fit, it says so instead:

What it says	What to do
So much of the ramp stands beyond the toe and must be built out	Widen the berm to the figure named, or allow for the extra fill
The ramp would cross itself climbing one lift	Flatten the grade, lower the lift, or widen the footprint — the dump is not far enough round for that climb
The top is narrower than the ramp arriving on it	Raise the least top width, or narrow the ramp

A dump with none of these

Leave all three empty and the dump is designed lift by lift until it closes, reaches the lift limit or reaches the top level. The design does say, in its message, when the top has closed to something nothing can tip on — the capacity is not wrong, the shape is unworkable.

Haul roads and ramps

A road is designed along a centreline, and reported as stations: chainage, centreline position, bearing, design grade, and the cross-section at that point, including the left and right running-surface edges a grader can be given as a string.

Parameter	What it is
Width	The running surface, total across both lanes
Crossfall	Percent, falling from the centre to each edge. 2–4% is usual — enough to drain, little enough that a loaded truck does not lean on it
Shoulder width	Beyond the running surface, each side
Berm height and width	The safety windrow at the outer edge

The berm is not decoration

On a haul ramp it is the regulated windrow, sized against the wheel of the largest truck on site.

The design reports total length, start and end level, and rise (negative for a descending ramp).

The first question any ramp has to answer

A 60 m rise at 10% needs 600 m of centreline. If the pit is 400 m across, the ramp has to switchback or go somewhere else — and the design will tell you so in those terms rather than drawing something impossible.

A ramp can also start from the ground. Measure the run on an open survey — see Measuring off the plan — and Design a ramp along this opens the editor with the centreline, its start level and its grade already filled in from what you measured, so the design is specified rather than sketched.

Underground headings

A heading is a road with a roof. A decline, a level drive, a crosscut or an ore drive is designed along a centreline exactly as a haul ramp is — stations cut at an interval, each carrying the profile swept onto it — and the difference is that the excavation is a tube, not a surface.

Parameter	What it is
What it is	A decline gets between levels, a drive runs along one, a crosscut reaches across to the ore, and an ore drive is driven in the ore itself so its rock is fed rather than tipped
Width, Height	The hole the machine cuts, metres. A twin-boom jumbo drive is 5 to 6 m wide
Arch rise	How far the back rises above the springline. Zero is a flat back, which is what a jumbo cuts in competent ground
Start level	Where the floor sits at the first point of the centreline
Grade	Per cent, positive uphill. A decline falls, so its grade is negative
Steepest allowed	The steepest the equipment will drive. Exceeding it is reported, not refused
Station interval	How far apart the sections are cut

Running it gives the stations a survey crew sets out from, the metres driven — which is what development is priced by — the fall from end to end, the face area the profile cuts, and the rock it breaks, which has to be hauled out and tipped like any other. A heading too steep for the equipment says so, and one told to arrive at a level its centreline is too short for says how much centreline that level actually needs.

Why the metres matter more than the shape

Underground, everything is priced and scheduled per metre advanced. A plan that knows how far a decline is knows when the level below it can be mined, which is the whole of underground scheduling. See Underground: stopes and headings.

It leaves as its centreline and both walls on the UG-CENTRELINE and UG-WALL layers, and as a closed body for a package that takes the excavation itself.

Underground drill rings

A stope's drill design: rings set out along a drive, each with its holes fanned to a boundary.

Parameter	What it is
Burden	Distance between rings along the drive
Toe spacing	Target distance between neighbouring hole toes
Standoff	How far short of the boundary each hole stops
Hole diameter	Carried for the charge sheet, not for the geometry
Minimum length	Holes shorter than this are dropped as not worth the setup
Maximum length	Holes longer than this are flagged — a rig has a reach

Each ring reports its chainage, the collar where the driller sets up, the drive bearing, every hole with its dip, azimuth and drilled length, and the metres drilled for the ring and for the whole design.

A hole past the rig's reach is flagged, not dropped

The designer may shorten it or move the drive. Both are decisions, so the design leaves them where they belong.

Taking a design away

An open design writes out as a Surpac string file or a DXF drawing, on the mine grid, with each kind of line on its own layer:

Design	What comes out
Pit	Every bench's toe and crest, as closed rings on PIT-TOE and PIT-CREST, each named with its level
Road or ramp	The centreline, and both running-surface edges — the string a grader is actually given
Drill rings	One line per hole, collar to toe, named R<ring>-<hole>

And as bodies — LandXML surfaces with their faces, or a DXF with one layer per body — for a scheduling package that takes mining blocks rather than strings: a pit as its surface, one closed solid per bench and one per stage's cut through each bench; a dump as its surface and one solid per lift; a road as its running surface.

The export is generated too

It is whatever the stored parameters currently produce, so a design sent last month and the same design sent today will differ if the rules changed in between. That is the point of not storing the geometry.

See Working with other packages.

When something looks wrong

What you see	Why, and what to do
A pit stopped after two benches	It closed on itself. The floor is too narrow for the batter angle asked of it — widen the floor or flatten the wall.
A pit or dump stops a bench or two earlier than expected	An offset narrower than the ring it moves does not fold, it turns through itself and comes back a plausible smaller ring. The design catches that and stops where the ground actually closes rather than carrying on into shapes that are not there. Benches beyond that point would not be buildable — widen the floor or footprint, or flatten the slope.
A pit ran to the bench limit	It never reached the topography. Raise the bench limit, or supply a surface to design to.
A ramp reports it needs more centreline than exists	The rise cannot be made at that grade over that distance. Switchback, or flatten the grade.
A ring has fewer holes than expected	Holes below the minimum length are dropped. Check the minimum against the stope width.
A design looks different from last month	It is generated, not stored — so its parameters, or the surface it designs to, have changed. That is the behaviour, not a fault.
A dump stops before it closes to a point	It has a least top width, so it stands at the last lift that can be tipped on rather than closing to an apex. The lifts above it would not be workable.
A dump's ramp goes round and round	Each lift needs its rise divided by the grade in running: a 10 m lift at 8% is 125 m, and a small dump is not that far round. Flatten the grade or accept the laps.
A drawn pit's slope rules do nothing	By design: a pit read in as drawn is those benches, and the rules only describe it. Back to the rules puts the rules in charge again.
The bench file read nothing	It holds fewer than a toe and a crest, or the rings are not closed. Name the strings TOE and CREST with their levels and the reader pairs them by name.