24-MMP-A5 Surface Mining Methods and Design · May 2016
Question 6 of 11: Range Diagrams for Surface Mining Equipment Selection
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Notes on this paper
Paper format. National Exams, May 2016 — 09-MMP-A5, Surface Mining Methods and Design. Three hours, closed book; one hand-written, double-sided 8.5×11″ reference sheet and an approved Sharp or Casio calculator are permitted. Question 1 is compulsory (six parts, 40 marks); candidates then choose three of the five optional questions (2–6, 20 marks each) for a 100-mark paper — only the first three optional answers appearing in the answer book are graded. All six parts of Question 1 and all five optional questions are answered here, because this set is a study resource rather than an exam script.
Reference texts. The answers below are keyed to the works normally recommended for this syllabus code:
W. Hustrulid, M. Kuchta & R. Martin, Open Pit Mine Planning and Design, 3rd ed. — block modelling and record addressing (Ch. 4–5), pit-limit optimization: floating cone and Lerchs–Grossmann (Ch. 12–13), truck–shovel systems, match factor and dispatch (Ch. 15–16), slope design (Ch. 14).
SME Mining Engineering Handbook, 3rd ed. — open-pit design and materials-handling chapters; mine closure and reclamation planning.
H. Lerchs & I. F. Grossmann, “Optimum Design of Open-Pit Mines,” CIM Bulletin (1965).
Y. Lizotte, “The Economics of Computerized Open Pit Design,” International Journal of Surface Mining, Reclamation and Environment, 2:59–78 (1988) — the floating-cone procedure cited directly on this paper's Question 1.3.
BC Health, Safety and Reclamation Code for Mines — mine closure planning and reclamation security (Canadian regulatory context for Question 5).
Question 1.6: Range Diagrams for Surface Mining Equipment Selection (7 marks)
What a range diagram is. A range diagram is a scaled, side-view (cross-sectional) envelope drawing of a piece of overburden-removal or loading equipment — classically a dragline or bucket-wheel excavator, but the concept applies equally to a shovel or backhoe — superimposed on the actual geometry of the material it must move: the pit bench height, the overburden/parting thickness, the seam depth, and the position from which the machine stands. It is drawn to answer one practical question before any equipment is purchased or committed to a mine plan: can this specific machine, standing on this specific bench, physically reach, dig, and dump the material this mine plan requires it to move, at the reach and depth this deposit demands — not merely whether it has enough bucket capacity or engine power in the abstract.
Important parameters read from (or checked against) the range diagram.
Maximum digging depth below the machine's standing (ground) level — must exceed the overburden thickness plus any sub-grade the mine plan requires the machine to reach.
Maximum dumping radius — the horizontal reach to the spoil pile or previously-mined-out area; must clear the working bench width plus any safety berm.
Maximum dumping height above standing level — must be sufficient to build the spoil pile to its planned final height without repositioning.
Machine standing (operating) level relative to both the pre-strip surface and the coal seam floor — draglines and BWEs are normally positioned on top of the material being stripped, which sets the datum every other dimension is measured from.
Bench height / overburden (parting) thickness — the actual material column the machine must remove in one pass, compared against its rated digging depth with margin for seam-floor irregularity.
Coal seam thickness and dip — affects both the required digging depth and whether the range envelope must be re-checked along the length of the panel as seam depth varies.
Working (operating) radius at the required digging depth — machine reach envelopes are depth-dependent (deeper digging generally narrows available radius), so the check must be made at the specific depth in question, not just at maximum reach.
Angle of repose of the spoil and the resulting spoil-pile footprint, which competes with dumping radius for the available room on the mined-out side.
Swing angle and cycle geometry — the horizontal angle through which the machine must swing between dig and dump position, which drives cycle time and therefore productivity, not just physical reach.
