24-MMP-A5 Surface Mining Methods and Design · May 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Mining and Mineral Processing Engineering, 09-MMP-A5 Surface Mining Methods and Design, 2014-May. 3 hours duration, closed book; one hand-written 8.5×11 inch reference sheet and an approved Casio or Sharp calculator permitted. Question 1 is compulsory (40 marks, all six parts 1.1–1.6); a candidate then selects THREE of Questions 2–6 (each worth 20 marks).
Reference texts: Hartman & Mutmansky (eds.), SME Mining Engineering Handbook, 3rd ed. (dragline stripping systems, truck-shovel productivity, mine cost estimation — the primary reference throughout this paper); Hustrulid, Kuchta & Martin, Open Pit Mine Planning and Design, 3rd ed. (block-model economics, floating/moving-cone algorithm, the Lerchs–Grossmann graph-theoretic pit-optimization method, annual push-back scheduling); Kennedy, B.A. (ed.), Surface Mining, 2nd ed., SME (dragline range-diagram geometry, stripping methods); Lerchs, H. & Grossmann, I.F. (1965), “Optimum Design of Open-Pit Mines,” CIM Bulletin, 58, 47–54.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
1.2.1 Simple side casting. The dragline sits on the seam/bench being uncovered and casts overburden directly, in a single pass, into the void left by the previous cut. It is the lowest-cost stripping method (no rehandle) but is geometrically limited: it only works while the dragline’s rated dumping (spoil) radius and stacking height can reach the crest of the growing spoil pile without repositioning, i.e. while overburden depth stays within roughly 1–1.3× the machine’s digging depth.
1.2.2 Advanced bench mining. The dragline stands on a bench ABOVE the coal/ore, cut from part of the overburden itself (a “key cut” or advanced bench), rather than on the seam floor. Standing higher lets one machine reach a much greater total overburden depth than simple side-casting alone, at the cost of an extra bench-forming pass and a slightly longer average swing.
1.2.3 Extended bench mining. A variant of advanced-bench mining in which the dragline’s advanced bench is pushed still further ahead of the coal-face position (extended forward over already-stripped ground), extending the reach even more so a single dragline can handle overburden depths that neither simple side-casting nor a standard advanced bench can reach; the trade-off is a wider spoil footprint and more re-handled material near the highwall toe.
