24-MMP-A5 Surface Mining Methods and Design · December 2016
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
Surface Mining Methods and Design (09-MMP-A5) — December 2016 National Exam. Compulsory Question 1 (six sub-questions) plus all five optional Questions 2–6 are answered in full below (candidates select only three of Questions 2–6 in the real exam; all are solved here as a complete study resource).
Reference texts: Hustrulid, Kuchta & Martin, Open Pit Mine Planning and Design (3rd ed.) — pit optimization, Lerchs–Grossmann, floating cone, dragline stripping geometry; SME Mining Engineering Handbook (3rd ed.); BC Health, Safety and Reclamation Code for Mines; Newnan, Eschenbach & Lavelle, Engineering Economic Analysis — sinking funds and future-worth factors.
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.
The dragline sits on the original ground surface at the edge of the cut, strips the overburden in a single pass and casts the broken spoil directly into the void left by the immediately preceding (adjacent) cut, without rehandling. It is the base-case geometry used for the Q2 calculation below and is only feasible while the overburden depth stays within the dragline's own bucket-reach/dump-radius/stacking-height envelope.
As overburden gets deeper than a single dragline pass can strip, the dragline first casts an upper "pioneer" bench of spoil ahead of/beside the final void, then walks up onto that self-created bench (elevating itself above the original grade) to strip the remaining, deeper overburden from the new, higher operating level — effectively using its own spoil as a working platform to extend its reach and stacking height beyond what a single ground-level pass could achieve.
A further elaboration of advanced bench mining in which the dragline builds and works from a SEQUENCE of progressively higher spoil benches (each pass's spoil becomes the platform for the next), so a total overburden thickness many multiples of the machine's single-pass digging depth can eventually be stripped; the trade-off is lower net productivity per bank cubic metre because material is effectively rehandled/re-stacked bench-over-bench rather than cast once.
