24-MMP-A4 Mine Valuation and Mineral Resource Estimation · December 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Mining and Mineral Processing Engineering, 09-Mmp-A4 Mine Valuation and Mineral Resource Estimation, 2014-Dec. 3 hours duration; one handwritten 8.5×11 in reference sheet permitted (not an open-book exam); only approved Sharp or Casio calculators allowed. Question 1 is compulsory (40 marks, parts 1.1–1.7); candidates then select FOUR of the six optional Questions 2–7 (15 marks each) to complete the paper.
Reference texts: Isaaks & Srivastava, An Introduction to Applied Geostatistics (variogram modelling, kriging estimators, volume–variance relations); Hustrulid, Kuchta & Martin, Open Pit Mine Planning and Design (mine valuation, NPV and cut-off grade methodology, mineable reserves); Gentry & O'Neil, Mine Investment Analysis (Canadian mining taxation, smelter/refining contract terms, net smelter return); SME Mining Engineering Handbook, 3rd ed. (mineral exploration/evaluation stages, ore reserve classification); CIM Best Practice Guidelines and NI 43-101 (Canadian Securities Administrators).
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.
Five contrasting deposit types are chosen to span the main genetic families — magmatic, volcanogenic, orogenic, porphyry-related and diamond-bearing:
2.d Porphyry (e.g. Highland Valley Copper). Large (100s of Mt), low-grade (0.3–0.6% Cu), bulk-disseminated stockwork of quartz–sulphide veinlets centred on a felsic-intermediate porphyritic intrusion emplaced at shallow crustal depth; concentric alteration zoning (potassic core → phyllic → propylitic) surrounds the mineralized stock, and grade grades gradually outward with no sharp ore boundary, favouring bulk open-pit mining and statistical (kriged) grade control.
2.b Volcanic Massive Sulphide (e.g. Bathurst). Stratiform, lens-shaped sulphide accumulations (Cu-Zn-Pb ± Ag-Au) formed by seafloor hydrothermal venting onto or near submarine volcanic rocks, typically with a discordant stringer/feeder zone below a conformable massive-sulphide lens; deposits are geologically tabular and stratabound, syngenetic with the host volcanic pile, and commonly occur in clusters along a favourable stratigraphic horizon.
2.c Lode Gold (e.g. Timmins). Structurally controlled quartz-carbonate veins hosted in shear zones/faults within deformed and metamorphosed (greenstone-belt) terranes, formed by deep crustal metamorphic fluids depositing gold with sulphides (pyrite, arsenopyrite) along dilational structural sites; geometry is narrow, discontinuous and vein-like, strongly structurally controlled rather than stratigraphically controlled, requiring close-spaced structural mapping to trace.
2.a Magmatic Ni-Cu-PGE (e.g. Sudbury). Sulphide liquid immiscibility within a mafic-ultramafic intrusion (or, at Sudbury, an impact-melt sheet) concentrates Ni-Cu-PGE sulphides at the base of/within the intrusive body as massive, net-textured or disseminated sulphides; geometry follows the intrusive contact and internal magmatic layering, giving relatively predictable, often steeply dipping tabular zones distinct from both porphyry and vein-hosted systems.
2.i Kimberlite Diamonds (e.g. Ekati). Steep, narrow, carrot-shaped volcanic pipes of ultramafic kimberlite magma that rose explosively from the mantle, entraining diamond xenocrysts from depth; the pipe geometry (diatreme facies over a root/hypabyssal facies) is fundamentally different from all the above — a discrete, roughly circular intrusive body in plan rather than a tabular vein, stratiform lens, or disseminated stockwork, mined as a bulk pit that narrows with depth following the pipe's own taper.
