24-MMP-A4 Mine Valuation and Mineral Resource Estimation · May 2018
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, 2018-May. 3 hours duration; closed book, with one handwritten 8.5×11 in. reference sheet (both sides) permitted; only an approved Sharp or Casio calculator allowed. Question 1 is compulsory (40 marks, parts 1.1–1.9); candidates then select THREE of the five optional Questions 2–6 (20 marks each) to complete the paper.
Reference texts: Isaaks & Srivastava, An Introduction to Applied Geostatistics (variogram modelling, kriging estimators); Hustrulid, Kuchta & Martin, Open Pit Mine Planning and Design (mine valuation, cut-off grade theory, incremental analysis); Gentry & O'Neil, Mine Investment Analysis (Canadian mining taxation, cash flow/risk, smelter contract terms, NSV/NSR); SME Mining Engineering Handbook, 3rd ed. (ore deposit models, mineral exploration/evaluation stages, equipment utilization); O'Hara, T.A., “Quick Guides to the Evaluation of Orebodies,” CIM Bulletin, Feb. 1980 (parametric capital-cost estimating); CIM Definition Standards for Mineral Resources and Mineral Reserves / National Instrument 43-101 (resource/reserve classification and reporting).
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.
(a) Deep narrow copper/tin vein. A vein is a structurally controlled, tabular body typically less than a few metres true width, hosted in a fault or shear zone, with grade concentrated hard against sharp hangingwall/footwall contacts and often erratic along strike and dip (nugget-rich, high coefficient of variation). Because continuity is structural rather than statistical, estimation depends on tracing the vein geologically — close-spaced diamond drilling on cross-sections, underground face mapping and channel sampling — and classical section-based methods (method of sections, or polygonal assignment along the vein plane) remain common because a purely statistical interpolator cannot “see” the structural discontinuity at the vein/wallrock contact. Sample spacing must be tight relative to the vein width, and estimation is highly sensitive to dilution from mis-picked contacts.
(b) Extensive epithermal gold deposit. Epithermal systems (e.g. low-sulphidation vein/stockwork swarms in a volcanic host) are broader, often a swarm of sub-parallel veinlets and disseminated silicification rather than one clean vein, with grade varying more smoothly across a large footprint even though individual veinlets are themselves narrow. Because the mineralized envelope behaves more like a bulk-tonnage domain once enough drilling defines the overall geometry, geostatistical estimation (variography plus kriging or inverse-distance within a domained block model) is appropriate, provided domain boundaries (alteration/vein-density zones) are honoured so that grade is not smeared across a genuine discontinuity.
In both cases the geological model comes first: the estimation METHOD is chosen to match how continuity actually behaves in the deposit, not the reverse.
