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.
Treatment charges (TC). A fixed fee, in dollars per dry metric tonne of concentrate, that the smelter charges the mine to process the concentrate into refined metal — covering the smelter's own energy, labour and reagent costs; TC is negotiated annually/multi-annually and is one of the two dominant deductions from gross concentrate value (alongside RC).
Refining charges (RC). A fee, in dollars (or cents) per pound/tonne of payable metal, charged for the electrolytic or pyrometallurgical refining step that converts blister/anode metal into saleable refined metal; unlike TC it scales with the payable metal content rather than the gross concentrate tonnage.
Deductions. Standard reductions applied to the assayed metal content before payment is calculated — e.g. a "unit deduction" of 1 percentage point off the assayed copper grade, or a minimum-deductible threshold below which a metal is not paid for at all — compensating the smelter for its own inevitable metallurgical losses in processing.
Price escalation and participation. A clause allowing the treatment/refining charges themselves to rise (escalate) if the metal price rises above an agreed threshold, so the smelter "participates" in windfall price gains rather than being locked into a fixed TC/RC regardless of how favourable metal prices become for the mine.
Impurities. Contract clauses (penalty schedules) charging the mine additional deductions per unit of deleterious elements (arsenic, antimony, bismuth, fluorine, mercury, etc.) present above a stated free limit in the concentrate, because these elements damage smelter equipment, create environmental/handling liabilities, or contaminate the refined metal.
