24-MMP-A4 Mine Valuation and Mineral Resource Estimation · December 2013
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, 2013-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, compositing and support); Hustrulid, Kuchta & Martin, Open Pit Mine Planning and Design (NPV/cut-off grade methodology, cost estimating, financing structures); Torries, Evaluating Mineral Projects: Applications and Misconceptions (SME) (mine valuation, cost of capital, inflation treatment); Gentry & O'Neil, Mine Investment Analysis (net smelter return, smelter/refining contract terms); SME Mining Engineering Handbook, 3rd ed. (mineral economics, capital and operating cost estimating).
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.
Mismatching real and nominal terms. The most common error is mixing a real (constant-dollar) discount rate with nominal (current-dollar, inflated) cash flows, or the reverse. Discounting nominal cash flows at a real rate systematically overstates NPV (the inflation component of future cash flows is never discounted away), while discounting real cash flows at a nominal rate systematically understates NPV – either error can flip an accept/reject decision or mis-rank competing projects.
Differential inflation across cash-flow components. Applying one blanket inflation rate to every line item ignores that metal prices, labour, energy, consumables and capital equipment do not escalate at the same rate. If costs (often labour- and energy-heavy) inflate faster than the metal price, a valuation built on a single common escalator will overstate future margins; the correct treatment models each cash-flow category's own expected escalation rate.
Tax-shield timing distortions. Capital cost allowance (CCA) pools are fixed in nominal dollars at the time the asset is purchased and are NOT re-inflated in later years, so an inflation-adjusted revenue/cost forecast run alongside an un-inflated CCA schedule erodes the real value of the tax shield over the project life – a valuation that fails to model this understates tax paid (overstates after-tax cash flow) in later years.
Consequences. Collectively these errors distort project NPV/IRR, can make a marginal project look attractive (or an attractive project look marginal), bias comparisons between projects with different cash-flow timing profiles (front- vs back-loaded capital), and – for multi-jurisdictional projects – can compound with currency/exchange-rate effects if domestic and foreign-currency inflation are not separately tracked. The remedy is internal consistency: real cash flows with a real discount rate, or nominal cash flows (with realistic, category-specific escalation) with a nominal discount rate, never a mix of the two.
