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.
Cash flow. In the mining context, cash flow for a given period is Revenue − Operating Costs − Sustaining/Growth Capital − Income Tax − Royalties ± Working-Capital changes, summed over the mine life to build the project's NPV/IRR. Unlike accounting profit it excludes non-cash items (depreciation/CCA) except through their effect on the tax calculation.
Risk and sensitivity drivers. The dominant sensitivities are almost always metal PRICE (revenue scales directly with it and price is the least controllable input) and head GRADE/recovery (both scale revenue and are geological/metallurgical, not managerial, uncertainties); secondary drivers are capital and operating cost overruns, exchange-rate movement (costs often in local currency, revenue in USD), and permitting/construction schedule delay (which defers and compresses the present value of cash flow). Taxation is a further risk layer because both the RATE and the STABILITY of the fiscal regime affect the cash-flow forecast itself.
Stable vs. unstable fiscal regimes. Canada and Australia offer transparent, legislated, slowly-changing corporate tax and royalty regimes (in Canada, federal/provincial corporate tax plus CCA-based depreciation under a defined asset-class system, with the half-year rule), and mining-law/contract sanctity is high, so a project's after-tax cash flow forecast is reasonably reliable over a multi-decade mine life. Many emerging economies in South America and Africa instead carry a real risk of mid-life fiscal-regime change — royalty-rate increases, windfall taxes, forced local/state equity participation, or outright expropriation — on top of the STATED tax rate. The appropriate response is not simply to forecast the current stated rate; it is to raise the DISCOUNT rate used to value the project (a country-risk premium layered on top of the base cost of capital, commonly several percentage points, sometimes 15%+ real for genuinely high-risk jurisdictions vs. roughly 8–10% real for Canada/Australia), and/or to explicitly model a probability-weighted fiscal-change scenario, rather than pretend the headline rate will hold for the life of the mine.
