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.
Porphyry: grade interpolation is relatively easy — disseminated, gradational mineralization with high continuity supports reliable kriging on a coarse drill grid, giving high-confidence Measured/Indicated tonnages early and tight, statistically-controlled grade control on production benches.
VMS: moderate complexity — the massive-sulphide lens itself extrapolates well along strike/dip once its stratigraphic control is understood, but the stringer/feeder zone below it is discontinuous and harder to model, and abrupt lens pinch-outs require closer infill drilling near deposit margins before resource confidence can be upgraded to Measured.
Lode Gold: difficult — narrow, structurally controlled veins with nugget-affected, erratic gold distribution (high nugget effect in the variogram) make grade extrapolation between drill holes unreliable beyond short ranges; grade control must rely on face mapping and close-spaced channel sampling rather than block-model kriging alone, and resource classification is often held back at Inferred/Indicated until underground development directly exposes the vein.
Magmatic Ni-Cu-PGE: moderate-to-easy for the massive/net-textured sulphide zones (strong, continuous grade signal tied to the intrusion's basal contact) but more difficult for the disseminated halo, where PGE grades in particular can be erratic; grade control benefits from strong geological/geophysical (EM) control on the contact position.
Kimberlite Diamonds: uniquely difficult because grade is expressed as carats/tonne from a population of discrete, sparsely distributed stones rather than a continuous assay value — ordinary variogram/kriging methods are poorly suited, and resource estimation instead relies on large-diameter bulk sampling and micro-diamond/macro-diamond size-frequency modelling; grade control is correspondingly coarse (pipe-wide averages by internal facies zone rather than block-by-block).
