Mining and Exploration Geology
Domain focus
Mining and Exploration Geology tests exploration targeting, drilling and sampling, QA/QC, resource estimation, mine geology, and grade control. The exam emphasizes data quality and the difference between geological potential and economic reserve.
Core rules and concepts
- Exploration combines mapping, geochemistry, geophysics, and remote sensing; anomalies must be followed up with field checking and drilling.
- Diamond drilling provides oriented core for structure and sampling. Core recovery, sample interval, and contamination control affect representativity.
- QA/QC uses blanks, certified reference materials, duplicates, and umpire assays. Failures indicate contamination, bias, or analytical error.
- Resource classes are measured, indicated, and inferred, based on confidence. Reserves require modifying factors: mining, metallurgy, economics, legal, and environmental.
- Open-pit planning uses stripping ratio (waste:ore); underground methods depend on geometry, grade, and geotechnical conditions.
Worked example
A hole returns 12 m at 2.0 g/t Au above a 0.5 g/t cut-off. The grade–thickness product is 12 × 2.0 = 24 gram-metres. If the cut-off were 1.0 g/t and the same interval averaged 2.0 g/t, it would still qualify, but a 0.3 g/t interval would not. The reasoning is that cut-off is applied to grade, while metal accumulation depends on grade × thickness.
Traps
Do not average grades without weighting by sample length. Do not treat a mineralized intercept as a reserve. Do not ignore sample bias from coarse gold or core loss. Do not confuse a geophysical anomaly with a drill target until geological plausibility is checked.