PEC EPE Mining cheat sheet
PEC EPE Mining · Keep the key ideas within reach.
Mining Engineering Practice (PEC EPE)
Cutoff grade: g_c = (mining cost + processing cost + refining cost) / (metal price × recovery × payable factor); material below cutoff is waste or stockpiled.
Stripping ratio (SR) = waste volume (or mass) / ore volume (or mass); break-even SR = (ore value per tonne − ore processing cost) / waste mining cost per tonne.
Resources vs reserves: a mineral resource is a concentration of material of economic interest; a reserve is the economically mineable part of a measured or indicated resource, requiring a modifying factor study.
Reserve reporting follows the CRIRSCO template; measured, indicated, and inferred classification depends on confidence in geological data and the qualified person's judgment.
Blasting: powder factor = explosive mass / rock volume (kg/m³); firing pattern, burden, spacing, and stemming length control fragmentation and flyrock risk.
Ventilation: air quantity Q = A × v; methane is explosive between roughly 5% and 15% in air; minimum ventilation rates are set by local regulations.
Ground control: roof bolting and mesh support hanging wall in underground mines; slope stability in open pits depends on bench height, slope angle, and groundwater.
Mine closure and rehabilitation: progressive rehabilitation is planned at design stage; financial assurance (bond) is required before disturbance in most jurisdictions.
Mining Engineering Practice - Operations, Safety, and Economics
Haulage cycle time = load time + haul time + dump time + return time + queue/spot time; cycle time and truck-shovel match drive fleet productivity.
Truck-shovel match: number of trucks per shovel = (shovel cycle time) / (truck cycle time) rounded up; too few trucks starve the shovel, too many cause queueing.
Ore grade control uses grade control drilling, face sampling, and ore-waste boundaries; misclassification causes dilution, which lowers head grade and recovery.
Dilution: mining dilution = (waste mined with ore) / (ore mined) × 100%; controlled by selective mining, stope design, and blasthole layout.
Mine safety: principal hazards include ground fall, blasting, mobile equipment interaction, dust (silica), and diesel particulate; controls follow the hierarchy of controls.
Dust and silica: respirable crystalline silica causes silicosis; wet suppression, ventilation, and personal protective equipment reduce exposure.
Mine economics: NPV = Σ (cash flow_t / (1 + r)^t); discount rate, capital cost, operating cost, and metal price assumptions drive project viability.
Permitting: environmental impact assessment, mine plan approval, water licence, and rehabilitation bond are typically required before construction.