1. Parameters of mining method evaluation What we are looking for choosing the mining method This objectives are contradictory Maximum recovery of reserves recovery characteristics Maximum daily tonnage for productivity characteristics minimum stopes in operation Minimum cost consumption and economic characteristics Under good security conditions
2. Recovery characteristics : sources of dilution and loss Loss in pillars Loss and dilution on irregular ore/waste contacts Dilution when stope opening is larger then ore thickness Loss on irregular footwall Loss and dilution on the working surface during the loading Loss and dilution during extraction under caving waste minerai remblai
4. Direct calculation of dilution and loss R - recoverable reserve, t R =10000 t P - loss, t P = 900 t S - dilution with waste, t S = 1600 t TV - run of mine tonnage, t TV = R - P + S = 10000 - 900 + 1600 = 10700 t t R - average grade of metal in recoverable reserve, t R = 0,08 t P - average grade of metal in loss, t P = 0,11 t S - average grade of metal in waste (dilution), t S = 0,015 t TV - average grade of metal in run of mine, t TV = (R * t R - P * t P + S * t S )/TV= (10000*0,08 - 900*0,11 + 1600*0,015)/10700 = 0,068 metal ore
9. Productivity characteristics Stope output : tonnes per stope and per month Relative weight of development : metrage of drifts par 1000 t of recoverable ore percentage of development in cost of a tonne of ore Productivity of personnel : tonnes per man and per shift tonnes per man and per year Level of mechanization : percentage of labor in costs
16. Relative operating cost of mining methods compared with room and pillar mining Operating cost of room and pillar mining vary between 2 et 27 $/t with country, it’s 14,5 in average
