Metsim is proving to be a powerful tool when designing a heap leach
operation. The most useful outputs arc determining the fluctuations in
pregnant solution recovery rate, make-up water rate, gold recovery rate.
and pond levels. Detailed data are needed for input: a pad loading schedule, a mining
rate schedule for each ore type, column leach test data for each ore type,
column tests on water dynamics (ie hourly flow-out versus-in during
saturation and drain-down), monthly rainfall and evaporation data, and
proposed pond dimensions. These data allow 'what if' studies on
application rates, leach rates, loading rates and other variables of interest. Examples will he given of modelling both a rectangular pad and a
valley fill operation.