FLOW-FIELDS ASSOCIATED WITH IN-SITU MINERAL LEACHING

A simple model for underground mineral leaching is considered, in whic h liquor is injected into the rock at one point and retrieved from the rock by being pumped out at another point. In its passage through the rock, the liquor dissolves some of the ore of interest, and this is t herefore recovered in solution. When the injection and recovery points lie on a vertical line, the region of wetted rock forms an axi-symmet ric plume, the surface of which is a free boundary. We present an accu rate numerical method for the solution of the problem, and obtain esti mates for the maximum possible recovery rate of the liquor, as a fract ion of the injected flow rate. Limiting cases are discussed, and other geometries for fluid recovery are considered.