DETERMINATION OF HYDRAULIC CONDUCTIVITIES THROUGH GRAIN-SIZE ANALYSIS: ENHANCING THE RECOVERY OF PRECIOUS METALS

Sediment samples (n=906) from a mine in Central Chile are analyzed using nine methods to calculate hydraulic conductivity (k) as a function of grain size. The goal of this research is to produce a master curve that is representative of the hydraulic conductivity of a unconsolidated granular media of a certain grain-size distribution. Grain size, grain shape, porosity, sorting, uniformity, and dynamic forces are common factors that affect the value of k in the sediments used in constructing leaching piles in open pit mines. Preliminary results based on theoretical and statistical models, and validated through constant-head permeability tests, will be shown. A master curve showing a mean value of k for a certain grain-size distribution will effectively enhance the recovery of precious metals in open pit heap-leaching mines.