Permeability modeling of ore stockpile for the stabilization of leaching solution filtration properties
A gradual decrease in the values of filtration indicators of leaching solutions due to the formation of low-permeability layers or zones inside the stockpile is often observed during heap leaching. Traditional methods of heap leaching have the disadvantage consisting in a decrease in the degree of recovery of useful component (metal) due to a decrease in the values of filtration indicators of leaching solutions over time, due to the compaction of the ore mass during the formation of a stockpile by bulldozers or other mining and technological factors. That leads to the formation of low-permeability layers or low-permeability zones inside the stockpile. Ensuring the continuous flow of technological solutions in a heap leach stockpile is a rather difficult geomechanical task that to be solved may require the use of mathematical simulation methods. This work is aimed at studying and changing the physical and mechanical state of the soil to improve its hydrodynamic properties. The mechanism of settling of large particles (anthers, clay, silt, sludge) in a stockpile, considering their size, has been revealed. It has been established that the process of clogging the stockpile pore space occurs in three stages. We have calculated the hydraulic characteristics of the solutions, depending on various factors, which allows us to increase their seepage rate and the level of wettability of the pieces of ore. In particular, the influence of natural or artificial channels on soil characteristics is considered. We have established the dependence between permeability and the investigated layer volume, the volume of pores in it, the number, diameter, height and angle of inclination of the channels, and the initial porosity of the layer.