The basic steps of any heap leaching evaluation method involve assaying for copper, metals and anions, analyzing the mineralogy, measuring the moisture content, the physical properties, the acid consumption, the acid cure dose, the particle size distribution, and the Bond work index. These basic determinations are usually followed by column tests under various leaching conditions to determine those that will yield the best results. Experience has shown, however, that the leaching conditions identified by this simple procedure may not be effective when applied in the field. Consequently, a more rigorous testing method has been developed which, in addition to the above-mentioned basic tests, carries out the following steps: (a) analyzes the driving forces of the process with each ore, (b) uses the preliminary column tests to establish the thermodynamic and kinetic interactions among copper recovery, impurities dissolution, acid consumption and their related solution requirements, (c) defines the context of a complete Leach-SX-EW plant to evaluate the possible interactions among them, (d) allows the clients to define the PLS quality and outlines the most feasible way to reach this objective, and (e) verifies through a mathematical model the column tests results and allows adjusting the factors to achieve optimal conditions.
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