Kinetic Testwork for Mine Planning, Metal Recovery, Environmental and OH&S Management and Mine Closure

Kinetic testwork in the form of column leach and humidity cell testwork is widely used for mining approvals to assess the indicative chemistry of leachate from sulfidic mine wastes. Advanced kinetic testwork methods based on oxygen consumption measurements can also reveal, a) the likely duration of sulfide oxidation processes, b) an accurate assessment of lag times (time before the onset of acid conditions), and c) the likely pollution loads over time. Oxygen consumption measurement techniques permit the quantitative assessment of sulfide oxidation rates (i.e. pollution generation rates) as a function of key waste storage facility variables such as temperature, moisture content, particle size distribution, oxygen concentration, pore water pH, and bacterial activity. Covers for sulfide wastes, capping zones, thin-lift and compacted oxygen control (encapsulation) bands and oxygen consuming layers can be accurately tested in the laboratory and field to optimise installation configurations (e.g. composition, particle size distribution, thickness, compaction, etc.) for operations and closure.

Oxygen consumption testwork on sulfidic materials is also finding increasing application to metal recovery and related metallurgical applications. A detailed understanding of the geochemical behaviour of ore materials can quantify a diverse range of outcomes including, a) establishing the relationship between sulfide oxidation and gold recovery, b) determining the rate of natural copper loss from long term copper ore stockpiles, c) specifying the precise neutralisation requirement for a gold heap leach operation as a function of time and oxygen concentration, d) determining reagent requirements for oxidation and neutralisation to complete metal leaching processes, and e) quantifying the optimum duration of a heap leach operation. Rapid response and portable oxygen consumption techniques can also be applied to assess the spontaneous combustion risk of sulfidic materials in the field.

Uptake by the mining industry of oxygen consumption techniques for a range of applications is increasing as the testwork, a) provides improved simulation of real-world scenarios, b) accurately assesses more key variables than conventional kinetic tests, c) produces more accurate outputs, far more rapidly and at a much lower cost, and d) can be used in both laboratory and field settings. Key benefits include rapidly facilitating approvals, improving OH&S for workers dealing with spontaneous combustion, increasing operational profits and lowering closure and remediation costs.

For assistance with kinetic testwork programs, or more information on the additional applications of kinetic testwork contact Earth Systems.