EGi’s proprietary techniques and test procedures have been developed to classify mine materials according to acid forming potential, risk of metal leaching, salinity, and possible toxicity due to metals, cyanide and other chemicals.
To classify acid forming potential, EGi utilise net acid producing potential (NAPP, or acid base account – ABA) and net acid generation (NAG) test results as initial screening tools. Utilising both independent measures significantly reduces the risk of prediction errors and better defines the ARD characteristics of samples. Additional specialised static tests are used to help resolve uncertainties in classification.
Kinetic test procedures, such as leach columns, involve a number of measurements over time and are used to assess a range of ARD/NMD issues including sulphide reactivity, oxidation kinetics, metal solubility and the leaching behaviour of test materials.