The process where the sulphide minerals are exposed to atmospheric conditions during production and storage of minerals which begins with their interaction with oxygen in aquaose medium and for as long as the water sources in the environment and suitable geological material form high-metal content acidic water, is called Acid rock drainage / metal leaching (ARD/ML). However, the water quality is not always acidic, and sometimes it can be neutral or basic in case the minerals that buffer the acid drainage in the area are predominant.
The very first step of the problem as well as the solution is the site-specific geochemical and hydraulic modelling that enables determination of representative conditions that contribute formation and prevention of ARD. Forward planning after understanding the dominant reactions among mineral, water and gas components that turns the basin- and site-specific precipitation and groundwater into ARD or prevent the same or managing the entire system is critical for management of the system.
The differences arising from varying geological, mineralogical and facility status cause differences in waste, tallow or stock piles. Kinetic tests provide a near-realistic approach, but they can create problems in terms of time and cost. To reduce the costs of geochemical static and dynamic tests, mathematical and geochemical models (PHREEQC, MINTEQ, etc.) are made. Oxidation of sulfur minerals, dissolution of buffer-affecting minerals, redox reactions, these models in bacterial catalysis are used to simulate the time-dependent change and behavior of parameters. With the obtained outputs, the optimum solution can be applied to the ARD problem by setting the measures and treatment options for the characterization resulting from the ARD characterization.
Mitto Consultancy is your solution partner in ARD characterizations of feasibility projects, in taking preventive measures and in eliminating ARD problems in operations.