The pursuit of higher metal recovery enters the digital age — where even time-tested, conventional leach-optimization techniques stand to benefit from emerging automation and analysis capabilities
Heap leaching is typical of most mineral extraction methods in that it is easy to grasp in concept and difficult to perfect in practice. At first glance, percolating a solution through a pile of crushed rock to capture metal values sounds like the easiest possible way to recover gold, copper and other amenable metals, surpassed in simplicity only by in situ mining.
However, in the same vein as the military maxim that “the enemy always gets a vote” in a battle’s outcome, a number of complicating factors often have votes in the outcome of a heap leaching campaign. These include local weather conditions, ore composition variability, leach pad design and maintenance, and the hard-to-figure settlement and segregation behavior of rock fragments and particles, to name just a few. Regulatory and societal concerns involving the use of cyanide or sulphuric acid in large quantities as well as the potential for environmental damage by fluid leakage from pad linings or piping can also affect the operational ‘ballot.’