• Large OPEX costing for acid consumption vs recovery rate and grade.
• EPA issues and regulations regarding massive mound open atmosphere leaching.
• strict Environmental guidelines due to possible leaks and bund failures, causing acid to contaminate environment.
• it's easy to show an atmospheric leach and heap leach work in pilot plant or laboratory conditions..
Imagine 200t pile of Nickel having acid pumped through it in mega amounts to start the leaching process.. (or what ever size pile they intend to leach at a time)
• it's far more common and standard for HPAL process because it's more economically viable. CAPEX is more but OPEX is significantly less over the LOM.
