From memory BWI , is Bond Working Index , that is the energy needed to grind to a set diameter at 80% (p80) passing through a mesh size , ie 16 would be 16 Kwh to grind one tonne (relatively high number)
Much of the ore in Nevada is refractory , which is expensive to process in OPEX and CAPEX ,
Fortunately what RIE has in Arizona looks to be processable by a standard flow sheet , although a bit more complicated in practice than a normal Au CIL circuit in WA .think more along the lines of SLRs deflector Au/Cu mine in the Lower Murchison that unlke most plants , uses a flotation circuit for concentrating the ore into a higher grade substance of both Au and Cu .
In this case there could also be Zn and Pb to take out for credits (why lose around $US50 a tonne (half a gram of Au eq) in credits by not also collecting the Zn and Pb .
Maybe RIE could get the ore processed by a local copper miner produce a concentrate and then send the concentrate to a gold miner for final processing through a CIL circuit and do the elution and pouring there ? just guessing on my part .
