According to the company, it has been running solution containing robust concentrations of gold and silver through the Merrill Crowe process, which is used to recover the gold and silver in solution after leaching.
This Merrill Crowe Process Facility has reportedly been expanded and upgraded to accommodate the current Lucerne Mine production plan as well as the increased production capacity of an expanded mine.
The permit will allow for the expansion of Merrill Crowe Process
Building and related processes, including the heap-leach pads.
The orders cover Ishigaki's fully automatic LASTA MC filter press for tailings applications and Micronics semi-automatic filters used for tailings and in the Merrill Crowe process
The company believes that previous estimates can be reduced by about $20 million with minimal impact on production by reducing the number of leach tanks, building a smaller Merrill Crowe process
plant/refinery, using modular crushers, and reducing the number of transformers.
Due to the presence of zinc-cyanide complexes in mill tailings resulting from the Merrill Crowe process
, cyanide is stripped at a pH of approximately 5.
Dump leaching and the Merrill Crowe process
were selected for gold recovery.