Nevada-based gold mining company Paramount Gold Nevada has received positive results for gold recovery using atmospheric alkaline oxidation.
Use of the process increased gold recoveries to 83.4%, the company said. Paramount tested 14 composite samples, with oxidation of the sulphide material occurring within two days.
Previous results from cyanide column leaching tests and bio-oxidation testing in 2015 posted recoveries averaging 76%, and up to 81%. Paramount tested samples from the West Wood Zone, which was not included in its 2015 PEA.
Sleeper is a formerly producing mine that is estimated to hold over 4 million ounces of mineralised material.
Gold recovery using atmospheric alkaline oxidation does increase the amount of gold extracted from ore when compared to conventional cyanidation, according to several mining companies which have tested the process.
Corvus Mining tested AAO in June 2017 with positive returns, while Hycroft Mining, also in Nevada, demonstrated the viability of an AAO process without using a traditional mill in 2019.
The next step in the testing process will be to determine several aspects of the AAO process, including oxidation time, temperatures, and crush size, to further compare with 2015 results.
Paramount will also analyse several mining and processing plans, with the aim of completing a new PEA. This PEA will include the use of conventional heap leaching as well as the selected oxidation method.
Paramount also owns the Grassy Mountain gold project in Oregon, the Frost lode claims near Grassy, and the newly acquired Bald Peak project in Nevada.
