In some cases, silver will recover very well by gravity. In laboratory testing, two kilograms of plant feed was ground to 80µm F80 and passed through a Falcon concentrator. The Falcon concentrate was panned to upgrade the concentrate and reduce the mass recovery to what is typically achieved by plant operations. A flowsheet and summary of results are shown in Figure 1.

Gravity concentration on the feed showed good amenability for silver and gold recovery to a gravity concentrate.

About 60 percent of the gold, and 53 percent of the silver was recovered into the Falcon concentrate having a mass recovery of 3.3 percent. The Falcon concentrate was further concentrated to a pan concentrate grading 340 g/tonne gold, and 3.6 percent silver. This concentrate, at a mass recovery of about 0.5 percent, recovered 39 percent of the gold and 31 percent of the silver.

Copper was also concentrated, with 19 percent of the feed copper revered to the pan concentrate, at a grade of 1.1 percent copper.