North Bay Resources Inc. (OTC:NBRI) said it has delivered 344 pounds of gold concentrate to its refinery partner, Just Refiners in Nevada.
The concentrate, produced from roughly 15 tons of ore processed at the company’s Bishop Gold Mill, was derived from the gravity-only circuit, with flotation circuit testing currently underway.
Recent upgrades at the Bishop Mill—including repairs to the Raker/Classifier and the replacement of grinding balls in the ball mill—have improved ore grind size to minus 150 mesh, which the company says is optimal for gold recovery.
North Bay recently received settlement for its first shipment of concentrate and is now focused on optimizing its flotation circuit. Testing of Clarkson-Feeders, which titrate five reagents used in the flotation process, has been completed. The company is now determining whether staged or single-step addition of reagents—such as gold and sulphide promoters, activators, and frothers—will deliver the best performance.
All mechanical and post-processing equipment, including a leaf-press and propane-fired drying circuit, are operational, the company said. A final decision on the configuration of the flotation system, including whether to use a single or dual conditioning tank, is expected soon.
Prior metallurgical work suggests that Fran Gold ore could yield up to 97% gold recovery using a combined gravity and flotation process.
Meanwhile, North Bay continues to recompile data from 104 historic drill holes at the Fran Gold Project, incorporating Leapfrog 3D modeling and pit-shell design as it works toward a resource estimate.
Located near Centerra Gold’s Mt. Milligan Project and Artemis Gold’s Blackwater Mine—two of North America’s largest new gold and copper-gold mines—the Fran Gold Project has seen over 18,000 meters of past diamond drilling and hosts a mineralized zone measuring more than 1,000 by 100 by 300 meters within a 1,700-meter strike length.