Reagents modification study for improved flotation of a gold ore at the Dundee Precious Metals Krumovgrad mine, Bulgaria

A laboratory study was conducted with the view of replacing the currently used secondary collector (promoter) at the Dundee Precious Metals, Krumovgrad (Bulgaria) flotation plant with a more efficient one securing better recovery of the electrum from the ore. Eight reagents from various suppliers have been tested to benchmark their performance against the currently used promoter. The promoters were compared based on concentrate mass pull and gold and silver grade and recovery. Three of them have shown superior performance on a comparative basis and have been subjected to further optimization. SEM inspection of the precious metals grains lost in tailings was completed in parallel. The effect of reagents dosage on precious metals grades/recovery levels achieved by the best performing promoters is discussed.