Ampella Mining Limited announced the results of its Metallurgical Test Work Program for the 3.1 million ounce Konkera Gold Resource at Batie West, Burkina Faso.
An extensive metallurgical test program has been conducted for the Konkera Resource. Samples from Main/East, North and Kouglaga areas were tested at ALS Ammtec in Perth and HRL-Testing Laboratories in Brisbane.
1. Metallurgical Test Work Results;
The results of the Metallurgical Test Work Program confirm that excellent gold recoveries can be achieved at Konkera for all ore types using conventional metallurgical processes.
2. Oxide and Transition Ores;
Results of the test work on oxide and transition ores show that more than 30% of the gold is easily recoverable by conventional gravity methods with the remainder recoverable by conventional leaching at a modest grind size of P80 of 106µm. Overall gold recoveries for oxide ores range from 94 to 98%. Overall gold recoveries for transition ores range from 88 to 95%.
3. Sulphide Ores;
Sulphide ores at Kouglaga are amenable to gold extraction by conventional gravity and leaching methods at a grind size of P80 of 106µm. 50% of the gold is recoverable by conventional gravity methods and overall recoveries of up to 98% are achievable.
Initial leach tests on Konkera North sulphide ore shows that 80% of the gold is recoverable by leaching at a grind of P80 of 75 µm. The ore responds well to flotation with 92% of the gold reporting to a flotation concentrate comprising less than 6% of the feed mass.
Ultra fine grinding to a P80 of 10 µm and subsequent cyanide leaching tests on the North concentrate shows that 92% of the gold reporting to the concentrate is recoverable. In addition, leaching of the flotation tail shows that 78% of the gold reporting to flotation tails is recoverable providing an overall recovery of 91% using a combination of UFG and tails leaching for North sulphide ore.
Initial leach tests on Konkera Main/East shows that 56% of the gold is recoverable by leaching at a P80 of 75 µm. The ore responds well to flotation with 95% of the gold reporting to a flotation concentrate comprising less than 5% of the feed mass.
Ultra fine grinding to a P80 of 8 µm and subsequent cyanide leaching tests on the Main and East concentrate shows that 72% of the gold reporting to the concentrate is recoverable. In addition, leaching of the flotation tail shows that 67% of the gold reporting to flotation tails is recoverable providing an overall recovery of 71% using a combination of UFG and tails leaching.
Albion testing at HRL Testing Laboratories show that gold recoveries for Konkera North and Main/East flotation concentrate can be increased through a combination of sulphide oxidation and subsequent cyanide leaching. The Albion Process is a simple new process for the recovery of base and precious metals from sulphide ores. Preliminary results utilizing the Albion process indicate that in excess of 95% of the gold reporting to a flotation concentrate can be recovered following sulphide oxidation.
4. Flow Sheet Implications;
The test work results indicate that a simple conventional gravity and CIL flow sheet is suitable for treating all the oxide/transition ores as well as the Kouglaga sulphide ore. Treatment of the Konkera North and Main and East sulphide ore would require flotation and ultra fine grinding to improve CIL recoveries to an overall 84%. An oxidative treatment process on Konkera North and Main and East sulphide ores could increase recoveries to 95%.
Dr Paul Kitto MD of Ampella said that “The Company was very pleased with the final metallurgical results using conventional processing techniques. The very high recoveries from all oxide and transition ores, together with Kouglaga sulphide ores, mean that the Konkera Project has the potential to generate significant cash returns in the early years of operation. The overall recoveries for life of mine of between 84% for CIL and 95% for Albion, will provide the basis for a profitable long-life mining operation for the Company even without the addition of new resources from the two new discoveries at Foumbiri and Doubema announced in 2011 or from additional exploration success in 2012 along the 110km Batie West Shear Zone.”
