Metallurgical Manager of Morila Mine, Peet Van Schalkwyk & Peter Simpson of Knelson Concentrators Africa hold an 18 kg gold bar resulting from the first 24 hour run of one of the KC-XD48 concentrators at Morila.
MORILA MINE, Mali - Affectionately known to many as "Morila the Gorilla", Morila Mine poured its first gold resulting from the gravity recovery circuit that comprises of two 150 metric tph Knelson KC- XD48 concentrators. Development of the mine, which is jointly owned by Anglogold Ltd and Randgold Resources Ltd, began in August 1999. A fast-track project carried out by Metallurgical Design and Management (MDM) of South Africa ensured that the recovery plant was brought on stream within budget and on time in mid October 2000.
Both Knelson XD48 concentrators were fully commissioned by October 18th, whilst commissioning of most of the plant was still ongoing. At time of writing, the Knelsons produced 161 kg of gold in 6 days (an average of 27 kg/day) despite mill availability of only 87% (mill downtime due to normal commissioning and teething problems). On a mill feed tonnage basis, the recovery to date equates to approximately 4.5 g/t, which is well in excess of design criteria.
Peter Simpson of Knelson Concentrators Africa who carried out the commissioning of the two concentrators described his experience when the mine released the results. "In 13 years of representing Knelson Concentrators, I have never yet seen a primary concentrate so visibly rich in free gold. In fact, this poses somewhat of a problem right now as the Gemeni 1000 bullion table which is being used to achieve smeltable secondary concentrates simply cannot cope," Simpson noted. "The sheer richness of the concentrate forces a high proportion of flake gold to table tails, that is then recycled to the mill. As a conservative estimate, I would guess that the table is running at no more than 70% recovery, which means that effectively the Knelsons are probably recovering more like 35-40 kg gold per day ."
"Fortunately the table is an interim measure only, and the imminent commissioning of a concentrate intense cyanidation plant will hopefully alleviate the problem," said Peet Van Schalkwyk, Metallurgical Manager. "It's a nice problem to have. Were producing too much gold! The gold is not lost as it simply recirculates, and we look forward to producing even more. The cashflow benefits of quick gravity gold to a project such as this are very obvious."
Peet Van Schalkwyk also noted, "The two Knelson XD48 concentrators are currently operating at rough-tuned settings, and ongoing optimization of parameters is likely to further improve recovery. The mine has ordered a third KC-XD48 which when installed in a few weeks time will further boost gravity recovery."
Brian Putland, Principal Metallurgist - Orway Mineral Consultants, Australia
"I previously installed a 30 " knelson on a 5 g/t gold ore and achieved 70% gravity gold recovery. They are excellent technology and I'm very confortable recommending their use in gravity seperation applications." ...more > >