Roscan Gold Corporation (TSXV: ROS) (OTC Pink: RCGCF) has received positive results from the metallurgical test work programme completed on samples from gold prospects at Mankouke South (MS1), Mankouke Center- Kandiole (KN1) and the Kabaya (KB1- KB2) within the company’s land package called Kandiole Projects located in west Mali, Africa.
President and CEO, Nana Sangmuah, said all of the samples representing the deposits (Mankouke South MS1 and Center, Kandiole KN1 and Kabaya KB1-KB2) tested in this programme exhibit non-refractory metallurgical features, indicating that a simple, industry-standard cyanide leach process provides excellent gold and silver extraction.
- Total gold recoveries by gravity, plus 48 hours of CIL on all prospects, have averaged 97% for oxide (saprolite) samples, 89% for a transition sample and 90% for fresh mineralisation samples.
- Flagship Mankouke South achieved 97.6% in the oxide and 92.9% in fresh rock.
- Both Oxide and Fresh mineralization are amenable to gravity concentration to recover free gold within the milling circuit.
- The gravity recovery average from all samples and CIL tests is 23%.
- The coarse ore leach tests in two Kabaya saprolite samples, to examine heap leach amenability, provided an average of 79% recovery of gold and 93 % silver after 8 days.
- One sample reached 88.4% gold recovery after 72 hours.
“This is a major de-risking milestone for the Kandiole project confirming simple processing flow sheet with Oxide recoveries 97% including average gravity recoveries of 23% and up to 58% in certain deposits,” Mr Sangmuah said.
“We are also encouraged by the potential for silver by-product credits at our relatively lower grade Kabaya deposit which should further bolster project economics.”
All results from the gravity plus carbon in leach tests were positive, indicating that:
- The program included testing of gravity separation, grindability and grind size variability, agitated leach kinetics, Carbon in Leach (CIL) and for two of the composites, Heap Leaching amenability determinations. Results from this metallurgical test work provide significant progress in the Resources estimation process.
- A simple gold processing flowsheet for these deposits (Mankouke South MS1 and Center – Kandiole KN1 – Kabaya KB1- KB2) is applicable and will be considered in the maiden Mineral Resource estimation.
- The CIL results for the oxide zone, which carries a large proportion of the mineralization (70-80%) at Mankouke South MS1 and Center – Kandiole KN1 – Kabaya KB1- KB2, are particularly favorable with 97% total gold recovery.
- From different metallurgical tests, in Mankouke South, the most important portion of the overall mineralization, the gravity recovery reached 27% in saprolite and 25% in transition-fresh rock.
- In Kandiole, the gravity extraction varies from 48 % to 58%, and in Kabaya the average is 23.3%.
- Silver content of the Kabaya samples reaches 8.6 g/t with an average of 3.6 g/t and recovery in the gravity plus leach tests is above 95% for the saprolite.
- After further analysis of more Kabaya samples, the assays could demonstrate that Silver is a potential economic by-product.
- Encouraging leach kinetics indicate excellent gold extraction within 24 hours and averages only 0.5% below the extraction obtained in the maximum time of 48 hours.
- Bond Ball Mill Grindability of 3.3-6.2 kWh/t (saprolite) – 10.4-21.5 kWh/t (transition-fresh rock) is comparable to other gold operations in the region.
- Overall, the cyanide and lime consumptions indicated in this preliminary testing seem typical for these types of deposits.
In total, 12 composite samples of 20 to 40 kg have been sent for the metallurgical test work: two saprolite (oxide), one transition and two fresh rock samples from Mankouke, 1 saprolite (oxide) sample from Mankouke Centre, one saprolite (oxide) sample from Kandiole and four saprolite (oxide) and one fresh rock sample from Kabaya. Each composite comprised 1/3 of low-grade (0.3-1 g/t), 1/3 of medium-grade (1-3 g/t) and 1/3 high-grade (> 3g/t) drill sample intervals (all g/t values stated are for gold only).
For Mankouke South, the fresh rock has been separated between sedimentary and felsic intrusive rocks. Most of the composite samples have been prepared from ¼ of NQ diamond drill core, one composite was RC samples only and three have been prepared with a mix of core and RC samples. All individual samples which comprise the composites are well distributed spatially in the mineralisation.
The test work was undertaken by Base Metallurgical Laboratories, Vancouver, Canada 200-970 McMaster Way, Kamloops, BC, Canada, V2C 6K2. The samples have been selected by Pascal van Osta, Roscan’s VP Exploration.
For further information please visit: https://roscan.ca/