Burkina Faso, West Africa
Studies | Engineering Design
BFS and Detailed Design
Yaramoko Gold Project – At Mintrex nothing makes us happier than witnessing our clients’ successes, and for one of our clients, Roxgold Inc. the successes just keep on coming. Since breaking ground at their Yaramoko Gold Mine on the 7th April 2015, they achieved their first gold pour just thirteen months later and have declared commercial production with 32,987 ounces of gold produced in the third quarter of 2016.
“Bringing Yaramoko into production ahead of schedule and under budget is an achievement we can all be proud of, and I want to thank Roxgold’s employees and contractors for their continuing hard work and dedication.” commented John Dorward, Roxgold’s President and CEO.
Our involvment in the Yaramoko project began in 2013 when we were engaged by Roxgold Inc., to prepare the process plant and infrastructure component of the Bankable Feasibility Study (BFS). In August 2013, Mintrex engineers Ian Kerr and Naim Abou-Rjeily travelled to Burkina Faso, West Africa, approximately 180km southwest of the capital Ouagadougou to visit the proposed site for the purpose of gathering local knowledge around conditions, suppliers and contractors to support an accurate estimate.
Mintrex Project Manager Naim Abou-Rjeily commented “The site visit was of prime importance to allow the assessment of the local capabilities and the logistics requirement for access and delivery to the Yaramoko site. It provided valuable contacts for local contractors which were used to obtain pricing for the feasibility study and assessment of local labour skills to allow the construction of the processing plant. In addition the site visit was key to develop a better understanding of the social and environmental impact of the project on the local community and the various regulatory requirements to obtain project approvals.”
On completion of the BFS in April 2014, Mintrex commenced the detailed design of the treatment plant. Focus was placed on supplying Roxgold with a fit for purpose design they were able to provide to contractors with confidence the plant would be built to specifications and produce desired outputs as defined in the BFS. Mintrex executed the detailed design for a fixed price, and completed it in September 2014.
The process plant was designed to process 0.27 Mtpa of underground high grade (~12g Au/t) ore. The comminution circuit includes single stage crushing, with provision in the layout for future secondary crushing should the ore characteristics at depth, or future plant expansion, require this. The crushing circuit is followed by single stage SAG grinding (SS SAG), gravity recovery of free gold from a portion of the cyclone underflow, and a five stage CIL circuit preceded by a pre-leach tank. The stripping plant includes a 1.5 tonne split AARL elution circuit with electrowinning and smelting. A tailings thickener is included to recover both water and reagents prior to discharge to the lined tailings storage facility.
Roxgold’s onsite engineer commented “Many compliments were given regarding the thoroughness and completeness of the design as well as the quality of the shop detailed drawings. This was definitely a contributing factor for the construction being completed ahead of schedule.”
The Yaramoko mine was built on budget, ahead of schedule and is one of the highest grade gold mines in the world. Since completion, the plant has operated at or above nameplate levels, with both plant operating time and unit throughput rates meeting or exceeding design of 91.7% and 34 tonnes per hour respectively. Similarly, gold recoveries, averaging 97.2%, have met or exceeded the design rate of 96.9%.
Yaramoko gold mine achieved commercial production as a result of the successful mining and extraction rates achieved since commencing stoping in August and September 2016, together with high processing plant availabilities and gold recoveries above Feasibility Study assumptions.
Roxgold COO, Paul Criddle stated “Mintrex have been solid partners throughout the development of Yaramoko. They have been flexible and cognizant of Roxgold’s needs throughout. The finished product being our processing facility and infrastructure is one that has started up and ramped up without incident and one that Roxgold is very proud of.”