Tag Archives: InLine Leach Reactor

Gekko InLine Leach Reactor heads to Barrick Gold’s Bulyanhulu

Gekko has announced the purchase of an InLine Leach Reactor (ILR) for the Bulyanhulu gold mine, in the north-western region of Tanzania within the Kahama district, an operation under the ownership and management of Barrick Gold.

The introduction of the ILR to this location is a significant development, building upon the success of its implementation at various other mines operated by Barrick, including Hemlo, Kibali and Loulo-Gounkoto, Gekko says.

The ILR’s innovative design and efficient mineral leaching chemistry is providing high gold recoveries and production improvements to many operations worldwide, Gekko says. ILR orders have continued to respond positively to strong gold prices, with interest from a range of milling operations across the globe including North America, South America and Africa.

The ILR can be retrofitted into any gold grinding circuit, with the unit receiving gravity concentrates or flotation concentrates into a fully enclosed rolling drum. Inside the drum, the ore concentrates are mixed typically with a 1-2% sodium cyanide solution and an oxidant, known as intensive leaching. Specialised baffles inside the drum keep the solids in constant contact with the chemical solution providing a high shear environment. The correct combination of chemicals and concentrate, plus the rolling action of the drum, creates a highly efficient leaching reaction, Gekk0 says. This drives faster kinetics primarily through mixing and attrition which is critical to remove the oxidation layer away from the surface of the gold particles and allow enriched solution containing the required reagents to access fresh. Leach rate can be directly correlated to the attrition energy absorbed, according to Gekko.

Lifters inside the ILR drum mechanically agitate the slurry, forming an oxidant-rich zone with high solids-liquids mixing for leaching. Gekko says it has conducted multiple comparisons on the scale-up between bottle rolls and site data, consistently demonstrating that the ILR has performed equal to, or in some cases better, than laboratory bottle rolls.

The Batch and the Continuous ILRs work to chemically leach metal from ore concentrates using the same leaching principle. The ILR’s horizontal “rolling bottle” design keeps the concentrates in suspension and continuously mixes to accelerate the chemical reaction within the solution. The rolling bottle provides a pure mixing zone, preventing the risk of the solution short circuiting, the company explains.

When leaching in the batch units is complete, the pregnant ‘metal-rich’ solution is clarified and transferred to an electrowinning circuit. With the continuous units, there is an additional process route. The options include the pregnant solution reporting to carbon columns, resin columns, Merril Crowe circuits and in some cases direct electrowinning can still be applied. The barren residual solution can report back to the circuit, detoxification process, recycled or in some cases a combination is applied.

Gekko commissions third InLine Leach Reactor at New Liberty gold mine

Gekko Systems says a third InLine Leach Reactor (ILR) has been successfully commissioned at Avesoro Resources’ New Liberty gold mine in Liberia.

This installation, expected to further enhance gold recovery and decrease processing costs at Liberia’s first and largest commercial gold mine, is one of several Gekko has completed across Africa. Other notable ILR deployments have been witnessed at West African Resources’ Sanbrado gold mine in Burkina Faso and Asante Gold’s Bibiani gold mine in Ghana.

The latest ILR installation at New Liberty has been achieved thanks to the hard work of Gekko Senior Process Engineer, Jacob Asare, and the team at the mine, Gekko said.

The ILR is an automated, high-performance leaching system that effectively recovers gold from concentrates, and is widely used in the mining industry due to its high gold recovery rates, Gekko explained.

Second Gekko InLine Leach Reactor heads to West African Resources’ Sanbrado mine

Gekko says a second InLine Leach Reactor (ILR) has been ordered by West African Resources for its 90%-owned Sanbrado gold mine in Burkina Faso.

The order is one of several to have emerged on the back of strong gold prices, with interest from a range of milling operations across the globe including Russia, North America, South America and Africa, Gekko says.

First developed in 1997, the ILR has provided an alternative from traditional physical separation steps, such as using recovery tables, into a lucrative chemical separation process.

It offers superior recoveries in a proven, high efficiency, safe and highly secure system, according to the company.

Available as a completely automated batch model for processing high grade gravity gold concentrates, the ILR can also be configured as a continuous model for treating high throughput gold, silver and complex sulphide concentrates from InLine Pressure Jigs and flotation circuits.

“The ILR’s innovative design and unparalleled flexibility in gold and silver leaching chemistry is providing cost and production benefits to operations across more than 40 countries across the globe,” Gekko said.

Construction on Sanbrado commenced in late 2018, with first gold poured in March 2020, six months ahead schedule and $20 million under budget.

West African anticipates Sanbrado will produce between 250,000-280,000 oz of gold at all-in sustaining costs of $720-800/oz.

The company says: “The estimated operating costs for the project highlight that the project will be a conventional, low cost and high margin operation. This is a result of high grade ore from M1 South and the significant proportion of oxide and transition material in the mine schedule and the free milling nature of all ore types (average life of mine recovery of 93%), low reagent consumption and a high component of gravity recoverable gold.”