Resource World Magazine

64 www.resourceworld.com D E C E M B E R / J A N U A R Y 2 0 2 0 MININGWORLD Gekko commercializes OLGA – proven gold detecting system by Kathrine Moore GEKKO SYSTEMS, headquartered in Australia, with offices in eight countries, serves the mining industry by developing energy efficient, capital effective flowsheets, equipment, modular plants, and service solutions for gold, coal and polymetallic applications. In the summer of 2017, Gekko announced they were partnering with CSIRO (Commonwealth Scientific and Industrial Research Organisation), Australia's national science research agency, to commercialize a technology that can determine the gold content in mineral processing in real time. OLGA (OnLine Gold Analyser) is described in a Gekko August 2017 news release as built upon "new X-ray fluorescence tech- niques patented by CSIRO. It is capable of detecting ultra-low levels of gold and other elements from a continuous process stream." Since that announcement, OLGA has performed successfully in field trials at a gold mine in Queensland, Australia. Trials determined that OLGA can detect gold in slurries at 10 parts per billion with its pair of patented X-ray lenses that magnify the slurry's gold signal as it passes through a tank. The lenses reduce background levels of other elements, allowing direct real time measurement of gold (down to sub-ppm levels) in both slur- ries and solutions. The company states that OLGA detects gold in slurry with 1,000 times greater accuracy than conventional methods that have a detection limit that is usually in the tens to hundreds of parts-per-million range. Richard Goldberg, Gekko's head of innovation and collabo- ration said, "We know that gold grade can vary over relatively short periods and that it will do so between the samples taken as part of traditional process control regimes … As the results from those samples are also delayed, they are unlikely to accurately reflect the changes occurring in the process stream." He added, "OLGA's value stems from its ability to provide important infor- mation in near real time. In effect, the operators of a plant will no longer be blind to changes in its performance." OLGA delivers an updated sub-parts per million (ppm) Au measurement every ten minutes, providing insights into process performance that are unobtainable with assayed sample sets. Gekko announced a significant milestone achievement on October 25, 2019. The success of field trials has resulted in the sale and permanent installation of a unit at Evolution Mining's [EVN-ASX] Mt Carlton operation 150 km south of Townsville, Qeensland, Australia. The release stated that OLGA was installed and trialed on a number of slurry streams including feed and tailings before the unit was purchased. Evolution Mining's Mt Carlton gold mine was commissioned in 2013 and is one of the world's highest-grade open pit gold mines. The mine has pro- duced more than 100,000 ounces of gold for the past three years. The company states, on their website, "During the year we achieved a world first by trialing an online gold analysis (OLGA) technology developed by the CSIRO. This gives the processing team the ability to adjust processing parameters effectively, in real time, with the effect of reducing losses to tailings." According to Andrew Dixon, Gekko's performance consultant manager, "the new system is proving its triple bottom line creden- tials. Economically it allows you to control the processing plant to allow maximum efficiency of gold recovery." He explained, "This has environmental benefits as well. It will allow you to optimize reagent additions and to reduce any emissions from the plant that may have to be detoxified or treated to be made safe…This means that a plant will end up with less reagent chemicals in the tailings." According to Gekko, OLGA is modular, skid mounted, and all components are pre-integrated making OLGA fast and easy to install. The system is delivered to site fully pre-calibrated using a range of samples representative of the plant stream allowing fast installation and commissioning into the existing process plant. As the system measures a sample slurry stream, it can be taken offline without interruption to production. n Gekko Systems' OLGA (OnLine Gold Analyser). Photo Courtesy of Gekko Systems.

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