Show & Tell

• Sulphidization:

This stage entails the addition of a sulphide reagent to precipitate copper as a copper sulphide concentrate.

Copper and gypsum precipitates are thickened and after dewatering, the copper can be shipped as a saleable product.

Although SART is a widely known technology, it has not been widely implemented to date. SART, however, is now gaining acceptance in an environment of strong gold prices and with proven application of SART at several sites around the world. This has led gold producers to look closely at it as an enabling technology that can improve gold yields, reduce operating costs and minimize the environmental footprint for gold mines that have copper and zinc-complexed gold ores. Given these conditions, SART has the ability to improve the project economics of new, closed or operating gold mines.

While all four stages of the process are important in achieving a balanced and metallurgically efficient result, the sulphide precipitation circuit and its control are particularly critical. Producing high-grade sulphide products with good settling and filtration characteristics through the precipitation of metals has often been challenging.

Our company is a world leader in sulphide precipitation process technologies. For the past decade, we have been providing mining companies around the world with sulphide precipitation processes that effectively remove dissolved metals from waste water, producing clean water that can be safely discharged to the environment. In addition, the metals can be recovered and sold to generate an incremental revenue stream, thereby creating a sustainable treatment process.

Since introducing this sulphide precipitation technology to the market in 2001, we have been working with an increasing number of mining operations in South America, Asia, North America and Australia, to address various waste water treatment challenges.

In this respect, our experience from designing and operating commercial sulphide precipitation plants at eight different mine sites around the world has proven invaluable to the application of the SART process. In the past three years, we have successfully designed and commissioned two SART plants.

The first was at a small gold mine in Mexico. Following construction and commissioning in 2008, the plant entered a six-month trial period during which it produced a high-grade saleable copper concentrate containing up to 65% copper, while up to 70% of weak acid dissociable cyanide in the SART feed was regenerated and recycled for gold recovery. As a result, gold recovery was enhanced with improved purity of the gold dore, the quantity of cyanide required was reduced and incremental revenues were generated from the recovered copper.

The plant in Mexico was followed by the design and commissioning of another plant for a gold mine in Turkey, with both open pit and underground operations.

When we began working on the project, the mine had been operational but had been unable to process some of the ore due to the presence of high concentrations of cyanide-soluble copper. The presence of copper-cyanide complexes in the tailings solution also interfered with cyanide destruction which could have resulted in the final discharge exceeding approved discharge limits.

In applying SART, the gold mine was able to improve gold yields, reduce operational costs and reduce the overall quantity of cyanide used in gold leaching, thereby reducing the long-term environmental liabilities associated with cyanide destruction.

Commissioned in 2010, the plant has recovered more than 250 tonnes of high grade copper which has generated a significant incremental revenue stream for the operation. Furthermore, the gold mining company has been able to significantly increase its gold production.

Following the success of these SART projects, there is growing interest in applying this Canadian technology to a number of gold mining initiatives. As gold prices continue to stay strong, and easily mined reserves become depleted, the business case for SART is now well established, further solidifying Canada’s reputation as a technology innovator in the mining sector.

*David Kratchville is the President and Chief Operating Officer of BioteQ Environmental Technologies, a Vancouver-based water treatment company.