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Cyanide-Free Gold Extraction Process

The mining industry is facing growing pressure to improve its current practices and to develop environmentally-friendly alternative processes to reduce environmental liabilities. Several mining jurisdictions around the world have banned or restricted the use of cyanide. As a consequence, mining companies are struggling to obtain the permits for their projects due to increasing environmental and social concerns related to the use of cyanide.

The Corporation’s patented process is providing an alternative to the conventional cyanidation process for precious metal extraction.

The Corporation has developed a novel process which uses chlorination in order to extract precious metals from refractory minerals. The Corporation’s process operates in a closed loop circuit, which implies that no liquid effluents are generated, eliminating the need for costly tailings ponds. The chemistry and process design allows precious metal deposits containing base metals to be treated viably. The tailings from the process are inert from toxic substances, sulphide depleted and not acid generating, and as a result, meet environmental norms. The efficiency of the process has demonstrated high gold recoveries within a fraction of the time needed for cyanidation to obtain similar results.

Chlorination Circuit Overview

DST has completed the construction of its Demonstration plant. The plant is located in Thetford-Mines and has a nominal capacity of 15 Tonnes per day of mineral concentrate, and the ability to extract gold and silver utilizing DST’s chlorination technology.



The efficiency of the process, coupled with its operating conditions, plant size, construction material allow for competitive operating and capital costs. DST received, from environment Canada, through the Canadian Environment Technology Validation Program, an independent certification of the performances of its cyanide-free gold extraction process.


Since the foundation of the company in 1997, the technology has evolved from laboratory experiment to optimization at the industrial scale.