BacTech Environmental Corp has shipped approximately 150 kg of arsenopyrite gold concentrate to Laurentian University in Canada. With the supervision of Inspectorate Ecuador (subsidiary of Bureau Veritas), the concentrates were collected from various flotation plants in Ponce Enriquez, southern Ecuador. In addition to concentrate, smaller samples of oxidised rock and unprocessed arsenopyritic ore were shipped.
The material contains various levels of arsenic and will be subject to a test work program aimed at demonstrating the economic, environmental and technical viability of using BacTech’s Bioleaching Technology as a pre-treatment method for gold extraction. The test work will be conducted and partially funded under the Ontario government’s Center of Excellence program.
BacTech is investigating the use of bioleaching as a substitute for traditional processing methods which includes the current use of mercury in the gold recovery process. As it stands, artisanal miners have created an environmental problem in southern Ecuador, using mercury to obtain gold and silver from refractory ore with poor recoveries. To increase recoveries, tolling plants have installed flotation circuits in the area, and artisanal miners are being paid more for their product by selling ore to the flotation plants, instead of using mercury.
A major issue that has arisen is the creation of very high grade arsenic concentrates which severely diminish the market value due to the arsenic. The company believes it can capture the discount by implementing BACOX bioleaching technology in the area. Bioleaching can effectively stabilise the arsenic, oxidise the concentrates, and produce gold/silver doré bars.
The test work will take place in Sudbury, Ontario at Laurentian University, under the guidance of BacTech’s Dr Paul Miller and Laurentian’s Dr Nadia Mykyczuk. Results are expected in six months from the commencement of the test work.
Should bioleaching prove to be a suitable process for treating high grade arsenopyrite, BacTech will move towards constructing a bioleach facility in Ponce Enriquez. Given the fact flotation plants are already operating in the area, the capital costs should be reduced as the company would not be obligated to install crushing, grinding and flotation, steps that would normally be associated with a bioleach plant.
From BacTech’s perspective, buying material that is already concentrated provides easy access to product and reduced equipment size. At present, arsenopyrite concentrates are being shipped to Asia for processing, and buyers pay as little as 45-50% of the metal value of the concentrate.
BacTech holds the perpetual, exclusive, royalty-free rights to use the patented BACOX bioleaching technology for the reclamation of tailings and mining waste materials. The company’s principal focus is a high-grade silver/copper/tin tailings project called Telamayu, located in Atocha, Bolivia (pictured), in association with COMIBOL, the state mining group.
