Snow Lake Arsenic Stockpile
In December 2011, BacTech Environmental signed a contract with the Mines Branch of the Manitoba Department of Innovation, Energy and Mines to remediate a stockpile of arsenopyrite concentrate located in the community of Snow Lake in Northern Manitoba.
BacTech proposed a “no cost to the taxpayer” approach to the clean up. The Company would have recovered payable metals for its own account from the stockpile, while stabilizing the contained arsenic. The Company’s bio-oxidation technology has been used successfully in the gold industry for many years to aid the extraction of gold from arsenical concentrates, while stabilizing arsenic values into a benign form.
BacTech’s interest in the project stemmed from test work completed in 2010, in which bioleaching technology was determined to be well suited for the stabilization of the high levels of arsenic in the stockpile.
The Snow Lake stockpile was created in the 1950s as a by-product of gold production from the Nor Acme Mine. Due to the refractory nature of the ore and its high arsenic levels, it was decided at that time to float an arsenopyrite concentrate that would be processed at a later date. Based on an independent NI 43-101 report , the stockpile is estimated at approximately 300,000 tonnes, with an average grade of approximately 9.7 grams per tonne of gold. The stockpile is 6 m to 10 m high and encompasses an approximate area of 19,500 m2.
Since signing the contract with the government, BacTech engaged the services of Micon International Limited to provide an independent Economic Study for the proposed reclamation. In August 2012, the study was completed and preliminary results released. The final study was posted to Sedar in October (www.sedar.com) and is also available on this website in the Snow Lake NI 43-101 section.
There are three inherent problems with the Snow Lake project that, unfortunately, could not be overcome. First, the price of gold dropped dramatically thereby reducing the value of the concentrate going into the bioleach circuit.
Second, the iron to arsenic ratio, which should be 3:1 to make a benign ferric arsenate product, was only 1.8:1 The additional cost of adding ferric iron to the process raised the cost per ounce of production dramatically.
Finally, limestone, which is usually ubiquitous, apparently isn’t so in Manitoba. Bioleaching uses a lot of limestone to neutralize the acidic nature of the liquids in the tanks. The closest source to Snow Lake was 400 km away. Normally, $5-$10 per tonne, we were quoted prices, delivered to Snow Lake, of over $70 per tonne. The combination of these three factors led to the Company’s departure from the project.
We do want to go on record and state that the people of Snow lake were very welcoming to us and assisted us at every opportunity. There is an answer out there for this clean up but it will not be bioleaching.
Snow Lake NI 43-101
Show Snow Lake Reports and Applications
Notice of Environment Act Proposal
Environmental Approvals Branch
Conservation and Water Stewardship
Environmental Assessment Report: Remediation Project
BacTech Environmental Corporation
Submitted to Environmental Approvals Branch
Manitoba Conservation and Water Stewardship