Jessica Smith
With the launch of an environmental assessment (EA), Osisko Hammond Reef Gold held its first public consultation here June 18, with reps from the company and environmental consultant Golder Associates outlining gold mine plans to around 250 attendees. The final submission of a project description – an overview of current and planned studies of impacts to water quality and quantity, fish, animals, vegetation, terrain and air quality – to the Canadian Environmental Assessment Agency launched the permitting process for the proposed mine.
The EA process will require numerous permits from federal and provincial agencies and span at least the next two years. It includes the study of the socio-economic impacts of a mine in Atikokan and adjacent First Nation communities. As part of that, the company will conduct an ongoing series of public meetings and stakeholder workshops both in town and with FNs to hear feedback on the project.
“[This open house] is part of a larger initiative of doing proper public consultation – it’s sort of an opening of this process, which will evolve,” said OHRG project manager Anne Charland.
The company is planning to mine at two open pits located in Marmion Lake’s Lynxhead Bay peninsula at the A and 41 zones, to depths of 345 metres and 225 m respectively.
Mine creation involves draining Mitta Lake, a small, 17 hectare water body which sits atop the main part of the deposit in the A zone. Where feasible, lake sediments and soils will be stockpiled for future reclamation. Current study indicates the lake hosts a small number of forage (non-sport) fish; no other lakes, streams or ponds have yet been mapped, except for the far east end of the 41 Zone, where the last 25 metres of pit strike length that links to a marsh which drains into Marmion’s Sawbill Bay.
The mine plan includes a crushing plant, a waste rock stockpile, explosives plant, ball grinding mill and gold extraction process facilities – which includes the use and destruction of cyanide, before the tailings are pumped to a management facility for solids disposal. The non acid-generating solids will be permanently impounded on-site, notes the report.
The company’s “base case” tailings site is located 6 km northeast of the project and takes advantage of a natural northern ridge, requiring only the construction of berms along the south, west and east sides of the containment site.
Other options being considered just further NE and east of the mine. The preferred site will result in the loss of small streams that drain southwest into the upper end of Sawbill Bay and southeast into the Lizard Lake watershed.
The EA will require geochemical testing of effluent quality to determine if further treatment is required before releasing the treated effluent into Marmion Lake, preferably through Lynxhead Narrows.
“The final effluent from the tailings waste management area will need to meet discharge criteria and the design may need to include a polishing pond and/or further treatment prior to discharge,” notes the report.
Water use
In terms of water needs, OHRG is conducting a detailed plan for accessing up to 22,000,000 litres daily from Upper Marmion for ore processing, but anticipates requiring closer to 3,200,000 daily, with as much water as possible reclaimed from the tailings basin and seepage collection systems which capture run-off.
Water balance calculations are currently underway to determine the viability of accessing water from the lake (the proposed intake would be on the eastern shore); the study will take into account fisheries and an agreement with downstream hydro electric operators.
The study will also investigate alternate water sources during low water levels such as construction of an on-site reservoir, a pipeline outside the Marmion Reservoir, or consideration of other brown water sources.
Air quality
Air quality is another important piece of the environmental study: pollution would be created from dust generated by mining activities and gold extraction; the smelter will be required to meet provincial air quality standards.
The report indicates plans to store hazardous waste in sealed containers in lined, bermed areas for shipment to off-site licenced facilities, and discussions with the Town to send non-hazardous waste to a municipal landfill, as the municipality plans to identify a new site this year.
Finally, the project description also outlines current plans for mine closure and rehabilitation, including permanent rehabilitation of the tailings area, flooding of the two open pits and vegetative recovering of major disturbed areas, with ongoing physical and chemical site monitoring.
A more detailed closure plan and time line will be created over time, notes the company. The current project description is available at www.osisko.com/pdfs/10-1118-0020_Project_Description-text[8APR11].pdf
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