McClean Lake is an open pit uranium mine in northern Saskatchewan. The property consists of two mineral leases covering an area of 980 ha and nine mineral claims covering an area of 3,148 ha. McClean Lake has the newest, most technologically advanced uranium mill in the world.
McClean Lake is a joint venture of AREVA Resources Canada (Cogema), Denison Mines and OURD (Canada). The mine is operated by AREVA.
The McClean Lake mine is in northern Saskatchewan, 700 kilometres north of Saskatoon.
Highway 11 goes to Prince Albert, then Highway 2 to La Ronge. North of La Ronge, the population is getting very sparce and Highway 102 deteriorates. This area, on the east side of the Athabasca Basin, has small, remote communities, with about 4,000 residents, most of them Aboriginal. Eighty km to the north, the road joins Route 905, a bumpy 300 km haul road that leads to the uranium mines in the area of Wollaston Lake.
Northern Saskatchewan is a land of lakes (about 100,000 of them) and low-lying land scraped by glaciation. Drainage from the region moves both into Hudson's Bay to the northeast and the Arctic Ocean to the northwest.
As with the other mines in the Athabasca Basin, McClean Lake is a fly in / fly out operation. Of the 265 people employed at the mine, more than half are residents of northern Saskatchewan, flying in for a seven day shift, then flying out to go home.
Geology and Mineralization
The uranium deposits at McClean Lake lie near the eastern margin of the Athabasca basin in the Churchill Structural Province of the Canadian Shield. The bedrock geology of the area consists of Precambrian gneisses unconformably overlain by flat lying unmetamorphosed sandstones and conglomerates of the Athabasca Group. The Precambrian basement complex consists of an overlying Aphebian-aged supracrustal metasedimentary unit infolded into the older Archean gneisses. The younger Helikian- aged Athabasca sandstone was deposited onto this basement complex. The basement surface is marked by a paleoweathered zone with lateritic characteristics referred to as regolith.
There are a number of uraniferous zones on the property. Depths of the unconformity are shallow, rarely exceeding 175 metres, making open pit mining feasible.
McClean Lake includes the Sue A, B, C and E, the McClean North, the JEB deposits, and other prospects. Two of these deposits, JEB and Sue C, have been mined out. The JEB pit has been converted into the JEB tailings management facility and will receive tailings from Midwest, Cigar Lake, and McClean Lake ores. Special low-grade uranium-bearing waste from the Sue C deposit has been deposited in the mined-out Sue C pit.
Open pit mining at McClean Lake restarted in 2005, at the Sue A and Sue E deposits. Uranium ore from the Sue open pit mines is transported by 100 ton trucks to be stockpiled at the JEB mill.
All of the low-grade special waste that was recovered while mining the JEB and Sue C pits is being disposed of in the mined out Sue C pit.
The JEB mill was commissioned in 1997 at a cost of $250 million. The mill initially had a production rate of 6 million pounds per year which will be expanded to 12 million pounds in 2007. The mill is expected to run for 40 years.
It is designed for health, safety and environmental protection for the short and long term. The plant buildings have been grouped by industrial risks, to reduce exposure, with shielding, containment, ventilation and innovative work procedures to protect the workers.
Uranium ore is transported by 100 ton trucks to be stockpiled at the JEB mill. The ore mixed with water is ground to a fine sand, and the mixture or slurry is pumped to the leach tanks. In the leaching process, sulphuric acid and hydrogen peroxide are added to the slurry to dissolve the uranium from the ore. Waste solids are separated from the product solution in the countercurrent decantation (CCD) process. Solids are neutralized and pumped to the tailings facility.
The solution containing uranium is put through sand filters for clarification. Clarified solution is processed in the solvent extraction (SX) circuit for purification and concentration. An organic solution is used to extract the uranium. Ammonium sulphate then strips the uranium from the organic solution, which is recycled through the SX circuit. Ammonia gas precipitates the uranium out of the purified product solution. Excess moisture is removed in the dryer (calciner). The remaining uranium concentrate or yellowcake, which is about 99% UO3 or 84% uranium, is shipped in barrels to a refinery.
Environment and Community
Northern residents monitor the environmental impact of McClean Lake and other operations through the Athabasca Working Group's Community Environmental Monitoring Program. The program trains and equips community members to collect samples from the air, water, lake sediment, plants and animals in the vicinity of their communities. Three years of monitoring show no environmental effects from uranium mining.
Traditional land use in the Athabasca region is hunting, fishing and trapping. Mining at McClean Lake temporarily curtails this and compensation agreements have been signed with trappers.
Within the broader Athabasca region, the Impact Management Agreement between the Athabasca communities and First Nations, Cogema, and Cameco, includes an environmental protection and compensation agreement. The companies agreed to take all reasonably required measures to protect the environment. If uranium project emissions damage natural resources, the companies will clean up the damage and compensate individuals or communities that have suffered a loss.
Once mining ends, the area will be reclaimed to blend with the surrounding countryside.
McClean Lake received ISO 14001 certification in 2000.