The environmental impact assessment (EIA) process for Denison Mines Corp’s 90%-owned Wheeler River project has formally begun with the acceptance by Canadian national and provincial regulators of the project description for the proposed in-situ leach (ISL) uranium and processing plant.
The company has also announced a series of non-binding memoranda of understanding (MoUs) with indigenous communities in support of the advancement of the project. These agreements formalize the parties’ intention to work together to identify practical means by which to avoid, mitigate, or otherwise address potential impacts of the project on indigenous rights and other interests, and to facilitate sharing in benefits from the project.
Denison CEO David Cates said acceptance by the Canadian Nuclear Safety Commission (CNSC) and Saskatchewan Ministry of Environment (SK MOE) was a “critical first step” for the development of Wheeler River. The company would continue to work with indigenous communities, regulatory agencies and the public during the environmental assessment process, he said.
“Successfully engaging, and entering into MoUs with local indigenous communities, ahead of the initiation of the EIA process, signals strong support for the advancement of Wheeler River in future years. We look forward to building on the relationships that we’ve established over the past several years to develop a collaborative vision for the future of the project.”
The CNSC and SK MOE are expected as far as possible to carry out a coordinated federal-provincial EIA, Denison said. A 2005 cooperation agreement allows for the production of a single environmental impact statement (EIS) for the project, which is intended to present the EIA’s finding in accordance with the requirements of both levels of government.
The CNSC has launched a public participation period on the project description, which it describes as involving a new uranium mining and processing operation located in the Athabasca Basin in northern Saskatchewan, about 600 kilometres north of the city of Saskatoon, and midway between Cameco Corporation’s Key Lake Mill and McArthur River Mine. Written comments must be submitted by 30 June.
According to Denison, Wheeler River is the largest undeveloped uranium project in northern Saskatchewan’s Athabasca Basin, with combined indicated mineral resources of 132.1 million pounds U3O8 (50,812 tU) at an average grade of 3.3% U3O8 plus inferred resources of 3 million pounds U3O8 at an average grade of 1.7%. These are in two high-grade deposits: the Phoenix deposit, which was discovered in 2008, and the Gryphon deposit, discovered in 2014. The project is a joint venture between 90%-owner Denison – which is also the operator – and JCU (Canada) Exploration Company Ltd, which owns the remaining 10%.
The project description is for the ISL recovery of uranium from the Phoenix deposit, and would mark the first use in Canada of the technique, which is sometimes referred to as in-situ recovery, or ISR. The Gryphon deposit is not suitable for ISL recovery, but its potential development is a “reasonably foreseeable” project and will therefore be included as part of the project’s cumulative effects assessment.
ISL methods are only applicable to sandstone-hosted uranium deposits located below the water table in a confined aquifer. For Wheeler River, this will involve injecting an acidic mining solution into the uranium deposit through a series of cased drill holes, or injection wells, to dissolve the uranium. The uranium-rich mining solution is recovered and pumped back up to surface through another set of cased drill holes called recovery wells and then processed to recover the uranium.
This will offer environmental and permitting advantages, particularly when compared to conventional uranium mining in Canada, Denison said. The Wheeler River ISL operation is expected to produce no tailings, generate very small volumes of waste rock, and has the potential for low volumes or possibly no water discharge to surface water bodies, as well as the potential to use the existing power grid to operate on a near zero carbon emissions basis, the company said.
It is also proposing the use of a “freeze wall” to encapsulate the ore zone and deposit and create an isolated mining chamber. This will prevent the mining solution from travelling into the regional groundwater system and at the same time prevent the regional groundwater from entering the mining chamber, and will streamline the mining process, minimize interaction with the environment, and facilitate controlled reclamation of the site at decommissioning, the company said.
“Taken together, the project has the potential to be one of the most environmentally friendly uranium mining and processing operations in the world,” Denison said.