Tailings Management Best Practice: A Case Study of the McClean Lake Jeb Tailings Management Facility
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Abstract
COGEMA Resources Inc. (which is part of the Areva Group) is a Canadian company with its head office in Saskatoon, Saskatchewan. It owns and operates mining and milling facilities in Northern Saskatchewan, which produce uranium concentrate. McClean Lake Operation commenced production in 1999 and its tailings management facility represents the state of the art for tailings management in the uranium industry in Canada. Tailings disposal has the potential to cause effects in the surrounding receiving environment primarily through migration of soluble constituents from the facility to surface water receptors. In-pit disposal of mill tailings has become the standard in the uranium mining industry in Northern Saskatchewan. This method of tailings management demonstrates advances in terms of worker radiation protection and containment of soluble constituents both during operations and into the long term.
Sub-aqueous deposition of tailings protects personnel from exposure to radiation and airborne emissions and prevents freezing of tailings, which can hinder consolidation. The continuous inflow of groundwater to the facility is achieved during operations, through control of water levels within the facility. This ensures hydrodynamic containment, which prevents migration of soluble radionuclides and heavy metals into the surrounding aquifer during operations.
The environmental performance of the decommissioned facility depends upon the rate of release of contaminants to the receiving environment. The rate of constituent loading to the receiving environment will ultimately be governed by the concentrations of soluble constituents within the tailings mass, the mechanisms for release from the tailings to the surrounding groundwater system, and transport of constituents within the groundwater pathway to the receiving environment. The tailings preparation process was designed to convert arsenic into a stable form to reduce soluble concentrations within the tailings mass. The design of the TMF itself relies on the high permeability sandstone unit to provide a preferential flow path for groundwater around the low permeability tailings mass. This provides a passive means of minimizing the long-term release of constituents from the decommissioned facility to the environment.
A comprehensive tailings optimization and validation program was developed to reduce uncertainties related to the performance of the tailinGs management facility associated with the chemical and physical properties of tailings. This paper will describe the JEB tailings management facility and provide a summary of the findings of this research program.
Sub-aqueous deposition of tailings protects personnel from exposure to radiation and airborne emissions and prevents freezing of tailings, which can hinder consolidation. The continuous inflow of groundwater to the facility is achieved during operations, through control of water levels within the facility. This ensures hydrodynamic containment, which prevents migration of soluble radionuclides and heavy metals into the surrounding aquifer during operations.
The environmental performance of the decommissioned facility depends upon the rate of release of contaminants to the receiving environment. The rate of constituent loading to the receiving environment will ultimately be governed by the concentrations of soluble constituents within the tailings mass, the mechanisms for release from the tailings to the surrounding groundwater system, and transport of constituents within the groundwater pathway to the receiving environment. The tailings preparation process was designed to convert arsenic into a stable form to reduce soluble concentrations within the tailings mass. The design of the TMF itself relies on the high permeability sandstone unit to provide a preferential flow path for groundwater around the low permeability tailings mass. This provides a passive means of minimizing the long-term release of constituents from the decommissioned facility to the environment.
A comprehensive tailings optimization and validation program was developed to reduce uncertainties related to the performance of the tailinGs management facility associated with the chemical and physical properties of tailings. This paper will describe the JEB tailings management facility and provide a summary of the findings of this research program.
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