Summary:
Lithium is currently produced from either conventional hard rock mining of pegmatites or the evapo-concentration of subsurface brine.
The lithium production target across Saskatchewan occurs in the form of subsurface brines stored within sedimentary rocks. Huff (2019) has divided the Alberta Basin brines into Western and Central regimes.
During Devonian time in what is now western Canada, the Western-regime brines were dominated by the dissolution of halite near open-marine sea water. The brine concentrations were undersaturated in halite due to the periodic dilution of the brine by open sea water. Brines derived from sea water traversing the Western-regime show evidence of evapo-concentration not exceeding that of halite saturation. Lithium enrichment of Western-regime brines likely reflects the contribution of lithium enriched hydrothermal fluids.
Brine concentrations present in the Central-regime may reflect progressively increasing evapo-concentration of sea water and the subsequent precipitation of salts. Including potash and lithium salts, the Central-regime brines in southern Saskatchewan represent the most highly evapoconcentrated sea water that interacted with late-stage evaporite minerals. Lithium enrichment of Central-regime brines may reflect dissolution of lithium enriched late-stage evaporite minerals.
The Devonian-aged Duperow Formation is the primary aquifer that the Company will be targeting for lithium enriched brines across the Kindersley Lithium Project (KLP). Devonian-aged rocks extend in the subsurface across the majority of western Canada and the central United States. These rocks are overlain by younger-aged sediments including Mississippian, Jurassic, Cretaceous, Tertiary and Pleistocene strata. Regionally, the Devonian is segregated into three series/epochs including the Upper, Middle and Lower Devonian. Further subdivision of the Devonian based on stage/age included defining individual groups associated across western Saskatchewan which include:
• Upper Devonian – Three Forks Group, Saskatchewan Group, and Manitoba Group; and
• Middle Devonian – Elk Point Group.
Each associated Devonian group can further be segregated into individual formations including:
• Three Forks Group – Big Valley and Torquay;
• Saskatchewan Group – Birdbear, Ireton, and Duperow;
• Manitoba Group – Souris River, 1st Red Bed, Dawson Bay, and 2nd Red Bed; and
• Elk Point Group – Prairie Evaporite, Winnipegosis, and Ashern.
The Saskatchewan Group contains multiple lithologies observed within each individual defined formation including:
• Birdbear – limestone, dolomite limestone and dolomite;
• Ireton – shale; and
• Duperow – limestone, dolomite limestone, calcareous dolomite, dolomite, marlstones, anhydrite,
and salt.
The Saskatchewan Group represents the thickest accumulation of Upper Devonian age sediments across the greater project area with an overall observed isopach value ranging from 290 – 340 m (951 – 1,115 ft). Due to the overall thick stratigraphic section and complex assemblage of lithologies of the Duperow formations, overall lithostratigraphic subdivision of the Duperow becomes necessary to accurately assess and evaluate the overall Duperow aquifer system.