Study of a Potential for Rare Earth Elements Extraction from Kimberlite Mine Waste

Transition to renewable energy and clean technology applications increases global demand for critical minerals. Rare Earth Elements (REEs) are essential elements in the emerging clean efficient technologies. Their unique physiochemical properties are demanded by many industries. There is a high need for the identification of new REE sources for a long-term REE supply chain in the future. Some secondary sources including mine tailings (coal, bauxite ore, iron ore), by-products (coal, apatite and phosphate), industrial waste are considered as potential secondary sources for the extraction of REEs. REEs and other key critical elements (nickel, niobium, cobalt) occurring in low abundance in the continental crust achieve very high concentration in exotic mantle magmas such as kimberlites. Some kimberlites reach REE concentrations comparable to the concentrations in the currently mined REE deposits. Kimberlite pipes are the primary target for diamond exploration. However, only 0.01 to a maximum of 10 carats can be obtained from 1 metric tonne of ore. Therefore, a high amount of waste materials is accumulated in each diamond mine, where they are stored in surface stockpiles. This project is a collaboration of Geological Survey of Northwest Territories, De Beers Group Services (Pty) Ltd, and Dalhousie University. The proposed research will explore a potential of REE extraction from kimberlite tailings using two closed diamond mines Voorspoed diamond mine in South Africa (years of operation 1906 to 2018) and Snap Lake diamond mine in Northwest Territories, Canada (years of operation 2008 to 2015). Both mines reach the end of their active closure process. The potential outcomes of this research include: 1) developing new sources for the critical metals required for transition to renewable energy; 2) helping to extend the life of the existing mines mostly located within Northern Indigenous communities in Canada or remote places across the world; 3) help mining company to off-set site reclamation costs after diamond mining to support circular economy and sustainability.