Abstract:

In addition to sourcing critical minerals from mineral deposits, these minerals can be extracted from industrial waste. The world is awakening to an era of “reduce, reuse and recycle” – a phrase that we have historically applied to our household waste, but can also be applied to many industries. Turning to mine waste as a source for critical minerals and elements is attractive – providing necessary metals and minerals while reducing waste. Anomalous rare earth element (REE) concentrations have been found in coal and waste rock from Southeast British Columbia (SEBC) coalfields. Tailings are a waste type that has a fine particle size, usually less than 0.50 mm and is collected from the froth flotation stream in metallurgical coal processing plants. In tailings, the REEs are thought to be bonded to the organic matrix of the coal but predominantly occur in mineral form. The mineralogy for the REEs has been partially determined to be monazite and xenotime although it is suspected that the REEs occur in other minerals by substitution into the mineral structures. The mineralogy and grain size a has direct impact on the ability to concentrate and liberate these minerals in preparation for final processing by hydrometallurgical extraction. The source of the rare earth elements is unknown although based on the direction of sedimentation during the time of coal deposition, it is suspected to have originated in rock packages to the west of the SEBC coalfields. Chemical composition and dating of the REE minerals can provide data for comparison to those from known deposits, which will aid in determining the provenance of the REE minerals. In this paper we will discuss typical REE grades found in the coal seams, surrounding rock and waste types that were analyzed in this study. A summary of mineralogy and implications on the provenance of the REEs will be discussed as well as the potential for concentrating these elements by the reprocessing of tailings.

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Vinoth Kumar Kuppusamy