Microwave Impacts on More Sustainable Kimberlite Processing

Abstract.

Diamond mining from kimberlite ore has some challenges related to sustainability: (1) low recovery of diamond, (2) high waste management cost, and (3) high process water consumption. These problems are closely related to the liberation of diamonds in the crushing and separation process. Low diamond recovery comes from unlocked diamond particles from their gangue mineral due to inefficient crushing. In kimberlite ore processing, more than 99% of the feed will become tailings (waste). Therefore, the mine needs bigger tailings storage facilities (TSF) which consume higher costs to maintain relatively to any regular TSF. Typically, 70% of these tailings materials are fine fractions (<1 mm) produced directly from the crushing circuit [1]. These fine fractions are counted as ore loss because any diamonds inside cannot be recovered by the dense media separation process. Ultimately, handling fine fractions requires more water consumption in the thickening and slurry pum** to the final TSF [1, 2]. The sedimentation rate is also significantly slower, and thus coagulant and flocculant reagents consumption becomes necessary [3]. Selective liberation by producing coarser crushing products can potentially minimize these issues.