Kimberlite Tailings

Abstract

Kimberlite tailings are waste materials left after the recovery of diamond from diamond source rock. The material has a particle size ranging from 20 mm to 75 microns and can be categorized as a soft aggregate. It contains mainly silica, alumina, iron oxide, and magnesia. In the absence of a proper outlet, it accumulates around the diamond mines and causes environmental and disposal problems. With a view to assessing the potential use of kimberlite tailings in road works, the Central Road Research Institute engaged in a detailed laboratory study. Kimberlite tailings were characterized to determine their physical engineering properties. Results indicate that kimberlite tailings are a marginal material and possess adequate strength for use in the construction of rural roads. The feasibility of utilizing this material for the construction of various layers of road pavement by adopting stabilization techniques was investigated. A study was also undertaken to assess the suitability of this material for use in bituminous mixes. The laboratory studies indicate that kimberlite tailings can be used in subbase and base course layers in a road pavement. They can also be used in bituminous macadam as the base course and in premix carpet as a wearing course. A 1-km-long road was constructed near the diamond mine using kimberlite tailings, and its performance was monitored during a period of 1 full year. The road's performance was found to be satisfactory. It was concluded that the use of kimberlite tailings would not only conserve precious material resources, which are quickly being depleted, but also lead to considerable savings in construction costs.