The mining waste formed during the oil shale enrichment process will be recovered for the construction of a solar power plant

The Environmental Board granted Enefit Mines the right to recover the mining waste, i.e. the limestone originating from the oil shale enrichment process in order to construct a solar power plant foundation construction.In the past, Enefit Mines has also had the right to recover mining waste in the construction of squares and roads and in the production of chippings that meet the requirements of building materials. Now, however, the company is planning to use three million tons of mining waste to build a solar power plant foundation construction, thereby helping to increase the recovery of mine waste in Estonia.“The Environmental Board considers it crucial that our natural resources would be utilised in a sustainable manner. Oil shale mining and subsequent processing requires extreme resources. Among other things, to produce one ton of oil shale, about 0.4 tonnes of mine waste is formed, which must be utilized to the maximum efficient extent possible. For us, the preferred option is to use it instead of landfill, for example, in construction, thus saving other natural resources that would otherwise have been used,” explained Reet Siilaberg, Manager of the Waste Bureau of the Environmental Board.In order to generate one ton of oil shale, about 1.4 tonnes of rock mass must be removed from the ground. During the enrichment process, one ton of oil shale and 400 kg of mining waste are extracted from 1.4 tonnes of rock mass. The resulting mine waste is dumped in landfill, crushed to produce the chippings or used to renew old mines. In order to utilise these resources more sustainably, the government has set a goal of recovering at least 40% of the mining waste produced. In 2016, some 35% of the mining waste was recovered in Estonia and in 2017 the level was already 50%.The major challenge with regard to the recovery of mining waste is that it comes in large quantities. Moreover, it generates an average of 8 million tonnes of mining waste per year, so it is appropriate to recover it for major projects. As part of it, the Environmental Board has an important role to play in evaluating whether it is a material recovery activity that other natural resources are being conserved at the same time. If a new quarry or mine is left unestablished as a result of the recovery of mining waste, it will be very beneficial to the environment.More information: Reet SiilabergManager of the Waste Bureau of the Environmental Board e-mail: reet.siilaberg@keskkonnaamet.ee telephone: +372 5884 9116 Sille AderSpokesperson for the Environmental Boarde-mail: sille.ader@keskkonnaamet.ee telephone: 5745 0332