Põlevkivi kaevise allmaarikastuse jääkide ladestamine Uus-Kiviõli kaevanduses [Bakalaureusetöö. Juhendaja: E. Väli]

Oil shale is a brown sedimentary rock, which is an important strategic mineral resource. It is used as a raw material in chemical industry and to produce electricity. Active underground mines in Estonia are currently Enefit kaevandused AS Estonia (henceforth Estonia mine) as well as VKG Ojamaa mine (henceforth Ojamaa mine) and surface mines are Kiviõli Keemiatööstus OÜ PõhjaKiviõli open mine, Enefit kaevandused AS Narva open mine and AS Kunda Nordic Tsement Ubja open cast. In the event of the imminent depletion of Estonia and Ojamaa mines, part of the energy resource necessary for Estonia will be lost. Therefore, it is necessary to build new oil shale mines in the near future. According to various studies and development plans, the most economically and environmentally sound mine would be an underground mine in Uus-Kiviõli.

In order to reduce environmental pollution from mining in the form of above-ground mine waste storage facilities and diminish the potential effects of tailings from subsidence, the author recommends building an oil shale ore enrichment unit not on the ground, like it has been done for decades, but in the mine passages, where the oil shale is being mined. This measure would also be economically more advantageous for the mining company, as the cost of transporting the tailings will be several times lower. The economic effect is to be determined by subsequent research, this thesis does not include it.

The author of the thesis also suggests the location of a possible underground enrichment unit, selects optimum technology for oil shale ore enrichment and searches for the most suitable devices in terms of efficiency and size using the best examples in the world, and shows the proposed technological solutions for graphic drawings.

In addition, geological and technological indicators of the mine have been obtained from the archives of Eesti Energia, and VKG Ojamaa mines technology department. Those indicators were used in the calculation models to get the required quality for the enriched oil shale.

In the bachelor thesis, the calculation models created by Professor Emeritus Enno Reinsalu for the enrichment of oil shale were used. The calculations were based on the assumption that Eesti Energia’s Enefit technology oil mills and the vast majority of oil shale production capacities in VKG’s oil mills require product with heating value of 8,40 MJ/kg and shale size of 0…56 mm. Based on this assumption, an analysis of the ore and its components has been performed. 

Tähtajalise juurdepääsupiiranguga lõputöö. Täistekst avalikustatakse 01.07.2025