Põlevkivi kadude analüüs ja optimeerimisvõimalused Estonia kaevanduse näitel [Magistritöö. Juhendaja: E. Väli]

This master’s thesis is based on the correct selection of pillar and room parameters of the mining block 1906 of the Estonia oil shale mine. The choice of parameters largely depends on the depth of the oil shale production layer. The deeper the layer, the larger is the area of a pillar supporting the ground. The use of inadequate data and calculations causes unjustified increase in oil shale losses. Controlling or reducing oil shale losses improves the efficiency of the mining company.

The  aim  of  this  thesis  is  to  compile  possible  choices  for  developing  mining  operation  plans  for  the mining block 1906 of the Estonia mine. The losses of oil shale can be analyzed in their entirety on the basis  of  these  choices.  Three  possible  options  for  mining  operation  plans  of  the  mining  block  were prepared:  mining  with  barrier  pillars  throughout  the  mining  block,  mining  a  block  with  rectangular supporting zones and mining of a block with supporting zones. An in-depth study of mining conditions in the block provided additional information on how to perform further calculations.

An innovative approach was used for fulfilling the goal of this thesis –drone measurements. Thanks to this method, the ground overlying the mining block 1906 could be studied morein detail. The size of pillars and rooms for each possible option of mining operation plans were also calculated, taking into account  different  thicknesses  of  the  production  layer,  estimated  strength  of  the  rows  of  pillars  and deviations from the estimate. The calculations include also the lifetime of the mining block 1906, and possible volumes of mined rock mass and enriched oil shale.

The most important result of this study is a proposal for the technologically best mining operation plan with minimal losses while extracting the reserves of the chamber block 1906 of  the mine. If mining takes place in a mining block with rectangular supporting zones, which proved to be the best option, the oil shale losses in a pillar are the smallest compared to other mining operation plans, forming 28.39% of the total reserves of the block 1906.

As a result of this thesis, the following proposals for improved efficiency are made for the mine. Before designing new mining blocks, it is advisable to perform a survey of groundconditions using a drone. The Estonia mine is advised to use a mining operation plan with rectangular supporting zones when planning the mining block 1906, as such methodology leads to smallest losses. Moreover, in such a case it will be technologically more feasible to mine the mining block.