Surface Mining Technology in the Zones of Tectonic Disturbances, Estonian Oil Shale Deposit

The 150-300 m thick Ediacaran-Devonian sedimentary cover of Estonia, which contains the commercial oil shale deposit, is divided into blocks by linear fracture and tectonic disturbance zones. Along these zones the bedrock is modified, its composition and strength parameters are changed. Often there are restrictions on the use of new surface-mining areas as local people oppose excavation activities near their homes. Indirect methods were used for determination of the uniaxial compressive strength of rock. A wide variety of rock structures were considered and different excavation methods studied. Feasible mining technologies near the zones of tectonic disturbances have been proposed.