In 1964-1965 at the mine No. 3 of Slantsy Combine the resistance of layers of the industrial oil shale stack to mechanical destruction was determined. Resistance (strength) was determined in three ways: 1) by the method of pushing with the help of the POC device (strength coefficient f); 2) by the method of cutting from the open face with the help of the DKS-3 device (strength index A); 3) by the energy indicators of the Ural-33 cutting machine (strength index Avr)....

At Slantsy plant in 1965 there was carried out an experimental notching on the upper part of the limestone “slab” layer, where there is a 0,04 m thick interlayer of clay shale with lower strength. At the total height of the cutting slot of 115-120 mm, the destroyed part of the limestone was 75-80 mm, and 40 mm were in the clay shale interlayer. The cutting was made by the Ural-33 cutting machine mounted on skids above the scraper conveyor, with a bar length of 2 g and an unauthorized seven-line chain. The useful depth of the cut was 1.7 m. The machine was operated at a reduced cutting speed (1.6 m/sec) with I-80 cutters, whose back angle was increased from 5 to 15°.