MEASUREMENT AND ANALYSIS OF THE CONTAMINATION IN HYDRAULIC SYSTEMS OF COAL SHEARERS.

On the basis of contamination measurements and analyses of hydraulic fluids of coal shearers used in the Xiuzhou, Datong and Tangshan mining areas in China and elemental analysis of the contaminants, the author has pointed out that at the present time hydraulic systems of coal shearers in China are seriously contaminated and that the contamination has exceeded the proposed limits. Contamination is introduced thusly: during the transportation of new hydraulic oil to the mine from the surface to the underground and through injection into hydraulic systems. The current filter devices in hydraulic systems in coal shearers are not well designed, having low filtering accuracy. The contaminants in the hydraulic oil in coal shearers consist of carbon compounds and, to a minor degree, of silicon compounds.