AN EVALUATION OF TECHNOLOGICAL OVERBURDEN THICKNESS LIMIT OF OIL-SHALE OPEN CASTS BY USING DRAGLINES

This paper discusses an actual problem of Estonian oil shale open cast s: the technological limit of overburden thickness. The allowable prin ciple stripping operation schemes for walking draglines at Estonian oi l shale open casts are presented. Computer modelled methodology is wor ked out for evaluation technological limit of overburden thickness in Estonian oil shale open casts and in similar conditions As the result of the study if is possible to declare: the technological overburden t hickness is 16-27 m for dragline ES15/90 and 20-37m for dragline ES30/ 120 depending on geological and mining conditions. The methodology all ows mining engineers to calculate and evaluate open cast mining condit ions and cutting parameters for Estonian oil shale open casts or simil ar conditions and lends to solving one of the key problems in long ran ge planning, the limit of surface mining. If helps to prepare the docu mentation and diagrams of stripping operations.