Development of Lightweight Hydraulic Supports

摘要

After evaluating preceding studies and designs of lightweight supports, the all-hydraulic and the hydromechanical concepts were selected for detailed design and fabrication. Further analysis and testing showed that the all-hydraulic design was economically justified and met all the crucial engineering, manufacturing, and design criteria identified during the evaluation. Following Bureau of Mines approval of the detailed design, four all-hydraulic support models were fabricated. When functional and structural testing was completed, 40 additional units were constructed and distributed for in-mine testing. The units were acceptable by all three demonstration mines. The widespread interest in supports for seam heights greater than 8 feet led to expansion of the design data package. Four basic models were designed to cover the new height range, but no hardware has yet been fabricated.