Materiały konferencyjne SEP 1993 - tom 2

Underground Exploitation School '93 DESIGN OF IMPROVED SUPPORT SYSTEMS. IMPROVED DESIGN FOR RAPID YIELD HYDRAULIC PROPS TO CATER FOR THIS MORE SEVERE FORM OF ROCKBURST IN STOPES Using the formuła: W = + m.g.h. We can calculate the work to be done by the support system, tt is the kinetfc energy fmparted to the rock plus the change m potential energy. The force required of individual props can then be calculated taking into account prop spacings. The values of all three parameters have been defined from underground observations: a) Peak Grounti Velocities associated with $evere rockbursts, together with far field attenuatlon calcufations, were the basis on which tt was decided that the new design of rapid yield hydraulic prop should have a yiefd ratę capability of at least 3m/s. b) Thickness of Strata lnvoived in Rockbursts. It was found that the height of collapses oniy occasionally exceeds 3m. c) The Amount of Cłosure AHowed on Props. The amount of about 200mni closure can be tolerated in a narrow. I m high stopę. Other important parameters: d) Areai Co^erage. The need for areał coverage by props is greater for rockburst conditions. An essential component of the prop system is therefore an adequate load spreader. e) Biast Resistance. A support system that is installed I m from the face and can resist the blast would be suitable for gold mines. f> ResUience. Longitudinal resilience in the prop is important. This can be achieved by increasing the vo)ume of fluid or by Incorporating a compressible liguid such as silicone fluid in the hydraulic system. 120 Tom II