การปรับปรุงประสิทธิภาพการระเบิดหินแข็ง สำหรับหมู่เหมืองเฟลด์สปาร์ จังหวัดนครศรีธรรมราช

Abstract

This study involved how to increase hard rock blasting efficiency. It was divided into 2 phases: First phase was study on the appropriate powder factor (PF) and second phase was continue from the first phase to increase the explosion efficiency by stemming method with a natural rubber stem plug and a fresh latex plug. Then the blasted rock size distribution was analyzed by Rock Image program. The study was at feldspar mine, Sinluang Co., Ltd., Nopphitam District, Nakhon Si Thammarat Province. Phase 1: The effect of powder factor on rock fragmentation ranged from 0.6 to 1.0 kg/m3. The total blasting cost was calculated, including drilling and blasting cost, oversize breaking cost, and secondary blasting cost. The result shows that the powder factor of 0.7 kg/m3 is the lowest blasting cost at 39.51 baht/ton, which is a savings of 10.71 baht/ton over the current pattern (cost 50.22 baht/ton). The sizes d20, d50, and d80, all decreased by about 10.81%, 19.63%, and 31.31% respectively. Additionally, the oversize decreased by about 51.60%. Phase 2: The rock fragmentation improvement by using stemming plug; natural rubber stem plug and flesh latex plug. For the experiment, a powder factor of 0.7 kg/m3 was selected. With natural rubber stem plug, the blasted rock has d20, d50, and d80, of 2.20, 5.74, and 12.43 inches respectively. The oversize is 4.98%. The total blasting cost is 40.27 baht/ton. When compared to the current pattern, the d20, d50, and d80 decreased about 25.68%, 29.14%, and 35.36% respectively and the oversize decreased about 61.98% and the blasting cost decreased by about 9.95 baht/ton. While with fresh latex plug blasting, the blasted rocks had d20, d50, and d80 of 2.25, 5.91, and 12.76 inches respectively with oversize of 5.38%. The total blasting cost was 38.93 baht/ton. In comparison to the current pattern, the d20, d50, and d80 were reduced by about 23.99%, 27.04%, and 33.65% respectively with oversize reduction about 58.93%. The total blasting cost was reduced about 11.44 baht/ton. However this research was taken in account only the total blasting cost, the overall cost might be investigated further for actual cost of each pattern.