A NEW TECHNOLOGY OF DIRECTIONAL FRACTURE BLASTING IN ROCK DRIFT
Yang Yongqi;Jin Qiankun;Yang Renshu;Zhang Qi;Gao Quanchen(Beijing Graduate School, China University of Mining and Techiiology)Liu Shaofa; Song Hao; Jla Yunfeng(Datong Mining Bureau)
Based on lab study of model tests, stress field characteristics around the boreholes of dlrectioval fracture blasting have been measured and analyzed using photoelectric measuring techrjiques. The penetrating me-chanism of adacent boreholes has been presented with conmparatively praticaland effective directional fracture blasting method optimized and the feasibili-ty of drift working confirmed. Practice of 43 regular operation cycles in atransportation drift at Maiiliang Mine of Datong Mining Bureau shows thatin the sandstone( f=6～8 ) drift(driving section 12.39m￣2)using the new tech-nology of directional fracture blasting triangular compound cutting and me-dium-length bole blasting can give good blasting effect under the conditionof tbe existing air-leg rock drills, scraper rock loaders and mine-car trans-portation. The circumferential hole mark ratio comes to 96%and the irregu-larity is less than 100mm, borehole utilization ratio reaching 98%. Difficul-ties with quality index for smooth blasting are solved thorouglily. Implemn-tati0n of the new technology opens up broad prospects for improving smoothblasting techniqtie and raising the construction speed of rock drifts.