| Jiaojia gold mine of Shandong Gold Mining Co.,Ltd.belongs to mesothermal hydrothermal granite-type gold deposit which occurred in an extremely complex condition,joint fissures led to a fractured and unstable orebody of discontinuous grade,especially the Jiaojia fracture zone covered on the hanging wall closely,resulting in roof collapse in a slightly large exposed area.The dip angle of orebody is approximately 30° and the true thicknes is 15m,which belongs to the typical gentle dip,medium thickness and hard-to-mine orebody.The present mining method is upward drift sloping with cemented filling because of the prohibition of surface subsidence.There are following problems when the present mining method is applied:the small size of mining entrances,the little quantity of blasted volume,the huge number of stopes,the complicated construction organization and the low utilization rates of mining equipment,leading to the low production efficiency,the high labor intensity and the low production capacity of ore block.Therefore,there are vital theoretical value and practical significance in carrying out the research on dynamic control technology of safe and effcient mining,and seeking a safe,beneficial and effcient minning method aiming at the gentle dip and fractured orebody of Jiaojia gold mine.Aiming at the gentle dip,fractured and alteration type deposit condition of Jiaojia gold mine,the research on mechanical properties and stability dynamic classification of rock mass were carried out,the link that between the rock mechanical parameters and the stability of stopes were established,and the orebody stability of stope was evaluated;through numerical simulating and analyzing,the mining process including excavation,supporting and filling,the arrangement form of mining entrances and stoping sequence were optimized;The monitoring and analysis of Rock mass damage evolution in Mining process was realized by adopting geological borehole camera and ultrasounic monitoring,achieved the dynamic control over the Mining sequence and parameters,finally realized safe and efficient mining method for Jiaojia gold mine.These following conclusions could be drawn based on the above research:(1)By the means of Q system classification system of rock mass quality,the model of rock mass stability classification of trial stope in Jiaojia gold mine was established and the rock mass in Jiaojia gold mine was determined to be level III to level IV.(2)Rock mass damage assessment was supported based on geological borehole camera and ultrasounic monitoring.The research shows that the scope of loose rock mass is approximately 1.5m which provided theoretical basis on parameter optimizing of surrounding rock support.(3)The research on the optimizing of stope parameters in Jiaojia gold mine was carried out on the basis of correctional Mathews stability graph approach and critical span design method and its result shows that the stope is stable when the span of mining entrance is less than 8m.The mining entrance was stable without collapses and spalling from hanging wall or surrounding rock when its exposed size was 7.4m×15m through industrial test(4)The dynamic control method was established based on the variability of wave velocity of rock mass.According to the data from industrial tests,the wave frequency characteristic got lower,loose plastic zone got bigger and adjoining rock stability got lower with the stoping in mining entrance;By introducing control measures in the process of mining,it was realized that the test tope is still stable under the value of the mining entrance spans more than 2 times the original value of the case. |
PDF Full Text Request