Study On The Mining Technology Of Sublevel Caving Of Inclined And Fragmentary Medium-thick Orebody

The inclined medium-thick orebodies account for twenty-three percent of the total mine exploitation in the underground metal mining of China, most of which are fragmentary and uneasily mining orebodies. The mobile space of these caved ores is too bad; therefore the mining preparation should be advanced much more accurately. Once the road way that the mining preparation was just finished was destroyed, its quantity of the ore reserve would be lost in perpetuity. Even though the remedial measures will be taken immediately, the serious consequences of the ore loss and dilution are difficult to solve. Thus, the knotty mining problem of the inclined and fragmentary medium-thick orebodies is urgent for many mines to solve over the years.The Chambishi copper mine, taken over by China Nonferrous Metal Construction Group from the Zambia United Copper Limited (ZCCM) in 1998, is the typical inclined and fragmentary medium-thick orebody. This dissertation used the theory of "Three Law" proposed by the Northeastern University, studies from the law of ground pressure occurrencer、 law of rock mass roof falling and law of granules flow,and systematically studies the sublevel caving technology, which make this kind of the inclined and fragmentary medium-thick orebodies mined effectively and safely.This dissertation studies from the following six aspects combined with the condition of the inclined and fragmentary medium-thick orebody at Chambishi copper mine.(1) The stability of the surrounding rock at Chambishi copper mine is stable to unstable and the rock mass and the surrounding rock around rock mass are medium-stable to extremely unstable after the survey of the structural plane and the point load strength are carried on. The Chambishi copper mine is suitable for the sublevel caving in the roadway according to the caving character of the ore rock and form the covering layer of nature caving by the surrounding rocks of the hanging wall.(2) The experiment shows that the flow of the granular media is bad because of the lower part of the drawing ore body is much narrow. Therefore, the sublevel caving method that is arranged along the direction of the strike is used in order to get favorable stopping index.(3) The experiment monitors the roadway deformation and the deformation process underneath the transverse drift to get the distribution curve, which determines the location of the stress relief and the pressure area. Combined with the catastrophic collapse phenomenon in the field survey, this test, studied from the law of ground pressure behavior of the orebody and the ore mass close to orebody at Chambishi copper mine, shows that the pulling force is the main reason to cause the destroy of the surrounding rocks when the roadway was exploited.(4) The mining combination technology of the stress relief and the stress yield is proposed according to the distribution of the mining-induced pressure and the statistical analysis result, making the fragmentary medium-thick orebody whose dip angle is 38°to 50° mined effectively.(5) The ore loss and dilution at Chambishi copper mine was analyzed according to the granular media flow law. By this way, the forming process of the mullock funnel should be improved and the diversion drawing of the sublevel caving method is proposed. Then, the drawing condition was become better and the ore loss and dilution was decreased when the new technology was used.(6) The diversion effect of the drawing hole can used for the orebody whose dip angle is 23°to 38°nd that is unstable and uneasy to mine. Divided-flow drawing with the double roadways was proposed when the width of the shift zone of the granular media was increased. The laboratory that simulates the experiment and the industrial test shows that the technology of the divided-flow drawing with the double roadways can obviously improve the ore mining index.The theory and practice at the Chambishi copper mine show that the sublevel caving method can be improved significantly when the divided-flow drawing method, stress relief and combination technology and divided-flow drawing with the double roadways described in this dissertation would be used. If the condition will be suitable for the inclined and fragmentary medium-thick orebody, we can achieve the goal of safe and effective production.