It was easy to cake for sulfur ore after being blasted. At present, caking ore were mainly broken by blasting. To feature of the overlapping ore body, as well as the engineering characteristics of caking ore in Tongkeng Mine, measure was used to induce and break caking ore by blasting roof. Using LSDYNA numerical methods, numerical tests were designed to simulate breaking process of caking ore in different falling heights and angles, and changes of the strength parameters including compressive and tensile strength of weak structures. Broken effects and dynamic mechanics were analyzed. Broken laws were obtained. The results show that (1) It is advantage to the broken rate in the condition of the height of 5m and the angle of the 30°, the highest rate is 100%. (2) The parameters are proposed to induction caving impact to the caking ore, height is up to 5m and angle of the ultra-deep blasting surface is between 0°~ 30°. The theoretical basis is provided by the study results for the processes and parameters of the induction caving impact to break caking ore.
Under certain conditions, combined by pressure, temperature and humidity, the sulfured ore maybe be caked after accumulating for a long time. It is difficult to transport and recover these ore. Presently, the domestic and foreign scholars have studied on caking mechanism and detecting techniques of the caking ore. The uniaxial test method proposed by Michael Rock (ROCK M et al. 2006) became more mature, which can be used for coupling analysis of the caking factors. Through analyzing the stress and strain of shearing unit, Jenike got the rheological function to detect the caking ore (Weigl B et al. 2006). In engineering practice, mining enterprises often use blasting way to process the caking ore. But some secondary disaster would be induced by the blasting, which is dangerous for the workers.
Based on the consumer oriented solid transport technology (COSTT) uniaxial test of cement ore in Dong Guashan, the relations were analyzed between the caking property, caking time and loads. The results show: it is the certain positive relation between the sulfured cement strength and loads, during the same time. When loads set, the strength increased with time (LI Z.J et al. 2011; DENGY.X et al. 2010).
It has been known that, the rock can be damaged easier by dynamic load compared with static load (Yevgeny et al. 2012; LI et al.2011). Under the same damage, dynamic impact need less energy (WANG S.Y et al. 2011; ZHAO F.J et al. 2005). Failure of rock is dominated by tensile splitting failure (Refahi et al. 2009). Test demonstrated there have a energy threshold value in the process of rock failure, the rock will be broken when the input energy is larger than the threshold value. Density of energy consumption increases with increase of input energy (Li Q.Y et al. 2009). Based on the technique of induced caving, this study made use of the stress environment and mining space to realize induced caving and broke the caking ore (HU J.H. et al, 2007).
