The paper introduced complete sets of automatic equipment and technology used in thin seam coal face, and proposed the comprehensive mechanization and automation of safe and high efficiency mining models based on the thin seam drum shearer. The key technology of short length and high power thin seam drum shearer, and new type roof support with big extension ratio and plate canopy were introduced. The new research achievement on automatic control system of complete sets of equipment for the thin seam coal, which composed of electronic-hydraulic system, compact thin seam roof supports, high effective shearer with intelligent control system, and characterized by automatical follow-up and remote control technology, was described in this paper..
For mining extra-steep-thick coal seam, the sublevel top coal caving is a high efficient method in practical engineering. However, major challenges associated with mining high-section top-coal-caving （HSTCC） are related to the resulting high ground stresses. Inevitability, using the high-section sublevel top coal caving for extra-steep-thick coal seam, the large scale of mined-out area appears. If the prefracture blasting and hydraulic fracture techniques are utilized, the top coal damage and cracks will develop, and the mining complexity will increase, such as seam inclination, continuity, mechanical characteristics of roof and susceptibility of top coal, etc. First, the field conditions of B1＋2 seam were investigated at the ＋588 level of the Weihuliang Underground Mine of China. Subsequently, according to caving mechanism of strata response obtained from several special models including physical simulation tests and numerical simulation models, the prefracture process including blasting and injecting water were analyzed. Then, the prefracture blasting technique was successfully applied to the caving of 52 m-sublevel seam. Finally, the effects were verified by advanced detecting instruments, and the results show these methods and measurements are feasible and valid.
Because of the widely-used nonlinear loads, the problems of harmonics and low power factor in power systems are becoming more and more serious. In view of the above problems, a shunt three-phase active power filter （SAPF） based on discrete sliding mode control to suppress the harmonics was designed and the power factor improved. First, built the mathematical model of SAPF. Then, controlled the switch through analyzing the harmonic current that was controlled signal using discrete sliding mode control. Through simulation using MATLAB, verified the validity of the algorithm. By the simulation waveforms, it can be found that after the load current containing a large number of harmonics passes the active power filter, the waveform of the power current approximately becomes a sine wave and the harmonics is significantly reduced. As a result, it plays a good role in purifying power systems. Moreover, from the waveforms of harmonic current and power current, it can be found that the algorithm has a faster tracking speed. The waveform can fect.
Based on advantages of technology of distributive fiber-optic temperature sensing and specific to its applications in monitoring mine conflagration, the corresponding Processes such as connection arrangement, signal transmission and monitoring were illustrated. As applied in Sitai Coal Mine of Datong Coal Mine Group Co., this method is effective and accurate and could provide reliable gist for monitoring spontaneous combustion in gob area of mines.
