Protection And Safe Exploitation Of Scarce Coking Coal Resources

Coking coal is not only a source of energy, but an important industrial raw material, known as "food" of steel industry. Meanwhile coking coal is scarce, non-renewable and irreplaceable strategic resource. To avoid over-exploitation and waste,a lot of research has been done in this dissertation, coking coal must be protection.Based on one-variable generalized energy system (GES), a production model was proposed creatively and then calibrated by existing data. It indicates that link relative ratio of total production of coking coal and fat coal can be considered to be constant and its random fluctuation is normal. A model based on univariate stochastic differential equation for coking coal production was established to determine the quarterly growth rates in recent years. As per the protection policies and development strategies of China, a production-limited model was developed and can be used to determine the mining life of coking coal. As a result, two types of production-limited plans have been proposed based on the model. Considering international policies and national conditions on protection for exhaustible resources, a subsidized model for coking coal mining was developed.As the biggest coking coal producing area in China, Shanxi province should take measures to protect coking coal resources. According to the investigation of coking coal market in shanxi coking coal group corporation, a targeted protective mining plan for coking coal production was proposed.In this dissertation, suggestions on administrative legislation, technological innovation, resource survey, planning and supervision, resources integration and international cooperation were also proposed for exhaustible coking coal protection.In order to increase coking coal recovery ratio and safety, filling material and its mixing ratio for roof and rib supporting plates was developed for Tunlan coal mine in Shanxi province. A new supporting method that places steel mesh inside the filling materials instead of external reinforcement was proposed, not only reducing loss of coal pillar but increasing the recovery ratio. With less left coal, the possibility of coal spontaneous combustion become lower.In Baijiazhuang coal mine, stagger arrangement of entries between two adjacent faces in different layers and three-stage extraction process were applied. In addition, self-developed light-weight top coal caving support is used, reducing the residual coal behind the support in the panel. On the other hand, for the residual coals with high potential of spontaneous combustion in the gob, the upper layer residual coals on top of the thin roof of lower layer can be recovered through pillar caving technology and related mining hazards control technologies for methane, mine fire and flood. The return airway in the upper layer can be used to determine the height of the roof in the lower layer. Therefore, mining system will be simplified and the recovery ratio will be increased significantly by applying such a mining method.In Zhenchengdi coal mine, many innovative techniques and processes were used to keep a high quality coking coal production, such as, low top caving technology, rear conveyor contacting floor, box of tailgate shield for additional support, vibrating sieve for coal gangue separation underground and multistage coal gangue separation system from underground to surface. Lose of coal reserves will be significantly minimized through specially designed longwall panel for irregular area and changes of panel length and mining direction. With various kinds of technology to exploit boundary coal one space, the technical questions and safety loopholes were decrease.In order to avoid left coal spontaneous combustion in close distance coal seams, aiming at close distance coal seams in Xishan coal area, mining method and fire detection technology were researched. Retardant and nitrogen injection technology were used and it achieved a good result.