Advanced Materials Research Vols. 524-527

Abstract: Coal and gas outburst is a strong dynamic phenomenon in the process of coal mining, which the fierce degree and destroy effect is beyond imagination, also can cause the occurrence of secondary disasters, such as fire, gas explosion. Especially in coal roadway excavation face, it is frequent. Therefore, the reasonable prediction and evaluation for associated factors of coal and gas outburst in coal roadway excavation working face is important and guiding significant for coal production, sustained and healthy development. With the mathematical model of grey synthetically relational degree analysis, we gain quantitative analysis of six prediction indexes of coal and gas outburst, and determine the best predictors, provide quantitative basis for the selection of coal and gas outburst prediction indexes.

Abstract: With the increasing growing of metal mine exploitation degree and the developing of modern metal industry, the environmental pollution of production process in metal mine more and more gets the attention of people. Accord to the production technology of metal mines, this paper analyses the reason of environmental pollution, concludes the existent pollution factors and their harmfulness and finally discussed technology measures of treating and controlling for environmental pollution in production process of metal mine.

Abstract: Coal spontaneous combustion needs to have enough oxygen and heat, on the one hand, water salts inhibitor can isolate from coal exposure to air; on the other hand, water salts inhibitor interact with active groups in coal to form complex, increase the stability of coal and boost the heat of spontaneous combustion of coal. This paper has made use of quantum chemical calculation’s software Gaussian 03 to calculate the complex what coal’s active groups and Ca2+ inhibitor interacted to form, and research the mechanism for inhibitor suppressed the spontaneous combustion of coal.

Abstract: According to the practical conditions of the island coal face in No.2 Coal Mine of Pingdingshan Coal Company Ltd., China, the strata behaviors and methane emission were monitored and their two relationships were analyzed. The results indicate that strata behavior at coal face affects its methane emission rates at coal wall and goaf，which the quantity of methane emission rate at coal face is largely increasing after main roof weighting. So through the monitor of periodic roof weighting time, larger methane emission rate at coal face can be predicted. Then the related methane control measures can be taken timely.

Abstract: In order to solve the problem of forecasting airflow temperature in heading face, a new model of forecasting airflow temperature in heading face with Matlab programming is built on the BP neural network model, making use of genetic algorithms to optimize the initial weights and thresholds of the network. According to the analysis of test carried out in a coal mine in Huainan, the results show that the model of fast convergence and high prediction accuracy is one of the most effective ways of forecasting airflow temperature in heading face.

Abstract: Coal is one of the non-renewable resources, and in our country at present also is the main source of energy. It is very important to improve the coal mining rate, to exploit and to use the coal reasonably. Saving coal resource is an important measure for our coal industries sustainable development. Because large amounts of coal under complex conditions caused by fully mechanized mining can not be mined, the rotation mining with large angle for unequal and fully mechanized mining face and its design and main parameters are introduced in this article based on an engineering practice. Using this mining method, the coal under complex condition can be mined as much as possible. It is helpful for us to improve coal mining rate and to economize coal resources.

Abstract: A primary analysis is made in technology for preventing spontaneous combustion of coal to address the risk of safety in production of coal mine for spontaneous combustion of coal. The fire prevention effect and principle of fire per-venting technology were introduced in this paper, especially three phase foam and foamed gel were introduced in emphasis.

Abstract: In underground coal mining, a goaf-edge gateroad (GEG) in a longwall panel is often retained in full length, i.e. the length of the retained GEG is the same as the length of longwall block, for ventilation and gas control. In some cases, it can be extremely difficult to retain a GEG in its full length due to complex geological and geotechnical conditions. To address the issue, the concept of retaining a GEG in sections is introduced. The retained length of a GEG is optimised through the analysis of the inner and outer structures of surrounding rocks of the GEG. Retaining a GEG in sections avoids the intensive roof movement period and possible structural failure of its support. This method of retaining a GEG in sections was successfully applied in panel 24202 of Shaqu coal mine.

Abstract: Conventional rock mechanics parameters are not derived directly from loading rock specimens in laboratory or in situ. Instead, they are determined by many different rock classification codes and criteria in different countries, and some of them such as RMR and Q systems are widely used in many countries. None of these codes and classification systems has considered the important factor of unloading of real excavated rock masses for engineering purposes until Professor Ha Qiulin proposed his new concept of unloading rock mechanics some two decades ago. Since rock masses are not a true CHILE continuum, the loading and unloading behaviors differ greatly from each other. Ha and his co-workers such as Li Jianlin have demonstrated that strength and deformational characteristics, initial rock stresses, scale effects, creep, deformation and fracture patterns are quite different and stress path dependence is particularly emphasized. All these findings have practical significance and a brief introduction and some discussions will be presented in this paper.

Abstract: Coal and gas bursting is an important factor of causing coal mine safety accident, it may cause major accident, even effect on the safety of human life. Human disturbance is an important factor of causing coal and gas outburst. In this paper under the enlightenment of the water injection dustproof, the coal technology of static high pressure water expanding were researched and developed. And the main equipment of coal and the process flow and the mechanism of rock breaking and the matters needing attention were introduced. Field application showed that the technology can decrease the outburst of the coal and gas and can increase the driving speed. So the technology is effective method of coal mining.