Improved complex filter applied in enhancing EFT/B immunity at a coal mine monitoring substation

A monitoring system is an important guarantee of safety in a production mine. However, not all monitoring substations pass the electrical fast transient/burst （EFT/B） immunity test and the explosion-proof test simultaneously. To enhance the immunity, the values of capacitance and inductance should be increased, which are actually limited by coal mine explosion-proof standards. Hence, for the first time, an active filter was applied in an electromagnetic interference （EMI） output filter. As a result, the interference within 30 MHz clearly weakened, but the frequency spectrum had a wide range. An EMI input filter and ferrite beads were adopted to restrain higher frequency interference. An output interference spectrogram of the substation was obtained with an analyzer. The results indicate that the improved complex filtering markedly help to control interference. With the support of improved complex filtering and other enhancing immunity means about I/O ports, the substation managed to pass both the EFT/B immunity test and the explosion-proof test synchronously. We conclude that improved complex filtering is of vital importance in enhancing the electromagnetic compatibilitv （EMC） of the coal mine monitoring system.

Application of coal mine dynamic safety management and occupational health and safety management system

A method system was put forward based on the occupational health and safety management system to develop the dynamic safety management of coal mine. It aimed at the problems in the mining safety management and was put in practice in Lingxin coal mine of Ningxia Coal Industry Group Co., Ltd.. And good effect was obtained in safety work. It developed the mining dynamic safety management based on the building of occupational health and safety management system of mining enterprise and its main contents are as follows： timely identification and dynamic control of accident risk, persistent improvement of safety management performance according to the ＂PDCA＂ circle.

Issues in the outburst prevention work of coal mines in Guizhou Province and the analysis of its countermeasures

In order to reduce the occurrence of coal and gas outburst accidents, and improve the capability to prevent gas hazards and realize the safe and efficient mining of coal enterprises. The distribution of the outburst coal mining area of Guizhou Province and the status of coal and gas outburst and the problems in the current outburst prevention methods were analyzed. The main issues were pointed out such as the lack of regional outburst prevention measures, unsatisfactory effect in drainage, poor management and implementation, as well as personnel that need more training. The prevention situation of coal and gas outburst in Guizhou Province was considered. In accordance with the above problems, from the perspective of strengthening geological exploration, testing coal seam parameters, studying outburst prevention technologies, deploying mining systems rationally, improving mine safety management systems, and strengthening protection facilities and other aspects, a targeted outburst prevention measure and proposals were put forward.

Design and implementation of coal mine safety management system based on Ajax and RFID

This paper describes the design and implementation of a coal mine safety management information system based on Ajax. The whole system includes two alarm processing subsystem and management subsystem. Alarm processing subsystem in the server, used to analyzed monitoring data of underground mine, judged whether it is in an abnormal state, also including the crews time recorded by RFID, so that timely alarm data is written to the database for the use of management infonlaation system; management information system adopts the three layer system structure based on B/S, the client the use of ax technology for an asynchronous request to the server, the server operation backstagc Oracle database to complete the business logic processing, and the results in XML form and return it to the client, the subsystem to the user to provide an interactive platform, users can monitor the underground state in real time, at the same time when the abnormal status, the system can timely alarm, prevent the occurrence of coal mine accidents.