Liquid nitrogen freezing-type rock cross-cut coal uncovering method

Abstract

The invention discloses a liquid nitrogen freezing-type rock cross-cut coal uncovering method. The method comprises the following steps: when the coal uncovering face is close to a safety rock pillar,the coal uncovering face is provided with several freezing boreholes, which pass through the safety rock pillar and the coal seam; the freezing boreholes are injected with water; thermometer holes are arranged at one side of the freezing boreholes, temperature tubes are distributed inside the thermometer holes, and the thermometer holes are sealed; a freezing tube and a slip-casting steel pipe are distributed in each of the freezing boreholes; the freezing boreholes are injected with slurry to fasten the coal body; liquid nitrogen is injected into the freezing tubes and the liquid nitrogen absorbs heat of the coal seam during the gasification process so as to freeze and solidify the coal seam; temperature of the coal seam at the freezing region is monitored by the utilization of the thermometer holes to ensure that the coal seam is fully frozen, and then rock cross-cut is uncovered. The method of the invention has short construction period, is time-saving, has a good solidification effect on the coal seam, and can help raise efficiency and safety of the rock cross-cut coal uncovering operation effectively.

Description

technical field [0001] The invention relates to a method for exposing a coal seam underground in a coal mine, in particular to a method for exposing coal by a liquid nitrogen freezing stone gate which is suitable for a coal seam which is easy to protrude. Background technique [0002] Coal and gas outburst is one of the common disasters in the underground production process of coal mines. Among them, it is most likely to occur when the coal seam is pierced in Shimen. The outburst has a high risk and a relatively large outburst intensity. According to statistics, the average strength of coal outburst in Shimen is more than six times that of other roadways, and more than 80% of oversized outbursts occur in the process of coal outburst in Shimen. The reason for frequent outburst accidents and high outburst intensity at Shimen site is that the stress state of coal and rock in front of the coal mining face is prone to sudden changes, resulting in a large release of elastic potent...

AI Technical Summary

Problems solved by technology

These measures have achieved certain results in the work of uncovering coal and preventing outbursts in Shimen, but there are also great limitations

For example, although grouting reinforcement can effectively improve the strength of the coal body, it is difficult for the grouting material to diffuse in the coal body, and the reinforcement range is limited

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