Underground ultra-thin virtual protection layer hydraulic coal mining method

Abstract

The method for hydraulic mining of an ultra-thin virtual protective layer in a coal mine comprises the following steps: drilling and coring to determine coal seam parameters, selecting the type of hydraulic mining for an ultra-thin virtual protective layer; determining the horizon and minimum mining thickness of an ultra-thin virtual protective layer; Drilling parameters and hydraulic mining drill bits; carry out hydraulic directional jet parameter design; install blowout prevention devices at the orifice, and drill through layers; perform hydraulic directional jet flow; hydraulic directional jet flow until the coal output is small and the jet pressure increases When the amount of coal does not change much, stop the jet flow, withdraw the drill pipe and drill bit, and inspect the first hydraulic directional mining range; connect to the pipeline for pressure relief and gas drainage; check the effect of mining measures for ultra-thin virtual protective layer; and verify the regional outburst elimination. The invention has the advantages of short regional outburst elimination time, low application engineering cost and relatively simple process, fully improves drainage efficiency, shortens drainage time, increases drainage radius, reduces drilling engineering quantity, and eliminates gas disasters to the greatest extent.

Description

technical field [0001] The invention belongs to the technical field of coal mine safety production, and in particular relates to a method for hydraulic mining of an ultra-thin virtual protective layer underground in a coal mine. Background technique [0002] According to the statistics of coal mine gas accident data in recent years, it can be seen that although coal mine gas accidents in my country have been decreasing year by year, serious and extraordinarily serious gas accidents have not been effectively curbed, and coal and gas outburst accidents have ranked first among major coal mine gas accidents in the past two years , coal and gas outburst accidents are showing a serious trend. In 2009, the State Safety Supervision Administration promulgated the "Regulations on the Prevention and Control of Coal and Gas Outbursts", which clearly stated in the regulations that the prevention and control of coal and gas outbursts adheres to the principle of "preventing regional outbur...

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Problems solved by technology

[0050] The main problems: there are problems such as long punching time, large amount of water required for punching, uneven stress distribution and stress concentration that increase the risk of coal and gas outbursts, etc.

[0055] Existing problems: The technological process and facilities are relatively complicated, and the construction of the cutting process takes a long time. Due to the pre-pumping of the outburst coal seam, the current method is mainly to use the through-bed drilling. Drilling holes at different angles in the roadway realizes directional slotting. Therefore, the slotting of the cross-layer drilling can only form pressure relief in the local area of ​​the drilling. There are easy to exist blank zones between the drilling holes, forming stress concentration areas, and increasing the risk of coal and gas outbursts. sex

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