Study On Fully Mechanized Top Coal Caving Mining Technology For Ⅱ-3 Extra Thick Coal Seam In Eastern Plate Of Liuta Coal Mine

Fully mechanized caving mining is one of the main mining methods for thick coal seam.However,with the increase of coal cutting and coal discharge height,it will bring serious problems such as severe mine pressure,serious coal wall section,low production rate of top coal and large gas emission.The implementation of fully mechanized caving experiment in the eastern region of the Liuta coal mine is of practical significance to the rational exploitation of the extra thick coal seam(greater than 6m)in the Shendong mining area and the maximum coal recovery.Based on the analysis and demonstration of fully mechanized top coal caving mining technology,economy and safety of Ⅱ-3 coal seam in the eastern plate of the RTA mine,the following results are obtained.(1)through theoretical analysis,numerical calculation and riser analysis,Ⅱ-3 coal seam belongs to medium hard and caving,which can collapse under the action of mine pressure,but the collapse block is relatively large.Especially in the initial mining,measures should be taken to force the roof to eliminate the impact of the top coal collapse to the working face,and the top can be greatly reduced.Coal initial production loss.(2)through the analysis of engineering analogy and mining safety,it is believed that fully mechanized coal caving mining in Ⅱ-3 coal seam in the east of Liuta coal mine can achieve the purpose of safety,high yield,high efficiency and high recovery.(3)the design length of the fully mechanized coal caving face is 260 m,the height of the coal cutting machine is 3.5m,the average height of coal caving is 2.08 m,and the production and discharge ratio is 1:0.59,which not only meets the requirements of the national coal mine safety regulations,but also the overall recovery rate of the working face.(4)the working face is 9 knife,one knife and one knife,the cutting depth of the coal mining machine and the step distance of the coal discharge are 0.8m,the annual production capacity of the working face can reach 3 million T,and the recovery rate of the working face resources is 86.4%.(5)the support selection of ZF8600/19/38 low position four connecting rod caving support is reliable and economical,which can provide high strength support,meet the requirement of shallow buried deep mine pressure,and have strong capacity of top coal release and large block coal.At the same time,we can realize the unification of the fully mechanized caving support in the group.(6)the vertical arrangement of the rear conveyer in front of the work is adopted,and the working face does not adopt the end transition bracket to realize the full length working face,which can not only improve the recovery rate of the top coal,but also benefit the management of the working face equipment.(7)under the same mining conditions in the eastern part of Liuta,the large mining height ratio is 1 million T coal produced by fully mechanized top coal caving,and it loses more than 180 thousand T of coal.If every ton of coal is calculated by 50 yuan net profit,the implementation of fully mechanized top coal caving is 27 million yuan more profitable than the large mining height every year,and the economic benefit is considerable.It is estimated that the investment of equipment in fully mechanized top coal caving face is about 79 million 820 thousand yuan.The use of large mining height requires 126 million yuan.Fully mechanized caving mining in the Ⅱ-3 coal seam is technically safe and feasible and economically reasonable.The fully mechanized caving mining technology can be used in large power and high mining high traction shearer,high reliability and high reliability and high efficiency top coal caving hydraulic support,large slots and large capacity and high strength and high strength scraper conveyor.It has good technical and economic effect.