Study On Influencing Factors Of Water Conservation Mining In Shallow Seam Mine Area In The North Shaanxi Province

Yushenfu shallow seam mine area in the north Shaanxi province is the preferred base thatmine industry of our country strategical moves west, and the biggest reserves coalfield knownin our country now. It has predominant geographical location, excellent mine character, easemine condition, so, it has became our country primary export mine base of excellent characterdynamic mine. But, the coalfield locates arid-semiarid area which Maowusu desert and loessaltiplano borders on. In the area, the water resource is lithe, the land is leanness, thevegetation is sparse, the zoology environment is flimsy, the social development level is low.It’s environmtntal quality puts up the descendent current in natural state. The exploiture ofminal industry quickens the descendent current of the environmtntal quality. It is a fatalproblem that how to reasonal and effective empolder the coal resource, how to protect waterresource, how to accelerate the mend of zoology environment, how to make the area economycontinuable development. The key that the coalfield empoldered continual is that the coalfieldis empoldered under the condition protecting the ground water.The influencing factors of water conservation mining were researched in the paper. Theinfluencing factors of water conservation mining have the geotechnical character ofoverburden strata (including lithology,the combined connection of strata, the weatheringcingulum character of bedrock), geological structure, mine method, the stability of coal pillaretc. Former researcher on water conservation mining from aspects of mining method. geologycondition or hydrogeology，All technical factors of influencing water conservation miningwere researched synthetically in the paper，especially included geotechnical character ofoverburden strata included，geological structure and mine method. All factors that influencingthe development of water fluid crack were researched idiographic. That water conservation mining through controling the influencing factors of water conservation mining wasresearched. Synthesizing all factors effecting water conservation mining, the waterconservation mining area divisiory system in the north Shaanxi province shallow saem minearea was provided.The geotechnical model of water conservation mining was established in the research ofthe geotechnical character of bedrock, providing a model gist for similitude simulation testand numercial simulation. In the research of the influence of geologica structure to waterconservation mining, the default in the bedrock hight the height of water conducted fissurezone. When the mine method of water conservation mining is long wall interval mine, theadvancing distance of work face when the bedrock has default is less than the advancingdistance when the bedrock has not default. The mechanics mechanism of the defaultactivation was researched, pointed that the dip angle of the default decide the form of defaultactivation, deducted the calculational formular of critical mine depth and the advancingdistance when the default activates. Taking Yanhuopan mine for example，research therelation between the the default distance and default activates. Taking Daliuta mine forexample, with similitude simulation test and numercial simulation, the work face advancingdistance for protecting water mine were researched when the bedrock have default and thedirection of work face adnancing is different, educed that the distance of work face when thebedrock thinckness are15m,30m,42m,54m and60m, educed the calculational formularbetween the the work face advancing distance and the height of water conducted fissure zone.The stability of coal pillar is a key question achieving water-protecting mine. The paperresearched the reasonable width of the long wall interval mine based the geotechnical modelof water conversation mine.The research results shows：the width of15m is reasonable widthof coal pillar.In the research of influence of mining method to water conservation mining, insand-bedrock-coal mine area，throught researching the law of overlaying stratum, applying thetheory of solid mechanics, this paper founded the key protecting stratum criterion, offering aacademic calculational method for the water conservation mine in the coal mine of thediffering structural overiaying statrum, at the same time, validating the feasibility of thecriterion exemplifying the choosing of the method for shallow coal layer, validating thecalculational result applying the similitude simulating experiment and numerical simulation.In sand-soil-bedrock-coal mine area，The breached depth of fracture was calculated in shallowseam covered with rock soil and sand after mine considering the dilatability of clay aquiclude,adopting the estimation method of the ground movement deformation and the movement deformation in the interior of mining rock in Mining Damage, simultaneity ascertaining thethe height of water flowing fractured zone utilizing similitude simulation experiment. Finally,the thickness of aquiclude protection among two fracture was calculated when the minehighness is different. The water conversation mine was achieved if the thickness of aquicludemeet prescribed requirement, so, the reasonable mine method of water conservation mine wasconfirmed in shallow seam mine area covered with rock soil and sand. The method wascorrected, valiating with locate mine practice and similitude simulation experiment.Finally，the paper researched the affecting factors including the type of rock and soil, thegeotechnical character of rock and soil, the geological structure，the hydrological conditionsand the method of mine etc. The paper researched function that the different rock and soiltype and it’s geotechnical character effect water conservation mine, classified the mine areastratum according the need of water-protecting mine. According the research of function thatthe different rock and soil type and it’s geotechnical character effect water conversation mine,providing the area divisiory system in the north Shaanxi province shallow saem mine area,finding the correct mine method, reasonal designed parameter and technical measureprotecting ground water, preventing upper hungriness, providing the reference formacroscopical decision-making of water conversation mine.