Research On No.5^-2 Coal Seam Roof Classification And Zoning Forecast In Anshan Minefield

The stability of coal seam roof is a key factor of tunneling roadway and production safety.To classify roadway、immediate roof and main roof scientifically and to forecast unworkedmining area reasonably,which has an important effection to roadway supporting design andworking face arrangement. This paper is about a research of No.5^-2coal seam roofclassification and zoning forecast in AnShan minefield in order to provide methods of shallowburied coal seam roof classification and provide the basis for the unworked No.5^-2coal seammining area roadway support and roof management.Based on analysis of AnShan minefield No.5^-2coal seam roof lithologic structure andtaking the roadway broken rock zone throry as a guide, combined with the actual, this paperraises a suitable proposal for shallow buried coal seam characteristics’ roadway surroundingrock type classification which takes broken rock zone size and the thickness of theunweathered bedrock as the main indicators.According to analysis of the observational data onroadway broken rock zone of the first working face, this paper establish coal seam roadwayroof surrounding rock type forecasting model which takes roadway surroundingbroken rock zone size fitting formula for the key. This paper uses the forecasting model topredict roadway roof surrounding rock type and I draw a picture of AnShan minefield No.5^-2coal seam roadway roof surrounding rock type zoning forecast. The predicted results showthat：about north minefield the type of roadway roof surrounding rock of graben area in thenorth of F₂、F₅fault is mainly level I. About south minefield all kinds of roadway surroundingrock are distributed in the south of F₂、F₅fault.Taking first weighting interval of immediate roof and first weighting equivalent ofmain roof as the index of No.5^-2coal seam roof classification, this paper makes use of key strata theory to calculate47actual drillings and28envisioned drillings’ No.5^-2coal seam firstweighting interval of immediate roof and first weighting equivalent of main roof in theminefield. On this basis, this paper establish immediate roof classification forecasting modelwhich takes first weighting interval of immediate roof fitting formula for the key andmain roof classification forecasting model which takes first weighting equivalent of main rooffitting formula for the key, then I forecast unknown point by using the models, in addition, Idraw pictures of immediate roof and main roof classification zoning forecast in the minefield.The predicted results show that: there is no immediate roof in some areas of the minefield; thetypes in the area of having immediate roof are main instability immediate roof, mediumstability immediate roof and stable immediate roof for three categories, there is no very stableimmediate roof. Main roof in the minefield is main level I region in which pressure behavior isnot obvious supplemented by level II region in which pressure behavior is obvious and littlelevel III region in which pressure behavior is strong, not exist level IV region in whichpressure behavior is very strong.