This article set forth two types of destructive form of stopping tunnel coal wall: destructive form in coal and destructive form in interface of coal layer. In addition, the mechanism of destruction in stopping tunnel...This article set forth two types of destructive form of stopping tunnel coal wall: destructive form in coal and destructive form in interface of coal layer. In addition, the mechanism of destruction in stopping tunnel coal wall is analyzed.展开更多
Explaining fundamentals of application of cable bolting for a thick seam depillaring,this paper summarizes the results of field studies conducted during adoption of this approach in more than fifteen panels of Madhusu...Explaining fundamentals of application of cable bolting for a thick seam depillaring,this paper summarizes the results of field studies conducted during adoption of this approach in more than fifteen panels of Madhusudanpur 7 pit and incline mine.Nearly 7.0 m thick Kajora top coal seam of this mine is developed on pillars along the floor horizon to an average height of 3.0 m,leaving a coal band of around 4.0 m along the roof.Analysis of procured core samples showed that roof strata are easily caveable with a caveability index value of around 2000 only.Easily caveable overlying strata and shallow depth of cover alleviated most of the expected strata mechanics problems of the thick seam mining.However,extraction of total thickness at shallow cover caused differential-subsidence and cracks on the surface.These manifestations were immediately tackled to avoid creation of a breathing path for spontaneous heating in the extracted area.展开更多
Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2...Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.展开更多
The start point of this text is the bottleneck problem of bolt supporting coal entrythat is security problem of bolt supporting roof,we divide one entry into some sections withdifferent stress,simulate stress field of...The start point of this text is the bottleneck problem of bolt supporting coal entrythat is security problem of bolt supporting roof,we divide one entry into some sections withdifferent stress,simulate stress field of wall rock and rockbolt solidified at different sectionsused umbrella disperse soft UDEC(universal distinct element code),we educe that thestress level of wallrock and bolt solidified is higher in roof fall risk section,and roof rockboltload can reflect this rule clearly,that offer an important guideline in monitoring entry rooffall risk.展开更多
文摘This article set forth two types of destructive form of stopping tunnel coal wall: destructive form in coal and destructive form in interface of coal layer. In addition, the mechanism of destruction in stopping tunnel coal wall is analyzed.
基金sponsored by the general manager,Kajora Area of Eastern Coalfield Limited(ECL).Co-operation of general manager of the Area,project officer,Madhusudanpur 7 Pit and Incline Colliery,manager and safety officer,Madhusudanpur 7 Pit and Incline Colliery in conducting this study is thankfully acknowledged
文摘Explaining fundamentals of application of cable bolting for a thick seam depillaring,this paper summarizes the results of field studies conducted during adoption of this approach in more than fifteen panels of Madhusudanpur 7 pit and incline mine.Nearly 7.0 m thick Kajora top coal seam of this mine is developed on pillars along the floor horizon to an average height of 3.0 m,leaving a coal band of around 4.0 m along the roof.Analysis of procured core samples showed that roof strata are easily caveable with a caveability index value of around 2000 only.Easily caveable overlying strata and shallow depth of cover alleviated most of the expected strata mechanics problems of the thick seam mining.However,extraction of total thickness at shallow cover caused differential-subsidence and cracks on the surface.These manifestations were immediately tackled to avoid creation of a breathing path for spontaneous heating in the extracted area.
文摘Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.
文摘The start point of this text is the bottleneck problem of bolt supporting coal entrythat is security problem of bolt supporting roof,we divide one entry into some sections withdifferent stress,simulate stress field of wall rock and rockbolt solidified at different sectionsused umbrella disperse soft UDEC(universal distinct element code),we educe that thestress level of wallrock and bolt solidified is higher in roof fall risk section,and roof rockboltload can reflect this rule clearly,that offer an important guideline in monitoring entry rooffall risk.
