This paper reviews underground mining methods for total thickness of a thick coal seam in single lift(TTTCSSL). Review shows the required engineering for extraction of thick seams needs to be fitted with thickness of ...This paper reviews underground mining methods for total thickness of a thick coal seam in single lift(TTTCSSL). Review shows the required engineering for extraction of thick seams needs to be fitted with thickness of the seam, behavior of rock-mass and surrounding stress conditions for efficient mining.Variants of TTTCSSL are able to extract a maximum 10–12 m thickness only. An improvement in bending moment of the overlying coal band in longwall top coal caving(LTCC) provides better under-winning opportunity for the roof coal band. An acceptable limit of 25 MPa compressive strength of coal for the success of LTCC may be increased under favorable geo-technical conditions. Bord and pillar in India adopted induced caving of roof coal band for single lift depillaring of total thickness(SLDTT) of a competent thick coal seam developed along floor. Case studies are given to arrest the adverse effects of extraction height on pillars.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
基金funded by the Singareni Collieries Company Limited (SCCL)the support of Department of Mining Engineering, ISM for making use of different facilities
文摘This paper reviews underground mining methods for total thickness of a thick coal seam in single lift(TTTCSSL). Review shows the required engineering for extraction of thick seams needs to be fitted with thickness of the seam, behavior of rock-mass and surrounding stress conditions for efficient mining.Variants of TTTCSSL are able to extract a maximum 10–12 m thickness only. An improvement in bending moment of the overlying coal band in longwall top coal caving(LTCC) provides better under-winning opportunity for the roof coal band. An acceptable limit of 25 MPa compressive strength of coal for the success of LTCC may be increased under favorable geo-technical conditions. Bord and pillar in India adopted induced caving of roof coal band for single lift depillaring of total thickness(SLDTT) of a competent thick coal seam developed along floor. Case studies are given to arrest the adverse effects of extraction height on pillars.
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.
