What are the major types of longwall method?Which method is more popular and why?

 Longwall advancing and longwall retreating: There are 2 variants of long wall method-Long wall Advancing and Long wall Retreating.                                                       Long wall Advancing -In longwall advancing,extraction of coal commences from the vicinity of shaft and advance towards the boundary of the mine or panel.Approach to the face is by parallel roads formed at a specified distance apart,which is equal to length of face.The roof over the extracted area(goaf)is packed by sand(or packwalls of stone)or allowed to cave in.The method has the advantage that coal extraction can be started soon after reaching the coal seam by shaft or inclines.But maintenance of the approach roadways is costly and difficult.          Long wall Retreating -In longwall retreating,pairs of heading are driven in solid coal at an interval equal to predetermined length of face upto the mine or panel boundary.Here they are connected by a long road way one side of which is then used as a long face.As coal is extracted on this face.It retreats to wards the shafts.Hence it is called longwall retreating method.Roof in the goaf is allowed to cave in.Long wall Retreating method is the preferred method because it has several advantages.The devlopment galleries provide knowledge of geologycal disturbance and face operation can be adjusted accordingly. Maintenance of approach roads is easy,as they have solid coal on either side. Ventilation is good,roof Support at the face is easier and chances of spontaneous heating in the goaf are less

Mining Engineering

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Mining Engineering

First-aid station

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First-aid  station is a place fixed by the manger for rendering first-aid to person injured.Every first-aid station is provided with equipment as prescribed in the Third schedule of mines Rules namely: a stretcher and two blanket,Sets of splints(1.4m,0.9m,0.3m,)and sufficient tringular bandages.First-aid boxes(or cupboards),one per150 person,containin sufficient supply of large and small dressings and burn dressings,sufficient supply of sterilised cotton and adhesive plaster,roller bandages,Dettol or other antiseptic solution,a tourniquet,scissors and safety pins,soap.                                                  First aid station shall be provided at the following places On surface:-                     At pit top/incline mouth.In workshop,screening plant and    ...
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Audio visual alarm

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