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The drawbacks of the methods described in above mentioned US patent nos 6330860 and 6454359 are that these methods can not be applied in underground coal mines as there is unavailability of compressed air at the blasting face and in underground coal mines permitted explosives are used which usually have different air gap sensitivity
Send Message Chat OnlineThe two major underground methods are referred to as the roomandpillar method and the longwall method In both methods the coal seam is developed by driving entries and crosscuts to create blocks or pillars of coal by the roomandpillar method
Blasting and Mining Methods The mine used the method of shooting off the solid drilling and blasting without using a cutting machine to create a kerf to break coal from the working faces With this method coal remains confined in all directions from the loaded drill hole ecept toward the working face
Other underground coal mines are laid out in a checkerboard of rooms and pillars Fig 2 and the mining operation involves cyclical step bystep mining sequences The rooms are the empty areas from which coal has been mined and the pillars are blocks of coal generally 40 to 80 feet on a side left to support the mine roof
Permissible explosives or permissible blasting devices only shall be used in blasting coal or other material in underground coal mines It shall be unlawful to have use or store any nonpermissible explosives or nonpermissible blasting devices in any coal mine or on the premises of the mine without a permit from the director 22A230
Apr 11 2007 Blastingoffthesolid BOS in Indian underground mines has been a widely practised method for winning coal while developing mine galleries in Bord amp Pillar system Room amp Pillar system The blast holes are drilled in solid coal without free face in BOS method of mining and are blasted with permitted type of explosives and delay detonators
Apr 11 2007 Blastingoffthesolid BOS in Indian underground mines has been a widely practised method for winning coal while developing mine galleries in Bord amp Pillar system Room amp Pillar system The blast holes are drilled in solid coal without free face in BOS method of mining and are blasted with permitted type of explosives and delay detonators
UNDERGROUND COAL MINING amp MINERALS SOUTH Aug 24 2015 to mine by means of conventional mining methods due to the depth of the coal seams The use of underground coal gasi cation UCG technology to extract synthetic gas from coal deemed to be uneconomical to mine could be another game changer for the South African economy similar to the potential of shale gas
Almost all underground mines are less than 1000 feet deep but some mines This drawing depicts the room and pillar method of underground mining Most underground coal is mined by the room and pillar method whereby rooms are cut into the coal bed leaving a series of pillars or columns of coal to help support the mine roof and control the
Dec 09 2011 Underground coal mining produces finely divided coal dust that deposits throughout the mine and serves as a source of combustible material for coal dust explosions Limestone powder known as rock dust is spread throughout the mine workings on a regular basis This rock dust serves to inert the coal dust when applied in the proper proportion
The drawbacks of the methods described in above mentioned US patent nos 6330860 and 6454359 are that these methods can not be applied in underground coal mines as there is unavailability of compressed air at the blasting face and in underground coal mines permitted explosives are used which usually have different air gap sensitivity
Mar 16 2015 PRINCIPLES OF BLASTING IN COAL Underground coal mining operations could be divided into two categories namely Development and Depillaring Both for bord andpillar as well as for longwall mining driving galleries through coal seams are done there are two techniques employed for blasting in development galleries Blasting on precut face Solid blasting of coal
Blasting in Underground Coal Mines Blasting in Underground Coal Mines ACARP Project C20033 Blasting in Coal Mines Modern mechanised coal mines use machines and longwall mining methods to cut solid coal and convey the broken coal out of underground workings Continuous mining equipment has escalated coal production and introduced more effective and efficient coal handling
Aug 05 2009 About one quarter of the coal produced in Australia is by underground mining methods The most commonly used underground coal mining methods in Australia are longwall and room and pillar This paper provides a detailed review of the two methods including their advantages and disadvantages the major geotechnical and operational issues and the factors that need to be
