IN215649: A novel method of mining for underground extraction of coal from a critically thick coal seam standing on pillars and the development made along the roof horizon

A novel method of mining for underground extraction of coal from a critically thick coal seam standing on pillars and the development made along the roof horizon. In India, a coal seam is called thick if its thickness is 4.8m or more. Again, if two seams/sections are situated within 9m to each other then these are called contiguous seams/sections. According to the Indian Coal Mines Regulation, 1957, superimposed development is must for contiguous sections. On the other hand, minimum 3m thickness of the parting between the working of two contiguous sections is also a statutory requirement. Critically thick seams are less than 9m in thickness and they do not provide the required minimum 3m thickness of parting between the two contiguous sections to be developed for optimal exploitation of the seam. The novel method of the present invention can be used for extraction of a critically thick coal seam developed along the roof horizon. Multi-section working with stowing option of this method helps to maintain coal quality of a banded critically thick coal seam while the caving option of this method provides way to extract complete thickness of the seam in one lift.