Clean utilization of coal depends on the quality of raw coal,which depends on the coal-forming parent materials(petrology and chemical composition of coal),the
A 3rd generation roof bolter canopy air curtain(CAC)has been developed and constructed by J.H.Fletcher&Co.,Inc.As with the previous generation of the CAC,this d
The Early Cretaceous is an important coal accumulation period in China.Abundant coal resources were formed in the southeastern margin of Songliao Basin.Sequence