Test And Study Of Flaking Mechanism Of Iron Sulfide Concretions In Coal Seam

Downhole testings and numerical simulations on flaking of iron sulfide concretions in different coal wall depths with different drum pick points were carried out in the study, and the flaking mechanism was analysed. The research showed that through failure damage area with intensive cracks in the coal around the concretion was shaped under the loading of pick. There were four flaking types: translational flaking, rotating flaking, indentation flaking and truncation flaking. The flaking force of concretions in different coal wall depths with different drum pick points were different. The flaking force decreased with the deepening of the concretion's position. The flaking force was smaller with pick point near the end than in the center of concretion.