Devlopment in a seam over a caved lower seam
Devlopment over caved seam Dangers and difficulties : Difficulty in houlage and movement of machinery due to change of floor gradient from place to place.Difficulty in roof support due to fracture in strata.Leakage of ventilation due to cracks in floor.Eruption of black damp from the lower seam.Danger of entry of water from goaf of lower seam. Precautions: ...