Humidity Effects on Coal Mine Roof Stability.
NTIS: PB/276-484 Available for Reference At Bureau Libraries :164 pages
This report summarizes the results of an investigation into the causes of coal mine roof instability caused by the environmental characteristics of the air ventilated through a mine. The field studies concentrated on collecting data of surface weather conditions, mine air characteristics, roof material types, roof movements, and characteristics of roof deterioration. There are seasonal moisture interchanges between the mine rock and air, and that a mine will lose more water than it gains on a yearly basis. When the roof rock is shaley, seasonal changes in the humidity will cause roof deterioration because of the detrimental action of moisture on the shale. Neither temperature nor barometric pressure have a direct influence on shale durability. The rate and depth of moisture absorption into a shale is controlled strongly by bedding planes, fractures, and holes interrupting the exposed surface. It is evident that changes in the air humidity levels can cause certain shales to expand and generate swelling pressure that are sufficient to fail coal mine roofs.
CP; Final Contract Report;
NTIS Accession No.
NTIS: PB/276-484 Available for Reference At Bureau Libraries
University of Missouri-Rolla