ABSTRACT

To recover coal remnants around the end-walls, underground mining system is normally adopted by excavating some adits into end-walls. Due to longwall underground mining system, the fully caving method is used to manage the coal roof, and it will cause a greater ground subsidence. Hence, strip mining is usually adopted in some regions where only minor ground placement is permissible (Hu 1995 & Guo 2003). In this mining system, the coal field is divided into some regular strips, one strip is mined and the next strip is reserved. The reserved strips can support the load of the overburdened strata, as a result only minor and uniform movements happen on the ground. Thus, some unrecoverable reserves can be extracted on the premise of the controllable ground subsidence. Practice has proved that strip mining is an effective method to control the overlying strata and ground subsidence, and is usually used for extracting coal seams under buildings and railway lines. According to the past investigations about strip mining technology, we try to recover the residual coal under end-walls of open-pit mines with this system, which we called adit-strip mining system in this research. Thus, the key issue of this research is to ensure the extraction system and mining parameters.