ABSTRACT
World experience shows that the efficiency of coalmining enterprise increases with the intensification of the coal extraction process. At the same time for the stable operation of the mining enterprises is required to maintain its constituent elements in the normal operating condition. One of the most “difficult” in this sense element is mine working. To achieve high rates of longwall face advance the usage of direct-flow ventilation schemes is required, which is provided by maintenance of gateroads both before and behind the longwall face (Khalymendyk 2011, Zborshchik 2011). With increasing depth of mining, the mechanism of rock deformation around mine working changes (Litvinsky 2009a), that leads to significant displacements of mine working rock contour, especially in soft fissile enclosing rocks. Under such conditions usage of the standing supports only does not always lead to the intended result. Effective solution is to combine standing support with reinforcement of the rock mass by means of bolting. This scheme has proven its effectiveness at mining enterprises worldwide (Junker 2013, Prusek 2011). However, in areas of abutment pressure, especially behind longwall face, zones of rock disintegration around mine workings reach a significant size, resulting in an increased load on the standing supports and deformation of bolted rock layers. This eventually entails significant losses of mine workings cross-section. To prevent such processes, a system of deep-laid bolts only (usually cablebolts 3-8 m in length and more) (Tadolini McDonnell 2010), or a system of two-level bolting with conventional roof bolts (first level with bolts
2-3 m in length) and deep-laid bolts (longer than bolts of first level – usually cablebolts) (Razumov et. al 2011, Sasaoka et. al 2013) are applied in the world mining practice.
