Directional hydraulic fracturing method (DHF method) for controlling hard roof in coal mines and the means of its implementation is given paper. The allows getting extended, set a direction cracks stratification cutting off providing their controlled caving different technological schemes. Geo-physical methods are introduced, monitoring mine site experimental testing data on roofs applying extr...

A geothermal reservoir causes inhomogeneity in the physical properties of the subsurface geology due to the high changes in temperature. These physical properties can be ob‐ served by means of varying anomalies from geophysical observations from the surface. These physical properties include electrical conductivity, rock density, magnetic suscepti‐ bility, rock elasticity, and, finally, the tem...