Strength assessment of roof rock batches of coal seams by means of the geostatistical method

For the design of mine workings the knowledge of rock mass strength parameters is required. In the case of their insufficient identification and lack of possibilities to carry out investigations in the area of the designed working, the recognition of the estimated values of strength parameters enables the linear geostatistics method - kriging. The article presents the way of development of the function of an experimental variogram describing the spatial changeability of analysed parameters and carrying out of the geostatistical analysis of changeability of this parameter in the area comprised by the analysis. The practical way of application of this method in order to predict the strength Rc value of roof rock batches and to determine the estimation accuracy of this value by means of the kriging standard deviation ?k was presented. Maps of strength Rc value distribution and kriging standard deviation ?k for the roof of the seam 207 at the "Piast" colliery were attached. The analysis of maps of Rc and ?k distribution allows to conclude about the accuracy of area identification and possible estimation of the required number of additional measurement points and sites of their location.