Random dispersion of observed curvatures of mining terrain and measuring lines location relative to the exploitation edges

In the article an example of underground mining exploitation of hard coal deposits has been presented which by some mining plant in Poland has been conducted. Hard coal extraction took place in three seams numbered 338/2, 341, 358/1 which at the medium and great depths have been located. Exploitation was conducted by use of the longwall system with roof rocks cave-in. This exploitation caused an occurrence of curvatures on a mining terrain surface. The curvatures values on base of the surveys results have been calculated which on two measuring lines have been taken. Points of these lines in the ground perpendicularly and parallel to the longwalls runs have been stabilized. There have been determined the average graphs of observed curvatures along the observational lines, using the smoothed splines and the least squares method. Firstly an approximation of the subsidence measured values (with help of the R-project computer program) has been done. Determination of average graphs of measured curvatures allowed to calculation of values of the variability coefficients of a curvatures random dispersion. It the article was shown that location of the observational lines relative to the exploitation edges is very important and has an influence on shaping of values of a random dispersion of the measured deformation indicators of mining area.