IMPROVEMENT OF THE METHODOLOGY FOR PREDICTING THE IMPACT OF MINING CLEANING WORKS ON THE EARTH’S SURFACE USING DATA FROM SURVEYING INSTRUMENTAL MEASUREMENT

Abstract

The results of a study of the parameters of the earth surface displacement process above mining works in the Western Donbas are presented. The authors used a graphoanalytical method to study the geometric parameters of displacement obtained by field surveying instrumental measurements at special observation stations. It is proposed to improve the methodology for predicting displacements and deformations of the earth’s surface when mining coal seams with long pillars in the direction of the cross-strike of the seam. The issues of changes in the parameters of earth surface displacement during repeated mining are considered. Using the example of field observations of earth surface displacement in the Western Donbas, it is shown that they differ significantly from the conditions of primary mining. It has been established that in the case of longwall mining, the cross-section of the displacement mould takes on a “pear-shaped” rather than an elliptical form due to the mismatch of the half-moulds in the main cross-sections along the strike in the dip and rise zones of the seam. The difference in the coefficients characterizing the deformation of the earth’s surface in the main cross-sections along the strike in the “flat bottom” area leads to a gradual increase in the maximum subsidence towards the rise of the seam. A significant difference in the coefficients in the zones on the dip and rise sides of the stratum leads to a change in the nature of the distribution of shifts and deformations within the half-moulds. The established differences in the parameters of the earth’s surface shift during primary and secondary undermining are characteristic of the conditions of undermining at observation station No. 7. However, they allow us to conclude that such differences do exist and are so significant that they radically change our understanding of the patterns of earth surface displacement during mining operations in rock masses disturbed by mining. This, in turn, points to the need for systematic research into the process of earth surface displacement in the Western Donbas in order to establish the parameters of displacement during repeated and subsequent undermining.