Regularities of subsidence progress in terms of the repeated earth’s surface undermining in the context of Lviv-Volyn coal basin

Abstract

Study of deformation manifestation within the undermined rock formation and at the earth’s surface is among the key problems during underground mineral mining. The paper has analyzed the available methods identifying the earth’s surface subsidence in the process of its undermining through underground excavation. The analysis has shown branching as well as different approaches and numerous factors. The researchers believe they influence the results. Hence, the purpose is to substantiate regularities of the earth’s surface subsidence while its undermining by means of longwalls varying in their length. The study was carried out using materials of the actual observations on the subsidence in 31 profile lines under the conditions of SE Lvivvuhillia mines. To identify the functional regularities, the factors were assumed which researchers consider as the most influential ones. The performed correlation and regression analysis demonstrated clear relation only for longwall length and moderate relation between subsidence deviation and longwall length-mining depth ratio. A graphical-analytical technique was applied to define distribution of subsidence deviation points depending upon a longwall length-mining depth ratio; moreover, a coefficient was determined to be used while calculating design subsidence values if the longwall length-mining depth ratio is 0.1-0.7.