Introduction

Abstract

Wherever minerals are won by underground mining extending over any significant area, the overlying rock mass subsides into the underground cavities opened up by mining, and the upper surface of the ground subsides correspondingly, forming hollows and trenches, open cracks in the earth, abrupt steps, and extensive subsidence troughs. Ground can sink vertically or be displaced horizontally — or both — by as much as several metres. Since the middle of last century, and particularly over the coalfields of Europe, ground movements on this scale have led to severe damage to buildings, communications, and agriculture, for which the aggrieved land and property owners have demanded compensation from the mine operators and, when necessary, have pressed their claims in the courts. To be in a position to present an effective defence against unjustified claims, mine surveyors have since the beginning of this century made numerous measurements of underground excavations and observed ground movements with extreme care. From the experience thereby gathered, and the theoretical conclusions drawn on how ground movements develop, there has gradually been evolved a new branch of science and technology — mining subsidence engineering — which has been taught in German mining academies since 1931.