2. Investigations of Mining-Induced Subsidence

Mine subsidence and the factors that affect the subsidence vary significantly in different regions and different mines. Any investigations are to be designed to meet project objectives and tailored to site-specific conceptual site models. The requirements on data resolution typically increase as the project progresses from preliminary phase through planning phase to design and construction phases. During the preliminary and planning phases of a project, the primary objective is to evaluate the mine subsidence risk levels, whereas the primary objective of design and construction phases is to determine the depth, thickness, engineering properties of soil and rock, and hydrogeological conditions under the project site so that any potential of subsidence risk can be mitigated. As more linear projects such as roadways, railways, tunneling, and gas and oil pipelines cross large areas and new detection technologies are developed, selection of investigation techniques is not as distinctive between study scales. Many methods and techniques such as borehole exploration, groundwater monitoring, geophysics, tracer tests, and aquifer tests are applicable to in mine subsidence investigations. The level of effort depends on the complexity of the project site and severity of subsidence. It is a common practice that non-intrusive tasks precede the intrusive ones.