Shallow Coal Mining Research Articles

Estimation of grout take for small-scale developments in areas of shallow coal mining: some examples from the East Pennine coalfield

Abstract Large areas of the coalfields of the UK are underlain by ground from which coal has been formerly mined by shallow pillar and stall methods. At present the condition of these workings varies. In many the roof rocks above stalls have collapsed, giving rise to void migration and areas of disturbed ground. As such they pose a hazard to surface land use due primarily to the upward migration of voids and the compression of disturbed ground. Subsidence due to pillars punching into the roof or floor measures and occasional pillar collapse may also occur. Before construction work can be carried out in such areas it is normal practice for the condition of the ground to be investigated and appropriate action taken if old mine workings are present. In the case of small-scale developments, for example low rise housing, this must be carried out within tight budgetary constraints. In such projects the presence and character of adverse features are usually determined by open-hole rotary drilling. Treatment, if needed, consists of backfilling with cement-sand-pulverized fuel ash grouts. The problems experienced in investigating the presence and effects of shallow mining in the context of housing developments are considered. As the cost of treatment is strongly influenced by volumetric grout take, methods of estimating this quantity are reviewed. Various predictive formulae have been proposed; the efficacy of these is considered with reference to appropriate examples from the North Derbyshire and Yorkshire coalfields.

Identification of former shallow coal mining from aerial photographs: an example from West Yorkshire

Abstract Systematic, large-scale, aerial photography is now available for many areas of the exposed coalfields. In West Yorkshire 1:10000 or 1:10 560 scale cover is generally available, supplemented by 1:5000 and 1:3000 cover in more limited areas. Examination of aerial photographs, in conjunction with detailed geological mapping, has identified characteristic ground patterns associated with the existence of former shallow workings. These patterns are interpreted in terms of changes of style of mining with increasing depth. The presence of shallow mine workings is a major constraint on planning in areas of exposed coalfield. The examination of large scale aerial photographs offers a rapid reconnaissance method of identifying such workings.

A physical model of an underground coal mine prototype

A physical model simulated qualitative ground movement above a retreating longwall face in a shallow coal mine with considerable accuracy, after modification to allow for scale effects. It is considered that in prototype geometries such as mines where strata deformation involves rock fracture, the use of physical models may have advantages over other types of model.

Soil Mechanics Principles in Underground Mining

Soil mechanics principles can be successfully applied to many of the problems encountered in underground mining. A few typical problems are described, and the application of soil mechanics to their solution is indicated. The topics considered include: (1) The design and properties of stiff fill materials for the support of underground excavations; (2) stress distribution within the fill contained by an inclined underground excavation; (3) the design of water retaining underground plugs; and (4) the design of behavior of steel‐reinforced walls of granular material used to provide roof support in shallow coal mines.