case

In mining, a case is a narrow fracture or fissure in rock that permits water to seep into the underground workings. Unlike a major fault or a deliberately driven drainage gallery, a case is often small enough to go unnoticed until water begins pooling at the working face or flowing into a shaft. The presence of a case can transform a dry section of a mine into a wet one within hours, depending on the hydrostatic pressure in the surrounding strata and the permeability of the rock matrix feeding water to the crack.

Cases are most problematic in coal and metal mines where water accumulation creates safety hazards, reduces productivity, and complicates haulage. A case may be only a few millimetres wide, yet deliver enough water to overwhelm manual pumping or require installation of additional mechanical drainage equipment. The direction of a case relative to the dip of strata determines how water will flow once it enters the workings; a case running parallel to the coal seam or ore body may carry water along the entire length of a working, while one crossing the dip will deliver it to the lowest point within reach.

Detection and management

Miners detect cases by watching for seepage, damp patches on exposed rock faces, or the sound of running water behind the working. Once a case is found, the options are limited. Small cases can sometimes be sealed with clay, lime, or other stopping material, though water pressure often defeats these measures. Larger cases require permanent drainage infrastructure: bore holes drilled ahead to intercept the incoming water and direct it to sumps or pump stations. In some instances, abandoning that section of the workings and driving alternate routes around the problem is more economical than fighting persistent water inflow.

The term "case" reflects the practical language of underground workers: the fissure appears as an isolated opening or pocket (a "case" in the sense of a cavity or container) through which water enters the dry working space. It contrasts with distributed seepage through porous rock, which miners would describe as weeping or oozing. The distinction matters operationally because a case requires targeted intervention, whereas general wetness calls for ventilation and drainage of the entire level.