fork

A fork is the lowest point in a mine's sump, the basin or chamber where water naturally drains and accumulates under gravity. In hard rock mines especially, groundwater seeps through fractures and along strata, flowing downslope until it reaches this terminal point. The fork sits below the pump suction, allowing water to be extracted systematically rather than spreading across the mine floor.

The fork's depth and volume depend on the mine's water balance: how much flows in daily versus how fast the pump can remove it. A fork that is too shallow fills quickly and floods working areas; one that is too deep wastes pump effort lifting water from unnecessary depth. Most forks are excavated into bedrock or lined with concrete to prevent collapse. The walls are often sloped gently to channel water toward the pump intake.

Without a defined fork, water spreads across the floor, reducing air quality, promoting rust, and hazarding workers and equipment. A fork concentrates the water, making it easier to monitor level, test quality, and control drainage. In coal mines, the fork also catches coal fines and other sediment, which settle out before the water is pumped to surface treatment facilities.

The fork sits at the heart of mine dewatering operations. Its location and capacity affect the whole mine's ventilation strategy and worker safety. In some deep mines, multiple forks exist at different elevations, each serving a section of workings and feeding into a larger sump lower down. The term itself likely derives from the shape of water flowing into a confined point, though its etymology is not certain.