hushing

Hushing is the deliberate release of large volumes of water, usually from a reservoir or artificial pond, to erode hillsides and expose mineral veins or to wash loose ore down a slope for collection. The water does the hard work of excavation, moving rock, soil, and waste material without picks or explosives, leaving behind a scarred and remodelled landscape. The technique works because concentrated flow of water under gravity carves through soft overburden faster than hand labour ever could.

The method requires two things: a water source upslope and a target below. Workers build or divert a dam or cistern to accumulate water, then release it suddenly through a sluice gate or breach. The resulting flood scours the hillside, moving tonnes of material. In lead and tin mining regions of Cornwall and the Lake District, hushing shaped entire valleys during the 18th and 19th centuries. Water was sometimes artificially warmed to improve its erosive power, and iron-shod wooden sledges or channels guided the flow to direct where material would be pushed.

Variants and conditions

The scale of hushing ranged from small hill cuts, where a single reservoir fed a morning's work, to massive operations where a series of dams released thousands of gallons in sequence. Success depended on terrain: steep ground with weathered rock or clay responded well; hard granite or slate resisted. The ore or mineral had to be resistant enough not to disintegrate in the flow, and light enough to be carried downslope where it could be recovered from settling ponds or picked from the debris. Tin ore, being dense, survived hushing well; coal and some iron deposits did not.

The environmental cost was severe. Hushing generated enormous quantities of sediment that choked downstream watercourses, silted up mills, and altered water flow patterns for miles. The practice declined with mechanisation because steam-powered pumps, rail transport, and dynamite offered cheaper and more selective extraction. However, the landforms created by hushing remain visible today as distinctive amphitheatre-shaped valleys and scarps, particularly in moorland areas where little vegetation reclaimed the bare ground.

The name comes from the sound and action: the sudden gush or hush of released water. It is synonymous with opencast work in some contexts, though opencast mining now implies deliberate excavation rather than water-driven erosion. Hushing survives in specialist alluvial gold and gemstone mining in developing regions where labour is cheap but capital equipment is scarce, and where the necessary topography and wet season permit the method.