Drainage channels are provided, usually along the main haulage roads, by which the water flows to a sump excavated at the pump shaft.
When mine water is acid the working parts of the pump must be lined with or made of bronze or other non-corrosive material; or the acid may be neutralized by adding lime in the sump.
This method is rarely practised except by the rollers of zinc. A certain amount of refined zinc can be dipped from the furnace; a further amount, nearly free from iron, can be liquated out of the ingots cast from the bottom of the bath in a subsequent slow remelting, and it is sometimes possible to eliminate a zinciferous lead which collects in the sump of the furnace.
The lower reaches have streams and sump bypasses which are still going.
Cars using slick tires must be fitted with a dry sump.