Photograph of a placer gold mining operation. Placer is an open pit form of mining using water pressure to extract minerals from the earth without tunneling.
Grand Coulee Dam (Wash.);Hydroelectric power plants -- Washington (State);Dams -- United States -- Design and construction.
Preparation for constructing the pumping station to bring water from Lake Roosevelt into the Grand Coulee itself. Boring the tunnels for the pumping plant.