DCHP-1 Online
bed-rock mining 
See quote.
- 1887 (1888) . . . he was once hunting gold . . . by a method called, we believe, "bed-rock" mining. This consists in damming or diverting a river by erecting wing dams. . . .
- 1887 (1888) . . . he was once hunting gold . . . by a method called, we believe, "bed-rock" mining. This consists in damming or diverting a river by erecting wing dams. . . .