Pit frame

the framework over the shaft of a coal mine.

See also: Pit

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
Its main components are the pit frame, the hydraulic power pack and the pumping and mixing system.
Options include access ramps, pit frames for in-floor installation, 304 stainless steel versions, and indicator stands.