1) Mining equipment
Found on
https://www.crosswordclues.com/clue/raise-borer
A raise borer is a machine used in underground mining, to excavate a circular hole between two levels of a mine without the use of explosives. The raise borer is set up on the upper level of the two levels to be connected, on an evenly laid platform (typically a concrete pad). A small-diameter hole (pilot hole) is drilled to the level required; th...
Found on
http://en.wikipedia.org/wiki/Raise_borer
(from the article `tunnels and underground excavations`) ...upward by a cable in a previously down-drilled pilot hole. A more significant step toward mechanized shaft raising occurred in 1962 when American ...
Found on
http://www.britannica.com/eb/a-z/r/7
No exact match found.
