The Development of a Continuous Drill and Blast Tunneling Concept. Phase II.

摘要

A spiral drilling pattern is described which offers high efficiency drill and blast tunneling via frequent small blasts rather than occasional large blasts. Design work is presented for a machine which would stay at the face to provide essentially continuous drilling,loading,blasting,and mucking. Field tests provide the concept are described and photos of the spiral tunnel advance are provided. Successful testing of a suitable blast shield is also described and photos provided. Advance rates of four times conventional drill and blast practice are projected at about half the conventional cost per foot.