ABSTRACT
This chapter describes how laboratory based instrumented drag tool studies were used to design and construct boom tunnelling machine cutting heads for practical trials on a variety of boom tunnelling machines operating at Baypazari Lignite Mine, Turkey. The drag tools forming the head are mounted in tool holders welded to a steel boss to form spirals initiating at the nose of the boss and progressing to the back of the head. The influence of common variables on cutting tool performance such as depth of cut, spacing between tools and influence of tool geometry have been investigated previously on rock surfaces both prepared and flat. The in-situ investigations described in this paper are a part of intensive longterm underground trials which have been carried out by the authors since 1984, in the Middle Anatolian Lignite Mine, a subsidiary of Turkish Coal Enterprises. The cutting heads investigated in this chapter are of the type similar to the commercially available cutting heads.
