IMPROVED MECHANICAL EXCAVATION, PERFORMANCE INDICATORS OF DRAG-BITS AND BUTTON INSERTS

A series of experiments using different drag bits was conducted in order to determine the cutting characteristics of marble and granite. The experiments were conducted with a linear cutting apparatus and with a universal testing machine equipped with a special adapter for the button inserts. The experiments determined the optimum and the critical spacing and the variation of cutting characteristics with maximum normal force. For each experiment the following output parameters were measured or calculated: normal force, cutting coefficient, muck weight, specific energy, groove width or crater diameter, groove or crater spacing, largest chip size, and fineness modulus. On the basis of the results of these experiments, a set of guidelines for field applications of the results of this work was developed. It was concluded that the fragmentation process is greatly influenced by the distance between neighboring grooves or craters. However, the values of optimum and critical spacing can be obtained from any small set of the output parameters. If the type of cutting element and the rock type are not carefully matched, the fragmentation operations will become inefficient and possibly ineffective.

  • Corporate Authors:

    Clemson University

    Department of Civil Engineering
    Clemson, SC  USA  29634

    National Science Foundation

    1800 G Street, NW
    Washington, DC  USA  20550
  • Authors:
    • RAD, P F
  • Publication Date: 1976-2-1

Media Info

  • Pagination: 134 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00154609
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: Final Rpt.
  • Contract Numbers: NSF-GK-42125
  • Files: TRIS
  • Created Date: May 31 1977 12:00AM