Advanced-technology roof-bolt drill-bit development. Final report

Technical Report · Fri Jul 01 00:00:00 EDT 1983

OSTI ID:5971635

Ford, L M; Tillerson, J R; Longfellow, C E

Any improvement in coal- and rock-cutting tools which is to be utilized must result in an overall lower production cost per ton of the coal produced. This was of particular concern in this program since substitution of polycrystalline diamond cutters (PDC) for the presently used tungsten carbide incurs an increased cost. This increased cost must be offset by other savings. TRW Energy Systems Planning Division conducted an economic analysis to predict coal-production costs for three base-case mining scenarios. These results indicate that a PDC roof bolt drill bit costing $150.00 must have an expected life of 300 ft (compared to 2 ft for the conventional bit costing $5.00). Several materials were considered for cutters; however, most of the evaluation was conducted using the GE STRATAPAX. Two basic configurations, a wing bit and a center vacuum bit, were designed. Testing was conducted both in the laboratory (under controlled conditions) and in underground mines. After several design iterations, bits were developed which successfully met all objectives. The PDC bits dirlled significantly further, must faster, and with much less thrust. One important fact discovered was that much of the success of the bit was a result of the bit body geometry. Tests of carbide cutters of the same geometry on Sandia designed bits showed almost as high performance as the PDC. No life tests were done using the carbide cutters, but it is believed that no significant improvement in bit life compared to a conventional bit could be expected. The cost, however, of a carbide cutter bit in the new body geometry should be no more than that of a conventional bit. Thus, for the cost and lifetime characteristics of a conventional bit, a performance (drilling rate, thrust, and torque) similar to that of a PDC bit is possible.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5971635
• Report Number(s): SAND-82-2957; ON: DE83015278
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
42 ENGINEERING
36 MATERIALS SCIENCE
DIAMONDS
COMPARATIVE EVALUATIONS
DRILL BITS
COST
DESIGN
GEOMETRY
MATERIALS
PERFORMANCE TESTING
DRILLING EQUIPMENT
ROOFS
ROCK DRILLING
TUNGSTEN CARBIDES
UNDERGROUND MINING
COAL MINING
EXPERIMENTAL DATA
INSTALLATION
ROOF BOLTS
CARBIDES
CARBON
CARBON COMPOUNDS
DATA
DRILLING
ELEMENTAL MINERALS
ELEMENTS
EQUIPMENT
INFORMATION
MATHEMATICS
MINERALS
MINING
MINING EQUIPMENT
NONMETALS
NUMERICAL DATA
TESTING
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
012000* - Coal
Lignite
& Peat- Mining
420206 - Engineering- Mining & Drilling Equipment & Facilities- (1980-1989)
360205 - Ceramics
Cermets
& Refractories- Corrosion & Erosion
360604 - Materials- Corrosion
Erosion
& Degradation