Development of a system for high-speed drilling of small-diameter roof bolt holes. Final technical report as of April 1, 1982

Technical Report · Tue Apr 01 00:00:00 EST 1980

OSTI ID:5010006

Bonge, N; Ozdemir, L

This investigation had as its purpose the development of a new drilling technology capable of producing a roof bolt hole smaller than that which is typical of a conventional rotary-mechanical drill, while at the same time increasing the penetration rate. Reducing the hole size promotes the use of resin bolting as the quantity of materials used per hole is reduced, thereby lowering the cost of the operation. As resin bolting is widely recognized as being a safer method of roof control than mechanically anchored bolts, the overall safety of mining is improved. A system utilizing high velocity water jets in conjunction with a rotary-mechanical bit was developed and refined, with major emphasis placed upon hybrid-bit design and high-pressure rotary-sealing techniques. This required the development of theory and design models, as well as the system engineering itself. The WATER JET MECHANICAL system developed began with an experimental surface drill, followed by the development of a more advanced and reliable above-ground system and, finally, the development of an underground unit. Penetration rates in some rock types far exceeded those demonstrated by conventional rotary-mechanical drills and by pure jet drilling systems, typically by a factor of two or more. Bit thrust and torque were reduced by more than four to one compared to rotary-mechanical systems, and bit life increased by seventy-five times in even the hardest and most abrasive of partially metamorphosed sandstone. An analysis of the drilling data indicates that cost of the bolting operation may be reduced by 13 to 30% by the use of water jet mechanical systems and that the technology, which is currently in limited commercial use, may represent an important advance in mining technology.

• Research Organization: Colorado School of Mines, Golden (USA). Earth Mechanics Inst.
• DOE Contract Number: AC01-76ET12462
• OSTI ID: 5010006
• Report Number(s): DOE/ET/12462-1; ON: DE82017787
• Resource Relation: Other Information: Portions of document are illegible
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
42 ENGINEERING
DRILLING EQUIPMENT
COMPARATIVE EVALUATIONS
DESIGN
PERFORMANCE TESTING
ROOF BOLTS
INSTALLATION
UNDERGROUND MINING
DRILL BITS
ECONOMIC ANALYSIS
ENGINEERING
EXPERIMENTAL DATA
JETS
SERVICE LIFE
DATA
ECONOMICS
EQUIPMENT
INFORMATION
MINING
MINING EQUIPMENT
NUMERICAL DATA
TESTING
012000* - Coal
Lignite
& Peat- Mining
420206 - Engineering- Mining & Drilling Equipment & Facilities- (1980-1989)