Development of Underreamer for Small Spherical Cavities.
Abstract
A rotary drilling tool, with changeable, compressed-air-operated blades having cemented carbide inserts, capable of underreaming small spherical cavities in soft media was designed and constructed. Drilling tests were conducted in a specially built, soft concrete test block to determine the operating characteristics of the underreamer. The tests demonstrated that the tool is satisfactory for underreaming 24-in.-, 36-in.-, and 42-in.-diameter spherical cavities in drill holes in rock formations that have about the same consistency and hardness as halite (i.e. about 3 on Mohs' scale of mineral hardness). The cavities underreamed during the tests met the specified tolerances for dimensions and surface roughness. For underreaming operations in harder rock formations such as granite, the cutting edge of the blades would have to be set with diamonds.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1962
- Accession Number
- ADA006534