Method and apparatus for controlled small-charge blasting of hard rock and concrete by explosive pressurization of the bottom of a drill hole
US6035784A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 2, 1996 |
| Grant date | Mar 14, 2000 |
| Priority date | — |
| Expiry date | Aug 2, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF42D3/00
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Rock and other hard materials, such as concrete, are fragmented by a controlled small-charge blasting process. A cartridge containing an explosive charge is inserted at the bottom of a hole drilled in the rock. The explosive charge is configured to provide the desired pressure in the hole bottom, including, if desired, a strong shock spike at the hole bottom to enhance microfracturing. The cartridge is held in place or stemmed by a massive stemming bar of high-strength material such as steel which blocks the flow of gas up the drill hole except for a small leak path between the stemming bar and the drill hole walls. The cartridge-incorporates additional internal volume designed to control the application of pressure in the bottom hole volume by the detonating explosive.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.