Method and equipment for boring and casing air vent holes and/or delivery holes in medium-steep and steep dip coal deposits and rocks of loose structure
US4558748A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jan 22, 1985 |
| Grant date | Dec 17, 1985 |
| Priority date | — |
| Expiry date | Jan 22, 2005 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/28
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Forming a hole between lower and upper parallel galleries formed in a mine by boring upwardly from the lower gallery a bore hole having a first length equal to a fraction of the distance between the lower and upper galleries, then casing the bore hole by thrusting upwardly at least one pipe section having a diameter sufficient to be gripped by the shrinkage of the bore hole into the bore hole. Boring upwardly after casing the first length by a further length equal to a fraction of the distance between the lower and upper galleries, then casing the newly formed further length of the bore hole by thrusting upwardly at least one further pipe section having a diameter less than the inside diameter of any pipe sections previously disposed in the bore hole and sufficient to be gripped by the shrinkage of the newly formed further length of the bore hole through the any previously disposed pipe sections into the newly formed further length of the bore hole, and then repeating the two previous steps of boring a further length and casing the newly formed further length until the upper gallery is reached.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.