Method for recovering coal in situ
US4220203A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 6, 1978 |
| Grant date | Sep 2, 1980 |
| Priority date | — |
| Expiry date | Dec 6, 1998 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B43/243
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
For the purpose of in-situ recovery of coal a borehole is driven from the surface in the plane of the coal over at least a large part of its travel, as far as conditions permit. At or near its end this borehole is widened over such a length and to such a width as corresponds with at least twice the deviation to be expected in the horizontal projection of a second borehole which is driven so far as to connect the widened section described above. The widened section is preferably made with the aid of mechanical means. After the boreholes have been linked, the coal is recovered by gasification, dissolution or extraction, whether or not under supercritical conditions and whether or not with attendant chemical/physical disintegration. The method according to the invention is particularly suited for use in the `in-line` gasification technique.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.