US3845632A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of sealing coal against methane emission
Assignee: MINERAL IND
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Filing: 1973-05-21
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Granted: 1974-11-05
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Expires: 1993-05-21
Abstract
Abstract A method of sealing cracks in a coal seam to prevent methane gas from passing out of the seam at a face thereof comprising injecting a gelable, pumpable silicic acid composition into the cracks in the coal, and allowing the silicic acid composition to set to a gel forming a barrier against gas migration.
Inventors
- 👤 R Slobod
- 👤 E Burcik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:35
CPC Classifications
C; C09; C09K; C09K17/00; C09K17/02; C09K17/12; E; E21; E21F; E21F5/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
131 words
A PROCESS FOR REDUCING GAS EMISSION AT AN EXPOSED FACE IN A COAL SEAM DURING SUBSTERRANEAN MINING OF THE SEAM BY BLOCKING AND DIVERTING THE GAS TO A NON-WORKED LOCATION IN THE MINE COMPRISING INJECTING INTO THE SEAM AT MULTIPLE LOCATIONS TO ENTER CRACKS AND FISSURES AT THE BEDDING PLANES IN THE COAL SEAM AT LOCATIONS SPACED INWARDLY IN THE SEAM FROM THE EXPOSED FACE, A PUMPABLE SILICIC ACID COLLOIDAL DISPERSION CAPABLE OF SETTING UP TO A SEMI-SOLID GEL IN SAID CRACKS AT THE BEDDING PLANES AND THEREBY SEALING SAID CRACKS AND FISSURES AGAINST GAS MOVEMENT, SAID COLLOIDAL DISPERSION BEING CHARACTERIZED IN HAVING A VISCOSITY, WHEN INJECTED, OF LESS THAN 6 CENTIPOISES, A PH OF FROM ABOUT 2.0 TO ABOUT 12.0 AND AN SIO2 CONCENTRATION OF AT LEAST 0.25 WEIGHT PERCENT.
Claim 2
Dependent Claim
131 words
A PROCESS FOR REDUCING GAS EMISSION AT AN EXPOSED FACE IN A COAL SEAM DURING SUBSTERRANEAN MINING OF THE SEAM BY BLOCKING AND DIVERTING THE GAS TO A NON-WORKED LOCATION IN THE MINE COMPRISING INJECTING INTO THE SEAM AT MULTIPLE LOCATIONS TO ENTER CRACKS AND FISSURES AT THE BEDDING PLANES IN THE COAL SEAM AT LOCATIONS SPACED INWARDLY IN THE SEAM FROM THE EXPOSED FACE, A PUMPABLE SILICIC ACID COLLOIDAL DISPERSION CAPABLE OF SETTING UP TO A SEMI-SOLID GEL IN SAID CRACKS AT THE BEDDING PLANES AND THEREBY SEALING SAID CRACKS AND FISSURES AGAINST GAS MOVEMENT, SAID COLLOIDAL DISPERSION BEING CHARACTERIZED IN HAVING A VISCOSITY, WHEN INJECTED, OF LESS THAN 6 CENTIPOISES, A PH OF FROM ABOUT 2.0 TO ABOUT 12.0 AND AN SIO2 CONCENTRATION OF AT LEAST 0.25 WEIGHT PERCENT.
Claim 3
Dependent Claim
50 words
The process defined in claim 1 wherein said composition is injected by: drilling substantially horizontal infusion holes into the coal seam from said exposed face in a direction to intersect face cleavage planes in the coal at substantially a right angle; and injecting said gelable composition into said infusion holes.
Claim 4
Dependent Claim
63 words
The process defined in claim 2 wherein additional holes are drilled into the coal seam from said exposed face in a direction such that each of said additional holes intersects the vertical plane in which one of said first mentioned holes lies to form a plurality of criss-crossed hole pairs in said seam arrayed in plan view as a series of shallow V''s.
Claim 5
Dependent Claim
20 words
The process defined in claim 1 wherein said gelable composition is injected at a pressure of less than 150 psi.
Claim 6
Dependent Claim
36 words
The process defined in claim 1 wherein an injection pressure equal to at least the initial injection pressure is maintained on said gelable composition until the time when said gel sets up to a semi-solid gel.
Claim 7
Dependent Claim
22 words
The process defined in claim 1 wherein said silicic acid colloidal composition has an SiO2 concentration of at least 1 weight percent.
Claim 8
Dependent Claim
44 words
The process defined in claim 1 wherein said silicic acid colloidal composition has a gelling period, as measured from the time of initially formulating the composition to the time it sets to a semi-solid gel, of from about 1/2 hour to about 12 hours.
Claim 9
Dependent Claim
19 words
The process defined in claim 7 wherein said gelling period is from about 1/2 hour to about 2 hours.
Claim 10
Dependent Claim
39 words
The process defined in claim 1 wherein said silicic acid colloidal dispersion is prepared by mixing a water soluble silicate with a hydrogen ion yielding material selected from the group consisting of hydrochloric acid, sulfuric acid and sodium bicarbonate.
Claim 11
Dependent Claim
15 words
The method defined in claim 9 wherein said hydrogen ion yielding material is sulfuric acid.
Claim 12
Dependent Claim
39 words
The method defined in claim 10 wherein said silicic acid colloidal dispersion is prepared by adding the water soluble silicate to the sulfuric acid rapidly and with vigorous agitation to avoid formation of solid particles of gel during mixing.
Claim 13
Dependent Claim
15 words
The method defined in claim 9 wherein said hydrogen acid yielding material is sodium bicarbonate.
Claim 14
Dependent Claim
22 words
The process defined in claim 1 wherein said silicic acid colloidal dispersion has a pH of from about 7.5 to about 10.7.
Claim 15
Dependent Claim
27 words
The process defined in claim 1 wherein said silicic acid colloidal dispersion has an SiO2 concentration of from about 1 weight percent to about 10 weight percent.
Claim 16
Dependent Claim
44 words
The process defined in claim 14 wherein said silicic acid colloidal dispersion has a gelling period, as measured from the time of initially formulating the composition to the time it sets to a semi-solid gel, of from about 1/2 hour to about 2 hours.
Claim 17
Dependent Claim
22 words
The method defined in claim 15 wherein the pH of said silicic acid colloidal dispersion is from about 7.7 to about 9.9.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |