US3917346A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of blasting a subterranean deposit
Assignee: Atlantic Richfield Co
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Filing: 1974-08-22
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Granted: 1975-11-04
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Expires: 1994-08-22
Abstract
Abstract A raise is driven upwardly into a designated block of a subterranean mineral deposit from the roof of an undercutting cavity. A plurality of blasting holes are driven substantially horizontally into the block from the raise in a fan-shaped pattern at each of a plurality of vertically spaced levels and at least partially loaded with explosives. The charges are detonated sequentially in an upward progression to effect fragmentation and expansion of the overlaying block into the undercutting cavity.
Inventors
- 👤 Albert T Janssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:31
CPC Classifications
E; E21; E21C; E21C41/00; E21C41/16; E21C41/24
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
168 words
In the development of a permeable zone within a subterranean ore deposit wherein the deposit is undercut to form a cavity therebeneath communicating with the surface and a designated block of the overlaying deposit is thereafter expanded to form said permeable zone, the method of blasting said overlaying block comprising the steps of: a. driving at least one raise upwardly into said block from the roof of said cavity to a position adjacent the top level of said block, b. drilling a plurality of blasting holes extending from said raise along substantially horizontal paths into said block in a plurality of similar radially expanding patterns, said patterns being situated rEspectively at each of a like plurality of vertically spaced apart levels disposed from adjacent the top of said raise to adjacent the bottom thereof, c. at least partially filling said plurality of blasting holes with explosive charges, and d. detonating said explosive charges to effect fragmentation of said overlaying block and expansion thereof to fill said undercutting cavity.
Claim 2
Dependent Claim
168 words
In the development of a permeable zone within a subterranean ore deposit wherein the deposit is undercut to form a cavity therebeneath communicating with the surface and a designated block of the overlaying deposit is thereafter expanded to form said permeable zone, the method of blasting said overlaying block comprising the steps of: a. driving at least one raise upwardly into said block from the roof of said cavity to a position adjacent the top level of said block, b. drilling a plurality of blasting holes extending from said raise along substantially horizontal paths into said block in a plurality of similar radially expanding patterns, said patterns being situated rEspectively at each of a like plurality of vertically spaced apart levels disposed from adjacent the top of said raise to adjacent the bottom thereof, c. at least partially filling said plurality of blasting holes with explosive charges, and d. detonating said explosive charges to effect fragmentation of said overlaying block and expansion thereof to fill said undercutting cavity.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said raise is contiguous with said block.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the upwardly extending surface of said raise is entirely surrounded by said block.
Claim 5
Dependent Claim
29 words
The method of claim 1 wherein the convergent ends of said blasting holes are distributed substantially uniformly over the interface between said at least one raise and said block.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein said at least one raise is driven in a vertical direction.
Claim 7
Dependent Claim
25 words
The method of claim 1 wherein each of said blasting holes extends to the areal limits of said block at each of said plurality levels.
Claim 8
Dependent Claim
37 words
The method of claim 1 comprising disposing said explosive charges within said blasting holes so as to achieve a substantially uniform distribution thereof over the areal limits of said block at each of said plurality of levels.
Claim 9
Dependent Claim
25 words
The method of claim 1 wherein the maximum spacing between adjacent blasting holes in any of said fan-shaped patterns does not exceed a critical depth.
Claim 10
Dependent Claim
31 words
The method of claim 1 wherein the explosive charges in alternate nonadjacent blasting holes in each of said fan-shaped patterns are confined to a predetermined fraction of the respective lengths thereof.
Claim 11
Independent Claim
128 words
The method of developing a permeable zone within a subterranean ore deposit comprising the steps of: a. driving a tunnel into said deposit at a level below the top thereof, b. enlarging one end of said tunnel at said level to form a cavity undercutting said deposit, c. driving a raise upwardly into said deposit adjacent the juncture of said cavity and the remainder of said tunnel, d. drilling a plurality of blasting holes from said raise into a designated block of the deposit overlaying said cavity, said plurality of blasting holes being oriented so as to achieve a desired charge distribution throughout said block, and e. detonating said blasting holes to effect explosive fragmentation of said block and expansion thereof into the void volume of said cavity.
Claim 12
Independent Claim
128 words
The method of developing a permeable zone within a subterranean ore deposit comprising the steps of: a. driving a tunnel into said deposit at a level below the top thereof, b. enlarging one end of said tunnel at said level to form a cavity undercutting said deposit, c. driving a raise upwardly into said deposit adjacent the juncture of said cavity and the remainder of said tunnel, d. drilling a plurality of blasting holes from said raise into a designated block of the deposit overlaying said cavity, said plurality of blasting holes being oriented so as to achieve a desired charge distribution throughout said block, and e. detonating said blasting holes to effect explosive fragmentation of said block and expansion thereof into the void volume of said cavity.
Claim 13
Dependent Claim
38 words
The method of claim 10 wherein said plurality of blasting holes are oriented to provide a smooth blasted face for said permeable zone extending upwardly from said juncture in a plane transverse to the direction of said tunnel.
References Cited (Backward Citations)
US2896929A
Cited
US3790215A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |