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US3917347A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of developing a permeable underground zone

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
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Abstract

Abstract A subterranean ore deposit, such as oil shale, is undercut to form a cavity of predetermined void volume. A specific block of the deposit overlaying this cavity is designated together with an intermediate level thereof. From a suitable working space, explosively charged primary blasting holes are drilled substantially horizontally into the block so as to provide a uniform explosive charge distribution therein below the intermediate level. At least one secondary blasting hole is driven downwardly into the block from the surface of the earth or from an upper mining level and explosively charged above the intermediate level. The primary and secondary explosives are detonated in upwardly progressing timed sequence. This results in expansion of the overlaying block into the cavity and fragmentation thereof in a cone-shaped configuration above the intermediate level.

Inventors

  • 👤 Albert T Janssen
  • 👤 Richfield Company Atlantic

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 15:00
CPC Classifications
E; E21; E21C; E21C41/00; E21C41/16; E21C41/24

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 103 words
A method of developing and shaping a permeable zone within a subterranean ore deposit so that it will have a lower portion of substantially constant horizontal cross-section below a predetermined level from which it tapers upwardly to an apex to form a cone-shaped upper portion comprising the steps of: a. placing an explosive charge into the deposit adjacent said apex; b. expanding a volume of said deposit underlying said predetermined level to form said lower portion; and c. thereafter detonating said explosive charge to produce cratering of said deposit between said apex and said predetermined level so as to form said upper portion.
Claim 2
Independent Claim 103 words
A method of developing and shaping a permeable zone within a subterranean ore deposit so that it will have a lower portion of substantially constant horizontal cross-section below a predetermined level from which it tapers upwardly to an apex to form a cone-shaped upper portion comprising the steps of: a. placing an explosive charge into the deposit adjacent said apex; b. expanding a volume of said deposit underlying said predetermined level to form said lower portion; and c. thereafter detonating said explosive charge to produce cratering of said deposit between said apex and said predetermined level so as to form said upper portion.
Claim 3
Dependent Claim 24 words
A method as in claim 1 comprising placing said explosive charge within a blasting hole drilled into said deposit in a substantially vertical direction.
Claim 4
Dependent Claim 18 words
A method as in claim 2 wherein said blasting hole extends downwardly from the surface of the earth.
Claim 5
Dependent Claim 17 words
A method as in claim 2 wherein said blasting hole extends downwardly from an upper mining level.
Claim 6
Dependent Claim 19 words
A method as in claim 2 wherein said blasting hole extends upwardly from the bottom of said lower portion.
Claim 7
Dependent Claim 14 words
A method as in claim 1 wherein said ore deposit is a carbonaceous material.
Claim 8
Dependent Claim 13 words
A method as in claim 1 wherein said ore deposit is oil shale.
Claim 9
Independent Claim 146 words
A method of forming an upright retort in a subterranean ore deposit wherein the base of the deposit is partially undercut to form a cavity therebeneath connecting with the surface, a designated block of the overlaying deposit being thereafter expanded to fill said cavity, the improvement comprising the steps of: a. providing a substantially vertically directed blasting hole extending into said block so that said blasting hole lies at least partially above a predetermined level of said block; b. charging said blasting hole with a length of explosive above said intermediate level; c. explosively fragmenting the portion of said designated block below said intermediate level to effect expansion thereof into said cavity; and d. thereafter detonating the explosive in said blasting hole to produce a downwardly widening crater of fragmented material of said designated block extending from the top of said explosive to said intermediate level.
Claim 10
Independent Claim 146 words
A method of forming an upright retort in a subterranean ore deposit wherein the base of the deposit is partially undercut to form a cavity therebeneath connecting with the surface, a designated block of the overlaying deposit being thereafter expanded to fill said cavity, the improvement comprising the steps of: a. providing a substantially vertically directed blasting hole extending into said block so that said blasting hole lies at least partially above a predetermined level of said block; b. charging said blasting hole with a length of explosive above said intermediate level; c. explosively fragmenting the portion of said designated block below said intermediate level to effect expansion thereof into said cavity; and d. thereafter detonating the explosive in said blasting hole to produce a downwardly widening crater of fragmented material of said designated block extending from the top of said explosive to said intermediate level.
Claim 11
Dependent Claim 21 words
A method as in claim 8 wherein said blasting hole is approximately centered within the cross-sectional dimensions of said designated block.
Claim 12
Dependent Claim 28 words
A method as in claim 8 wherein said at least one blasting hole is connected to a source of air and fuel adapted to ignite said fragmented ore.
Claim 13
Dependent Claim 47 words
A method as in claim 8 wherein said ore deposit comprises an upper low quality layer lying above and contiguous with A lower high quality layer and wherein said intermediate level of said detonated block is situated at the interface between said low and high quality layers.

References Cited (Backward Citations)

US2896929A Cited
US3611933A Cited
US3661423A 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

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