CONTROLLED FRAGMENTATION OF HARD ROCK BY PRESSURIZATION OF THE BOTTOM OF A DRILL HOLE - Patent 0753096

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EP 0 753 096 A1

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(43)	Date of publication:
	15.01.1997 Bulletin 1997/03

(21)	Application number: 94923866.0

(22)	Date of filing: 14.04.1994

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International Patent Classification (IPC):

E21C 37/ 12^{( . )}
F42D 3/ 00^{( . )}

E21C 37/ 16^{( . )}

(86)	International application number:
	PCT/US1994/004135

(87)	International publication number:
	WO 1995/028551 (26.10.1995 Gazette 1995/46)

(84)	Designated Contracting States:
	AT CH DE ES FR GB IT LI SE

(71)	Applicant: SUNBURST EXCAVATION, INC.
	Denver, CO 80203 (US)

(72)	Inventors:
	WATSON, John, D. Evergreen, CO 80439 (US) YOUNG, Chapman, III Steamboat Springs, CO 80477 (US)

(74)	Representative: Williams, Janice, et al
	D. Young & Co., 21 New Fetter Lane London EC4A 1DA London EC4A 1DA (GB)

(54)	CONTROLLED FRAGMENTATION OF HARD ROCK BY PRESSURIZATION OF THE BOTTOM OF A DRILL HOLE