Title: Arrangement for forming vertical or steeply inclined shafts

Abstract: A stopping apparatus is suspended in a pilot shaft and blasting charge holes are drilled outwardly and downwardly from successive vertical positions from the bottom to the top of the pilot shaft to provide a circular array of holes fanned-out from each vertical position. The blasting charge holes are loaded with blasting charges, and detonated, proceeding from the bottom to the top of the pilot shaft.

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Inventors: Svensson, Torbjorn (Skelleftea, SE)

Application Number: 763823
Filing Date: 1977-01-31
Publication_date: 1979-01-02
Assignee: Linden-Alimak AB (Skelleftea, SE)
Primary Class(es): 173/1 173/53, 173/195, 299/10
Other Classes:
US Patent Ref:

2143848	Jan, 1939	Gilman	173/52.
2176885	Oct, 1939	Cadwallader	173/43.
2373276	Apr, 1945	Thornley	299/18.
2731235	Jan, 1956	Dellner	173/52.
2823899	Feb, 1958	Bain	299/10.
2980372	Apr, 1961	O'Leary	173/52.
3085794	Apr, 1963	Johansson et al.	299/10.
3113627	Dec, 1963	Ginocchio	299/10.
3302976	Feb, 1967	Grant	299/10.
3305272	Feb, 1967	Zhadaev et al.	299/18.
3471888	Oct, 1969	Grant et al.	299/70.

Other Refs: 61301110225371063711005608674 OF836705

Jan, 1961	CA
Jan, 1958	DE
Feb, 1875	FR
Apr, 1952	FR
, 1881	GB
Jun, 1960	GB

Primary Examiner: Staab, Lawrence J.
Assistant Examiner:
Attorney: