GENERAL54968

• Permit No: M1977342
• IBM Index Class Name: General Documents
• Media Type: D
• Archive: No

Amax prepares to cave the Henderson
after a decade and $400 milaion in deveDopment
The planned panel-~;aving mining system at Henderson-which is similar in
some respects to oF~erations at the Grace mine in the US and Grancfesberg in
Sweden-is an excellent example of the modern underground minE~
development necessary to bring on stream a mechanized, large sc31e. low cost
operation. With an I~ventual production goal of 30,000 tpd of molybdenum ore,
Amax intends the system to make full use of raise boring, LHDs, and the latest
in mechanized, rubber-tired drill jumbos. Mine design has eliminated use of
cumbersome finger raises/slusher drifts.
Richard Hoppe, Senior edit<rr
Some 5400 nut,uuN of~ F,M:xS 1=uND; have gone into the
largest privalrly finance) project in Colorado's history,
During the la«er hall of 1976, mining of the Henderson
molybdenurn orebod}~ will begin of a production rate of
2.000 tpd, with ore pri ncipelly derircd from undercutting
development work. The production rats will gradually be
incrzased w IO,OIb tpd in 1977, toward a goal of 30,000
tpd o(ore in 1979. The final hgure represents some 50 mib
hon Ih of molvhJrnum annually-which should boost
Amax's share of the Western world market to wmewhere
near 50"d.
r----.-,
i
fled Mountain
How the Henderson will cave
Amax's abilin~ to cave the Hendersim is premised on
figures developed from examination of drill core samples
of the orebody and earn?unding rock and-once under-
ground openings became available-from examination of
the intensity and orientation of fracture pa0erns in the
rock.
While the orebodv at Henderson may be termed "com-
petent;' management believes it will cave within an ac-
ceptable range of dif5cuhe. Rock quality designation
The Henderson orebody lies 3 700
to 5 400 It beneath the crest of
Red Mountain, on the eastern
edge ~~f the Continental Divide. At
the foot o! Red Mountain. in Clear
Creek Valley, some 1,700 ft above
the tnp of the orebody, is the
mine plant-headf tames, shops,
warehouse. offices, antl ancillary
facilities. The mine plant rs lo~
Gated alongside US route 40. 50
mi west of Denver and near his
toric Berthoud Pass.
The 9.6-mi haulage tunnel to
the mill is the worltl's thirtl long
est. Concentrates from the mill,
on the western side of the Conti
nental Divide in Williams Fork val~
ley, will be trucked 35 mi to the
railhead at Kremmling. Colo. The
mine plant mill site complex, at
an elevation of 2 mi and sur-
rounded by the sharp crags of the
Rockies, stretches between Grand
and Clear CreeM Counties.
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