Gilpin observer., 1905-02-02
Cripple Creek Resurvey.

study Of of the Geology OF the Cripple
Creek district OF Colorado, the people
OF that state were last year SO
strongly impressed with the economic
Importance of a scientific examination
of the ground opened by mining
operations during that period that
they urgently requested a resurvey,
agreeing to bear half the expense Of
the work. The re-examination began
accordingly with thorough revision
of the topographic map of Cripple
Creek by Mr.. R. #. Evans, who acted
under the supervision of Mr.. E. M.
Douglas. The study of the geology
and mines of the district was under
taken Jointly by Messrs. Waldemar
Lindgren and Frederick Leslie Ran
some. who were assisted by Mr. L. C.
Grafton. Messrs. A. M. Rock and
James Bruce also rendered aid as
craftsmen. The examination began
in June. 1908, and the field work was
concluded in April, 1904. Practically
every accessible mine in the district
was examined in greater or less detail.
A preliminary report on the work,
prepared by Messrs. Lindgren and
Ransome, has just been published.
1t is issued in advance Of the final lab
oratory examinations and is a sum-
| mary of those facts that bear upon
the economic development of the
region and are of immediate impor-
tance to the miners.
At the present time there are about
300 mines in the distrit. Many of
them are idle and others are consoli-
dated into larger properties. They
are situated in a group of bare,
rounded hills which form part of the
high plateau extending southwest
ward from Pixies Peak. The eleva-
tions range from 5000 to nearly II 900
feet above sea. The district contains
two important towns-Cripple Creek.
situated on the northwest side of the
producing area, and Victor, on the
southwest edge of the same area.
The mining methods employed in
this district present few features of
particular interest. Many large mines
are operated by strong companies.
but the system of leasing to individu-
ais and small companies, with roy
atty charges of Is to 25 per cent of the
net output, remains conspicuous
feature. The mining and milling
expenses of Cripple Creek are very
high compared with those of other
localities-Western Australia, for ex-
ample. where similar ores and con-
ditions are found. Few of the large
mines seem to have reduced total
expenses below SIG ton.
In the course of the present investi-
cation the geology of the district has
beea entirely remapped upon the
carefully revised topographic base
The GRANTEES, gneisses, and chists
have been differentiated and outlined
in greater detail than was practicable
in ha orIt
necessary notifications Of the earlier
report in the way of stronger empha-
sis on the intimate genetic relation
ship of the rocks have been indicated.
There is nothing in the history of
the district since 1894 which warrants
any extension of the bounds of the
productive territory as then known.
Now, as then, circle of three miles
radius described from the summit Of
Gold Hill would indicate all deposits
of known or prospective value. while
the really important mines would be
embraced by circle near the summit
of Raven bill. That scattered deposits
of greater or less value may be found
in outlying portions of the district is
by no means improbable, but the close
geographic relation of the Cripple
Creek ore deposits to the main vol
canic center seems by this time we'll
established. A brief review of the
mines within this charmed circle is
given in this report and mention is
also made OF the outside mining prop
critics.
At the time OF the earlier survey the
deepest shafts, those of the Moose,
Pharmacist, and Anna Lee mines,
were down only about 400 feet, while
few of the other mines were over 200
feet in depth. The deepest shaft at
present is the Lille, which is over 800
feet deep, although Stratton's Inde
pendence shaft, 1.400 feet deep, has
the lowest sump in the district. The
American Eagde shaft is nearly as
deep as the Lille. while there are
about twenty other shafts over 1000
feet in depth and at least 100 shafts
deeper than the deepest workings of
1894. The amount of drifting and
prosecuting accomplished since the
earlier survey is more than commen-
surate with the increased number and
depth of the shafts. The district is
further intersected in various direc-
tions and at different levels by two
long tunnels run for drainage pur-
poses and by dozen or more different
| adits.
The character OF Cripple Creek ores,
the structural nature of the deposits
and the types of auriferous ore bodies
found in the district, the depth of the
oxidized zone and the relations OF ore
bodies to depth. the conditions of un-
derground waters in the district and
| the subterranean gases found in some
of the mines are among the subjects
discussed in this interesting report.
| A final chapter on the future of the
district will arrest the attention of
many investors.
The statement is made that the ore
bodies, known or unknown. occurring
below the 1.000-foot zone. are probably
| npith so largo nor so abundant 40