The copper era. (Clifton, Graham County, Ariz.) 1899-1911, 1903-05-28

been formed short time after the
consolidation of the porphyry. In
lower levels the veins consist OF pyrite.
chalcopyrite and ziHc-b.eude. magne-
tjte being conspicuou>ly absent At
the surface many of the veins have
been completely lcached, and now
show nothing but linonite and silicl-
fed porphyav. This rule j.. however,
not a general one. "a, especially in por
phyry. oXidized ores are sometimes
found in the outcrops OF the deposits.
The most important vein system is
that which. under the general name OF
the Humboldt vein. extends from
northeast to southwest through Cop
sr Mountain at Moreuci. The out
.e.op5 OF this veir-sre practically har-'
reD, but at the depth OF about 200 feet
the deposit becomes productive and
contains chalcUcite associated with
pyrite. There are usually one or more
central seams Of massive chalcocite,
some Of which are fairly pcrsistant.
These seams are ordinarily al Joined
by decompOsed purphyry. now consist
gether with pyrite ana chulcUcitc.
These extensive imprCguations Of
the country rock are not always cor
fined by distinct walls. but often fade
into the surrounding porphyry. Their
character a. ti->ure veins. can, how
ever. not be doubted. 10 lower levels
the Cre i apt to change To pyritc and
Both the A-i1ona Cop
per Company aud the Detroit Copper
Com ruuy are now working the low
= rade bodies OF chaicOcile ore accom-
pauyiug the veins. The resources al
ready proved assure Il large production
fCc many Years.
Parallel veins. somewhat narrower
bat similar in character. are those
opened mp IN the Arizona Contra
Mine. also n Morenci. These veins
are partly in porphyry. partly in con
tact mctamorpho-ed limestone While
malacnite and aZurite sometimes Oc-
cur, they are bv no means a. prOmi
uent as in the limestone deposits. and
frequently the leachrd surface zone is
immedialeIy adjp.ncd b.; the chalco-
cite ore.
The Coronado u ne represents
different type Of deposit l., Is formed
on Il fauIt-ti~~urc hc wrcu 2r.taite and
guarHit'. iIdic.juI Il throv Of at
least | 0o9 fSrt. The is-ure j. followed /
IN places 10y dldba,e a.ke, showing ,
the effects of crushing aud movement /
alOHg tha vei1. The Groupings con- [
tain copper carbonate and siicate, but I
these minerals change at slight depth |
to chalcocite, and still further down it |
is believed that the ore bodies consist |
chiefly OF pyrite and chalcopyrite.
Somewhat different again are the |
iissure veins on Mdrkeen and Copper |
King mountains The granite of this |
OF hills Is cut by a great num- !
ber of dikes which &eHerAliy hava Il
northesterly direction. Along many
Df these movement and fi--uriug have
taken place. and Il varying amount OF
copper ores has been encountered.
The veins contain paratively lit
lie gangue, the copper minerals being
.hiehy distributed through the por.
)hYry or through the granite adioin-
NJ the dixie. At the surface q small
lmOunt OF carbOnatcS may be found. /
)ut they change at slight depth. some
INES only a few feet from the surface,
ntO an ore composed OF chaiCOcitc and
,yrite. which still further down ap-
,eare to change into pvritc and chal-
opyrite. The most prominent de
,Osit on this system Of veins is the
'opper King Mine. which j. situated
nly a few hundred feet below the sum
nit of the mountain Of the same
anne. The main mas OF porphyry be-
ween Morenci and Metcaif shows evil
eucc of very strong naturalization