The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1906-10-07

we'll sherman N OIdt5sbeTs
existing sulphide ore bodies which oc-
cupied assures in the limestone strata
that was 'uplifted BY tho intrusion of
monzonitc.
Undisturbed portions OF the most
important assures which contributed 10
the enrichment Of the monzuIites aro
70 be seen in the Chainmaa group of
the Nevada Consolidated company and
in tho Maceo, the Daunfle5s anl Robust
claims, formerly the property Of the
Ely Mining and Milling company, now
controlled by Senator Eearps ard
David Keith. All that now remains,
however, 70 mark the western e&ten-
sioa Of these dssures is huge Iaasses
OF brown iron-stained s.liciUus dry
bone, strewn in heaps aud roughly
parallel ridges upon the surface OF the
monzonites. This substance once con-
stituted the insoluhle gangue of tho
original ore veins, the limestone walls
of which have long since crumblcd un-
der tho crosive and solvent power Of
meteoric waters, and their substance
been carried TO the valleys and the
precious metal contents TO build new
type of lode IN the intruded monZo-
mite.
"The solvent power Of such waters
upon iron copper sulphides is ample, but
the monlonite was but little affected
thereby, and hence we find the 'secon.l-
ary' deposit of copper mineral in tie
Ely monzonites confined almOs: eNclu-
sively TO the joints and fracture planes
Of the rock, a fact, however, which
renders the mineral exceptionally
amerable TO recovery by simple meth
DDS of concentration, for the reason
that the mineral particles on slight
pressure readily separate from the rock,
without being subjected TO the abrasion
effect Of e;;5 essive crushins, aud this
leads me 10 suggest that Mr.. Requa
stacles that have heretofore prevented
the successful treatment Of those ores.
Wherefore he invites investigation In
the field of improvement, in order that
q more complete recovery of values may
be accomplished. On the other hand,
I think be greatly underestimate or
under -classiies the grade and value
of such ores in the economy Of copper
production Of the world. For instance,
the copper contents claimed to exist IN
the Ely monzonites exceeds that of the
average of all the ores of the Lake
Superior region mined during the last
forty years by nearly 100 per cent, and
fully equals that OF the Calumet &
Hecla mine, which during that period
has paid in dividends nearly Sl00,000,-
000 The average yield of fine copper
per ton OF ore mined and treated from
those mines which have been prohtably
worked during this period, at least dur.
ing the past ten years, cannot exceed
twenty pounds, Ind in Que instance
(the Atlantic mine) the annual aver
age has fallen below twelve ponnds per
ton, while the average depths from
which those ores were hoisted probably
exceeds $500 feet; besides, the orc IS
extremely hard, tough and diAlcult to
mine and crush; and although the cop
per occurs in metallic form, the recov-
cry does not exceed 81 per cent OF the
metallic contents, and this in coDdi
tion only about 6s per cent pure, and
IL is therefore subjected to smelling
or melting cost of about S5 per ton.
Concentration of Ely Ore,
1.-The Ely ores are said to contain
from forty-fve to sixty-five pounds of
copper per ton. The average recovery
should therefore not fall below thirty
five to forty-fve pounds per ton, and
the resulting concentrates should be
smelted and reduced to electrolytic cop
per at cost not exceeding So or 81
per ton of copcentrates. The cost Of
mining should be IN ratio OF at least
FIVE tons of Ely TO one of Lake, while
the cost of crushing and preparation
for concentration should be even in
greater ratio in favor of Ely; and final
ly, the concentration of Ely ores, owing
to the comparative low specific. gravity
of the gauge, should be and is great
ly in ITS favor. In the concentration
tests referred to by Mr.. Requa, which
the final character of the
machinery TO be employed in the stu
pendous plant soon to be constructed,
the machinery used was Of the same
old orthodox type which has successful
ly solved many moro difficult problems
during the past twenty years or more,
viz, the Huntington mill, which has
been in use for some twenty-five years;
the Wiley table, in use some. fifteen
years. and the travelling banner belt,
brought out some thirty years ago; and
il al this he uade no mistake, and 1t is,
moreover, probable that still older de"
vices OF similar nature may be Used
to advantage in his new plaut. [ have
INDUCED in these observations and de-
tails simply with the hope that 1t may
encourage miners or p1ospectors who
may become possessed OF SIMILAR orc
deposits, or of o.es requiring similar
treatment, thai they m:ly understand
that such ores are valuable and that no
mystery enyelops the processes by
which their values may be recovered.
"An examination of tho huge piles
of ore upon the various dumps Of the
Ely mines discloses the fact that fully
40 per cent of the entire mass rs it
falls from the mine car Is sufficiently
disintegrated to require no crushing
whatever Upon such material the
average Cornish tin miner, or his more
acute American pupil, with Tie-box
or sweeping buddle. and the aid of
boy TO operate broom and few sim