The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1909-07-12
BIG STEP FORWARD
IN CYAN|DAT|0N
Colorado MetalIurgists Solve a
Very Important Problem in
Ore Treatment.
DISCOVERY IS OF
WIDE APPLICATION
Cyanidation of the Heavy Iron
SuIphideS of Gilpin County
Assured.

Perry r Alsdorf. assisted and ad-
vised by Marshall D, Draper and Floyd
Weed of the Pcarl-Tatum Mining com"
pany, may now be reckoned among the
great discoverers of our time. They
have accomplished what has often been
declared to be the impossible, BY per
sistent, patient and skillful experiment
ing, first in a we'll equipped laboratory
in Central City and subsequently in the
large mill of the Fifty Gold Mines cor
poration at Black Hawk, of which Mar
shall D, Draper is general manager,
they have worked out to a definite con-
clusion the cyanidation OF the heavy
IRON sulphlde ores of Gilpin county on
a commercial scale. This is step far
In advance Of the cyaniding practice Of
this or any other mining field. / met
and had a long talk yesterday with
Fred Mel. Strout, Mr.. Draper and Mr.,
Alsdorf wherein all the essential fea~
lures of the discovery and its applica.
bllty 10 the ores in question were con-
sIdered. They presented an elaborate
report signed by John Gross and Mr..
Sirout, both associated for many years
with the cyaniding practice of South
Dakota and Old Mexico, and of high
standing in their profession, who, after
the Alsdorf method. declared it TO be
entirely feasible. They say in brief
that from technical standpoint there
is absolutely no reason why the ores
of GilpIn county should not WELD in
the same proportion as those of other
eamps-Cripple Creek, for example-if
the latest methods of mill design are
employed as elsewhere. 1t is thorough.
ly proven by elaborate analytical data
compiled by Mr.. Alsdorf that the gold
and silver values IN the ores follow the
iron pyrltc almost totally-that is to
say, the values that are not susceDti-
BILE to amalgamation and which have
been considered to be more or less re-
fractory.
The process employed is crushing by
stamps, amalgamatlon III the customary
form. Concentration of the taiings.
followed by cyanidation of the concen,
trates and waste In which the work of
Mr, Alsdorf appears with greatest ef-
feet. The residue after the extraction
OF the gold and silver contents is still
worth several dollars per ton for the
sulphur contents at the sulphuric acid
works in Denver and at the Dupont
powder plant In this form there is
practically an entire recovery of the
values in the ores To illustrate, Gross
and Strout present the following sum
marles OF all the tests made:
Free milling ore, original wall
Tie -.,s-,.....~.. 81. .SS
Recovered by amslgamation SO
Recovered by cyanidation of
concentrates ............... "a
Recovered by cyanidation Of
waste Observation-Disclosures. 10
Recovered by sale Of (no good
concentrates --,...,.-,...,- As III |
Total value lost .,......... II |
Another example:
Concentrating ore, original
Naluc ...........,... 81. l6 |
Recovered by amalgamation SO II.
Recovered by cyanida ton Of
concentrates -.,...-..,s.s... 4 OF
Recovered by cyanidaton of
Recovered by sale tno good
concentrates ,...s.s....s.s. .46 S. 90 |
Total value lost .... SO |
The percentage Of recovery for the
so-calIed free milling ore amounts TO
91.7 per cent and for the concentrate
ing ore 93l per cent. In this connec-
ton 1T Is stated that from metal
lurgHal standpoint. Cripple Creek ores,
which yield bullion recovery of within
fraction of total value, are much
more difficult problem than is present
ed IN Glipln county, requiring much
more costly installation and treatment,
which is overcome in that locality by
handling enormous tonnages.
Again, "there is not the slightest
question in our minds, say these emi-
nent authorities. "but that the expert
mental work Of Mr. Alsdorf can be
edualed and probably eXcelled in gen
eral practice. Treatment costs can be
estimated to a fraction of cent and
Hn enormous profit shown by a complete
mill installation over what is being
done now.
The quantity OF ore to make it sue
cessful is assured. The metal sllurgical |
features which have interfered hereto
Hz,- hon ,,,-1o 81,
slvely overcome. We make this state.
i'ent without any reservation. What is
BENG done With Cripple Creek ores can
be equally as well done with those of
GllpIn county.
The success Of the new method hav.
ing been unreseryedly iDdorsed by these
distinguished experts. the next step is |
to build a completely appointed mill
Of, to begin with, 300 tons daily ca
paclty with plans for enlargement as
the business develops. The treatment
charge to tho producer having been
placed al the low price of 50 per ton.
coupled with absolutely honest dealing.
there rs abundant assurance that the
supply from the mines will exceed any
past production, because the producer
can rely upon a profit on products con-
tanning from IS to $40 per ton.
Percy r. Alsdorf and his associates.
VINO have brought about what may
nt t'' ucu ~ TPIOluIlOn or |
the milling practice in Gipin county.
IS graduate Of the Ohio State uni.
versity in Mining Engineering, and
connected with the mining industry in
all lis phases for the past thirteen
years. Marshall D. Draper his coad-
wtor. graduated from tho Colorado
State School of Mines class of 1897. and
has since been engaged In the practice
of mine engineering in Nevada. Ari
IONA, Old Mexico and lately as manager
of the Fifty Gold Mines corporation Of |
Black Hawk. where his fine ability has
been manifested in the successful de-
Neiopment Of that company s mines and
mill. Floyd Weed graduated from the
Colorado School of Mines in the same
class. with DIR. Draper and has followed |
cyaniding and mining in all tho western
mining states TO the present time.
Plans for the mill have been outlined
and the intention is 10 have it complete.
ed during the present year Further OK |
periments arc being made continuously |
ON other sulphidc ores.-Geu. Franl, |
Hall III Denver Post