The Idaho Springs siftings-news., 1910-12-10
THE LOW GRADE ORE PROBLEM
AND THE PARTRIDGE
FURNACE.
Oh. p. Dickinson)

to its existence is tenable. In earlier
days, when our mine development was
confined to placers and comparative
ly shallow surface workings, the gold
discovered was in free condition
and yielded readily to amalagmation
but as shafts and tunnels were driven
in beyond the zone of oxidation the
\ precious metals were found to he
combined with iron and copper sui
phides SO that only a small percent
age could be recovered by amalgam-
alton. AS development has progress
ed this condition has become more
and more serious and today. in all of
the more extensively developed mines
throughout the country, operators are
confronted by this problem of how to
profitably recover the values from
the mass of commercially worthless
material by which they are incased
Water nc entration h been brought
to a high degree of mechanical per-
lection but the problem is not me-
chanical one-it is one that can only
be solved by chemistry. Numerous
lixiviation methods have been tried
and found wanting-but the one pro-
cess by which these low grade, base
ores can be profitably treated has
been long neglected in spite of the
fact that from the time of the earli-
est metallurgical operations of which
we have any record, down to the
present, the efficacy of its employ
ment has been well known and rec
ognized. The element that we must
call to our aid in the solution OF
this low grade ore problem is fire.
The problem as it stands is this:
Silica and the lighter rock constitu
ents can be successfully eliminated
by water concentration but in most
OF the ores from our deeper work
ings the silica content is insiSnlfl-
cant and the precious metals are
sparcely disseminated throughout
= masses of decomposed sulphides. the
specific gravity and composition OF
which make Wafef concentration In
effective for the reason that. so far
as the mechanical possibilities OF
treatment are concerned, the ore has
been concentrated by nature. How
then can we eliminate this mass OF
useless iron and sulphur and concen-
trate our values into small bulk there
nv making it commercially profitable
to ship them? FIRE is the answer
A number of years ago brainy young
engineer was confronted by this same
Grating a property in which the ore
was valuable but rebellious. Trans
nortation and other facilities for
marketing it, made his crude mine
output impossible Water concentra-
tion could not be employed owing to
tie nature of the ores. Cyanide ana
other lixiviation methods were out OF
the question for the same reason
Fire was left. Careful Investigator
of the then available means by which
fire could be made to do his work
nroyed them to be cumbersome, cost
ly Of installation and withal inade-
ouate to his needs. Knowing full well
what he wished to do-must do to
succeed-he went to work along orig
inal lines. Realizing that existing
methods of furnace construction dld
hot produce the results he was after,
he studied out why they did not.
satisfied as to this he inaugurated
a system of elimination and substi
tuition. In his furnace he needed
highly oxidizing atmosphere. He couid
not get this by using the standard
tvpe OF tuyers employed in regular
blast furnace practice. so he elimih-
ated the tuyers and substituted there
for an ingeniously contrived wlho
hox through which he could get large
volume of atmospheric oxygen under
. low blast pressure. That was sue
cess Realizing that existing mteh-
ods for heating this introduced air
(in order that a large portion OF the
energy evolved in the smelting zone
of bis furnace should not be wasted
in accomplishing this) were expens-
i've and unsatisfactory, it occurred
to him that by passing his blast over
tho molten Stag as it flowed from
the crucible, he could not only neat
the blast but cool the sag as VIC"
That was a success. His atmospner-
ic oxygen, introduced under low pres
sure. pre-heated by passing over the
s,as-the vase material in his ores
enabled him to utilize the sulphur In
tho ores themselves as fuel, cutting
down his coke charge to minimum
and sometimes, when there was suf
ficient sulphur present, to run with
o,,+ any coke at ALL That was