The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1919-06-26
LOCAL ORE TREATMENT.
AND THE BIG SHELTERS
RADICAL CHANGES IN SYSTEM
DUE TO NEW METAlLUR-
GIcAL PROCESSES.

1.-THE Revival Of Local Ore Treat
ment" was the subject of an ADDRESS
by Francis A. Thomson, dean OF the
Idaho school of mines, last Saturday
before the mining convention at Nell
son. b. C. Reviewing the changes that
had taken place in the last 80 years
in ore treatment methods, he gave II
as his opinion that the pendulum mad
swung to the limit in the direction OF
consolidated smelling plants at stra-
tegic centers Prior to 1890 there were
only three ore treating processes In
general use. amalgamation, smelling
and several more or less unsuccessful
teaching schemes. Little shelters dot
ted the landscape wherever there was
mining, except where the ore was
amenabe to amlagamation operating
often inefiiciently and always expen-
sively, owing to the lack of variety In
their ores. This condition continued
until about 1890, said Dean Thomson,
which may be regarded as the begin
ming of the period of consolidation. Or
the many small plants In British Col
umbia, only Trail survives, while In
the western states Tacoma, Selby,
two or three plants near Salt Lake,
one at Denver, one at Leadville, ana
one at East Helena represent the nun
dred or more large or small plants OF
which they are the successors.
Daun Vhnm
son, inevitable under the circum-
stances. Sitting Of competition OF
course due to the immutable laws or
chemical combination. The smelling
business is as natural a monopoly as
the street car business or the tele-
graph business. That does not mean
that II should be free from scrutiny;
quite the contrary"
Reaction Now Due.
Dean Thomson gave an illustration
showing the economy in centralized
plants for the treatment of various
kinds of ores through which mas
grown the present system and contin-
uing, said:
"Yet | believe we have gone about
as far as we are going in that partic-
uar direction--not that | think Trail
is going to be put out of business and
that we are going back to the days or
the little inefficient smelter, but met
allurgical developments of the last 30
years, beginning with the application
of the cyanide process by Macarthur
and Forrest in South Africa, have
made 1t evident that smelling has no
longer the supremacy in ore treatment
which it formerly enjoyed. This sit
uation Is due to the developments IN
two fields, flotatlon and hydrometal-
lurgy.
CAS- long as recoveries by water con-
centration were lowering around ~
per cent, direct smelling was often, in
deed l would say, in most cases, pref
cradle because of the higher recover
les possible by smelling. With the
coming of flotation making possible
recoveries of 80 per cent or better,
smelling is no longer necessarily pref
cradle as primary treatment pro-
cess-and hence the field of raw ore
smelling is being continually narrow
ed and more and more the smelters
are being embarrassed by receipt OF
larger and still larger tonnages of flo
tation concentrates
AT the same time great strides
have been made in the field of hydro
metallurgy This is perhaps best ex-
emplified in the case of zinc, the n.y.
drometallurgy Of which has progress
ed by leaps and bounds in the last five
years. The leaders in this work have
been the metallurgists at Trail and at
Anaconda. Indeed so successful has
electrolytic zinc become that in spite
of predictions to the contrary 1t Will
be able to stay in the market in COM
petition with retort zinc, even at the
present low price levels.
Teaching of copper ores both oXi-
dised and semi is being car
ried out on a large tonnage basis In
the southwestern states and In South
America. So far as sulphide copper
ore is concerned, not much progress
has been made but there is no inner
ent reason why a method similar to
that employed for zinc roasting, fol-
lowed by sulphate teaching, should
not be successfully developed.
"The hydrometallurgy of lead Tags
behind that of her sister metals, per-
haps because of the relative insolu
bllity of lead compounds. There is
promise, however, in the new process
of volatilization of lead and silver In
the form of chlorides followed by re-
covery in Cottrell treaters, phenom
email extractions having been made
with this scheme on large labora
tory scale.
Gold and silver we can always re-
cover, If the cost is justified, by cy-
aniding, sometimes only after roast
ing however.
''There is a further general advan-
tage possessed by hydrometallurgica
methods namely, that the residue oil
telling is readily amenable to further
treatment, condition not true OF
Stag, the pyrometallurgical residue
asJn view then of what has been sale