Gilpin observer., 1912-04-11
PAST AND PRESENT MINING
CONDITIONS COMPARED

f'N~SNf
dustry in Colorado. Between 1860
and 1870 not far from s25,OO0,0OO
in gold was taken from the stream
beds Of the state. After the ex-
haustion Of the rich placer deposits,
attention was directed to lode min
ing. The first ores encountered
were free milling and were easily
handled in Grade stamp mills. Later,
when refractory ores were found and
only small percentage OF the
known values could be extracted, the
mining industry was in danger Of ex-
tinc.ion. Scientific knowledge, how
ever, came to its aid, and Smelt-
ing plant of twelve tons capacity
was erected at Black Hawk by Nath-
aniel P. Hill, professc- of chemistry
in Brown Unive 'sity, Providence,
Rhode Island. 1t began operations in
January 1868 and was successful from
the start. The difficulties which had
to be surmounted were great. Every
single fire brick used in it's construc-
ton cost dollar; irCn cost % cents
Fer pound; skilled labor was paid IS
per day, and unskilled labor 81. Tie
matte" had to be hauled in wagons
to the Missouri river; then taken by
railroad to New York thence ship
ped to Swansea Wales, where the
gold and silver We're refined. So
great were the expenses of smeltirl5
that in 1878 the ore treated had to
produce 800 per ton in order to
leave a profit to the mine.
The early problems in mining were
simplicity itself, but since 1859 the
problems have been growing more
and more complex. requiring greater
and greater engineering skill. When
only 500 ore could be treated at
pro lit, vast quantities &C lower grades
were left in the mines or in the
dumps. With improved processes of
treatment, with reSuced cost of sup
plies, and with cheaper methods Of
transportation, the zone of profitable
treatment has steadily gone down, un
til even So ore can be treated at
steady r-ofit. Such results are only
possible by cheap methods of handl-
ing due to advanced chemical knowl-
edge. In 1868 the average smelling
, charges Were about $50 per Ton. Ten
years ago the saving CT the values
! in sulph.de ores varied from 80 TO
70 pc. cent, but now the percentage
has reached so.
| In the metal.urgy of copper the
chief economy of late has been the
general adoption of basis-lined con
ve-ters, by means of which the cost
of producing blister copper has been
materially reduced.
The fire treatment OF cres for the
purpose c: extracting the valuable
contents !S highly complex chem
ical r-otiem. The men at the head
Of this branch CT the industry are
invariably highly trained specialists
who understand every detail of the
work. At the present tine the only
Improvements that seem possible are
matters of detail ard increased re.
f!nements of operation.
| On low grade ores, it follows natur
ally, that a preliminary treatment
close to the mine will be neces sary
in order to condition the ore TO
stand the freight and smelter charges
except in cases, like that OF cyani a
ton, where the treatment is ccm-
plete. This is the great fled fcr
economy and eefic'ency-this field
OF localized treatment, when each
mine or group of mines proiucirg
+ similar ore shall have concent-at-
ing mill which will separate the gan
OF efficiency so that the original
low-e-ade ore becomes valuable
concentrate. II is easy to state the
problem; the solution is difficult.
Who knows that the treatment sug.
gested by the "ore doctor" will be
successful? To meet this difficulty
and offer solution, the Co.ora 20
School of Mines is erecting ara
equipping an experimental cre.dress.
ing and metallurg.cal pant, which
is intended to be mining hospi-
tai; that is, 1t win be place where
experimental work will be done upon
low,grade or refractory ores to dets~
mine II there is any method of treat.
ment that will make these ores com
I mercially profitable. The equipment
will consist OF commercial size mach
inery for sampling, crushing. sizing,
roasting, cyanidation. ANA 'gamation.
and, in fact, equipment fer all the
usual methods Of ore treatment. /