The Butte daily miner. [volume] (Butte, Mont.) 1885-18??, 1886-01-01

Of ore. The labor il much less, being about
a. one to two and one-half. Instead Of
tying up valuable ore for q month Or ak
weeks, ONE can begin to use II on the nth
day, and in fortnight II 10 entirely I'M
ished. lfproperly managed there is abso-
stalls; while In heap-roasting there 10 al-
ways q large quantity that must b re-
roasted. Even the flne covering, and the
raging just below it, can be thoroughly
burned in stalls II Q few baskets Of bark or
chips are scattered over the coarse ore be-
eulphurous smoke from stalls 10 mostly
discharged high in the atmosphere through
. tall chimney, thus avoiding the dense
fumes that come from even the smallest
ore heap.
should be glad to enumerate the disad-
vantages Of stall-roasting ascompared with
burning Gin II Sn+S eas sef s.I long Exp
to say on the other side, except that in cass
one has to deal with an. ore carrying q very
high percentage Of iron pyrites, II 10 easier
to prevent mating In heaps than In stalls.
To prevent disappointment, in case my
testimony should give rise to experiments
on the part Of metallurRists who desire to
escape the drawbacks Of heap.roastins.
l must particularly insist on the ,mpor-
tance OF having u strong draft, .whi;ch. Of
course, presupposes large fue, and .
chimney OF sufficient area and height. For
q battery OF thirty stalks, arranged In
double row, back to back, with q fue ex-
tending between the two lines, the main
feet; while the chimney with q correspond
ing inside area, should be carried to =
height Of seventy feet. With an insufh eient
draft. the roasting 10 delayed beyond al.
belief, and the percentage Of sulphur r.
tanned in the ore after tho completion q
the process will DO far from satisfactory.
!n case any considerable am09nt O. mstes
into pieces the size Of the fist, and when
so tons or more have been accumulated, u
should be roasted in heaps in very much
the same manner a. ore. A few necessary
changes, however. must be made. The bed
Of wood should be thicker than Tor ors, and
the matte pile should never be built
more than four and half feet high. Il
should have vents or temporary chimnsys
lormec by placing couple Of sticks Of
corawood In vertical position) Ut dis
tance not greater than six feet from each
other. Whatever fine stun u formed In
breaking the matte should be thrown ON
the heap in conjunction with the coarss. to
roasted ore. A heap Of afty tons, pre-
pared in this manner, will burn TOR .six
the heap should be welle covered with md
days, when the operation Of turning
may be begun, as one burning, or even two,
il seldom sufficient for matte. which differs
entirely from ore in this respect. II should
be turned directly. ON to another bed q
heap. taking care that the lump Of molten
matte which will always be found at the
bottom OF the heap 10 broken into small
pieces and piled directly upon the fresh bed
Of wood. The second burning will take q
week, and may be followed by Q third Il 4
~ desirable to remove the sulphur g
thoroughly 40 possible. The cost Of each
burning may be estimated ct stxty-6ve
cents per ton at present Butte prices q
labor and fuel. II 1t 10 found profitable
this roasted matte may be smslted by lteell
to produce q superior grade q copper. q
the numerous burnings and smeltinp which
it has undergone win have mostly ettmi
may have contained. Az 1t 10 essential Y
add certain amount Of siliceous flux d
smelling this material, any quert-soal
slass rich in copper that may elying abou.
the place will form the most advantageOua
addition, a. the copper produced from
them will be Of the best possible quality.
In most cases the first-class orc forml
. but q small proportion Of the matsria
treated, and We now come to the pFinctpa
ore from which the immense copper matt
product Of Butte II derived, namely, Oh
, concentrates obtained from the second
! class ore. These usually contain about 8
J, per cent. copper, 80 per cent. aulphur, n
9 10 per cent. silica, the balance being prime
= pally iron; and they arc thoroughly g.
cined in long fornAces, heated ~ woot
= worked by two men ON twelve-hour shi1tl
Il oAIcMMo TuRxAcns.
Il The furnaces which have bssns built undo
4 my supervision are e. iest BY 10 lest on
Il side, and have four hsarths, each ~ II
Il long by Is feet wide IN the clear. Ihe q
10 10 CHARGED from 8 hopper upon tho hsarl
m tiurtheet from the erate, "a quantit 49,