The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1922-02-23


siderable depth and length. galloway
are stretched across the excavation
ana by these the rock is lifted 10 th
-drIace and then conveyed to conYen
lent dumping points. In the larger o
the pits these steel lines span an in
terval Of 400 feet and more. Abou
three years ago some OF the ThetfOr,
mines began to abandon the hOistinl
of the quarried material by means o.
these agents and adopted, instead
what is technically known as the
glory hole system" which entaileo
handling Of the stuff by shaft. Sc
well has this innovation worked that il
is authoritatively declared that the
method is likely TO become the prevail
ing one hereafter
/ lserHhtincipnschen now is the time
In a general way the new practice
is a wedding of open cut and under
ground mining, or to be more specific,
the quarrying is done in the open,
while the hauling of the blasted rock
is below ground. The ore reaches the
surface thence by suitable lifts installed
in a main shaft From the main shaft
which is sunk outside but near the
glory hole, as the familiar quarry is
called, are driven levels reaching far
into the asbestos deposits. and from
these levels radiate cros-cuts. The
latter constitute points of departure
for a series of smaller vertical shafts
which rise until they break through
the floor of the glory hole. Their up
permost terminals are funnel shaped
and into them the asbestos bearing
rock is dumped as it is mined. These
mill holes" are the mouths by which
the mineral descends into chutes
which. in turn, discharge into little
mine cars traversing the cross-cuts
below. Trains are then made up of
these laden cars, which travel via the
levels to the main shaft where suita-
BILE connections are made with the
hosting equipment Some of these
shafts reach down to a depth of more
than 800 feet.
After the ore has come out of the |
mine it is then subjected to dressing |
Or "cobbing," /. e., separating the as
)estOs fiber from the rock Mechanical |
means are employed for this service |
save in the treatment of the higher |
grades of the stuff such as Nos. 1 and |
II. where hand dressing is relied upon !
because il is possible only in that way /
10 avoid the inevitable tearing of the |
'iber The workers that do the cob /
ping are experts and they skilfully /
break the asbestos clear from the SER
Dentine by hammer blows. In the first |
iressing they use one hand sledges |
weighing about six pounds and the |
'eleased fiber is screened from the |
shattered rock by 3-16th-inch mesh.
The remaining ore is carried to a sec
md cobbing shed. where most of the
contained asbestos is freed by opera
ives equipped with lighter hammers.
rhe resulting material is then screen
ID twice to get rid of any adhering
oclIy particles and to separate the fl
,ers into grades / and II. This as
,estos is known to the trade as
crude" The refuse from the cobbing
ables and the waste from the screens
re next handled mechanically in
Mill
Mechanical cobbing is done by an
pparatus commonly called the ICY
lone" Briefly the machine consists
of a strong metal cas-
lg that housese two oppOsitely re-
diving propellers. and these throw the ,
ieces of ore at great speed against |
he enVeloping walls or back and forth ,
pom the blades of the opposing rotors. !
4 this way the serpentine and the I
Der are broken apart. BY an induced [
raft the commnuted rock and the \
uffy asbestos are extracted from the |
cyclone" and are next carried over {
lmber of agitated screens which I
,gregate the fiber from the granu 7
ted or pulverized substance. sec t
nj suction system now gathers up the t
ihestos filaments and discharges b
EN- into settling chambers. In pass a
@. it should he said that the original +
ocks of serpentine are reduced in size d
one or more crushers. and that the C
.erage piece so prepared for the 10y
)ne" does not measure more than an p,
ch and a half Furthermore. the l.
oxen ore is put through rotary dry "
S to get rid of the moisture which n
,uld he apt to interfere with the OF
leasing of the asbestos 10y the me- Il
anical cobbers tc
Inasmuch as the filaments are of C,
rious lengths when they reach the W
.uing chambers. it is essential that W
ey be assorted subsequently into til
2 grades known to the trade. This
done by sitting the material through fr
Gems of different sized mesh. With IN
$ work finished, the asbestos is M
cked in bags ready for the manu- st
'tme Of all sorts of asbestos com ct
,dities Asbestos not classed as he
ide agreeably to the requirements No
eady mentioned. is known as fiber" on
mill" asbestos, and while this is ed
suited to spinning and weaving. as ~,