Daily Kennebec journal., 1896-11-18

ol Reaaskabls esld deposits Discovered Ia
Alaska.

Wonderful news is brought by a
geological survey expedition which has
Just returned from Alaska. under the
leadership of J. E. Spur. 1t is moth
ing less than the discovery in Uncle
Sans Arctic province Of an immense
gold belt, which promises to rival in
productiveness the mines of South
Africa. Unlimited quantities of ore
are actually in sight. the auriferous
area being not less than 500 miles long.
with a width of from so to 100 miles,
writes Rene Bache to the Boston Tran
script.
This expedition was sent out last
spring for the purpose OF ascertainihs,
if possible, the source OF the goid
found in the placers Of the Yukon val
ley. During the last three years there
has been a rush of miners to tnat
region. where the yellow metal is OBJ
tanned so abundantly as to yield ex-
cellent returns, notwithstanding the
difficulties involved in getting u. me
country has no resources worth men
tioning, so that even the resident IN
dams are half starved, not being able
to catch enough fish to supply their
wants. Consequently, provisions and
supplies Of all sorts for the miners
must be fetched from the state of
washington or from California, in
volying great cost. The expense of
transporting machinery is proportion
ate, and thus it comes about that the
workers employ the most primitive
means for securing the gold.
The placers occur in gullies through
which streams flow. The courses of
the streams are altered from time to
time, and so it happens that the entire
bottom of each gully is covered COM
monty with gravels that have been
brought by the water. The streams,
wearing the gold bearing rocks, have
carried down from the hills their bur-
den of detritus during thousands of
years. Naturally, the lighter stuff
was borne away by the currents, while
the heavier particles including the
gold sank to the bottom. Thus was
formed at the bottom of each gully a
sort of auriferous concentrate. Miners
wash thase gravels by means of sluice-
boxes, which are long inclined troughs.
with cleats at the lower end. Through
each trough a continuous stream of
water is made to flow, while the gravel
is shovelled into the upper end. The
gravel is carried off by the water,
while the gold sinks to the bottom of
the trough and is retained by the
cleats. 1t will be seen that this is
merely an adoption of the natural
method by which gold is accumulated
in, cft M hodc Of a uond doo
of the metal escapes with the gravel,
so that it pays to work over the
"tailngs.'
Now, 1t is obvious that the gold in
the gravels must come from some
where. 1t has been realized that the
original source Of supply existed in
rich gold-bearing rocks undiscovered
up to date. The expedition of the
Geological Survey was sent out for the
purpose of locating these rocks. and
with orders to gather all obtainable
facts respecting their geological forma-
ton, extent, etc. This has been most
satisfactorily accomplished by Mr..
Spur and his assistants, who have
brought back with them specimens to
show the richness of the deposits. The
auriferous belt passes from British
territory into American in the neigh
borhood of Forty Mile Creek. 1t has a
northwesterly trend, and keeps on par
allel to the Yukon on the northeast
and to the Tanana river on the south
west. 1t crosses the Yukon just below
the main bend of that great stream,
l. e., near the mouth of the Porcupine
river. Thence it trends still to the
northwest, and probably it continues
farther in the same general direction:
but the rest of that country remains
up to the present an unknown land.
The survey made by the expedition
proves that the gold belt is at least SOC
= miles in length. it's width being as
much as 100 miles in some parts. 1t
runs through a range of low noun
tains, which are composed chiefly OF
schists, gneiss and granite. Near the
rivers the land is covered with forests
but the hill are bare of trees. On the
slopes above the tree line grows q
thick moss. covering the rocks. 1t is
only on the higher levels, where the
rocks are bare, that the gold deposits
can be located easily. Occasionally
one can see the gold on the surface OF
the rocks, showing in bright yellow
specks. Some of these specks are big
enough to be observed with the naked
eye. while others are visible only with
the aid Of magnifying glass.
The gold-bearing formation is very
ancient. and its geological history is
quite complicated. Ages ago thai
whole region was under water, and or
the bottom was laid down sediment
ary deposit which eventually became
rock. In the course of time there oc-
Cured q great outburst of subter-
ranean fire, and great quantities OF
volcanic stuff were forced up through
the sedimentary layer Thus today
the sedimentary rocks are found mixed
up to considerable extent with vol
canic rock. All this business required
an enormous length of time. Mean,
while the crust of the earth wasunder-
gong important structural changes
ana its contraction or possibly other
causes folded the layer described into
series of huge corrugations, formine
ranges OF hills with valleys between
The folding process cracked the lave,
in all directions, and after a bit ho,
solutions bearing silica and gold were
poured into the cracks and creyices
The silica and gold were deposited b,
the solutions in the cracks. filline