The Superior times. [volume] (Superior, Wis.) 1870-1912, 1910-07-16
GkEEE4L IN QVEIEL4-'

lty to be worked The first of these.
which is found suitable for the dia.
mond- bearing streams OF the Diaman-
tina district, somewhat resembles
placer gold washing The process con-
sists primarily in digging out sand
and gravel. which are put into small
wooden bowls, each capable OF holding
5 or 10 pounds. The native miners
then proceed in Indian file with their
loads 10 some convenient part of a
river or stream, where they laborious.
ly wash out their material gradually
getting rid of all lighter particles and
debris until the hidden diamonds,
whose specific gravity is 81, reveal
themselves through their weight and
peculiar luster. Iron pans with smsll
perforated holes are sometimes used
10 hasten the process Of extraction 4
modification OF this plan, where
considerable pit has been excayated,
consists In finding a curve in the riy.
er some distance above, with a natural
fall OF 30 or 80 feet. and diyerting
thither part of the stream through
an artificial channel.
A different method o. mining has 10
be employed in the localities called
'chapadas," or plateaus, where dia.
monds are imbedded In compact, some.
what resistant, conglomerates. A
small reservoir, or If necessary. two
or three reservoirs, are britt, rude
dams are placed al various points
across the nearest available river. and
with the increased water power thus
obtained the cong,omcrates are washed
down a rayire &c the desired l1wer
level where the process Of fur her
diamond extraction may be continued.
Primitive as arc the processes g..
sor.1sA they have yielded in the past
one hundred and eighty years sur.
g~.singiy rich returns According t.
the best authorities. the total Bra.
lillian diamond production. including
the extensive contraband trade prac-
tised during the Portuguese colonial
regime. Is estimated at u 100000
carats, or 2i2 metric tons. The tots.
export value Of diamonds OF every sor,
from Brazil in 1905 IN conservatives
calculated al about s5,00O.0O0
One OF the first enterprises to inst,
dredging and hydraulic machinery K,
the extraction Of diamonds such q.
the alluyial diamantiterous deposits OF
the Republic require Was the Boa Wis
Ia company IN 1890 formed in Paris.
with a capital OF 100000 francs. or
100000. Their mining concessions
-or- 8 - ~ al Boa Vista. on the
north bank u. tic So Francisco river
above the Falls OF Paulo Alfonso. ana
aecN; sos miles from the Atlantic.
The Brazilian diamord,bearlng da
posts so far discovered are all aIm
val and surface. and they possess
laany natural advantages over the dta.
mantiievor fsldS OF South Africa
which, as mas already been EXPLAINED.
are dry diggiugs, requiring the mos.
expensive processes and n.shf-e-y
and every device hat human .genu-
lty can invent for the successful *.
traction a. diamonds In Brazil .
the other hand. the diamonds con.
Cealed can De easily extracted b.
means Of hydraulic snd dredging au-
paratus. \ aetwork Of rivers and
streams affords ar uufaiinE ari -.
pious water supply and power. There
is no deep mining to be done As is
the case IN south Africa Only q yer, .
small portion Of the probable total
brazilian alluvium has been explored
and The river grayels, except in IT,
reaches Of only moderate depth are
untouched. Moreover. these Eravels in
many cases carry enough gold 10 ~
for dredging. and even platinum NAV
be found