Wauwatosa news. [volume] (Wauwatosa, Wis.) 1900-1948, 1910-07-15

ity 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
S or 10 pounds. The native miners
then proceed In Indian Ale with their
loads to 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 3h, reveal
themselves through their weight and
peculiar luster Iron pans with small
perforated holes are sometimes used
to hasten the process of extraction. A
modification of this plan, where a
considerable pit has been excavated.
consists in finding a curve in the riv-
@r some distance above, with a natural
fall of 30 or 80 feet, and diverting
thither a part of the stream through
an artificial channel
A different method OF mining has to-
be employed in the localities called
"chapadas," or pIateaus, where dia-
monds are imbcdded In compact, some
what resistant, conglomerates. Al
small reservoir. or If necessary, two
or three reservoirs, are built, rude
dams are placed at various points
| across the nearest available river. and
With the increased water power thus
obtained the conglomerates are washed
| down a raVine TO the desired lower
level, where the process of further
diamond extraction may be continued.
Primitive as are the processes de.
| scribed, they have yielded in the past
! one hundred and eighty years sur
| prisingly rich returns. According toA
the best authorities, the total Rra
lillian diamond production. including
the extensive contraband trade prac-
used during the Portuguese colonial
regime, is estimated at 10000 00O
carats, or 2la metric tons The total
export value Of diamonds OF every sort
from Brazil in 1906 is conservatiyely
calculated at about $5,000,000.
One of the first enterprises to install
dredging and hydraulic machinery for
the extraction Of diamonds such as
the aliuvial diamantiferOus deposits OF
the Republic require was the Boa Wis
Ia company, in 1899, formed In Paris.
with a capital of 2,000,000 francs, or
100000. Their mining concessions
We're situated at Boa Vista, on the
north bank OF the Sac Francisco river
above the Falls of Paulo Alfonso. and
about 300 miles from the Atlantic.
The Brazilian diamond bearing de-
posits so far discovered are all aIlra
vial and surface. and they pggses~
many natural advantages over the dIa4
mantiferous fields of South Africaj
which, as has already been explained
are dry diggings,' requiring the most.
expensive processes and machinery.
and every device that human ingenuj
ity can invent for the successful ex1
traction of diamonds. In Brazil onl
The other hand, the diamonds con,
cealed can be easily extracted bv
means OF hydraulic and dredging an
paratus, A network OF rivers and
streams affords an nnfailing and co.
pious water supply and power. There
Is no deep mining to be done. as is
the case in South Africa Only a very
small portion Of the probable total
Brazilian alluvium has been explored.
and the river gravels except in the
reaches OF only moderate depth, are
untouched. Moreover. these graveIs i'm
many cases carry enough gold 10 nav
ioF Dredging, and even platinum may
be found