Willmar tribune. [volume] (Willmar, Minn.) 1895-1931, 1910-07-20

more extensively and systematically
pursued in the states of Minas Geraea
and Bahia than elsewhere in BRAZIL
Matte Crosse, Goyaz, and Parana have
yielded sufficient results to justify the
belief that their future as centers Of
diamond production will be prosper
Gus.
The primitive methods of mining
employed in Brazil until recent years
have, nevertheless, abundantly rel
vealed the natural productiveness Cd
the Brazilian diamantiferous deposits.
Two native methods are still very|
largely In use, according to the local.
tty to be worked. The first o. these,
which is found suitable for the dial
mond.bearing streams of the Diaman1
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
8 or 10 pounds. The native miners}
then proceed in Indian file with their
loads to some convenient part of a
river or stream, where they laborious4
~ wash out their material, gradually
getting rid of all lighter particles and
debris until the hidden diamonds,
whose specific gravity is 31s, reveal
themselves through their weight and
peculiar luster. Iron pans with small
perforated holes are sometimes used
to hasten the process of extraction. Al
modification of this plan, where q
considerable pit has been excavated1
consists in finding a curve in the riv.
er some distance above, with natural
fall of 20 or 30 feet, and divertink
thither a part of the stream through
an artificial channel. 7
A different method Of mining has til
be employed in the localities called
"chapadas," or plateaus, where diaj
monds are fmbedded in compact. some1
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 ravine to the desired lower
level, where the process Of further
diamond extraction may be continued.
Primitive as are the processes del
scribed, they have yielded in the past
one hundred and eighty years SUR
prisingly rich returns. According td
the best authorities, the total Bra
lillian diamond production, includina
the extensive contraband trade prac1
tlsed during the Portuguese colonial
regime, Is estimated at 10000 OO0I
carats, or 2k metric tons. The total
export value of diamonds of every sort
from Brazil in 1906 is conservatively
calculated at about $5,000,OOO. !
One OF the first enterprises to INSTALL
dredging and hydraulic machinery for|
the extraction of diamonds such as|
the alluvial diamantiferous deposits od
the Republic require was the Boa Vis1
ia company, in 1899, formed In Paris.
with capital of 100000 francs, or
100000. Their mining concessiona|
were situated at Boa Vista, on theI
north bank of the Sac Francisco river
I above the Falls of Paulo Alfonso, andI
about 300 miles from the Atlantic.
The Brazilian diamond-bearing del
posits so far discovered are all allul
vial and surface, and they possessj
many natural advantages over the dia-
mantiferous fields of South Africa
which, as has already been explained
are dry diggings,' requiring the most|
expensive processes and machinerv
and every device that human ingenu1
ity can invent for the successful ex1
traction Of diamonds. In Brazil, on]
the other hand, the diamonds COM
cealed can be easily extracted BY
means of hydraulic and dredging apl
paratus. A network of rivers and
streams affords an unfailing 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 gra>els in
many cases carry enough gold to pay
for dredging, and even platinum may
be found.