The Greenville journal. [volume] (Greenville, Ohio) 1850-1918, 1910-07-14

more extensively and systematically
pursued in the states of Minas Geraes
and Bahia than elsewhere in Brazil,
Matto Crosse, Goyaz, and Parana have
yielded sufficient results to justify the
belief that their future as centers oi
diamond production will be prosper
Gus.
The primitive methods Of mining
employed in Brazil until recent years
have, nevertheless, abundantly re-
vealed the natural productiveness OF
the Brazilian diamantiferous deposits.
Two native methods are still very
largely in use, according to the local. |
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
| or 10 pounds. The native miners
then proceed in Indian file with their
loads to some convenient part of
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 31s, 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
considerable pit has been excavated,
consists in finding curve in the riV-
er some distance above, with natural
fall of 20 or 30 feet, and diverting
thither part of the stream through
an artificial channel.
A different method of mining has to
be employed in the localities called
"chapadas," or plateaus, where dia-
monds are imbedded In compact, some
what resistant, conglomerates. A
small reservoir, or IL 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 conglomerat2s 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 to
. the best authorities, the total Bra.
! lillian diamond production, including
g the extensixe contraband trade prac,
r tised during the Portuguese colonial
J. regime, is estimated at $4,000, 900
}, carats, or 215 metric tons. The total
h export value OF diamonds Of every sort
2 from Brazil in 1906 is conservatiVely
+ calculated at about $5,000,000.
h One of the first enterprises to install
l. dredging and hydraulic machinery for
: the extraction of diamonds such as
l. the alluvial diamantiferous deposits oi
Q the Republic require was the Boa Wis
n ia company, in 1899, formed in Paris
=, with a capital of 100000 francs, ol
l, S400,000. Their mining concession.
d were situated at Boa Vista, on thu
north bank of the Sac Francisco river
h above the Falls of Paulo Alfonso, anC
q about 300 miles from the Atlantic.
d The Brazilian diamond-bearing de
d posits so far discovered are all allu
e vial and surface, and they possess
Is many natural advantages over the dia
d mantiferous fields of South Africa
a. which, as has already been explained
n are dry diggings,' requiring the mos
e expensive processes and machiner.
If and every device that human ingenu
1t ity can invent for the successful e1
n- traction of diamonds. In Brazil, o.
I'd the other hand, the diamonds cor
O. cealed can be easily extracted b
% means of hydraulic and dredging eI
8. paratus. A network Of rivers an
u streams affords an unfailing and CT
O. pious water supply and power. Their
5. is no deep mining to be done, as
20 the case in South Africa. Only yer
n small portion Of the probable tota
10 Brazilian alluvium has been explored
s, and the river graVels, except in tn
=, reaches of only moderate depth, ar
IT, untouched. Moreover, these gravels 1
In many cases carry enough gold to pa
for dredging, and even platinum ma
IN be found.