Freeland tribune. (Freeland, Pa.) 1888-1921, 1897-11-08
MINING FOR DIAMONDS.
GRAPHIC DESCRIPTION OF THE
METHODS IN SOUTH AFRICA.

| more Inan len IONS OF the Precious
Stones Since opened-valuabIe Dia-
monds Sometimes Explode in the Hand
"Under the conditions present in
natures laboratory the wonder is not
that diamonds are found as big as ones
fist, but that they are not found as big
as ones head"
The above impressive sentence was
spoken by Professor William Crookes
in a remarkable lecture upon the sub
lect of diamonds given at the Royal
Institution in London recently. This
lecture is the most interesting and au-
thoritative exposition of Crooke's, who
is one of the foremost chemists and
physicists of our day, made trip of
inspection early last year to the Afri-
can diamond fields, and gave in his re-
cent speech the results of his travels
abroad and of the experiments in his
laboratory at home.
The most noted diamond mines, the
Kimberley, the De Beers, the Dutoit-
span, the Bulfontein and the Vessel
ton, are all contained in q circle of
ground three and one-half miles in di-
ameter. The mines proper are irreg-
ularly shaped round or oval pipes ex-
tending vertically downward to an un-
known depth. They are filled with
broken fragments of various rocks ce-
mented together by hard blue clay,
called "blue ground" in which the
diamonds are found. At first the mines
were worked from above, as stone
quarry or gravel pit is worked, but
that system proved unsatisfactory, and
at present underground workings are
the rule. In early days they belonged
to different people and different COM
panies, but they have gradually fallen
into the hands of one rich concern,
the De Beers Consolidated Mines,
Limited, which to-day owns practical
ly all the valuable diamond mines in
this region. The method of mining is
to sink shafts in the solid rock at
some distance from the diamond pipes,
and then run in tunnels to the "blue
ground" which is cut away and mined
out by peculiar system that enables
the miner to take out all valuable ma
terial and leave the refuse rock behind.
Pro.sssor Crookes says of this mining:
'The scene below ground in the
labyrinth of galleries is bewildering
in its complexity and very unlike the
popular notion of diamond mine. All
below is dirt, mud, CRIME; half-naked
men, black as ebony, muscular as ath-
letes, dripping with perspiration, are
seen in every direction, hammering,
picking, shoveling, wheeling the trucks
to and fro, keeping up q weird chant,
which rises in force and rhythm when
q titanic task calls for excessive mus
cular strain. The whole scene is more
suggestive of coal mine than diamond
mine, and all this mighty organiza-
tion, this strenuous expenditure of
energy, this costly machinery, this
ceaseless toll of skilled and black la
Dor, goes on day and night just to win
a few stones wherewith to deck my
lady's finger"
The work Immediately after the
"blue ground" leaves the mines looks
more like farming than mining. When
the "blue ground" is brought to the
surface it is as hard as sandstone, and
has to he exposed to the influence of
the sun, the air and water to prepare
it for the pulverization necessary later
in the world. The hard Jumps and
powders are spread out on the floor,
exposed to the weather, and are al
lowed to stay there with occasional
waterings and harrowings until they
begin to crumble very readily. The
friable mass resulting is then taken to
revolving, perforated cylinders, in
which it is agitated for some time with
water. Refractory Jumps which re-
fuse to pass through the holes are
taken back for more weathering. The
material running through the perfora-
tlons is led to immense pans, provided
with ten arms, in which teeth are set
spirally. When these arms revolve
and when plenty of water is made to
flow over tie pans the very light stuff
is carried away by the waste pipe in
the centre, while the coarse material
containing the diamond collects
around the edges of the pan. By a
somewhat similar arrangement this
diamantiferous gravel is concentrated
until the diamonds can be picked out
by hand. The men who pick over the
coarsest gravel are the most trust
worthy employees, since, of course, the
most valuable diamonds are found
there. Sometimes as much as $780,
600 worth of diamonds is separated in
one day. From the sortingroom they
go to the office, to be cleaned and
sorted according to value. In this
Office may be seen heaps containing
white, black, cinnamon, blue, green,
pink and orange diamonds. 1t is
quite remarkable that the diamonds of
different mines possess certain dis
motive characteristics which enable
experts to know at once from what
mine each stone came.
Large diamonds are rather common;
it would be quite easy to collect in
Kimberley a hundred gems which
would weigh an ounce apiece. Pro-
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