Perth Amboy evening news., 1922-09-01
Geographic News
Bulletins by the
National Geographic Society
How Diamonds Arc Mined

~ IuoA SuCh al
ica knew in its free-land days, pus
in this case to peg out claims III a
newly discovered diamond neId was
mentioned in recent dispatches from
South Africa. This new
country opens up possibilities OF a
rival to the great Kimberly dia-
mcnd field in the same general re-
gion, the worlds greatest source OF
the sparkling white gems
The methods of mining DIAMONDS
at Kimberly. which may be follow
ed in the new fields ii the formation
proves the same, are outlined IN a
! bulletin from the Washington, -. c.,
headquarters OF the National Geo.
graphic Society.
Like Needle in Haystack
THE mines at Kimberly" says
the bulletin. ARE in very ancient
volcanoes which ages ago lost all
semblance of activity. But during
their youth the great heat ana pres
sure of these volcanoes created 81
gantic laboratories in their depths
in which thousands of the hdrd
white carbon crystals, which are dia-
monds, were created. The precious
little Jumps are embedded IL a
great volume of worthless rock
known as blue ground and under
old conditions were as hard TO ma
as the ~proverbial needle in a nay
stack. But just as a clever searcner
could probably locate his needle win
a powerful magnet, despite the
straw. so engineers have eVolved
mechanical means cleverly to seQa''
rate the few tiny diamonds from
the many tons of dirt in which they
are hidden.
The effectiveness with which Ma
49, . 10
| evidenced by the fact that the bile
ground brought up from the depths
! of the mines and carrying its price
less gems, is spread out in the open
for four months to a year to h
weather. The diamonds are perfect
Ily safe, for officials who have walk
ed yer the weathering floors for
many years assert that they have
never found a diamond in this way.
AS the blue ground weathers 1t
crumbles and great harrows like
those used on the bonanza farms OF
the West r dragged over 1t to
facilitate the process.
Gems Trapped in Grease
Eventually the material is broker
down into relatively fine particles.
1t is then taken in truck-loads to
the mechanical plant of the nine
for treatment. The ground is mixed
with water in great mixing machines
and passed over screens of fine wire
meshing.
When as much as possible Of the
foreign material has been removed
in this way, the coarse residue. con-
tanning the diamonds. is passed over
sloping, vibrating tables covered
with thick grease. Because Of some
little understood physical property.
Il 10 - - L., Cktnly % tho rnnc>
the worthless material flows over
the edge of the tables. The grease
with its load Of crystals is then
scraped into a perforated contanier
and heated by steam. The grease
melts away and leaves the small hut
highly valuable objecti of these
months Of work.
How widely spaced the diamonds
are in their matrix Of earth can be
shown best perhaps by a comparison
of volumes. The earth taken out in
a yea by the largest mining COM
pany in the field, would form a cube
more than 430 feet In each d!men-
sion. This would fill a large city
stories. The diamonds found in this
vast amount of earth would fill only
two oil three desk drawers or a cubi-
cal box three feet in each dimen-
sion. But these few pecks of stones
for which a mountain was moved
were worth perhaps in excess of
s25,000,000
Laborers Voluntary ExiIes
Zone of the most striking fea-
lures Of the mining of DIAMONDS by
the large companies in Kimberly is
the existence Of the unique labor
compounds. Since diamonds are SO
easily stolen. only those native la
borers are employed. who will agree
and remain for that period, (when
not in the mines, or on the 'loors')
within a walled enclosure. In the
largest compound, covering more
than four acres, 5000 men live. Not
only are these compounds surround
ed by high walls. but they are aiso
covered overhead by fine wire net
ting so that diamonds cannot be
thrown outside to confederates.
"Laborers entering or leaving a
compound must go through a pro-
cedure not unlike that when enter
ing a foreign country having strict
immigration and custom laws. They
must pass a health examination and
quarantine. Only certain articles
may be taken into a compound. and
no boots, shoes or other hard or
solid materials may be taken out
only clothing which has been search
ed. In the largest of the compounds,
where some laborers have chosen to
stay for years. are stores, a church,
a school, a hospital and dispensary,
athletic grounds and a swimming
pool. The manager Of the COM
pound is a sort of mayor and Judge
rolled into n and Is called upon to
L dacida MI ara bla diSni.4orO