Big companies had gone out of existence, and everybody
spoke of hard times.
The principal diamond mines worked are the Kimberley,
the De Beers, Du Toit’s Pan, and Bultfontein.*
The Kimberley Mine is a huge quarry situate in the
town. I t is about 500 feet in depth, measured by plumb
line to the centre. The mine was being worked by five
different companies.
The mode of excavating was a simple system of quarrying
and blasting, for which dynamite was used, the explosions
taking place at mid-day and midnight respectively. The
richness of the diamond treasure that has been taken
from the crater is fabulous. Statistics say that from two
to three millions of pounds sterling per annum have represented
the aggregate value of the output of the mines.
Prospect channels and shafts seemed to be run, but to a
very trifling extent. The excavations are sent up on steel
wire rope “ roads,” the various companies having their
respective hoisting works leading from the depths of the
gradually lessening area of the basin. Two heavy wire
ropes form the “ roads.” They run parallel, and are
stretched tightly from the pit head through the air and
down to an anchorage at the bottom of the mine. These
ropes are the rails, so to speak, on which run the flanged
wheels of the skip or cage. This system of hoisting is
quite unique, and very effective for the class of work
carried on at the diamond mines.
The soft blue rock in which the gems are found decom-
* A Standard (23rd April, 1886) correspondent, writing from Kimberley,
gives the following s t a t i s t i c s _
Assessed Value o f Mines.-—Kimberley, £2,805,635 ; De Beers, £934,737;
Du Toit’s Pan, £1,283,591; Bultfontein, £682,266.
Value o f Diamonds exported from Kimberley.—1883, £2,742,521;
1884, £2,807,288; 1885, £2,492,755.
poses under atmospheric and aqueous action. I t is taken
from the mine and spread over large spaces covering
acres of land, where it is left exposed to the sun, while it is
wetted at intervals by means of a hose, and broken by large
hammers. This process of disintegration goes on for about
two months, when the jewelled earth is taken to the mill.
An exceedingly simple and unscientific contrivance is
this mill. The blue gravel first passes through a tapered
cylindrical sieve, revolving in a horizontal position. I t is
thrown in at the small end of the sieve, and after its course
along the inclined plane the refuse is thrown out at the
other end. Thé stuff which falls through the meshes is
conducted by a sluice into a sort of settler, consisting of a
big tub about ten feet in diameter having a vertical central
driving shaft, about which revolve four arms fitted with long
teeth, which reach close to the bottom of the settler. This
keeps the pulp constantly agitated, and, with the regular
stream of water which is kept flowing, the waste and light
sands are carried through an overflow on the inner edge of
the settler. The refuse is akin to “ tailings” in gold
mining. Diamond tailings, I understand, are not worth
much. The tailings flow directly into a small well, where
a dredger, or bucket pump, lifts them to an elevation of
about fifteen feet. From that elevation the trucks deposit
them in all directions, so that they form a large sand
bank.
The sands, or gravel rather, which are taken from the
bottom of this tub or settler are passed over four wire
screens of different-sized meshes, the last being very fine.
All the gravel is then placed on iron-faced tables. By
means of a kind of steel trowel it is sorted, and the diamonds
picked out. The sand last screened, which is the very
finest, is dried in the sun, and given to the Kaffirs to sort ;