an interest in the subject, and yet but little more than was needed to
impart the information necessary for following the further development
of the theme, we approach the discoveries in this connection which have
specially distinguished our century. We must transfer the reader’s
attention to South Africa, and if he can refer to any recent map of that
region, particularly to one showing its physical features, it will be of
advantage.
In 1867 some children, playing near the banks of the Orange River, found
what they thought to be merely a pebble prettier than the rest. A
neighbour seeing the stone in the children’s possession, obtained it
from their mother for a trifle. It passed through several hands, and was
bought at last by the Governor of the colony for £500. The discovery
shortly afterwards of other diamonds in the same locality attracted
numbers of persons to the district, and especially to the banks of the
Vaal River, which speedily became the scene of a great search for
diamonds. Though this search was confined to merely the surface of the
soil, it was attended with considerable success, and many fine diamonds
rewarded the diligence of the eager seekers. One of the most remarkable
stones for its great size, which equalled that of a walnut, was
discovered by a Kaffir. When this gem had finally reached the hands of
Messrs. Hunt and Roskell, of London, its value was estimated at no less
than £25,000. News of these discoveries having spread, a rush set in for
the diamond-fields of the Vaal River, and the banks of this stream soon
presented an animated spectacle. Europeans flocked to the spot, London
jewellers sent agents, and the inevitable Jews appeared on the scene to
purchase the precious gems from the lucky finders. It turned out that
many of the larger stones had a slightly yellow tinge, varying in
different specimens from the palest straw to a decided amber colour,
and, as this detracted greatly from their value, no little
disappointment and loss were sometimes experienced when the gems came to
be sold in London and Paris.
One of the first settlements which sprang up on the banks of the Vaal
River was a place called Pniel, of which the reader may form some idea
from Fig. 332, which is copied from a sketch actually taken from the
windows of Jardine’s Hotel. It was then only a little straggling
village, chiefly of wooden sheds or corrugated iron erections, with but
two or three more substantial structures. The diamonds which were found
in this neighbourhood were obtained from gravel which lay on the slopes
of the hills rising from the river. The mode of conducting the search
for diamonds in these gravels was simple enough. The first operation was
the washing of the material, in order to remove sand and dirt, and this
process was usually performed at the margin of the river, where the
gravel was brought down in carts and deposited in a suitable place, at
which a cradle was erected. The cradle was simply a strong wooden
framing sustaining sieves of wirework or perforated metal, placed one
above the other, those at the top having the largest meshes, so that the
lowest would only permit sand or very small pebbles to pass through. The
cradle was capable of receiving a rocking movement, and while the gravel
was thus sorted, water was freely poured on the uppermost layer, so that
the stuff was in a short time thoroughly cleansed and sorted. When this
had been accomplished, the gravel was thrown in successive lots on a
table, at which the digger sat and rapidly examined it for diamonds by
help of a flat piece of wood or iron (see Fig. 328). The larger gems
were readily detected, and indeed could be picked out from among the
pebbles on the sieve before the stuff was thrown on the sorting-table.
Crystals of quartz, which sometimes glisten among the mass, often
excited groundless delight in the bosom of the inexperienced worker.
[Illustration:
FIG. 332.—_Pniel, from Jardine’s Hotel_ (_c._ 1870).
]
On the payment of certain fees, the digger obtained a “claim,”—that is,
he acquired the right of working an assigned portion of the soil. But if
the claim had been left unworked for a week, it might be, in mining
parlance, “jumped”—that is, any person might take possession of it, or
jump into it, on procuring a proper licence.
Since the first rush of diamond-seekers to the river-banks, the stones
were abundantly found elsewhere, namely, at the “dry diggings,” where
the soil, dug out with a pick or shovel, was sifted first through rough
sieves, afterwards through sieves having fine wire meshes The sieve, in
such cases, was often suspended by thongs of hide between two upright
poles, in the manner represented in Fig. 333. The miner was thus enabled
to swing the sieve rapidly about, until the sand and dirt were
separated, when the remaining gravel was emptied on the sorting-table in
the manner before described. As the idea was formerly entertained that
diamonds lie only on or near the surface of the soil, the early miners
seldom penetrated more than a foot or two beneath the surface. But it
was discovered that, so far from it being true that diamonds are present
in superficial deposits only, the finest stones are met with at
considerable depths to which no defined limit can be assigned; thus in
sinking a well large diamonds have been found at 100 ft. below the
surface. When these facts became known, many of the abandoned claims
were worked over again down to a depth of 30 ft. or 40 ft.
[Illustration:
FIG. 333.—_Sifting at the “Dry Diggings”_ (_c._ 1870).
]
The rapid rise of localities under such conditions may be illustrated by
the case of Du Toit’s Pan, which is the centre of a dry-digging
district, and grew in a wonderfully short space of time from nothing to
be a town hiving several large hotels, two churches, several public
billiard-rooms, a hospital, and a theatre. In 1871 the _claims_ at this
place, each 30 ft. square, sold at prices varying from £1 to £50–-the
person who worked a claim paying also a small monthly sum for the
licence. But those who were lucky enough to have obtained the first
possession of the claims at another famous dry-digging locality, named
Colesberg Kopje, at the cost of only the licence at 10_s._ per month,
must have been still more fortunate, and have realized an enormous
percentage on their investments; for, four months afterwards the ruling
prices at the last-mentioned place were £2,000 and £4,000 per claim.
This great increase in value cannot be wondered at, if the accounts
related of the value of the diamonds found here are true. For instance,
it is stated that one individual, who just before the great rush had
bought a claim for £50, found in it diamonds worth £20,000. Colesberg
has become a populous town, with good buildings and regularly laid-out
streets, while a great camp of tents and other temporary structures
still surround it on all sides.
At all the towns above-mentioned newspapers were published, relating
chiefly to matters interesting to the miners—giving, for example, lists
of “finds,” with the names of the lucky finders. It is curious that the
term “diamondiferous” has, in these localities, come to be used as a
general term denoting excellence of any kind. Thus, when it is desired
to apply an epithet of superlative praise to a pickaxe or to a piece of
furniture, this significant adjective is made use of; and a salesman in
the diamond-fields will not hesitate to speak of _diamondiferous_ coats
and trousers!
[Illustration:
FIG. 334.—_The Vaal River, from Spence Kopje_ (_c._ 1870).
]
It will be seen that the early diamond-seekers at the Cape followed very
primitive methods, by simply washing in sieves the gravel and sand
shovelled out of the river banks; and indeed, it was only when, about
1871, they began to dig deeper that their working seems entitled to be
called mining. The “dry-digging” operations began at the since famous Du
Toit’s Pan, by the circumstance of a Boer farmer finding to his great
surprise diamonds sticking in the walls of his house, which had been
built of mud. When the locality of this mud was examined by digging,
more diamonds were found; and when the excavation was continued
downwards, still more. At this place and at four others, all within a
circuit of less than four miles diameter, have been developed the
richest diamond _mines_ in the world, throwing into the shade the
produce of all the river gravel washings; and what is still more
remarkable, showing no signs of exhaustion after nearly thirty years of
working, but rather the contrary. The locality soon presented a scene of
the most active industry, and it was not long before the town sprang up
which has since become celebrated all the world over—Kimberley, the
diamond capital. Kimberley is situated at the northern part of the
British territory known as Cape Colony, not far within its boundary, and
about 14 miles from the Vaal River, in Lat. 28° 43´ S., Long. 24° 46´ E.
It lies in a north-easterly direction from Cape Town, at a distance of
about 550 miles. When the existence of diamonds at the Cape became
known, a great influx of strangers seeking fortune set in to a land that
had failed to offer the attractions to colonists that America and
Australia did. Before the establishment of the overland route opened a
more direct way to India, China, and Australia, Cape Colony owed
whatever importance it had to its position as a provisioning and coaling
station for ships and steamers. As a British settlement it was little
regarded, and its somewhat somnolent condition would have been deepened
by the opening of the Suez Canal in 1869, had not the diamond discovery
in that very same year brought about a great change. But the early
diamond-seekers found their land of promise a wilderness without roads
and without habitations, for the development of civilization did not
then extend far from the coast. It is true, that here and there, at
great distances apart, a few primitive missionary stations might be
found, like that of Pniel shown in one of our cuts, which also represent
the inhospitable aspect of the country. One cannot but admire the pluck
of the adventurers, who, though unversed in their quest, encountered in
its prosecution prolonged toils and many hardships. But they were young
men, and their perseverance gained its reward. They came from all parts:
from Britain, from America, from Australia, from Germany, even from
Russia.
The finding at Du Toit’s Pan, and at contiguous places, of diamonds at
some depth below the surface of the soil, led to geological examinations
of the district, which ultimately resulted in discoveries of the highest
interest and importance, as will now be explained, with first a few
words about the external features of the country.
A traveller directing his steps northward from the sea-shore at almost
any part of the southern coast of Cape Colony will be faced by several
successive ranges of mountains, or what will appear to be such, running
more or less parallel to the coast, and of no great elevation. When he
has reached the summits of these heights he will not find corresponding
declivities on the northern side, but nearly level plains, bounded
northwards by other similar ranges. Supposing him to set out at a point,
say, 150 miles east of Cape Agulhas (the most southern point of Africa),
he will, about 50 miles from the shore, have reached the top of the
third of the great escarpments which rise up like the stages of a
gigantic terrace, and having thus gained the ridge of the Black
Mountains, he will see one of these almost level plains stretching
before him a breadth of 80 miles, for the most part arid and
inhospitable, with a much greater length east and west, and bounded on
the north by a portion of the range of elevations that in an almost
unbroken line runs through Cape Colony to Delagoa Bay nearly parallel
with the coast, at a distance from it between 100 and 150 miles. This
extensive plain is known as the _Groot Karoo_ (Great Karoo),—_karoo_
being the generic name for such plains in South Africa. After crossing
the Great Karoo, our traveller, on mounting the last far-reaching step
of the Brobdignagian staircase, may find himself on the summit of the
Nieuveldt Mountains, at an altitude of nearly 10,000 feet above the
sea-level, attained in several widely separated stages within a distance
of 140 miles. From the summit of these elevations there is no descent by
terraces northwards, but the high tableland or plateau stretches away
for hundreds of miles, descending by only a gentle slope towards the
Orange River, but maintaining an average altitude of nearly 6,000 feet,
and extending far beyond the Orange River towards the Equator. Kimberley
is situated about 50 miles north of the Orange River, and 4,042 feet
above the sea-level.
It was soon observed that the Karoos had common geological characters,
consisting in a certain series of shales, coal, limestones, etc., and
this series naturally came to be called the “Karoo formation,” just as
we in England speak of the Wealden formation, etc.; and it was found
that it extended over a greater part of Central South Africa, covering
an area of at least 200,000 square miles, with an estimated thickness of
5,000 feet. The reader need not imagine that a boring nearly a mile in
depth had to be made for the ascertainment of this last dimension, if he
will remember what has been said in the last paragraph about escarpments
of the rocks looking everywhere towards the coast. There is reason to
believe that these beds were originally the sedimentary deposits of a
vast fresh-water lake, or inland sea, far back in geological times. But
here we need only concern ourselves with the development of the Karoo
beds about Kimberley. There the ground is covered by a sandy soil of a
red colour, for it contains much iron. Below this there is a layer of
decomposed basalt, also containing much iron, its thickness varying from
20 to 90 feet. This lies upon a bed of very combustible shale, with
carbon and iron pyrites, 250 feet thick, which from its great
development here is known as Kimberley shale; then, after a conglomerate
stratum 10 feet thick, is found a very hard compact rock, resembling
hornblende, extending 400 feet downwards, and resting on another hard
rock of quartz, also 400 feet in depth. These beds are _nearly_
horizontal, but dipping a little towards the north. In speaking of them
collectively we may use the local term of the miners and call them “the
reef.”
Now, there are a few certain spots near Kimberley, and two or three
elsewhere, in which the strata forming “the reef” are not found, but
something quite different. These may be compared to large dry wells,
extending vertically downwards to unknown depths, which have been filled
up with matters from below. They are called _pipes_, but they are
uncommonly large ones; for though of a somewhat irregular circular or
oval shape, their diameters range from 200 to 500 feet. Nor must it be
supposed that the enclosing reef presents itself as a smooth wall, as
the name “pipe” might suggest. These _pipes_ are true diamond mines.
They are believed to have been formed by an eruptive action originating
from below at a great depth, and this was not by the escape of red-hot
lava or other molten rocks, but by that of steam or other gases. It is
known that the eruptive forces acted from below, for the edges of some
of the strata are seen in places in the walls of the reef that surround
the pipes to be turned a little _upwards_. It is known that the erupted
matter was not molten lava or rock, for the shale and other strata show
none of those changes of character near the pipes which would have
resulted from igneous action, and for the same reason the gas or steam
that escaped by these pipes could not have been highly heated. It must
therefore have forced its way through the strata by enormous tension or
pressure, and this either at one terrific outburst or possibly by the
gradual enlargement of smaller volcanic chimneys. These blow-holes are
filled with a mixture of subterranean débris, as if mud had been forced
up from below, carrying with it an extraordinary variety of rock
fragments and crystallized minerals. These are embedded in a mass of a
bluish-green colour much resembling indurated clay (but nearly as hard
as ordinary sandstone), and this on long exposure to the weather
crumbles down to a yellow friable substance. More than eighty different
kinds of minerals of the volcanic class have been found in this
_breccia_, as it is termed by geologists, and it is remarked that these
fragments could not have been exposed to any great heat, for their edges
show no signs of fusion. There are also embedded in the agglutinating
substance large masses of the surrounding strata, sometimes having an
area of several thousand square feet, and these are called in miners’
parlance “floating reef.” The cementing material is named “blue ground,”
and the same when crumbled down by exposure is known as “yellow ground.”
These colours are due to oxides of iron, which in the unaltered ground
give the blue-green tint, being lower oxides; but are converted by
absorption of oxygen into yellow and higher oxides. The upper part of
the pipes is filled to a depth of about 70 feet with “yellow ground,”
produced by the penetration of atmospheric influences. Blue ground and
yellow ground alike contain diamonds, and the yield of these is pretty
regular at all depths in the same mine (some have been explored down to
nearly 2,000 feet), although it varies considerably from one mine to
another, and in some the east side is often richer than the west. Thus
in one load (1,600 lbs.) of _ground_ from Du Toit’s Pan, in 1890, the
quantity of diamonds found averaged less than 2 grains (0·5 carat),
while Kimberley yielded 1·25 to 1·5 carats (5 to 6 grains). It is
singular that the stones from mines quite close together are so
distinctly different in character, that the Kimberley merchants can tell
at once the source of any particular parcel. This would indicate that
the blue mud was not forced up the several pipes at one and the same
time, carrying with it diamonds from one birthplace.
The existence of the diamondiferous pipes is pointed out by no
indication on the surface, which is covered nearly uniformly with the
red sandy soil already spoken of; although indeed the site of the
Kimberley mine was marked by a slight elevation, and that of Du Toit’s
Pan by one of the depressions there called _pans_, which, at least in
the wet season, are receptacles for surface water. The Wesselton mine,
which was found only in the last decade of the century, about a mile
from Du Toit’s Pan, also showed a surface depression, and that had been
utilised as a depositing place for dry rubbish. At a later period the
“Leicester mine” was accidentally discovered 40 miles away. At
Jagersfontein, in the Orange River Free State, 60 miles from the
Kimberley mines, is another pipe which yields the finest diamonds of
any, commanding prices nearly the double of those paid for the De Beers
and Kimberley gems, being in fact their nearest commercial rival. The
proprietorship of the Kimberley group having in 1889 become united in
the hands of one company, known as the “De Beers Consolidated Mines,”
this company is able practically to control the diamond market, as it
has sometimes turned out in a year as much as 3 million carats of
diamonds, which sell for about £3,500,000. Up to the end of 1892, 10
tons of diamonds had been derived from these mines, representing a value
of £60,000,000 sterling. In 1895, the De Beers Company sold diamonds to
the amount of £3,105,958, the total expense of working for that year
being £1,704,813,—the net profit was £1,401,145. The effect of
consolidating all the Kimberley diamond interest into the De Beers
Company has been to give an almost complete monopoly to this last, which
has however found it advantageous to restrict its production to an
annual output of about £3,000,000 in value, as the putting of a larger
quantity of diamonds on the market would cause lowering of their price,
and a diminution of the profits all round. The reason is, that though
the world at large annually spends between 4 and 4½ million pounds
sterling in the purchase of diamonds, yet it would not by a reduction in
their price be induced to spend proportionately more. The company are
sufficiently supplied by only two of their mines, the Kimberley and the
De Beers, the expenses of working these being also relatively smaller
than is the case with the others. It may be of interest to compare the
quantities of diamonds that have so far been produced from the world’s
greatest fields, leaving out Borneo, the Ural Mountains, Australia,
etc., as comparatively insignificant. Estimated produce of India, from
the remotest period, 10 million carats; of Brazil (since 1728), 12
million carats; of South Africa, in only 19 years, 57 million carats.
At the time of the discovery of the Kimberley mine (July 1871) it was
divided into about 500 claims, each 31 feet square, and between these
were roadways across; but when the claims were excavated to a depth of
100 feet or more the roadways became unsafe, and, the “blue ground”
underneath them being too tempting always to be left for their support,
they began to fall in, and the mine was often threatened with ruin from
this cause. The state of things became still worse when the unsupported
walls of the “pipe” itself began to collapse, so that by 1878 a quarter
of the claims were buried in the ruins of the reef. These falls
continued, and although very large sums were year after year expended in
removing the fallen reef, the cost amounting in 1882 to 2 million pounds
sterling, it was found at last that very few of the claims could be
regularly worked, and when in 1883 a tremendous fall of 250,000 cubic
yards of reef took place, covering half the area of the mine, it became
necessary to adopt another mode of working, namely, a regular system of
underground mining. Vertical shafts were sunk at a considerable distance
from the pipe itself, and tunnels from these carried through at
different levels, with a system of galleries so arranged that all the
“blue ground” is removable without danger to the miners. The whole mine
is illuminated by electric lights, and the different kinds of labour are
carried on by distinct sets of workmen, some of whom drill holes for the
reception of dynamite cartridges, others shovel the material into
trucks, others again wheel the trucks along tram lines, which converge
to a space where their contents are discharged into skips holding four
truck loads, in which they are hoisted to the surface at about the rate
of 400 loads per hour. This goes on day and night, the miners working in
three shifts of eight hours each. About 8,000 persons are employed,
6,500 of whom are blacks.
Fig. 334_a_ is a sketch section of the Kimberley diamond mine,
approximately to scale, and a glance at this will elucidate the
foregoing description. The thick vertical and horizontal lines show the
positions of the shafts and galleries that have at various times been
excavated, the lowest gallery being connected with a shaft a
considerable distance from the pipe, towards the right, but out of the
range of the sketch. The fringed lines at the top, with dates, give some
idea of the forms of the excavations until the final fall of reef that
determined the resort to subterranean working.
[Illustration:
FIG. 334_a_.—_Sketch Section of the Kimberley Diamond Mine._
]