Cessna Air King took off from Jan Smuts in Johannesburg
promptly at 7 A.m. for the two-hour flight to the Orapa
mine in Botswana. On board the plane with me were four
De Beers engineers who called themselves "the flying
circus." Their job was to periodically inspect and evaluate
the operations at all of De Beers' diamond mines, and
then report back to Oppenheimer's headquarters in Johannesburg.
We flew directly over the eastern
edge of the Kalahari Desert, which cut through Botswana
in a swath of brown barren earth. There were few signs
of life anywhere below except for scattered clumps of
twisted thorn trees and an occasional herd of oryx.
By 9 A.M., the sun, was baking down on the parched earth
which was partially concealed by a nimbus of dust. Suddenly,
appearing like some desert mirage out of this haze,
was a modern city. "Orapa," the pilot announced, as
he began circling for a landing.
Except for the fact that Orapa is
in the middle of nowhere, it might have been any suburban
city. I could see ranch houses with green lawns and
rectangular swimming pools laid out along a cross-grid
of paved streets. There were also a shopping center,
football fields, parks and high rise apartment houses.
The De Beers engineer sitting next
to me explained that most of the city of Orapa had in
fact been prefabricated in Johannesburg in 1971, and
then, piece by piece, reassembled on this stretch of
desert. It had been an enormous undertaking. A road
had to be bulldozed through the trackless wasteland
so that trucks could move the mining equipment in, an
artificial lake and a pipeline had to be constructed
to bring water into Orapa, power lines had to be strung
some 16o miles to the South African border, and an airstrip
had to be built so that diamonds could be flown out.
"This was the first mine I)c Beers ever developed outside
of South Africa," he continued.
At the Orapa airstrip, it took only
a moment to go through Botswana customs. Oppenheimer's
headquarters had telexed ahead that I was arriving,
and I was immediately issued a red badge. Without such
a badge, not even a citizen of' Botswana is allowed
into Orapa. I remarked to the engineer about how quickly
we were admitted into Botswana, considering that we
did not have visas and that he was a South African citizen.
"No problem," he laughed, "Harry
Oppenheimer owns Botswana lock, stock and barrel." I
later found out that he wasn't far wrong. Botswana,
a republic with some 6 million citizens, most nomadic
tribesmen, derives more than 50 percent of it s national
income from diamond, manganese and copper mines controlled
by Harry Oppenheimer. The Botswana government is dependent
on these mines for almost all its revenues and foreign
Jim Gibson, a lanky Scotsman in
his early forties, met me at the airport. He was De
Beers' chief geologist at Orapa, and he had been asked
to show me around the mine. He explained as we drove
back to Orapa that he had been at the mine since it
went into production in 1971.
When we arrived at the mine, he
handed me a steel helmet. As a safety regulation, De
Beers requires that everyone wear one at all its mines..
"You're looking at the second largest diamond mine in
the world," Gibson said, pointing to a long, oval-shaped
depression in front of us. (The largest was the De Beers
mine in Tanzania.)
I had imagined a mine deep underground
honeycombed with labyrinthine tunnels. Instead I saw
an open pit that looked like an excavation site for
a skyscraper. A number of dirt roads wound their way
down to the bottom of the pit, which was no more than
69o feet below the surface of the earth at its deepest
point. On the floor of the mine I could see about fifty
Botswana workers. They were dressed in khaki jumpsuits
and yellow helmets, and most of them were operating
steam shovels and other mechanized equipment.
Every few minutes, a large yellow
truck driven by a Botswana would drive down the winding
road to the bottom of the mine. A power shovel would
then load it with a pile of bluish earth. When the truck
returned to the surface, it would dump the bluish earth
on a moving conveyor belt. The entire process was highly
mechanized and required relatively few workers.
"It is simply an earth-moving operation,"
Gibson explained, "every afternoon at 4 P.M., a number
of dynamite charges are detonated to loosen up the ground,
then the power shovels simply scoop up the kimberlite."
Kimberlite is the blue ore in the
mine. "What you are looking down into is a kimberlite
pipe. If all the kimberlite was scooped out of that
pit, it would look something like this." He drew a sketch
in the ground of something that looked like a funnel
with an extremely long stem. "Millions of years ago
there were underground explosions that sent lava shooting
up to the surface. When the lava cooled, it hardened
into these pipelike formations." The kimberlite, containing
the diamonds, had come gushing up with the lava.
I picked up a handful of the kimberlite
ore and crumbled it into a loose mixture of stones and
bluish dust. "Where are the diamonds?" I asked.
"Finding a diamond in kimberlite
is like finding a very small needle In a haystack,"
he responded. It is necessary to slit through more than
two tons of kimberlite to find just one carat of diamonds.
A carat is a very minute measure.
It is based on the remarkably uniform weight of the
ancient carob seed, and weighs only 1/2000th of a pound.
Separating the diamonds from this mass of bluish ore
seemed a herculean task. I asked Gibson who separated
out the diamonds.
"The diamonds are never touched
by a human hand," he explained, as we walked along a
path parallel to the conveyor belt toward a glimmering
structure about one-quarter of a mile away. "That's
the separation plant," he said, pointing, to the building
ahead. It towered about twenty stories above the desert
and looked like some medieval fortress. As we approached
it, I could see that it was constructed of giant slabs
of metal and surrounded by a barbwire fence.
I had heard a number of stories
about natives stealing diamonds from mines by concealing
them on their bodies. I wondered whether this fortress
like building was part of some draconian security system.
I inquired whether they conducted body searches.
Gibson smiled and replied that there
was no need for anything like that. He explained that
the fully automated sorting machines kept the diamonds
from tempting anyone.
The conveyor belt carries about
one thousand tons of ore an hour into a plant. Inside
the separation plant, the conveyor belt dumps the ore
between two giant wheels-the ' 'crushers "-which are
large enough to pulverize automobiles. The kimberlite
must be broken into small fragments in order to be automatically
processed. The tiny particles, mainly sand, are screened
out by a series of sieves. The kimberlite then moves
on a conveyor belt into huge vats of swirling liquid
that resemble enormous whirlpool baths. These "cyclone
baths" were designed by Dc Beers to take advantage of
the heavy density of diamonds in separating them out
from lighter-density materials. Gibson explained, "They
work on the same centrifugal principle as dairy creamers:
at high speeds, lighter materials rise and are skimmed
off." More than 99 percent of the ore is removed in
the vats; what remains is a concentrate of diamonds
and other heavy minerals.
Back on the conveyor belt, the concentrate
is channeled into a battery of large, five-foot-high
black boxes called C~ sortexes." These machines take
advantage of one of the natural characteristics of diamonds:
the fact that they, unlike most minerals, phosphoresce
under X-rays. As the concentrate passed, the machines
bombarded it with X-rays. Whenever a diamond passes
through, it glimmers, activating a photoelectric cell
inside the sortex. The photoelectric triggers a Jet
of air that blows the diamond and the stones on either
side of it off the conveyor belt and down a chute that
leads to the sorting room.
We went next to the sorting room,
which is the most heavily guarded inner sanctum in the
entire diamond mining complex. Three different guards
were required to put their keys into separate locks
before the door could be opened. The windowless room
had in its center a row of large glass boxes, which
were all connected by pipes to the ceiling. "Not even
the sorters have the opportunity to lay a hand on the
diamonds in this system," Gibson explained.
On closer inspection, I could see
that each box had a pair of rubber gloves, called "evening
gloves," fastened to the glass wall of the box. Inside
the box was a set of tweezers.
Suddenly, a stream of small stones
came clattering through the pipe in the ceiling and
spilled into the glass sorting box I was watching. A
Botswana sorter immediately went to work. He thrust
his hands inside the evening gloves, which protruded
into the sealed glass container, and through these gloves,
he picked up the tweezers. He quickly separated the
stones into two piles-diamonds and non-diamonds. The
chief sorter then came over to double-check the sorting.
The sorter then pushed the non-diamonds down a hole
in one side of the box, where they clanked through a
pipe. "Those stones will be fed back onto the conveyor
belt just in case the sorter missed any diamonds," Gibson
The diamonds left in the glass box
were then released through a trap door in the bottom
into a steel container. This container is continually
guarded by two Botswana soldiers with shotguns.
The chief sorter allowed me to examine
the day's catch of diamonds through a window in the
steel container. The vast preponderance of the diamonds
were black chips resembling tiny fragments of coal.
"What are black diamonds used for?" I asked.
"They're industrial diamonds," Gibson
answered. "Most of them are ground down into abrasive
grit and used to grind tools and precision parts." "They
will probably bring about $2 a carat, which is only
a hundredth of what good gem diamonds will fetch in
today's market," he added. It still is financially rewarding
since the mine produces about 1.7 million carats of
industrial grade diamonds in a year. The mix is roughly
8o percent industrial diamonds and 20 percent gems.
The income from the industrial diamonds-even at a mere
$2 a carat-is sufficient to pay the day-to-day operating
costs of the mine.
I peered again into the box and
saw that the whitish diamonds, which looked like tiny
pieces of broken glass, had a wide variety of shapes.
Some were flat chips, others were twisted triangles,
and many were no larger than a grain of sand. It seemed
difficult to see how this batch of uncut diamonds could
ever be converted into fine jewels.
According to the chief sorter, there
were between i,ooo and i,5oo carats of gems in the day's
take. He explained that the exact determination of the
number of gem stones, and their value, was made by an
official appraiser in the Botswana capital of Gaborone.
The diamonds were then flown to London.
"How many of those diamonds are
large enough to cut into a one-carat engagement stone?"
I asked, recalling the concern about dwindling supplies
of the large diamonds.
"You might find only two or three
of that size here," he said. In light of this low ratio
in Botswana, it seemed that the concern was well founded.
When we left the separation plant,
I looked at the huge mountain of kimberlite waste behind
it. Each day the plant processed and spewed out some
20,000 tons of ore. It seemed to be an incredible undertaking
for a mere handful of gem diamonds.
"Gem diamonds can be worth anywhere
between $ioo and $5,000 a carat depending on their quality,"
said Gibson, adding, "and quality is, for all practical
purposes, what the official appraisers say it is." He
explained that appraisers had to take into account such
nebulous factors as the shade of color, shape, and the
cutability of the uncut diamond in making their evaluation.
This evaluation was of considerable importance to the
Botswana government, for it derived most of its revenue
from the 50 percent share of the profits it received
on the diamonds.
Diamond mines, unlike most other
kinds of mining operations, could not measure, or even
reasonably estimate the value of their own product.
Gold mines can calculate how many ounces they produce
each day, and copper mines can estimate their tonnage,
but the Orapa mine could not immediately determine whether
its production of gem diamonds that day was worth $ioo,ooo
or a million dollars. Both the diamond mine and the
Botswana government had to await the outcome of the
official evaluation by the De Beers-trained appraisers.
We had lunch that afternoon at the
Orapa Club. During the meal, Gibson told the story of
how he and another De Beers geologist named Gavin Lamont
discovered the Botswana diamonds.
It began in 1962 when Harry Oppenheimer
decided to acquire the prospecting rights in Botswana
(which was then the British protectorate of Bechuana
land). Prospectors had already discovered three diamonds
on the banks of the Moutlouse River, but unable to find
the source of the diamonds they had abandoned the search.
For nearly four years, Gibson and Lamont scoured the
headwaters of the Moutlouse without finding a trace
of diamonds-or any of the minerals associated with them.
At this point, Lamont came up with a highly speculative
geological theory. Since there had been enormous upheavals
of the earth's crust in southern Africa in prehistoric
times, he suggested that the Moutlouse river may have
been truncated by the rising earth; its previous source
might have been on the other side of the mountains.
Even though there was no corroborative evidence for
this theory, Lamont and Gibson believed it was worth
the gamble to explore it. They moved their prospecting
team north to the edge of the Kalahari desert.
Sand proved to be an immediate problem
for the prospectors. If there was a rich kimberlite
pipe in the desert, it would be buried under hundreds
of feet of sand and gravel. How could they sample the
minerals under the desert?
White ants, which had built towering
mounds on the desert, provided the solution. Gibson
and Lamont realized that these ants had tunneled hundreds
of feet below the surface of the desert in searching
for humid earth for their nest, and with the mud they
retrieved they also brought up traces of minerals from
below the surface. By analyzing samples from these ant
colonies, Gibson and Lamont found traces of two other
minerals-garnets and ilmenites. Since both these minerals
frequently occurred in kimberlite, they had reason to
hope they were on the right track.
Finally, in March 1967, Gibson narrowed
the search to a spot located a few miles away from a
cattle trading camp called "Orapa" by the natives. Here
he began drilling for core samples with equipment that
De Beers had flown up from its Kimberley headquarters.
"Those diamonds literally poured out of the small rotary
pan," Gibson recalled. "We realized that we were on
to something very big indeed." Gibson next ordered a
series of aerial photographs taken of the area. Examining
them, he delineated a depression more than a half mile
in diameter. It was, in fact, the mouth of the Orapa
pipe. "It was quite unbelievable that the whole area
could in fact be kimberlite," he remembered thinking
From that moment on, De Beers moved
quickly to bring the mine into production. It cost some
$ 3 3 million. Four years later, it went into production,
and it was officially opened on May 26, 1971, by President
Seretse Khania. Oppenheimer, indeed, had the entire
Botswana government flown in for the ceremony. "It was,
after all, the first diamond mine that De Beers had
ever found," Gibson added.
According to Gibson, De Beers had
completely missed the 44-acre Finsch pipe in South Africa,
and the 36o-acre Mwadui pipe in Tanzania, the largest
pipe mine ever found, even though both sites had been
explored by its geologists several years before the
respective discoveries. In every instance, up to discoveries
of Botswana, De Beers simply bought out the others.
De Beers presumably had been purposely avoiding unnecessarily
expanding the supply of diamonds by uncovering new mines.
The scarcity of diamonds one carat
or larger in Botswana raised the question of how De
Beers intended to meet the demand for these stones.
The answer suggested to me was a mine on a mountaintop
in the kingdom of Lesotho, which was my next step.