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THE GREAT WHITE CAMPS
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rich
" yellow ground " rose nearly to the surface under a thin coating of
chalk. It appeared in exploring the yellow ground in most of the
openings that the deposit was enclosed in an oval-shaped funnel of
shale, or decomposed basalt resting on shale, which the miners called "
reef." This reef contained no diamonds and marked the limits of any
profitable prospecting. The surface area of the yellow ground within
one of these funnels ranged from about ten acres at Kimberley to
twenty-three acres at Dutoitspan, and on these patches all the
diamond-bearing claims of the Fields were located.1
When
the bottom of the " yellow ground " was reached at a depth of from
fifty to sixty feet below the surface, it was supposed at first that
diamond digging in the funnels had come to an end; but the hard
underlying rock was cut by experimenters, and it was found, to the
delight of the miners, that this also was diamond bearing. It was a
breccia composite, essentially like the " yellow ground" above,
but much more compact and hard, and of a prevailing bluish slate color,
so that it was familiarly known as " blue ground." 2
Exposure to the air, sun, and rain decomposed it so rapidly that most
of the rock could be readily pulverized after a few weeks, and its
precious contents extracted by sifting. The whole mass of the ground in
the funnels was diamond-bearing, in greater or less extent, except in
occasional streaks and masses of barren shale, floating reef, floating
shale, or non-diamond-bearing volcanic mud, and volcanic rocks. So the
pit sinking was widened to the extreme limits of the claims, and the
entire area of yellow and blue ground excavated in open quarries.
The
work was pushed with feverish energy and remarkable rapidity in view of
the bare hand labor and crude mining appliances, but there was no
uniformity of method or extended cooperation. Every claim-holder cut
down his patch with pick and shovel, and lifted the broken ground in a
way that suited his individual notion. Some set stout windlasses in the
surface ground near the edge of their claims, and hoisted buckets filled
1 "The Diamond Diggings of South Africa," Payton, 1872. - Ibid.
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