ncased for ages is pertinent and worthy of some space in even so compact a book as the present.
The
diamond-bearing blue earth from the mines is automatically dumped into
ore bins and thence conveyed in trucks drawn by endless wire rope and
impelled by steam to the deposit-ing floors on the receiving grounds,
which are planed and rolled hard as if for use as tennis courts or
brick drying floors. The De Beers mine floors are rectangular sections,
six hundred yards long and two hundred yards wide, and extend for four
miles; each floor holds about fifty thousand truck loads, a full load
weighing about sixteen hundred pounds; spread out until about a foot in
thickness, such a load covers about twenty-one square feet. In this
great area of blue earth lie the invisible diamonds, for, although
some of the rough diamonds may be as large as walnuts, persons walking
over the blue earth have almost never seen one. Weathering
disintegrates the breccia or blue earth, which process is carried and
hastened by wheeled harrows drawn by steam traction engines. Eain
accelerates this weathering Process and drought retards it. The blue
ground from Kimberley mine becomes well pulverised in six months, with
the favourable con-
