334 THE DIAiMOND MINES OF SOUTH AFRICA
present Whiting system, the saving amounting to more than £ 2000
per annum. This system as modified in the diamond mines is as follows :
The round winding rope, made of the best plough steel, extends from the
skip over the sheave on the pithead frame down to the reel on the
crank shaft of the engine, thence four times around this reel and a
corresponding reel on a lay shaft (centres of shafts being 12 feet
apart); thence the rope passes around an idler sheave, the shaft of
which runs on bearings set upon a movable frame, which is attached at
each end to a carriage by means of trunnions. The carriage in this case
runs upon a track 50 feet long. From the idler or tension sheave the
rope passes around a second reel which is loose upon the crank shaft,
the centre of which is in line with the second sheave upon the pit-head
frame.
By
the completion of the new plant the output of blue ground from the
Kimberley mine was greatly increased. During the fiscal year ending
June 30, 1893, 1,453,152 loads were taken from the mine as against
1,310,994 loads, the output for fifteen months previous, an increase
almost wholly due to the new hoisting facilities, for fully
three-fourths of the yield was drawn through the main shaft. The
product of De Beers mine for the same year was still greater. The total
quantity hoisted was 1,637,031 loads, of which 1,403,060 loads were
drawn through the main or rock shaft, and only 233,971 loads through
the No. 2 or west end incline shaft.
Drainage
Thorough
drainage is of manifest importance in the operation of any mine, but
it is peculiarly essential in these diamond mines. At the commencement
of underground mining the inflowing water was removed by steam pumps.
The use of such pumps was an error, for the resultant heat and moisture
caused the blue ground to crumble, and made the ladderways so hot that
they were at times impassable.
As soon as the vertical shafts were completed at De Beers
