40 THE DIAMOND MINES OF SOUTH AFRICA
there has been no serious spread of fire in the mines since the occurrence of this great disaster.
The
chief peril to life and damage to the workings of the mine, for a
number of years, has come from the destructive " mud rushes," as the
miners call them. There is no water in the blue ground or the mine
itself, but the water flowing into the mine from the surrounding reef
makes a muddy mixture of the disintegrated shales, decomposed basalt,
floating reef, and low grade blue ground, which had fallen into the
worked out section of the open mines. At times the tremendous pressure
of the shifting ground above forces this mud in vast quantities into
the working levels of the mine, and the miners do not have time to
escape this inrushing mass even by instant flight. On several occasions
tunnels in the mine have been filled to the extent of thousands of feet
by these rushes in a few minutes. As the work in the mines reached the
deeper levels, these rushes became so frequent that the working of the
mines was seriously interfered with, and no watchfulness could avert
the loss of life.
In
June, 1897, one of the worst mud rushes known in the record of the
mines occurred in De Beers mine, filling up almost instantly a large
number of tunnels on the 1000-foot level. Two native miners were
overtaken by the rush, and shut up in a drainage passage that was in
progress to tap the water in that section of the mine. For a stretch of
28 hours they were held fast in this narrow prison chamber, momentarily
dreading a further rise of the mud that would bury them alive.
Meanwhile the most daring efforts were made to rescue them from their
stifling prison, and two heroic men, Thomas Brand and John Brown,
finally burrowed through 200 feet on the top of the mud, and brought
the two natives out safely at an appalling risk to their own lives. The
rescue was barely in time, for the next morning another rush followed,
filling up the tunnels again still further, and rising to the top of
the passage that had given breathing room to the imprisoned men. For
this signal heroism medals of the Royal Humane Society were very fitly
given to Brand and Brown.
