improved
labour supply and partly to technical improvements. These changes in
technique were given pride of place in Ernest Oppenheimer's speech to
the shareholders of Anglo American Corporation on 16 May 1925:
No
review of the year's work on the Rand would be complete without some
reference to the remarkably increased efficiency of rock breaking.
Although the heavier type of drill has done good work, pride of place
now belongs to the jack-hammer, without which the efforts to improve
the fathomage broken could not have been so successful.
During
the year much time has been devoted by our head office and mine
technical officials to the continued study of the numerous problems
connected with drill steel and its economical use. I am pleased to say
that great progress has been made in these matters. In particular,
experiments in connexion with electrically heated furnaces resulted in
greatly improved designs of furnaces, which arc giving excellent
results. The introduction of electric butt welding for broken drill
steel, which was first put into successful operation at Springs Mines,
has intensified the necessity of routine heat treatment of drill steel
in order to reduce the quantity of broken steel and to secure a length
of life dependent only on actual consumption due to wear. Means for
attaining this object have now been devised by our technical staff, and
will be put into operation as soon as the necessary plant, which is now
on order, can be supplied.
But something was also due, not only to an improved labour supply, but to the more effective utilization of time:
It
must not be overlooked that without the reorganization of underground
work dating from the 1922 strike and without the introduction of
overlapping shifts the industry could not have obtained the results of
which they are now justly proud.
The
improved fathomage broken is not only due to the better types of
machines and drills now used, but also largely to the fact that the
effective drilling time has been practically doubled.13
