Abstract:
The increasing mining depths of South African gold
mine deposits are resulting in ever-increasing heat
loads associated with depth and the geothermal gradient.
Together with changes in the mining horizons
brought about by the depletion of older, shallower, highgrade
reserves, this leads to the need for the continuous
review and redesign of cooling requirements.
Traditionally, cooling requirements were met by using a
combination of cooling strategies, including bulk air
cooling on surface and underground. If this proved to
be insufficient, chilled service water and secondary
remote air-cooling systems were introduced.
This paper reviews these practices in order to provide
a cost-effective means of catering for the introduction
of hydropower at the Gold Fields Ltd South African
operations. Some of the equipment that has been
developed to meet the requirements of both hydropower
and refrigeration includes hydropower fans, cooling
coils and in-stope venturis. These are individually
described and discussed, together with their roles within
the greater strategy.
The planned change in the cooling strategy and the employment of these technologies have effectively doubled
the cooling available, from 10 MW to more than 20
MW, extracted from the hydropower water used to drive
the mining equipment. In conclusion, the cooling strategy
described allows a total heat load of approximately
52 MW to be successfully ventilated and cooled
through the use of combined surface and underground
refrigeration installations, and through the use of
hydropower-chilled water.
