dc.description.abstract | This thesis contends that optimization of energy resources through active control and
predictive simulation modelling is possible, and that such monitoring l e d to large savings
in the electricity costs of hot mines (where refrigeration has to be employed). In addition,
active monitoring and control can positively affect the establishment of a safe, healthy and
productive working environment.
In the entire optimization process certain guidelines were set to ensure that the requirements
of the Mine Health and Safety Act were met. Varying the quantity of air supplied
underground by means of Variable Speed Drives (VSD's) is one of the crucial factors in the
interactive approach towards the optimization of ventilation, as is refrigeration and the
pumping requirements associated with refrigeration. This research highlights the interaction
between the amount of air supplied and the effect it has on refrigeration requirements
underground. This thesis also considers the effect that this would have on contaminant
control.
Various tools are available for ventilation and cooling design for mining. These tools are
based on the assumption of steady state conditions and do not take into account
instantaneous changes in conditions day to day or hour to hour (such as for temperature and
contaminants). They also do not take into account the optimization of energy resources
related to the creation of the acceptable underground conditions. With these tools worst case
and best-case scenarios are identified and strategic decisions are made accordingly.
Currently, the amount of the fresh air, the velocity of the air, and its general temperature in
the mine are only changed when one production phase changes into another (or when
unacceptable conditions occur as a result of poor design or neglect). This means that during
a specific production phase (which can last for several months), there can be an oversupply,
or undersupply, of energy resources, which will obviously affect the concentration levels of
the various contaminants (through under or oversupply of air).
Studies done at the Target Mine in the Free State, South Africa, investigated the possibility of
optimizing air cooling, air supply, and water pumping. A unique simulation programme was
designed for the mine - initially to monitor how the mine normally utilized energy resources
in air-supply cooling and water pumping. Once this had been done, an 'optimization
schedule' for energy use on the mine was established using predictive simulation. A
potential saving in energy costs of approximately R2.6 million per annum was identified
This study en& with recommendations for the implementation of simulation programmes, as
well as with suggestions for future work. | |