BIFFI, M., STANTON, D., ROSE, H. and PIENAAR, D.

Ventilation strategies to meet future needs of the South African Platinum Industry. International
Platinum Conference ‘Platinum Surges Ahead’, The Southern African Institute of Mining and Metallurgy, 2006.

Ventilation strategies to meet future needs of the South

African platinum industry
M. BIFFI*, D. STANTON†, H. ROSE* and D. PIENAAR†
*Prysm Resources (Pty) Ltd
†Anglo Platinum

This paper provides an overview of possible approaches for structuring the ventilation systems for
mines that will become operational within the next decade. Features addressed in the paper
include: aspects of airway design and layout in the absence of centralized vertical return shafts,
the impact of using diesel-powered trackless equipment in conjunction with conveyor belts in the
development and production phases of the project, and the need to balance increasing electrical
power costs against the requirement for reduced capital expenditure.
The paper provides brief descriptions of the strategies employed in real-life situations and
presents an overview of various operational parameters affecting the design of ventilation systems
that will be used as ‘platforms’ for much deeper mines in the future.

Introduction and that cater for different system performance

The provision of ventilation systems for modern mines is an requirements at different stages in the life of the project.
integral part of the mine’s technical design. The art of mine
ventilation consists in finding a balance between what is a Background
safe and healthy environment while providing a cost The range of platinum mining operations currently
efficient infrastructure in terms of both capital and undertaken in Southern Africa varies greatly from new
operational expenditure. operations where the reef outcrops or is very close to
The definition of a safe and healthy working environment surface to operations currently approaching a third phase in
is derived from baseline risk assessments aimed at their lifespan at depths approaching and sometimes beyond
identifying the hazards and quantifying the risks relating to 2 000 m below surface. The challenges presented by the
the working environment. This process leads to the latter type are obvious in terms of the need for cooling and
application of what are termed ‘reasonable’ protective the provision of more extensive and sophisticated air
measures aimed at eliminating or in the least mitigating the conditioning systems. In addition, the extent of these
detrimental impact of the hazard on workers. The outcome operations on strike can be as much as 6 000 m
of this process is the ventilation engineered design criteria necessitating relatively high electrical power demand to
against which the performance of the system can be circulate the required air quantities
measured objectively. Mining methods are also varied and affect the ventilation
It is against this background that all the various facets of system requirements significantly. Modern platinum mining
modern ventilation systems are structured. Although operations are characterized by a higher degree of
ingenuity is a primary requirement of any engineering mechanization. Machinery is employed primarily for safety
design process to ensure effectiveness at an acceptable cost, purposes where the worker is removed from the danger
the strategy on which ventilation systems are based must zone. In addition, mechanization can accelerate and
remain focused on the mining and engineering requirements streamline production and enhance flexibility of mining
while attaining the design criteria generated in the risk methods. For example, the introduction of ultra low profile
assessment process. Ultimately a functional ventilation vehicles designed for hard rock mines has been stimulated
system must not become an impediment to mining primarily by the needs of this sector of the mining industry.
operations. On the other hand, the adaptation of the system Even in narrow channel width mining operations, it is not
design to meet mining and engineering requirements should uncommon to encounter conveyor belts in strike gullies that
not lead to the transgression of boundaries beyond which are developed by low profile LHDs. The ore is dumped on a
the resilience of any ventilation system will fail. comprehensive conveyor belt network that leads to vertical
It is for these reasons that the challenges presented by or inclined shaft systems for hoisting or that is extended all
modern platinum mining operations to the ventilation the way to surface surge bins directly. The use of conveyor
engineer have to be addressed in a logically structured and belts is further justified in terms of the extent of these
methodical manner. The design process to which a modern operations on strike where the advantages of this mode of
ventilation system has to be subjected must interact transport become apparent and also where the life of the
iteratively within the parameters posed by the mining and project is relatively long.
engineering requirements of the project so as to provide It is also typical that a trackless equipment fleet should be
solutions that reflect the dynamic nature of a mining project powered by diesel combustion engines that offer greater

VENTILATION STRATEGIES TO MEET FUTURE NEEDS 277

flexibility and better all-round performance in terms of In all cases return air is conveyed through the reef
production per unit power output. The use of trackless horizon to main horizontal return airways that are linked to
equipment is maximized during the primary development of the various upcast shaft systems. The dependence of
the orebody’s infrastructure in order to reduce production ventilation systems on the worked-out reef horizon and
lead times and anticipate creation of revenue. abandoned levels as return airways present challenges and
For the purpose of this paper it might be useful to risks — particularly for deeper mines where the risk of
categorize different mine types into three groupings: increased airflow resistance and airway failure is
• Category A consists of mines that operate from surface heightened by stress-induced deterioration and eventual
down to a depth of 700 m below surface. These failure of excavations and by the effects of seismic activity.
operations tend to be relatively new and in many cases
represent the first stage of mines that will expand to a Primary ventilation
greater depth in this century. These operations are
Perhaps the most dreaded question asked of a ventilation
characterized by direct access from surface by means of
planner is: ‘What size airway (shaft or decline) do you
adits and vehicle and conveyor belt declines. Chairlifts
require?’ This is not an easy question to answer at the time
may be provided for the transport of workers.
it is usually asked — usually at the very start of the project.
Hoisting shafts are not used and will form part of the
The size of the main intake airways may only be
next phase of the project. Typically the infrastructure is
determined once the mine layout (both in terms of
limited — not only due to restrictions imposed by the
production levels and methods), extent of mining
strategy of a ‘pay as you go’ strategy — but also due to
operations served by the airway and production scheduling
restrictions posed by limitations in infrastructure
are established with a degree of finality.
availability such as electrical power and process water
The mine layout determines quantitatively the air flow
supply. Being the latest generation mines, occupational
requirements at different stages of the life of the project.
environmental impacts are of primary importance.
This is dictated by the tonnage produced and the
These also affect the location and number of access
methodology adopted (usually degree of mechanization).
points into the mine for ventilation purposes.
The size of ventilation systems is also determined by the
• Category B operations typically extend from about 700
degree of scatter of mining operations. The creation of a
m to a depth of about 1 200 m below surface. These
number of stopes in a regular array will require less air per
operations are beyond the initial phase and are well into
ton than that consisting of clusters scattered both on dip and
their production target zone. The infrastructure is more
on strike.
developed than that of category A mines and typically
The primary requirement in both a breast stoping or room
inclined or vertical shafts are in use forming platforms
and pillar arrangement is the provision of adequate air
for production as well as for the next phase of
velocities at the face (for breast mining) or in the last
expansion. The use of air cooling to varying degrees of
through road (room and pillar). Consideration for air
complexity through the use of mechanical refrigeration
leakage completes the air quantity requirements per stope.
is a reality for these operations. Aspects related to the
The air requirements for each stope together with the air
availability of electrical power and water supply are
requirements for development activities determine the air
managed, although future expansion will entail super-
quantity for each half level. Table I summarizes a set of air
linear increases in power demand for hoisting,
velocity criteria in stoping sections.
pumping, ventilation and cooling. The surface
Similarly, during the development phases of a vertical
infrastructure in terms of ventilation shafts is in place
shaft or a decline cluster, criteria are used to provide the
and further expansion at depth will maximize the use of
required air quantity. Typically, these are based on
the existing and older infrastructure in terms of intake
providing a minimum flow rate per unit area of the
and return airways. For this category air cooling is in
excavation — for example 0.20 m3/s/m2 for development
the form of primary surface bulk air coolers that
ends and 0.30 m3/s/m2 for sinking shafts — that will allow
process various proportions of the downcast air
and adequate number of air changes during the re-entry
quantity.
period. Usually, however, the development of a decline
• Category C comprises mines that can be termed ‘ultra-
cluster may need to handle air volumes well in excess of the
deep’ from a ventilation system design perspective. In
values thus obtained and this may affect the dimensions of
some cases these mines operate at depths approaching
the decline itself. The additional air flow requirements cater
and in excess of 2 000 m below surface where the rock
temperature is in well in excess of 60°C. Mines in this
category are in the third stage of development typically
employing deep vertical shafts or sub-decline clusters Table I
that extend on dip the reach of the current surface Stoping air velocity criteria
vertical shafts. In future, this category of mines will see
the sinking of sub-vertical shafts. These systems are an Minimum face Notes
extension of the surface intake shaft infrastructure and air velocity
(m/s)
play an essential role in conveying fresh air to the
Breast mining
workings. At this stage of the development of these Depth to 650 m below surface 0.40 For VRT < 37,5°C only;
mines, primary surface air cooling is supplemented by else use next value
secondary underground air cooling as well as by in- Between 650 m and 1 500 m 0.60
stope cooling in some instances. In this category of Depth in excess of 1 500 m 1.00
mines underground chilled water reticulation systems
are employed and electrical power requirements are Room and pillar
affected significantly by higher water pumping and Last through road 1.50
refrigeration capacity. Adjacent road 1.00

278 PLATINUM SURGES AHEAD

for any development operations that originate from these
primary structures.
The use of diesel-powered vehicles in the development of
decline cluster on minor gradients is favoured as it provides
greater flexibility and has the potential of faster rates of
advance. Figure 1 shows schematically a typical twin
development arrangement. The dimensions of the ends are
4.0 m wide and 3.5 m high for a total area of 14 m2. A
primary flow of 50 m3/s is induced by fans at the head of
the return airway. In accordance with the criterion
ventilation rate of 0.2 m3/s/m2, each end will require a
minimum of 4.2 m3/s. However, mining operations require
the use of diesel powered LHDs and trucks. The application
of an exhaust diesel fume factor of 0.06 m3/s/kW (as will be
discussed later) increases the fresh air flow requirements at
the face to 13.0 m3/s, for, say, a total rated power of 210
kW.
Figure 2. Schematic layout of decline development
Figure 1 (not to scale) also indicates the use of rigid
exhaust ducting. These are usually sized to handle the
required air quantities and are likely to interfere with
loading, transport and construction operations. In vertical limits the size of vehicles that may effectively operate in
shaft systems development operations will be setoff once this decline.
the shaft is completed and a permanent up-cast facility is in As part of the longer-term use of shafts and decline
place. For decline systems, as considered presently, clusters as airways, the following should be noted:
development of levels may be setoff as soon as the level • Although equipped shafts inherently present a higher
elevation is reached and therefore the system has to handle frictional resistance to airflow, they are designed for
enough fresh and return air for operations until through- higher air velocities. Air velocities in equipped shafts
ventilation is established on each level. A cursory analysis may be as high as 12 m/s whereas in access declines
of Figure 1 highlights the fact that the number of levels that the velocity is limited to 8 m/s due to worker and
may operate from such a primary system is limited by the vehicular access.
capacity of the primary air mover at the top of the return • Air velocities of up to 22 m/s may be tolerated in
airway and the number of diesel-powered vehicles unequipped shafts — particularly in instances where
operating simultaneously. they have been raise-bored.
In some instances the need to integrate mining and • Vertical shafts are shorter than inclined airways and
engineering requirements to the maximum create very therefore for equivalent frictional losses, they are more
complex arrangements, as shown schematically in Figure 2. aerodynamically efficient.
The figure represents a layout that was proposed for an • Use of declines for equipment such as conveyor belts
operating platinum mine and although this is not an and chairlifts limit the capacity of the excavations. For
engineering drawing, the relative proportions of the conveyor belts a maximum velocity of between 3.0 m/s
equipment are consistent with the size of the excavation. and 5.0 m/s is recommended (for an air flow contrary
The mining team proposed in this case to combine two to the conveyor’s operational direction) while the air
excavations into a single larger entity. On paper the layout velocity in chairlift excavations is limited to 6.0 m/s.
is feasible but in reality it presents a number of issues that Furthermore, due to the fire risk posed by conveyor
are too detailed for the purpose of this discussion. Suffice to belts, there an increasing reluctance to use excavations
say that the capacity of this arrangement to support further containing this equipment as a main intake airway.
development is very limited and that therefore the net Therefore, although the concept of surface or sub-surface
advance rates were affected accordingly. It is also to be decline systems may offer a number of opportunities, the
noted how the relatively small ducts (maximum total potential limitations that these might impose on the
capacity of about 40 m3/s of air for significant distances) ventilation system capacity must be recognized and
considered accordingly. At present the capacity of surface
decline cluster is increased by positioning vertical raise-
bored holes that can ‘inject’ high velocity fresh air from
surface to strategically advantageous positions in the mine’s
intake airway system.
A last remark in terms of ventilation requirements is
needed at this point. Although the criteria and parameters
discussed previously give adequate indications of the air
flow requirements, the sequential use of air will assist in
limiting the air flow. This ‘optimization’ may be possible
particularly in breast stoping environments where there is
very limited or no use of diesel-powered vehicles. In well-
ventilated room-and-pillar sections where the relative
vehicle power to tons to air ratio is low, re-use of air may
be possible as long as the air quality entering the last
working place in the series is within acceptable standards.
Figure 1. Schematic twin development end layout Breast stopes may also be ventilated sequentially if these

VENTILATION STRATEGIES TO MEET FUTURE NEEDS 279

are developed in regular grid pattern. temperature with depth and also shows that ‘milestone’
The ability of ventilating working places sequentially rock temperatures in the BIC are reached at much shallower
maximizes the utilization of fresh air but has its limitations. depths than in the West Wits Basin. Therefore, in the BIC a
In fact the limiting factor in many instances proves to be virgin rock temperature of 40.0°C will be reached at an
high wet bulb temperature increase experienced as the air approximate depth of 650 m as compared to a depth of
absorbs heat energy in working places further downstream. about 1 800 m in the West Wits Basin.
Another observation in relation to Figure 4 is that the
Considerations relating to heat loads trends shown are generic and that actual profiles will vary
from site to site in relation to geophysical properties of
Another question that the ventilation engineer is often
overlying rock structures. In addition, the presence of hills
asked is, ‘When will refrigeration be required?’ The answer
and mountains close to the surface will increase the
depends on a number of variables that include the mean
effective temperature gradient as a function of ‘depth below
rock breaking depth, production rate, strike distance over
surface’ irrespective of wherever surface might be. This
which operations take place (linked to the ambient rock
effective increase is not directly proportional to the height
temperature), the equipment operating in the mine and the
of the hill or mountain but effectively decreases
criterion used to determine the acceptability of the
significantly with the depth below collar at which
environment, to name the more significant ones.
‘milestone’ temperatures are encountered.
Currently the air wet bulb temperature is the thermal
The virgin rock temperature and the geophysical
property that is used to define the acceptability criterion for
properties of the host rock in the design of a ventilation
ambient conditions in the occupational environment.
system determines the surface temperature of the rock
However, there is a growing support to use the concept of
exposed to the airflow. This in turn establishes the heat
air cooling power as a more adequate indication of the
energy flux form the rock into the cooler air and results in
working environment’s ability to provide the necessary
the increase of the air temperature of the air stream.
cooling capacity. Presently there are two shortcomings
Computerized modelling of the mine using software
preventing the wide-scale use of the air cooling power
packages such as VUMA and ENVIRON 2.5 are tools used
concept as a criterion:
to assist designers in determining the aerodynamic and the
• air cooling power is not readily measurable at the
‘thermodynamic’ performance of the system.
working place and, more importantly,
• scientific verification of a data-set that would validate These tools are used to:
the acceptability of such a criterion has not been • Generate a balanced airflow model of the mine to
performed. ensure that airflow patterns meet the distribution
It is for these reasons that a wet bulb temperature varying determined by the application of the design criteria
between 26.5°C and 28.5°C (depending on the operation) • Determine the fan performance characteristics to verify
and termed ‘reject wet-bulb temperature’ is used as the fan operating points, and the need for main booster fans
design criterion. Figure 3 demonstrates the versatility of the • Optimize the location and dimensions of main airways.
air cooling power concept in defining ‘equivalent • Determine heat load and temperature variations
environments’. throughout the mine to verify compliance with design
The figure shows that an air stream at a wet bulb criteria (be these in terms of reject wet bulb
temperature of 29.0°C and an air velocity of 1.2 m/s has an temperature or air cooling power)
air cooling power of 300 W/m 2 . This is equivalent to • Determine the capacity and position of primary,
another air stream at 27.4°C wet bulb temperature at an air secondary and tertiary air coolers
speed of 0.6 m/s. The concept forms the basis of the • Provide an indication of the overall cooling system
differentiated face air velocity criteria demonstrated earlier extent, capacity and performance
in Table I above and allows greater latitude for the All the data gathered from these simulations are collated
introduction of air cooling — particularly in borderline into a set of performance specifications that are used in the
situations selection of equipment, optimization of the chilled water
The geophysical properties of formations constituting the distribution system and the positioning and selection of the
Bushveld Igneous Complex (BIC) are such that the refrigeration plants. Other software packages such as
temperature gradient increase with depth is twice as severe Coolflow may be used in conjunction with these to assist in
as in the West Wits Basin. This is depicted in broad terms this process.
by Figure 4. The graph indicates the variation of virgin rock All this software simulates steady-state conditions and is

Figure 3. Equivalence of air cooling power Figure 4. Virgin rock temperature variation

280 PLATINUM SURGES AHEAD

deemed to be adequate for the purpose of defining suitable for system design purposes but that transient
performance parameters. However, in hot environments the conditions may differ significantly from the average.
effect of transient conditions has to be considered as a Designers must be aware of these pitfalls and adapt systems
function of the geophysical properties of the host rock. to cater for transient demands.
The thermodynamic properties of the BIC rock mass The usefulness of software simulations is highlighted in
being mined (mostly norite) are such that the rock will cool terms of the speed with which alternative designs may be
more rapidly than quartzite (representative of the West Wits evaluated and the data that may be obtained detailed as well
Basin) and will find equilibrium at a sensibly lower surface as from ‘first order’ analyses. Figure 6 shows the variation
temperature. This will result in a lower energy flux per unit of cooling load as a function of virgin rock temperature
tunnel length for the same virgin rock temperature and the (VRT) for a number of reject wet bulb temperatures. This
same air temperature, as shown in Figure 5. The figure analysis is typically performed at pre-feasibility and
shows the theoretical heat flux variation over a period of feasibility level to assess the extent of the cooling
ninety days after exposing a section of the tunnel to an requirements. The results shown in Figure 6 are for a deep
airstream having a constant dry bulb temperature of 30.0°C. level platinum project in the BIC. The results are once more
It is stressed that the results shown here are approximate very site specific and depend on the production rate, strike
and indicative but that they point to the fact that the heat extent and mine methods, among the most relevant
flux in norites is considerably lower. The figure also parameters.
indicates the limited effect that tunnel insulation (100 mm Figure 7 demonstrates further how software simulations
thick and with a conductivity of 0.1 W/m2/K) would have in may be used in the analysis of different mining methods.
reducing the heat flux and that indeed norites are better off The graph shows the variation of heat load as a function of
than the best insulated tunnel excavated in quartzite. depth below surface for a set of different mining methods.
The following points are noted from the above and Figure 5: The heat load is ‘normalized’ by the tonnage produced at
• The heat flux in the first three to four hours after the different depths — which in this case would represent mean
blast is extremely high, resulting in high temperatures rock breaking depth. The mining methods analysed as part
during re-entry and at the beginning of the cleaning of this work were variations of breast stoping operations
shift. with different ore transport and access strategies and
• Although in terms of ‘average conditions’, different cooling system applications. The noteworthy
temperatures may appear to be acceptable, on re-entry aspect of this analysis is the comparison of the two ‘I series
and during cleaning operations conditions at the face alternatives’. These options are identical except that the ‘D’
are likely to exceed acceptability criteria. option utilizes diesel powered vehicles while the ‘E’ option
• The use of diesel-powered vehicles during cleaning has a corresponding fleet of electrically powered vehicles.
operations will aggravate the situation further. The difference in the heat loads between the two options
• The use of tertiary cooling (at the face) together with is appreciable and it is shown in relation with the overall
extensive use of chilled service water (water jetting) heat load that comprises the effect of the rock mass
will assist in cooling the excavation, the ambient air temperature, depth, extent and auto-compression of the air
and the blasted rock relatively quickly and reduce the in circulation. Although the use of electrically powered
heat flux at a rate greater than that induced by the air machinery offers distinct advantages in that it will translate
flow alone. into lower cooling plant costs, these have to be offset
• Design of the cooling system in terms of equipment against the higher cost of the electrical vehicles, higher
and capacity must cater for high demand peaks to infrastructure costs and ease of operation (trailing cables,
handle this additional load profile. battery re-charging).
The foregoing comments briefly highlight the challenges This example demonstrates that trade-off studies
presented both in terms of design and operational issues involving aspects relating to the underground environment
that will arise with deeper operations. The findings also may be undertaken with relative ease and will yield results
point out the usefulness of software currently available in within the required degree of confidence in order to
arriving at these conclusions. It is stressed that the results enhance the validity of the comparison.
are very site specific and that, as with many other types of
modelling, the validity of the results is dependent on the
quality of the input data. Also it is noted that the results
obtained from a steady-state analysis of the system are

Figure 6. Air cooling variation as a function of VRT and design

Figure 5. Comparison of heat flux variation as a function of time reject wet bulb temperature

VENTILATION STRATEGIES TO MEET FUTURE NEEDS 281

 • Low emission diesel fuel is used.
• All vehicles are maintained regularly by suitably
qualified and equipped staff.
Without these ‘additional’ measures, the required dilution
factor would increase to 0.08 m 3/s/kW and up to 0.12
m3/s/kW thus requiring more extensive ventilation systems,
which will complicate mining operations as demonstrated
previously.

Underground fires
The danger posed by fire is another aspect of large-scale
mechanization in mining operations. Fire is a constant
hazard wherever large sources of energy are stored and
Figure 7. Heat load variation as a function of VRT for different used, as is the case in mining machinery. The outbreak of a
mining methods sudden, highly intense fire underground has the potential
for catastrophic outcomes and must be avoided at all costs.
The combination of combustible materials such as
Aspects of health and safety hydraulic oils and rubber tyres in the vicinity of hot
surfaces has to be managed continuously and safely
As stated previously, the objective of any ventilation wherever vehicles operate. The fire risk posed by diesel-
system is the provision of safe and healthy conditions powered machinery is further intensified by the presence of
within the working environment. In this section certain diesel fuel, which may participate in the combustion
aspects relating to environmental health and safety relating process and increase the intensity of the heat, smoke and
to modern platinum mining requirements will be gas emissions in the event of a fire.
highlighted. A further dimension to the risk in terms of using diesel
power underground is found in the large-scale transport and
Choice of power plant distribution of the fuel as part of routine operations. The
The comparison outlined above highlights one aspect of the storage of fuel underground requires awareness in terms of
many dilemmas facing modern mine designers: diesel or a thorough risk assessment and the adoption of protective
electric mining equipment? Part of the answer was given and preventative measures to limit the fire risk.
and, in terms of the ‘bigger picture’, the choice of diesel- The large-scale use of conveyor belts also presents a
powered equipment for the options described by Figure 7 significant risk for the rapid development of underground
may be the correct one. fires. The flow of fresh air over conveyor belts provides a
However, it is a fact that, excluding the case where continuous source of oxygen that may cause the fire to
thermodynamic work is done (as for example where a become self-sustaining under certain circumstances. In
loaded truck hauls ore up a ramp) diesel-powered vehicles addition, the location of conveyor belts in intake airways
will produce three times more energy as heat energy provides the potential for large-scale contamination of the
discharges to the surroundings as is drawn mechanically by mine’s atmosphere.
the engine. In the case of an electrically powered unit, the These hazards are managed effectively by the analysis of
heat energy emission is equal to the energy drawn by the various risk scenarios and the implementation of protective
motor. and preventative measures devised in accordance with such
Another aspect that has to be considered is the fresh air analyses:
dilution that must be provided to minimize the adverse • Issue-based risk assessments are essential to identify
effect of diesel exhaust fumes. The dilution factors will practices and situations that require specific
dictate primarily the air quantity required in sections where intervention.
diesel-powered vehicles are operated — as was mentioned • The prevention of fires through the adoption of
earlier in this paper. In the case of highly mechanized adequate design, equipment, procedures, maintenance
operations, vehicle operation may be seriously hampered by and inspections is an essential aspect of this process.
limited fresh air quantity availability. In addition, the nature
• Routing of fresh air away from high risk areas
of operations is such that maximum dilution will be
required in ends being mucked where poor ventilation (conveyor belts, underground rubber tyre, fuel and oil
conditions and accumulation of exhaust fumes, particulate storage areas, etc.) will limit air contamination during a
and hot air are more likely. fire.
The dilution factors are selected in terms of best practice • The identification of high risk areas by management
and are in general not regulated in terms of the Mines and workers will highlight the presence of the hazard
Health and Safety Act. The dilution factor mostly applied is and provide the necessary awareness.
0.06 m3/s of fresh air arriving at the point of application for • The provision of early detection systems, action
every kilowatt of rated diesel power operational in the protocols and firefighting procedures is essential in
working place. In general, this represents a minimum limiting the spread of a fire. This includes the remote
applied by the industry and assumes that a number of other monitoring of the air flowing through high risk areas,
protective measures are in place: the provision of adequate and back-up communication
• Latest generation (at least Euro IV) engines are in use. systems and protocols, the provision of effective fire-
• Catalytic converters are installed as part of the fighting equipment (e.g. on-board automatic and
vehicles’ exhaust systems. manual fire suppression systems; fire hoses at strategic
• Particulate filters are used and maintained properly and position within the high risk areas; automatic
regularly. sprinkler/water deluge systems; etc.) In addition and

282 PLATINUM SURGES AHEAD

 more importantly, adequate training of key personnel development and production methods has been highlighted
such as operators, supervisors, etc. in fighting fires in the paper. Ventilation systems designed as
safely using the equipment at their disposal is essential ‘afterthoughts’ are likely to provide the required outcome
in preventing the degeneration of a small fire into a but at a considerable additional cost — both measured in
major catastrophe. terms of time and money. The impact of inefficiencies on
• The timely provision of protective measures and the operational costs seen against the backdrop of ever
training of workers in the use of protective equipment increasing power costs is going to hamper future
is the last component of the strategy. Of particular profitability considerably. In shallow operations where the
importance are systems designed to provide respirable metallurgical process is off the mine site, the cost of
atmosphere to workers who are affected by the smoke electrical power for ventilation systems is likely to rank
and gases emanating from the fire and who may not be second only to that of ore transport.
able to reach a point in fresh air. These measures The ‘modular’ design approach to new operations and to
typically include the provision of self-contained self- extensions of existing ones provides opportunities to devise
rescuers and the location of adequately equipped refuge a ventilation infrastructure to a large extent also modular in
bays at strategic positions that may be reached by nature. It is important, however, not to lose sight of the
workers using self-rescue devices. ‘final’ picture so that adequate capacity is incorporated to
• Adequate awareness and training are essential in
avoid delays or becoming an excessive burden on the
providing adequate and timely response as soon as the
financial viability of the project.
fire is detected.
The paper has also shown the value of using computer
modelling for the generation of comparative tools that are
Conclusions essential for the preliminary as well as for the detailed
This paper has provided a brief overview of the ‘ventilation phases of the project. The software provides a basis for
perspective’ on future challenges facing the expansion of more sophisticated analysis of costs and facilitates the
platinum mining operations. The space and time at one’s completion of trade-off studies.
disposal make it difficult to provide a justly extensive
Cooling strategies pioneered in the gold mining sector
coverage of the many facets of this subject. The authors
serve as a useful basis for aspects of future ventilation
have provided an insight on the more important aspects.
The most significant aspect is that the solutions to these planning. However, the adaptation and expansion of this
challenges are well within reach of technologies currently knowledge to meet requirements particular to platinum
at the disposal of designers. Having said this, the mine operations has already been undertaken by designers
importance of integrating the ventilation system design as a and equipment manufacturers alike.
fully fledged component of the overall mine design is The challenge remains the provision of a healthy and safe
emphasized. working environment that is effective and cost-efficient and
Maximizing the use of the infrastructure to convey air to that is adequate for all facets of mining operations from the
the various working places at different stages of the life of initial establishment to closure of operations.
the mine is likely to reduce costs. The integration of The authors acknowledge the management of Anglo
ventilation requirements in the planning of primary Platinum for permission to publish this paper.

VENTILATION STRATEGIES TO MEET FUTURE NEEDS 283

284 PLATINUM SURGES AHEAD