(For mandatory purposes)
The following notes are provided for general guidance and possible consideration for addition in the structuring of action plans or of associated preventative measures.
Fixed plant
| (a) | Electrical cables and electrical equipment should be located so that they cannot be damaged by impact from vehicle collision or blasting in accordance with MHSA regulation 3.22 and 3.23. |
| (b) | Fixed electrical installations should be designed to minimize the need for maintenance personnel to work on live apparatus in accordance with MHSA regulation 3.13. |
| (c) | Oil-cooled transformers' sites be built on a bonded floor, impervious to fuel and provided with drainage facilities for handling spillage of cooling oil. |
| (d) | These sites should be adequately protected from incidental damage caused by vehicle movement in the vicinity. This implies that sites should be adequately selected in relation to vehicle traffic flow and that the erection of bollards or barriers should be considered. |
| (e) | Reflectors should be attached to fixed electrical installations and cables to make them clearly visible to operators. |
| (f) | Thermostats should be provided on electrical motors to stop the motor being governed automatically if pre-set temperature requirements are exceeded. |
| (g) | A minimum of two fire extinguishers rated for the classification of fire for which it is to be used must be provided for substations and transformers. For substations one should be located on the inside of the sub and the other on the outside of the substation in an upwind position. Transformers should have a fire extinguisher on either side located as close as practical to the entry. Newly designed mines should make provision for underground substations with oil filled equipment should be ventilated to the return airway when a fire occurs and have automatic fire extinguishing equipment. |
| (h) | Electrical protection against earth leakage and overload should be provided for all fixed mechanical equipment and electrical Trackless Mobile Machines. These installations should be designed in such a manner so as to prevent a temperature rise in the cables that could lead to a fire. |
| (i) | Critical items of plant that are associated with potential fuel sources should have thermal monitoring installed. |
| (j) | All materials used in the construction of fixed mechanical equipment should be flame retardant. |
| (k) | As a reference, a number of SABS publications may be considered: |
| (i) | SANS 484-1 (2009): Conveyor belting - step splicing for multi-ply textile reinforced rubber covered conveyor belting: |
| • | Part 1: Hot-splicing method |
| • | Part 2: Cold-splicing method" |
| (ii) | SANS 486-2 (2009): Conveyor belting - finger splicing of solid woven construction conveyor belting; |
| (iii) | SANS 340 (2006): Conveyor belts - laboratory scale flammability characteristics - requirement and test method; |
| (iv) | SANS 968 (2013): Conveyor belting - textile reinforced solid woven carcass Ed 1 construction; |
| (v) | SANS 971 (2013): Conveyor belting - methods of testing fire retardant properties of all conveyor belt construction; and |
| (vi) | SANS 54 (2009): Rubber, vulcanized or thermoplastic - accelerated aging and heat resistance tests. |
| (l) | MHSA regulation 8.9(3): The employer must take reasonably practicable measures to prevent persons from being exposed to flames, fumes or smoke arising from a conveyor belt installation catching fire, including instituting measures to prevent, detect and combat such fires. |
| (m) | Conveyor belts should be provided with a slip monitoring system that should stop the belt if a slip of 5% or greater is detected. |
| (n) | Consider the installation of automatic fire suppression systems on the drives, tail and transfer points of conveyor systems. This does not apply where flame retardant belt and drum frictional surface is used and regularly (based on risk assessment) maintained. |
| (o) | Equipment should be designed to minimize the need for welding and flame cutting underground or in confined spaces. |
| (p) | Hydraulic and lubrication systems should use steel piping wherever possible. Where hoses are used they should be. |
| (q) | Belt drift switches should be provided to stop the belt if excessive drift is detected. |
| (r) | Fluid couplings if used should not be source of ignition. |
| (s) | Idler bearings should be sealed. |
| (t) | Temperature monitoring devices and alarms should be installed, in readily identifiable locations, on main bearings of conveyor drives. |
(u) Where possible, compressors should be located on the surface rather than underground.
| (v) | Compressors should be designed so that in the event of a compressor fire, the amount of smoke entering the main intake is minimized. |
| (w) | Where compressors are operated underground, consider the following: |
| (i) | Thermal monitoring devices should be installed on the output of the compressor screws that alarm and stop the compressor in the event of a temperature or oil pressure overload or high discharge air temperature being detected; and |
| (ii) | Compressors should be installed so that the ventilating air flows over them directly to return. |
| (x) | Flow switches should be provided to stop pumps in the event of low flow conditions. |
