Mine Health and Safety Act, 1996 (Act No. 29 of 1996)NoticesGuideline for the Compilation of a Mandatory Code of Practice for the Prevention of Flammable Gas and Coal Dust Explosions in CollieriesAnnexuresAnnexure 2 : Guidance Note for the prevention of flammable gas and coaldust explosions in collieries5. Preventing the Ignition of Flammable Gas |
The management of a mechanical miner’s section should be of such a nature that the prevention of an explosion should have priority over production requirements.
In order to accomplish the above mentioned requirement, the following should be addressed:
5.1. | Examination and making safe |
At the commencement of each shift and at specified intervals during the shift the competent person should:
5.1.1. | Determine and record the last through road/face velocities, the operation status of the secondary ventilation system, any relevant distances to the face and whether all headings are being ventilated as per the code of practice. |
5.1.2. | Record and sign for all flammable gas measurements taken at specified intervals during the shift. |
No mining is to commence or continue should the section not be ventilated as per the code of practice.
5.2. | Pre-operational checks |
All face machinery is to be inspected, prior to the commencement of every shift, according to an official check list authorised by the employer. The results of these inspections are to be recorded and signed for by the authorised competent person immediately after the completion of such inspection. This checklist is to include inter-alia:
— | Flameproof enclosures |
— | Pick condition |
— | Condition of water spray nozzles |
— | Adequacy of the water supply to the mechanical miner |
— | Continuous flammable gas detecting device |
— | Trailing cable condition |
— | Dust scrubber system condition |
— | Condition of dust suppression system at tip |
No mining may commence prior to the completion of such inspections and no substandard machine may be utilised.
5.3. | Safeguards |
5.3.1. | Monitoring |
The last through road/face velocity is to be monitored. Should a situation occur, where the velocity does not comply with the code of practice, no further mining should proceed until the situation is rectified.
5.3.2. | Electrical interlocks |
5.3.2.1. | The automatic isolation of the electrical power to the cutting drum of the mechanical miner should be made possible should any one of the following occur: |
5.3.2.1.1. Flammable gas be detected in an amount in excess of the legislated maximum.
5.3.2.1.2. The water supply to the mechanical miner be adversely affected.
5.3.2.1.3. Any component of the secondary ventilation system ceases to operate
5.4. | Water sprays |
Water through a system of sprays should be directed effectively onto the face whilst cutting to allay the dust, and to direct air onto the cutting zone.
5.5. | Ventilation planning |
A formal system of ventilation planning should be established whereby any change from standard ventilation arrangements should be set out in advance and be approved by the appointed manager after consultation with the section 12.1 of the Mine Health and Safety Act (Act 26 of 1996) appointee.
A ventilation change over should be properly and sequentially controlled. Production should not commence unless authorisation to do so has been obtained from the appointed manager, after consultation with the section 12.1 of the Mine Health and Safety Act (Act 26 of 1996) appointee who has ascertained the prevailing conditions in the section.
NB: No alterations to ventilation system should be allowed unless authorized by the manager in consultation with the section 12.1 of the Mine Health and Safety Act (Act 26 of 1996) appointee.
5.6. | Change in production arrangements |
No unauthorised change in the approved mining layouts/sequence is to be permitted. Only the appointed manager, after consultation with the section 12.1 of the Mine Health and Safety Act (Act 26 of 1996) appointee, may authorise such change.
5.7. | Mining sequence |
The mining sequence is to be so planned so as to complement environmental control conditions.
5.8. | Burnt coal and geological anomalies |
Mining with a mechanical miner in burnt coal is not to be permitted unless the mechanical miner is equipped with a system that will prevent frictional ignition. The precautions to be taken when approaching such areas should be well documented in the code of practice.
Special precautions should be stipulated to prevent any dangerous situation developing. This may include additional gas detection and or additional ventilation.
5.9. | Flammable gas emission rate |
The flammable gas emission rate should be ascertained so as to assist in the design and planning of an effective ventilation system. Special precautions shall be instituted by the manager to maintain the concentration of flammable gas in the atmosphere to within acceptable limits.
5.10. | Continuous flammable gas detection devices |
Continuous monitoring for flammable gas should be done in the heading being mined by the mechanical miner. (use of continuously operating devices)
This unit should effectively monitor the flammable gas concentration present and should be in compliance with the SANS 101515 specification.
5.11. | Maintenance |
It is imperative that on-going maintenance throughout the shift be done and records be kept. This would inter-alia include the following:
5.11.1. | Changing of blunt picks. |
5.11.2. | Installing picks where they are missing. |
5.11.3. | Rectifying defective flame proof enclosures. |
5.11.4. | Installing water spray nozzles where they are missing. |
5.11.5. | Ensuring that all sprays are in effective operation. |
5.11.6. | Replace/repair damaged ventilation ducting. |
5.11.7. | Cleaning of clogged dust filters/scrubbers. |
5.11.8. | Cleaning of water filters |
5.11.9. | Replace/repair leaking water hoses. |
5.11.10. | Updating secondary ventilation appliances. |
5.11.11. | Updating primary ventilation appliances. |
5.11.12. | Replacing suspect trailing cables. |
5.11.13. | Replacing defective flammable gas monitoring equipment. |