In August 1994, eleven miners were killed in an explosion in the underground coal mine at Moura in Queensland, Australia. The mine was owned and operated by BHP Coal. A commission of inquiry later established that the cause of the incident was the heating of the coal seam from spontaneous combustion, the build-up of methane gas in the mine, followed by a gas explosion.
Such spontaneous combustion is a well-known phenomenon in the coal mining industry. It is often detected early due to the presence of abnormal amounts of carbon monoxide. High carbon monoxide levels were detected in the mine weeks prior to the explosion, but these were ignored and dismissed.
The normal mining practice is to divide the mine into areas called 'panels', and mine one panel at a time. The mined network of tunnels are sealed after they are ventilated by constructing a number of walls (seals) at relevant tunnel intersections. If sealing is carried out, before the section is properly ventilated, any gas generation from 'heating' can result in gas build-up to flammable concentrations. If ignited, this will result in a major explosion. This is what happened at Moura. On the eve of the incident, a panel was sealed in a hurry, while gas build-up was occurring. This meant that there was no potential to ventilate the sealed area and so gas concentration kept increasing, ultimately resulting in the explosion.
The inquiry found that there had been a number of organisational failures that resulted in the disaster. The list below is not comprehensive, but provides sufficient information on the system inadequacies.
1. A management decision was made to send the workers down the mine, even though management was aware of abnormal levels of gas build-up.
2. This potentially dangerous situation was not explained to the workers, as the communication system was inadequate. It was assumed that the workers would have been aware of the information through the informal system that was widely prevalent (the 'grape vine').
3. There were no clearly defined levels of responsibility and authority in the organisation with respect to identification and management of major hazards underground.
4. One of the deputies in the mine had obtained readings of high levels of carbon monoxide generation, but this information was not communicated to the mine manager. The communication system appeared to have failed badly in the capturing the information and responding appropriately.
5. While the deputy's shift reports covered safety matters. The under-manager's report (mainly ready by the mine manager and senior management) did not have any information on safety, and covered only production matters.
6. The mine had a continuous carbon monoxide monitoring system. However, when the reading rose to the 'considerable danger level', no effective action was taken. The continuous reading was backed up by measurements with hand-held instruments by deputies, which confirmed the high level of carbon monoxide, but no action was taken on this either. There was no guidance on response to the high carbon monoxide alarm, which went off repeatedly. Apart from acknowledging the alarm, no action was taken. The alarm system was completely undermined by the lack of a response procedure.
7. The decision to seal the area was taken in a hurry, when people were aware that high gas concentrations existed, and that the gas was not adequately ventilated. This management decision was further aggravated by the decision to send personnel underground to work near the sealed area shortly before the explosion. All these men died in the explosion.
8. The corporate audits carried out by BHP had failed to identify many of the shortcomings of the safety management system. Therefore, senior management did not have a chance to comprehend the magnitude of the problem. This was attributed to the poor quality of the audit, and the auditors were not considered sufficiently independent.
a) Using the Safety Management (SMS) framework, identify the elements and sub-elements that are relevant for safe management of the mine.
b) Briefly outline specific procedures that require updating and implementing to prevent future accidents.
The SMS framework is provided below:
Elements and components of process safety management
1. Accountability: objectives and goals
- Continuity of operations
- Continuity of systems (resources and funding)
- Continuity of organisations
- Company expectations (vision or master plan)
- Quality process
- Control of exceptions
- Alternative methods (performancevs specification)
- Management accessibility
2. Process knowledge and documentation
- Process definition and design criteria
- Process and equipment design
- Company memory (management information)
- Documentation of risk management decisions
- Protective systems
- Normal and upset conditions
- Chemical and occupationalhealth hazards
3. Capital project review and design procedures (for new or existing plants, expansions and acquisitions)
- Appropriation request procedure
- Risk assessment for investment purposes
- Hazards review (including worst credible cases)
- Siting (relative to risk management(
- Plot plan
- Process design and review procedures
- Projectmanagement procedures
4. Process risk management
- Hazard identification
- Risk assessment of existing operations
- Reduction of risk
- Residual risk management (in-plant emergency response and mitigation)
- Process management during emergencies
- Encouraging client and supplier companies to adopt similar risk management practices
- Selection of businesses with acceptable risks
5. Management of change
- Change of technology
- Change of facility
- Organisational changes that may have an impact on process safety
- Variance procedures
- Temporary changes
- Permanent changes
6. Process and equipment integrity
- Reliability engineering
- Materials of construction
- Fabrication and inspection procedures
- Installation procedures
- Preventive maintenance
- Process, hardware and systems inspections and testing (pre-startup safety review)l
- Alarm and instrument management
- Demolition procedures
7. Human factors
- Human error assessment
- Operator/process and equipment interfaces
- Administrative controls versus hardware
8. Training and performance
- Definition of skills and knowledge
- Training programs (e.g. new employees, contractors, technical employees)
- Design of operating and maintenance procedures
- Initial qualification assessment
- Ongoing performance and refresher training
- Instructor program
- Records management
9. Incident investigation
- Major incidents
- Near-miss reporting
- Follow-up and resolution
- Incident recording
- Third-party participation as needed
10. Standards, codes and laws
- Internal standards, guidelines and practices (past history, flexible performance standards, amendments, and upgrades)
- External standards, guidelines and practices
11. Audits and corrective actions
- Process safety audits and compliance reviews
- Resolutions and close-out procedures
12. Enhancement of process safety knowledge
- Internal and external research
- Improved predictive systems
- Process safety reference library