ILUMINACIÓN EN INTERIORES

Westray was an underground coal mine located at Plymouth, Pictou County, Nova Scotia owned by Curragh Resources Inc. The coal seams in the Pictou County coalfield included the Foord seam that Westray attempted to mine. The coal field had a history of being gassy and permeable, relative to Western Canadian coals.

Any drilling activity that disturbs the Foord seam leads to releases of methane. Depending on the concentration of methane in the air mixture, the ignition reaction can propagate spontaneously throughout the mixture in an extremely dangerous manner. Even though previous studies indicated that there were high concentration levels, the feasibility study for the mine stated that “methane will not be a limiting factor in the mine ventilation requirements”. The official opening of the mine was on 11 September 1991.

On May 9th 1992, an explosion occurred in the depths of the Westray coal mine, killing 26 miners. An excessive accumulation of methane in the southwest section of the mine found an ignition source that rapidly propagated and caused a coal-dust explosion and devastation in seconds. The mine ceased operations at the moment of the explosion and never re-opened.

Synopsis of the event

The result of inadequate ventilation permitted the accumulation of undetected methane gas as a fuel source for the explosion on May 9th. The most probable source of ignition was the cutting mechanism or picks of the continuous miner that caused sparks of sufficient intensity to light the gas.

The ignition triggered a rolling flame which propagated into the southwest sections consuming all of the oxygen and leaving behind high quantities of carbon monoxide. The main flame did not initially develop into a methane explosion, although it increased in intensity.

The flame continued to propagate until a combination of running equipment, location of an auxiliary fan and a change in direction of the tunnels created the right conditions which triggered a methane explosion. The shock wave resulted in an increase in pressure and turbulence, which caused dust particles to become airborne9 and eventually generated a full-blown coal-dust explosion.

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Airborne dust is particle or Particulate Matter (PM), made up of tiny solid particles or liquid that floats in the air. Additionally, if enough coal dust particles are dispersed within the air in a given area, under certain circumstances it can cause an explosion hazard.

The explosion spread through the entire mine causing devastation and the death of 26 miners.

Figure 5 Southwest 2 Section of the mine, showing the location of the equipment at the time of the explosion

Key Findings

1. Organization and management

 The senior staff management ran the mine at their discretion and disregarded contributions and suggestions by others. Also, the managers’ qualifications were in serious question.

 The foremen and overmen10

had little or no opportunity to perform their day-to-day duties as set out in the Coal Mine Regulation Act. Instead, they just followed the orders of the mine general manager.

2. Training

 Training proposals seemed to have been formulated to satisfy the inspectorate and the board of examiners. However, insufficiently trained personnel were working at the mine and there was poor monitoring of the training requirements.

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“overman” means an employee who holds a third class certificate as a mine official and who is appointed as an overman;

 Training in safe underground practices was inadequate. Insufficient safety orientation was given to the miners. They generally accepted to perform unsafe tasks or to take shortcuts in their work without a proper understanding of the danger involved.

3. Hazardous operating conditions

 Coal-dust accumulations were at hazardous levels. Still, no enforcement or systematic underground stone dusting was performed.

 Methane conditions were unacceptable, excessive underground gas levels were routine and recurring. Under those conditions, every worker should have been withdrawn from the mine to comply with relevant regulations. Management chose to ignore the hazardous conditions and the potential impact on workers.

 The safety approach was focused on reduction of safety issues that had a direct impact on production. Also the incentive bonus scheme was based on production and it was not conducive to safety in the workplace.

 The length of the shifts (12 hours) increased the risk of injury and accident to the workers due to mental and physical fatigue and was in violation of the Coal Mine Regulation Act.  Illegal and unsafe practices were condoned by management. Practices like storing and

refuelling vehicles underground, use of torches, altering of safety equipment, the lack of lockout systems, the presence of non-flameproof equipment underground, and of the permanency of temporary repairs were all dangerous practices.

 The regulating, control and the monitoring of the main airflow were inadequate and poorly planned. Factors that made it impossible to remove high levels of methane from the working area of the mine included:

o The lack of monitoring of the barometric pressure.

o The lack of a water gauge to monitor conditions of the mine from the surface. o Improper sizing of ducting and poor airflow.

o The shut-down of ventilation fans due to maintenance without any provision for the safety of the workers.

o The relocation of machine-mounted methanometer monitor heads away from their correct location and interference with the equipment set points.

 The environment monitoring system was ineffective. Deficiencies in the installation and maintenance of the equipment combined with the lack of sufficient and accurate

monitoring stations, inexperience of personnel responsible for the operation of the system and the lack of independence from production personnel rendered the system ineffective.  Communication of safety issues was discouraged; management had an aggressive and

authoritarian attitude toward employees. The open-door policy was in contradiction with their behaviour.

 Management’s attention was diverted away from main safety concerns which should have included mining conditions, ground control requirements, and the adverse roof and rib conditions which made the mine difficult to operate.

 The company lacked a effective disaster plan, including an emergency procedure manual and call-out list.

o The Westray mine rescue teams were well trained and proficient in rescue duties; however, the company was not prepared for a disaster of any proportion due to a lack of safety equipment, tools and testing devices required for safety rescue operations.

o Rescue operation roles were not clearly defined.

4. The Department of Natural Resources failed to carry-out its statutory duties and responsibilities. This failure was shared with the Department of Labour with regard to the coordination of several aspects of the mine regulations. Examples included:

 Little or no communication between departments.

 Poor enforcement of regulatory provisions including the lack of a final mine plan that addressed issues of safe and efficient mining.

 Issuance of a mining lease and approvals without confirmation that issues had been addressed.

 Inspectors had inadequate training and the mine’s plan was not routinely reviewed therefore, inspection did not revealed safety problems that might have encouraged the company to make changes.

Analysis

Policy and Commitment- Company policies were established to enforce safe practices and to

provide stewardship but were not implemented by management.

Planning- The inherent hazards associated with the mine were poorly mitigated at the planning

stage. Feasibility studies were disregarded, designed control measures were inadequate and the mine plan for safe and efficient mining was incomplete at the time the explosion occurred.

Implementation- The organizational structure had more than a physical separation between

executives in Toronto and managers at the mine. The management hierarchy was not effectively followed as programs were implemented without the required approvals.

The employee handbook outlined the roles and responsibilities of every position. However, employees were not made aware of their responsibilities. Also, there were conflicts between statutory responsibilities and assignments as production was the main concern.

Due to the lack of proper planning, changes to operations were made based on how the situations developed. Changes were not properly communicated and did not follow a management of change process to analyze effects and implications on safety.

The challenging work environment and new set of specific conditions required a rigorous training program to keep pace with technologies in mining operations. Only a small portion of the required training took place despite miners’ complaints. Miners were insufficiently trained with no proper certification of competence to work under Westray conditions and there was poor monitoring from regulatory bodies. Education, training and supervision are essential to a comprehensive and ongoing training program to maintain safe operations of any mines.

The existence of adequate communications at all levels was not part of day-to-day operations. Employees were hampered by insufficient experience, training, technical and management support.

All procedures set out in detail in the Operation and Maintenance Employee Handbook became pointless when management ignored them.

Procedures were often not followed, illegal practices were promoted, the environmental monitoring system was ineffective and poor management-worker relations were part of a system driven by production targets and little attention to safety.

Checking and Corrective Actions- The absence of safety ethics was obvious at every step of the

operation. For example, surveillance and monitoring programs for: mine conditions, standard practices, the environmental system, and, safety and occupational health were not properly executed or were disregarded.

Managers at the mine were aware of the hazardous conditions and the history of fire-related accidents; however, no incident investigations to identify causes and non-compliance issues or to

develop corrective and preventive actions were implemented. Instead, a multitude of illegal practices were used to cope with adverse conditions.

Data that was being collected was not the correct data and no records were maintained of the data collected and no assessment or tend analysis was completed using any data collected.

Management Review- The policies and procedures were never promoted and enforced. During

the short life of the mine, the mine was not subject to routine reviews to verify the suitability of the mine plan. The plan was incomplete and changes required to adjust to the conditions faced during the development phase were not properly addressed.

LONGFORD 1998