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NSW Resources Regulator

1901 Broken Hill South Mine

Case Study

On Friday 24 May 1901 a rock fall occurred at the Broken Hill South Mine located in the far west of NSW, killing six mine workers.

The mine

The Broken Hill South Mine produced lead and silver with the ore obtained by the method of stoping. Stoping is practised in underground mineral mining when the surrounding rock is strong enough to permit the drilling, blasting and removal of ore without caving.

The deepest shaft at the time of the incident was 800 feet. The rock fall happened at 500 feet. There had been a crush in the stope, a steplike excavation made in a mine to extract ore, at this level approximately two years before this incident which had been allowed to settle gradually for five months with no securing of ground. Work was resumed and re-timbering of the stope had continued for nearly eighteen months prior to this incident.

The incident

On the morning of the incident, eight men started work on the day shift. Upon reaching the work area, a shot was placed and fired. The duty of the shift manager was to ensure the work area was safe before they started work and before resuming work after firing a shot. After examining the scene of the shot and being apparently satisfied with the result, the men were told to resume working.

One truck had been filled but, as the second truck was being filled, a large amount of stone fell, burying the four men furthest from the timber and partially burying two others. Nearby workers rushed to provide rescue assistance but were immediately deterred by a second fall which entirely covered the buried men, killing all six workers.

The two surviving men agreed that the area where the incident took place was not examined as required after the shot was fired and the procedural examination of the condition of the backs, also known as the roof or upper part in any underground mining cavity, had also been neglected.

The cause

It was determined by the Commissioner that the cause of the falls was the existence of a ‘soapy head’, which refers to the joints of stones, which are filled with a saponaceous or talc-like mineral.

Although all the men interviewed declared that they saw no cracks, it was noted that if the ‘soapy head’ is deep-seated it may not be discovered even with the greatest of care. The adjoining rock became detached, possibly from the pressure or the disintegrating influence of the atmosphere, the concussion caused by firing shots, or a combination of those factors. There was a large area of unsupported roof, the formation in parts was of a friable nature (easily crumbled) and there were small veins of silica penetrating the rock. The method of working required men to work under the unsupported roof.

Conclusions

In the Royal Commission Report (1901), the Commissioner concluded that:

  1. The accident was caused by a fall of rock which was brought about by the rock becoming detached through a ‘soapy head’.
  2. The work was dangerous and known by the workers to be so, but the method adopted to perform this work was reasonably safe if faithfully carried out.
  3. The deceased men, generally speaking, had performed their work with due care.
  4. On the day of the accident, those in charge had not made a proper inspection before commencing operations, but this omission did not contribute to the fatalities.
  5. The system of inspection adopted by the mine officials was sufficient.
  6. The Inspector of Mines discharged the duties required of him by the Mining Act, 1874.
  7. For greater precaution in the future, where the work involves extraordinary risks, an inspection should be made of the working places by a competent mine official before the men commence work.
  8. The result of such inspection should be daily recorded in a book accessible to the workmen and officials.

This incident claimed the lives of 6 people: Samuel Havelock (49), Harry Downs (46), Edgar Mason (39), William Bennetta (age unknown), John Edwards (age unknown), John Prideaux (46).

Ground or strata failure is a principal hazard under current regulation

Mine operators must prepare a principal hazard management plan which provides for the management of all aspects of risk control in relation to the principal hazard of ground or strata failure (refer clauses 5 and 24, Work Health and Safety (Mines and Petroleum Sites) Regulation 2014).