1902 Broken Hill Central Mine

Case Study

At approximately 3am on 8 October 1902 a series of falls of earth occurred at the Broken Hill Central Mine, causing the deaths of two miners.

The mine

The mine was a silver-lead mine with the lowest working levels at 800 feet below the surface. The ore was raised by drives and crosscuts. The lode was irregular and very extensive, sometimes 300 feet in width.

At the time of the incident, the working system used when the ore was soft or unsafe involved square-set timbering filled with mullock. Where the ore was hard or solid, it was worked in stopes. As the ore was removed it was replaced by mullock and each layer of mullock became solidified to the consistency of the original ore body. Over time gradual shrinkage of the mullock caused settlement and where that got beyond control, it became creep.

Mullock chutes were used to transport mullock to various parts of the mine, often from the surface to the lower levels. Sometimes the chutes became choked and mullockers would need to free the pass in order for the mullock to run through.

The incident

The incident occurred in the area of the principal chute known as B5 which was in the southern portion of the mine.

On the morning of the incident, Thomas Campbell, Leopold Jordan and Joseph Lyons were trucking mullock from the B5 chute. At approximately 3am, Mr Lyons could not locate Mr Campbell and Mr Jordan and believed they had gone up to free the pass to run the chute. A few minutes later there was a rush of wind and dust down the chute extinguishing Mr Lyon's light.

Other nearby workers came to assist, believing a fall had taken place. Although the B5 chute was still standing, Mr Campbell and Mr Jordan could not be found. Another heavy fall followed, affecting a large area of the mine. Large cavities were discovered with workings disturbed for 260 feet. During the rescue attempt it was discovered that the B5 chute had completely collapsed and although every effort was made and the scene of the collapse carefully inspected, the bodies of the two men could not be recovered.

The cause

The area where the men were working was on the boundary of the Central and Broken Hill South mines. There had been previous falls of earth on this boundary in 1892 and 1901. There had also been a huge slide in 1895 and a movement (known as creep) of about 80 feet from the boundary in June 1902. The Commissioner found that the most probable cause of the incident on 8 October 1902 was a continuation of the creep of June 1902.

Conclusions

In the Royal Commission report (1903), the Commissioner concluded that:

The fatal incident was caused by a fall or series of falls of earth.
Such a fall or falls were a continuation of previous movements in 1892 and June 1902.
Managers and officials of the Central Mine used every endeavour to ensure the safety of their property.
No act or omission by the manager or officials of the Broken Hill South Mine contributed to the disaster.
Inspectors of mines faithfully carried out the duties of their office.
With regard to future safety, the mullocking or filling of stopes and workings should have the most careful attention.
All filled stopes should have constant attention, additional mullock added, and bulks wedged when necessary.
The utmost endeavours be made to locate depleted stopes at the higher levels to enable the same to be filled.
That pillars of ore be left on the boundaries of metalliferous mines when the width of the lode or other surrounding circumstances render such a course necessary or desirable.

This incident claimed the lives of 2 people: Thomas Jordan (19) and Leopold Campbell (21).

Ground or strata failure is a principal hazard under current regulation

Mine and petroleum site 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 clause 24, Work Health and Safety (Mines and Petroleum Sites) Regulation 2014).