Shivrajpur Manganese Mine

While 27 persons were working at the bottom of a quarry, a sudden collapse of the overhanging side took place which killed 12 persons and injured 3 others. Four days elapsed before all the bodies were recovered owing to the restricted area of the place and the large volume of rock which fell.

The manganese deposit was 2 to 3 m in width and outcropped along the top of a hill ridge, about 60 m above the general ground level. The deposit was inclined at 340 from the horizontal with the enclosing rocks being quartzite. The rocks were so intensely folded that a complete anticlinal and synclinal fold occurred about every 45 m.

The deposit was worked from the outcrop and the waste rocks were thrown down the slope of the hill. Only so much of the barren rock was removed as was necessary for extraction of the ore with the result that masses of folded rock had been left overhanging. Being strong, the overhanging quartzite stood well and no extensive fall had ever occurred in the history of the mine. Occasionally isolated pieces showed signs of loosening which were immediately dressed down.

This accident occurred at 3.45 p.m. when the persons were working in a synclinal fold at a point about 14 m below the top of the quarry with the fold of the footwall projecting over them. Without any warning, a shell of rock 15 m long x 9 m wide x 0.75 m thick fell upon them. This shell was probably a stratified bed of rock before it was metamorphosed. The probable explanation for the sudden collapse could be the unsuspected tendency of the quartzite to weather along the original lines of stratification after it had been exposed for a long period.

Inquiry into the accident revealed that the place had not been inspected by anyone on the day of the accident. It was last inspected at about 4 p.m. on the previous day by an Assistant who was then satisfied with its safe appearance.

That an overhanging rock in such unsound condition should escape detection by the official is a condemnation of the system of inspection in force. Both the Manager and his Assistants appear to have been satisfied with simple visual inspection. An overhanging rock was considered unsafe only where cracks were visible. Detection had been followed by quick remedy in the past and it may be conceded in this case that the Management was quite unaware that the miners were working under a dangerous condition. Thus in this case the danger was not ignored, it was simply not recognised.

Relying solely upon a sight inspection was a mistake. “Sounding” would have been much more trustworthy. In all probability, the dangerous condition of the rock would have been revealed days before, if this simple expedient had been used.

New Rules were about to be promulgated for manganese mines which stipulate that the sides of all open cast workings shall be sloped or secured in such a manner as to prevent danger from falls of material. Enforcement of this provision should prevent such accidents in future.

After this accident the Management gave the assurance that in future the following precautions would be strictly observed:

1. No person would be allowed to work beneath any overhanging side and all such sides shall be dressed back to a safe slope before work is resumed.
2. The present method of examining the working places by sight shall be supplemented by ‘sounding”.
3. A daily inspection of the mine shall be made by a competent person and when the mine is not worked for more than 12 hours, this inspection shall be made within 2 hours before any person is allowed to enter the mine.