United States
Department of Labor

Search form


Stone Mine Massive Pillar Collapses - Safety Alert

Fours massive clapses have occuerd in line stome mines since October 2020
This notice represents the causes and dangers of massive pilar colapses


Best Practices: 

Address Potential for Future Massive Pillar Collapses:

•    Properly design pillars for benching (width-to-height ratio >0.8 and assess pillar stability)
•    Maintain planned dimensions
•    Account for pillar raveling or blasting overbreak
•    Assess geologic features in the pillar

Identify At-Risk Areas:

•    Recognize signs, such as spalling and hourglassing, that may indicate a pillar is overstressed
•    Assess benched areas and verify pillar dimensions
•    Evaluate potential air blast pathways

•    Reduce exposure of miners to airpaths
•    Protect mine infrastructure