270 likes | 281 Views
Explore the rise in roof/rib fatalities, contributing factors, victim demographics, and preventive measures in underground coal mines from 1994 to 1999. Learn about rib fall dangers, intersection hazards, and traumatic asphyxiation risks.
E N D
Roof/Rib Fatalities (1994-1999) Roof/Rib Fatalities (1994-1999) CMS&H
Roof/Rib Fatalities • Roof/rib fatalities have increased in recent years • Roof/rib fatalities represent almost 70% of all underground fatalities • MSHA is focusing on roof/rib fatality prevention
Underground Coal Mine Fatalities Study Period Study period through September 6, 1999.
Underground Fatality Mix Other Roof/Rib
4 7 2 8 7 13 20 Fatalities by Occupation
Mine Size Rib Fall Roof Fall Employees
Fatalities by Type of Mining 4 4 26 12 15
4 3 4 6 3 1 Roof/Rib Fatalities (‘94-’99) 14 12 7 8 2 By District
Distance from Working Face Rib Fall Roof Fall Feet
Citations Issued MULTIPLE
Contributory Fatality Factors • New at mine • Intersection hazards • Inby support • Rib hazards • Boom holes/overcast openings • Traumatic asphyxiation
Contributory Fatality Factors Occurrences Note: These factors are not mutually exclusive.
Roof/Rib Fatalities (‘94-’99)Total Mining Experience Median = 16 yrs. Frequency
Roof/Rib Fatalities (‘94-’99)Experience at Mine Frequency Median = 1 yr.
New at Mine • Increased workforce relocation rate • Mature, experienced work force • Roof/rib control complex • Knowledge of roof does not transfer • Site-specific, roof/rib training deficit
Victim 50% of Roof Fall Fatalities
Intersections • One-half of roof fall fatalities in intersections • Intersections are typically 10-20% of developed area • 80% of these fatalities in wide intersections • Intersection roofs weaker due to lack of rib support
Fatalities Inby Roof Support Inby Under
Inby Fatalities - By Occupation 8 3 4 3
Inby Fatalities • One-half of inby fatalities were bolters • Four fatalities were due to bolter not following plan (inby single boom ATRS) • Four fatalities were marking unsupported roof • Four CM operators inby support (all remote-control, extended cuts)
Fatality Classification Outburst Rib Roof
Rib Falls • Rib fall fatalities increasing • All rib fatalities mining heights greater than 7 ft. • Most rib falls depths greater than 1000 ft. • 80% of rib falls - roof had fallen or was mined • 75% of rib falls involved overhanging rock brow
Overcast/Boom Holes • Several fatalities in overcast/boom holes • Most holes are shot and then re-supported • Miners often work under unsupported roof • ATRS can’t reach roof
Traumatic Asphyxiation • Several causes of death were traumatic asphyxiation, compression asphyxiation, etc. • One victim’s last words were “Can’t breathe” • Moving rocks only an inch or so may mean life or death • Quicker means of relief needed
Roof/Rib Fatality Targets • New, experienced miners • Intersections • Inby roof support • Rib hazards • Boom holes and overcast holes • Traumatic Asphyxiation