On Friday, March 22, 2013, a 29-year old continuous mining machine operator, with 9 years of mining experience, was killed while operating a remote-controlled continuous mining machine during retreat mining. While mining a left hand lift, the victim and his helper were positioned near the right rear corner of the continuous mining machine and the right rib. A section of roof, approximately 8 feet long by 7 feet wide and 16 inches thick, fell and broke several roof bolts. The fallen rock struck the victim and knocked down the victim’s helper, injuring him. The slab of rock that fell was a portion of a larger fall, approximately 20 feet wide by 25 feet long, that included the bolted roof between the rear of the continuous mining machine and the mobile roof support units located inby.
Best Practices
- Ensure that the approved Roof Control Plan support provisions are suitable for the geological conditions at the mine and that the plan is followed.
- Develop a map of geologic features, so additional support can focus on those areas.
- Conduct frequent and adequate examinations of roof, face, and ribs. Be alert for changing conditions. When hazardous conditions are detected, danger off access to the area until it is made safe for work and travel.
- Maintain proper entry widths and pillar dimensions.
- Develop a safe procedure to align Mobile Roof Supports with the lift being mined.
- Install and examine test holes regularly for changes in roof strata.
- Take additional measures when hazards associated with draw rock are encountered, such as mining shorter cuts and decreasing roof bolt spacing.
- When joints are encountered, install adequate supplemental support.
Click here for: MSHA Preliminary Report (pdf), MSHA Investigation Report (pdf).