# MACHINERY
> MSHA accident `220262160002` · 07/30/2026 · Knife River Corporation Mountain West
## Details
- **Degree of injury:** NO DYS AWY FRM WRK,NO RSTR ACT
- **Classification:** MACHINERY
- **Accident type:** Struck by flying object
- **Occupation:** Maintenance man, Mechanic,  Repair/Serviceman, Boilermaker, Fueler, Tire tech, Field service tech
- **Activity:** Hand tools (not powered)
- **Injury source:** WRENCH
- **Nature of injury:** FRACTURE,CHIP
- **Body part:** MOUTH/LIP/TEETH/TONGUE/THROAT/TASTE
- **Days lost:** 0
- **Mine experience:** 0.27 years
## Operator
- **Controller:** Knife River Corporation
- **Operator:** Knife River Corporation Mountain West
- **Mine:** [1002089](https://api.morvs.ai/mine/1002089)
## Narrative

An employee was tightening countersink allen bolts on a rock shelf for an impactor. TM was holding an allen wrench on the bolt head while another TM put an impact gun on the backside nut. Force of impact gun on the nut threw the allen wrench from TM's hand toward EE's mouth and fractured a tooth.

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*Source: [MSHA Open Government Data](https://arlweb.msha.gov/OpenGovernmentData/) · MORVS · CC0 1.0*