# IGNITION OR EXPLOSION OF GAS OR DUST
> MSHA accident `220110330016` · 01/30/2011 · Heidelberg Materials US Cement LLC
## Details
- **Degree of injury:** ACCIDENT ONLY
- **Classification:** IGNITION OR EXPLOSION OF GAS OR DUST
- **Accident type:** Accident type, without injuries
- **Occupation:** —
- **Activity:** —
- **Injury source:** —
- **Nature of injury:** —
- **Body part:** —
- **Days lost:** 0
- **Mine experience:** — years
## Operator
- **Controller:** Heidelberg Materials AG
- **Operator:** Heidelberg Materials US Cement LLC
- **Mine:** [1200063](https://api.ai-analytics.org/mine/1200063)
## Narrative

At 9:28pm the control room operator received an alarm that the East rupture vent door for the #1 coal mill system was open.  The primary air fan belts had slipped causing the primary air to slow and then resume normal speed.  This caused a low sweeping velocity in the piping and was likely the ignition source.

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