# Relationship history for MSHA mine 4300767

Current hierarchy: **Dana M  Gravel; Dean A  Gravel → Gravel Construction Co. Inc. → Powerscreen Chieftain 2100**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Dean A  Gravel  et al → Powerscreen Chieftain 2100; 2005-07-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Gravel Construction Co. Inc. → Powerscreen Chieftain 2100; 2015-06-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dean A  Gravel  et al → Gravel Construction Co. Inc.; 2015-06-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dana M  Gravel  et al → Gravel Construction Co. Inc.; 2015-06-16 to current/open; source msha-controller-operator-history