# Relationship history for MSHA mine 0404072

Current hierarchy: **Campbell Earl L → Campbell Ready Mix → Clifton Pit**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Don Clifton Company → Clifton Pit; 1950-01-01 to 1983-03-15; source msha-controller-operator-history
- **controller_controls_mine:** Clifton Donald E → Clifton Pit; 1950-01-01 to 1983-03-15; source msha-controller-operator-history
- **controller_controls_operator:** Clifton Donald E → Don Clifton Company; 1950-01-01 to 1983-03-15; source msha-controller-operator-history
- **operator_operates_mine:** Campbell Ready Mix → Clifton Pit; 1983-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Campbell Earl L → Clifton Pit; 1983-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Campbell Earl L → Campbell Ready Mix; 1983-03-16 to current/open; source msha-controller-operator-history