# Relationship history for MSHA mine 3501125

Current hierarchy: **Chisman Bill & Francis Gatchall → Q-Bit Rock Company → 7 Mile Hill 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Richard Ward Crushing Company → 7 Mile Hill Pit; 1950-01-01 to 1979-05-08; source msha-controller-operator-history
- **controller_controls_mine:** Ward Richard → 7 Mile Hill Pit; 1950-01-01 to 1979-05-08; source msha-controller-operator-history
- **controller_controls_operator:** Ward Richard → Richard Ward Crushing Company; 1950-01-01 to 1979-05-08; source msha-controller-operator-history
- **controller_controls_mine:** Chisman Bill & Francis Gatchall → 7 Mile Hill Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Q-Bit Rock Company → 7 Mile Hill Pit; 1979-05-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chisman Bill & Francis Gatchall → Q-Bit Rock Company; 1979-05-09 to current/open; source msha-controller-operator-history