# Relationship history for MSHA mine 1507678

Current hierarchy: **Swartwood T Marshall → Coal Fuels Inc → Coal Fuels Mine No 6**

- 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:** Hard Rock Coal Company → Coal Fuels Mine No 6; 1975-01-21 to 1975-06-01; source msha-controller-operator-history
- **controller_controls_mine:** Benjamin R.  Bennett → Coal Fuels Mine No 6; 1975-01-21 to 1975-06-01; source msha-controller-operator-history
- **controller_controls_operator:** Benjamin R.  Bennett → Hard Rock Coal Company; 1975-01-21 to 1975-06-01; source msha-controller-operator-history
- **operator_operates_mine:** Coal Fuels Inc → Coal Fuels Mine No 6; 1975-06-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Swartwood T Marshall → Coal Fuels Mine No 6; 1975-06-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Swartwood T Marshall → Coal Fuels Inc; 1975-06-02 to current/open; source msha-controller-operator-history