# Relationship history for MSHA mine 1506374

Current hierarchy: **Potter Hobert E → Joan Coal Company → Joan Coal Co No 4 Tipple**

- 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:** Hall Robert Scott → Joan Coal Co No 4 Tipple; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Joan Coal Company → Joan Coal Co No 4 Tipple; 1973-01-01 to 1977-04-27; source msha-controller-operator-history
- **controller_controls_mine:** Potter Hobert E → Joan Coal Co No 4 Tipple; 1973-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Potter Hobert E → Joan Coal Company; 1973-01-01 to 1977-04-27; source msha-controller-operator-history
- **controller_controls_mine:** Tackett Curtiss → Joan Coal Co No 4 Tipple; 1974-09-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hall & Adkins Coal Corp → Joan Coal Co No 4 Tipple; 1977-04-28 to 1979-03-15; source msha-controller-operator-history
- **controller_controls_operator:** Hall Robert Scott → Hall & Adkins Coal Corp; 1977-04-28 to 1979-03-15; source msha-controller-operator-history
- **operator_operates_mine:** Hall & Adkins Coal Company Inc → Joan Coal Co No 4 Tipple; 1979-03-16 to 1986-12-02; source msha-controller-operator-history
- **controller_controls_mine:** Coleman Roy Darrell → Joan Coal Co No 4 Tipple; 1979-03-16 to 1986-12-02; source msha-controller-operator-history
- **controller_controls_operator:** Coleman Roy Darrell → Hall & Adkins Coal Company Inc; 1979-03-16 to 1986-12-02; source msha-controller-operator-history
- **controller_controls_mine:** Collie  Hall et al → Joan Coal Co No 4 Tipple; 1982-05-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Traveller Coal Corp → Joan Coal Co No 4 Tipple; 1986-12-03 to 1989-11-08; source msha-controller-operator-history
- **controller_controls_operator:** Collie  Hall et al → Traveller Coal Corp; 1986-12-03 to 1989-11-08; source msha-controller-operator-history
- **operator_operates_mine:** C & N Coal Company → Joan Coal Co No 4 Tipple; 1989-11-09 to 1991-04-11; source msha-controller-operator-history
- **controller_controls_operator:** Tackett Curtiss → C & N Coal Company; 1989-11-09 to 1991-04-11; source msha-controller-operator-history
- **operator_operates_mine:** Joan Coal Company → Joan Coal Co No 4 Tipple; 1991-04-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Potter Hobert E → Joan Coal Company; 1991-04-12 to current/open; source msha-controller-operator-history