# Relationship history for MSHA mine 1511387

Current hierarchy: **Geo-Energy Ltd → Gri Coal Company (Ky) Inc → Tantrough Mine No 9**

- 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

- **controller_controls_mine:** Geo-Energy Ltd → Tantrough Mine No 9; 1977-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cardinal Resources Inc → Tantrough Mine No 9; 1978-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Gri Coal Company (Ky) Inc → Tantrough Mine No 9; 1978-09-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Geo-Energy Ltd → Gri Coal Company (Ky) Inc; 1978-09-01 to 1978-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Cardinal Resources Inc → Tantrough Mine No 9; 1979-01-01 to 1979-03-08; source msha-controller-operator-history
- **controller_controls_operator:** Cardinal Resources Inc → Cardinal Resources Inc; 1979-01-01 to 1979-03-08; source msha-controller-operator-history
- **operator_operates_mine:** Gri Coal Company (Ky) Inc → Tantrough Mine No 9; 1979-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Geo-Energy Ltd → Gri Coal Company (Ky) Inc; 1979-03-09 to current/open; source msha-controller-operator-history