# Relationship history for MSHA mine 1508914

Current hierarchy: **Thornsberry Garry K & George M Smith → S & T Coal Company → No 12-C Mine (D)**

- 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:** Cantrell Robert E → No 12-C Mine (D); 1975-04-29 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** S & T Coal Company → No 12-C Mine (D); 1975-09-15 to 1976-09-29; source msha-controller-operator-history
- **controller_controls_mine:** Thornsberry Garry K & George M Smith → No 12-C Mine (D); 1975-09-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thornsberry Garry K & George M Smith → S & T Coal Company; 1975-09-15 to 1976-09-29; source msha-controller-operator-history
- **operator_operates_mine:** Joeboner Elkhorn Coal Company Inc → No 12-C Mine (D); 1976-09-30 to 1977-11-08; source msha-controller-operator-history
- **controller_controls_operator:** Cantrell Robert E → Joeboner Elkhorn Coal Company Inc; 1976-09-30 to 1977-11-08; source msha-controller-operator-history
- **operator_operates_mine:** Todd Mining Company → No 12-C Mine (D); 1977-11-09 to 1979-06-05; source msha-controller-operator-history
- **controller_controls_mine:** James Bobby R → No 12-C Mine (D); 1977-11-09 to 1979-06-05; source msha-controller-operator-history
- **controller_controls_operator:** James Bobby R → Todd Mining Company; 1977-11-09 to 1979-06-05; source msha-controller-operator-history
- **operator_operates_mine:** S & T Coal Company → No 12-C Mine (D); 1979-06-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thornsberry Garry K & George M Smith → S & T Coal Company; 1979-06-06 to current/open; source msha-controller-operator-history