# Relationship history for MSHA mine 4607582

Current hierarchy: **American Metals & Coal International Inc → Alpine Development Company → Mine No 20**

- 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

- **operator_operates_mine:** Rock E Coal Company → Mine No 20; 1988-09-01 to 1992-02-29; source msha-controller-operator-history
- **controller_controls_mine:** Hagy Thomas → Mine No 20; 1988-09-01 to 1992-02-29; source msha-controller-operator-history
- **controller_controls_operator:** Hagy Thomas → Rock E Coal Company; 1988-09-01 to 1992-02-29; source msha-controller-operator-history
- **operator_operates_mine:** Silverado Mining Company Inc → Mine No 20; 1992-03-01 to 1993-05-20; source msha-controller-operator-history
- **controller_controls_mine:** Bailey Howard → Mine No 20; 1992-03-01 to 1993-05-20; source msha-controller-operator-history
- **controller_controls_operator:** Bailey Howard → Silverado Mining Company Inc; 1992-03-01 to 1993-05-20; source msha-controller-operator-history
- **operator_operates_mine:** Fox Chase Coal Inc → Mine No 20; 1993-05-21 to 1994-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Mark  Lester → Mine No 20; 1993-05-21 to 1995-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Lester → Fox Chase Coal Inc; 1993-05-21 to 1994-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Panther Creek Corp → Mine No 20; 1994-12-01 to 1997-09-29; source msha-controller-operator-history
- **controller_controls_mine:** David  Hopkins → Mine No 20; 1994-12-01 to 1997-09-29; source msha-controller-operator-history
- **controller_controls_operator:** David  Hopkins → Panther Creek Corp; 1994-12-01 to 1997-09-29; source msha-controller-operator-history
- **controller_controls_mine:** American Metals & Coal International Inc → Mine No 20; 1996-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Alpine Development Company → Mine No 20; 1997-09-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** American Metals & Coal International Inc → Alpine Development Company; 1997-09-30 to current/open; source msha-controller-operator-history