# Relationship history for MSHA mine 1515912

Current hierarchy: **Matney Henry & Frank Rash → Black Gem Coal Company Inc → G-1**

- 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:** Blair Ernest → G-1; 1977-02-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lester Harold → G-1; 1986-07-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Blair Coal Company Inc → G-1; 1987-02-01 to 1987-08-27; source msha-controller-operator-history
- **controller_controls_operator:** Blair Ernest → Blair Coal Company Inc; 1987-02-01 to 1987-08-27; source msha-controller-operator-history
- **operator_operates_mine:** Coal Dust Coal Company Inc → G-1; 1987-08-28 to 1988-02-10; source msha-controller-operator-history
- **controller_controls_operator:** Lester Harold → Coal Dust Coal Company Inc; 1987-08-28 to 1988-02-10; source msha-controller-operator-history
- **operator_operates_mine:** Coal Dust Coal Company Inc → G-1; 1988-02-11 to 1989-04-04; source msha-controller-operator-history
- **controller_controls_mine:** Deel William → G-1; 1988-02-11 to 1989-04-04; source msha-controller-operator-history
- **controller_controls_operator:** Deel William → Coal Dust Coal Company Inc; 1988-02-11 to 1989-04-04; source msha-controller-operator-history
- **operator_operates_mine:** Big Mountain Carbon Inc → G-1; 1989-04-05 to 1990-07-26; source msha-controller-operator-history
- **controller_controls_mine:** Frazier Robert B → G-1; 1989-04-05 to 1990-07-26; source msha-controller-operator-history
- **controller_controls_operator:** Frazier Robert B → Big Mountain Carbon Inc; 1989-04-05 to 1990-07-26; source msha-controller-operator-history
- **operator_operates_mine:** Black Gem Coal Company Inc → G-1; 1990-07-27 to 1990-10-04; source msha-controller-operator-history
- **controller_controls_mine:** Mc Clanahan Donald Keith → G-1; 1990-07-27 to 1990-10-04; source msha-controller-operator-history
- **controller_controls_operator:** Mc Clanahan Donald Keith → Black Gem Coal Company Inc; 1990-07-27 to 1990-10-04; source msha-controller-operator-history
- **operator_operates_mine:** Black Gem Coal Company Inc → G-1; 1990-10-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Matney Henry & Frank Rash → G-1; 1990-10-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Matney Henry & Frank Rash → Black Gem Coal Company Inc; 1990-10-05 to current/open; source msha-controller-operator-history