# Relationship history for MSHA mine 1511693

Current hierarchy: **Bryant Austin → A & B Coal Processing Inc → A & B Coal**

- 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:** Simmons Brothers Coal Company → A & B Coal; 1978-10-01 to 1981-12-01; source msha-controller-operator-history
- **controller_controls_mine:** Simmons Claude → A & B Coal; 1978-10-01 to 1981-12-01; source msha-controller-operator-history
- **controller_controls_operator:** Simmons Claude → Simmons Brothers Coal Company; 1978-10-01 to 1981-12-01; source msha-controller-operator-history
- **operator_operates_mine:** Can Do Stoker Inc → A & B Coal; 1981-12-02 to 1985-08-18; source msha-controller-operator-history
- **controller_controls_mine:** Smith Bradley E → A & B Coal; 1981-12-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Bradley E → Can Do Stoker Inc; 1981-12-02 to 1985-08-18; source msha-controller-operator-history
- **operator_operates_mine:** Smith Branch Coal Company Inc → A & B Coal; 1985-08-19 to 1988-10-03; source msha-controller-operator-history
- **controller_controls_mine:** Rice Larry G → A & B Coal; 1985-08-19 to 1988-10-03; source msha-controller-operator-history
- **controller_controls_operator:** Rice Larry G → Smith Branch Coal Company Inc; 1985-08-19 to 1988-10-03; source msha-controller-operator-history
- **operator_operates_mine:** Smith Branch Coal Company Inc → A & B Coal; 1988-10-04 to 1992-09-13; source msha-controller-operator-history
- **controller_controls_mine:** Prichard Herbert → A & B Coal; 1988-10-04 to 1992-09-13; source msha-controller-operator-history
- **controller_controls_operator:** Prichard Herbert → Smith Branch Coal Company Inc; 1988-10-04 to 1992-09-13; source msha-controller-operator-history
- **operator_operates_mine:** A & B Coal Processing Inc → A & B Coal; 1992-09-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bryant Austin → A & B Coal; 1992-09-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bryant Austin → A & B Coal Processing Inc; 1992-09-14 to current/open; source msha-controller-operator-history