# Relationship history for MSHA mine 4406364

Current hierarchy: **Progress Energy Inc → Powell Mountain Coal Company Inc → Wallins A**

- 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:** Amvest Corporation → Wallins A; 1981-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Powell Mountain Coal Company Inc → Wallins A; 1987-03-01 to 1997-09-24; source msha-controller-operator-history
- **controller_controls_operator:** Amvest Corporation → Powell Mountain Coal Company Inc; 1987-03-01 to 1997-09-24; source msha-controller-operator-history
- **operator_operates_mine:** Powell Mountain Coal Company Inc → Wallins A; 1997-09-25 to 2000-11-29; source msha-controller-operator-history
- **controller_controls_mine:** Florida Progress Corporation → Wallins A; 1997-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Florida Progress Corporation → Powell Mountain Coal Company Inc; 1997-09-25 to 2000-11-29; source msha-controller-operator-history
- **operator_operates_mine:** Powell Mountain Coal Company Inc → Wallins A; 2000-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Progress Energy Inc → Wallins A; 2000-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Progress Energy Inc → Powell Mountain Coal Company Inc; 2000-11-30 to current/open; source msha-controller-operator-history