# Relationship history for MSHA mine 4604628

Current hierarchy: **Mason Martin E → Blair Mining Company → Coal Fork #1 Mine**

- 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:** American Electric Power Company Inc → Coal Fork #1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Cedar Coal Company → Coal Fork #1 Mine; 1975-05-29 to 1979-12-09; source msha-controller-operator-history
- **controller_controls_operator:** American Electric Power Company Inc → Cedar Coal Company; 1975-05-29 to 1979-12-09; source msha-controller-operator-history
- **operator_operates_mine:** Blair Mining Company → Coal Fork #1 Mine; 1979-12-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mason Martin E → Coal Fork #1 Mine; 1979-12-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mason Martin E → Blair Mining Company; 1979-12-10 to current/open; source msha-controller-operator-history