# Relationship history for MSHA mine 1507349

Current hierarchy: **Keith Bryan Coal Company Inc → Bryan Keith Coal Company Inc → No 8 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Keith Bryan Coal Company Inc → No 8 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bryan Keith Coal Company Inc → No 8 Mine; 1974-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keith Bryan Coal Company Inc → Bryan Keith Coal Company Inc; 1974-09-01 to current/open; source msha-controller-operator-history