# Relationship history for MSHA mine 4603459

Current hierarchy: **Darvin  Rowe → Betty Coal Company Inc → No 13 B 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

- **operator_operates_mine:** Betty Coal Company Inc → No 13 B Mine; 1950-01-01 to 1974-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Belco Petroleum Corp → No 13 B Mine; 1950-01-01 to 1974-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Belco Petroleum Corp → Betty Coal Company Inc; 1950-01-01 to 1974-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Betty Coal Company Inc → No 13 B Mine; 1974-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Darvin  Rowe et al → No 13 B Mine; 1974-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darvin  Rowe et al → Betty Coal Company Inc; 1974-11-01 to current/open; source msha-controller-operator-history