# Relationship history for MSHA mine 1508766

Current hierarchy: **Boyd Chester → Jimmy Carter Coal Company → No 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Jeffrey Coal & Mining Co → No 1 Mine; 1974-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bailey Henry S → No 1 Mine; 1974-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Jeffrey Coal & Mining Company → No 1 Mine; 1975-09-04 to 1976-03-16; source msha-controller-operator-history
- **controller_controls_operator:** Jeffrey Coal & Mining Co → Jeffrey Coal & Mining Company; 1975-09-04 to 1976-03-16; source msha-controller-operator-history
- **operator_operates_mine:** Henry B Coal Company Inc → No 1 Mine; 1976-03-17 to 1976-08-24; source msha-controller-operator-history
- **controller_controls_operator:** Bailey Henry S → Henry B Coal Company Inc; 1976-03-17 to 1976-08-24; source msha-controller-operator-history
- **operator_operates_mine:** Jimmy Carter Coal Company → No 1 Mine; 1976-08-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Boyd Chester → No 1 Mine; 1976-08-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Boyd Chester → Jimmy Carter Coal Company; 1976-08-25 to current/open; source msha-controller-operator-history