# Relationship history for MSHA mine 1508250

Current hierarchy: **Warren Coal Co → Warren 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** B & C Coal Company → No 1 Mine; 1975-04-01 to 1975-12-29; source msha-controller-operator-history
- **controller_controls_mine:** Austin Bill & W C Forrester → No 1 Mine; 1975-04-01 to 1977-08-09; source msha-controller-operator-history
- **controller_controls_operator:** Austin Bill & W C Forrester → B & C Coal Company; 1975-04-01 to 1975-12-29; source msha-controller-operator-history
- **operator_operates_mine:** Warren Coal Company → No 1 Mine; 1975-12-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Warren Coal Co → No 1 Mine; 1975-12-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Warren Coal Co → Warren Coal Company; 1975-12-30 to current/open; source msha-controller-operator-history