# Relationship history for MSHA mine 4000300

Current hierarchy: **Campbell Ernest & Neil → E & N Coal Company → No 4 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:** Rex Mining Company → No 4 Mine; 1950-01-01 to 1976-04-01; source msha-controller-operator-history
- **controller_controls_mine:** Walden Mit N → No 4 Mine; 1950-01-01 to 1976-04-01; source msha-controller-operator-history
- **controller_controls_operator:** Walden Mit N → Rex Mining Company; 1950-01-01 to 1976-04-01; source msha-controller-operator-history
- **operator_operates_mine:** Rex Mining Company → No 4 Mine; 1976-04-02 to 1979-11-27; source msha-controller-operator-history
- **controller_controls_mine:** Walden John T → No 4 Mine; 1976-04-02 to 1979-11-27; source msha-controller-operator-history
- **controller_controls_operator:** Walden John T → Rex Mining Company; 1976-04-02 to 1979-11-27; source msha-controller-operator-history
- **operator_operates_mine:** Rex Mining Company → No 4 Mine; 1979-11-28 to 1981-01-07; source msha-controller-operator-history
- **controller_controls_mine:** Meredith Johnie → No 4 Mine; 1979-11-28 to 1981-01-07; source msha-controller-operator-history
- **controller_controls_operator:** Meredith Johnie → Rex Mining Company; 1979-11-28 to 1981-01-07; source msha-controller-operator-history
- **controller_controls_mine:** Campbell Ernest & Neil → No 4 Mine; 1980-05-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** E & N Coal Company → No 4 Mine; 1981-01-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Campbell Ernest & Neil → E & N Coal Company; 1981-01-08 to current/open; source msha-controller-operator-history