# Relationship history for MSHA mine 4604840

Current hierarchy: **E & M Coal Co → E & M 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

- **controller_controls_mine:** Robert  Day → No 1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Debbie Coal Company → No 1 Mine; 1975-07-01 to 1976-05-26; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Day → Debbie Coal Company; 1975-07-01 to 1976-05-26; source msha-controller-operator-history
- **operator_operates_mine:** E & M Coal Company → No 1 Mine; 1976-05-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** E & M Coal Co → No 1 Mine; 1976-05-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** E & M Coal Co → E & M Coal Company; 1976-05-27 to current/open; source msha-controller-operator-history