# Relationship history for MSHA mine 4404768

Current hierarchy: **Martin W D → Martin Coal Company → No 6 Strip**

- 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:** Martin W D → No 6 Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Coal Company → No 6 Strip; 1977-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin W D → Martin Coal Company; 1977-07-01 to current/open; source msha-controller-operator-history