# Relationship history for MSHA mine 3400924

Current hierarchy: **Hewett Roger L → Holly Coal Company Inc → Ol Kate**

- 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:** Holly Coal Company Inc → Ol Kate; 1975-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hewett Roger L → Ol Kate; 1975-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hewett Roger L → Holly Coal Company Inc; 1975-09-01 to current/open; source msha-controller-operator-history