# Relationship history for MSHA mine 0102323

Current hierarchy: **Yarbrough A M & Bert Burnett → Cougar Mining Inc → Mc Kenzie 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

- **controller_controls_mine:** Yarbrough A M & Bert Burnett → Mc Kenzie Mine; 1978-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Cougar Mining Inc → Mc Kenzie Mine; 1981-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Yarbrough A M & Bert Burnett → Cougar Mining Inc; 1981-06-01 to current/open; source msha-controller-operator-history