# Relationship history for MSHA mine 4608073

Current hierarchy: **Khrsnak G F → 51 Systems → 51 Systems 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

- **operator_operates_mine:** 51 Systems → 51 Systems Mine; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Khrsnak G F → 51 Systems Mine; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Khrsnak G F → 51 Systems; 1991-07-01 to current/open; source msha-controller-operator-history