# Relationship history for MSHA mine 0404557

Current hierarchy: **O'Leno Robert B-Philip L → Hi-Grade Mining Company → Hi-Grade 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:** Hi-Grade Mining Company → Hi-Grade Mine; 1981-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** O'Leno Robert B-Philip L Et Al → Hi-Grade Mine; 1981-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** O'Leno Robert B-Philip L Et Al → Hi-Grade Mining Company; 1981-12-01 to current/open; source msha-controller-operator-history