# Relationship history for MSHA mine 3606556

Current hierarchy: **O'Brien Thomas → William H O'Brien & Son Inc → Ruccio 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:** O'Brien Thomas → Ruccio Strip; 1976-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** William H O'Brien & Son Inc → Ruccio Strip; 1977-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** O'Brien Thomas → William H O'Brien & Son Inc; 1977-10-01 to current/open; source msha-controller-operator-history