# Relationship history for MSHA mine 1401345

Current hierarchy: **O'Rourke Brothers Inc → J A Tobin Construction Company → Tobin Quarry & Mill #1**

- 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:** O'Rourke Brothers Inc → Tobin Quarry & Mill #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** J A Tobin Construction Company → Tobin Quarry & Mill #1; 1980-01-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** O'Rourke Brothers Inc → J A Tobin Construction Company; 1980-01-18 to current/open; source msha-controller-operator-history