# Relationship history for MSHA mine 2500526

Current hierarchy: **Larry  Paulsen → Paulsen Inc → McCook Pit**

- 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:** Gilbert Central Corp → McCook Pit; 1950-01-01 to 1984-06-12; source msha-controller-operator-history
- **controller_controls_mine:** Peter Kiewit Sons' Inc → McCook Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Peter Kiewit Sons' Inc → Gilbert Central Corp; 1950-01-01 to 1984-06-12; source msha-controller-operator-history
- **operator_operates_mine:** Frick Sand & Gravel Inc → McCook Pit; 1984-06-13 to 1997-04-23; source msha-controller-operator-history
- **controller_controls_mine:** Thomas E  Frick → McCook Pit; 1984-06-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas E  Frick → Frick Sand & Gravel Inc; 1984-06-13 to 1997-04-23; source msha-controller-operator-history
- **controller_controls_mine:** Larry  Paulsen et al → McCook Pit; 1993-01-25 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Paulsen Inc → McCook Pit; 1997-04-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Larry  Paulsen et al → Paulsen Inc; 1997-04-24 to current/open; source msha-controller-operator-history