# Relationship history for MSHA mine 2100037

Current hierarchy: **Schulze Leland F → Hector Construction Company Inc → Hector Houston County Quarries**

- 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

- **operator_operates_mine:** Hector Construction Company Inc → Hector Houston County Quarries; 1950-01-01 to 1984-12-03; source msha-controller-operator-history
- **controller_controls_mine:** Nielsen Clarence C → Hector Houston County Quarries; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nielsen Clarence C → Hector Construction Company Inc; 1950-01-01 to 1984-12-03; source msha-controller-operator-history
- **operator_operates_mine:** Hector Construction Company Inc → Hector Houston County Quarries; 1984-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Schulze Leland F → Hector Houston County Quarries; 1984-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Schulze Leland F → Hector Construction Company Inc; 1984-12-04 to current/open; source msha-controller-operator-history