# Relationship history for MSHA mine 2500833

Current hierarchy: **Heimes Don → Central Sand & Gravel Company → Pt-80 Pit And Plant**

- 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:** Heimes Don → Pt-80 Pit And Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Troudt Sand & Gravel Company → Pt-80 Pit And Plant; 1950-01-01 to 1981-09-13; source msha-controller-operator-history
- **controller_controls_mine:** Troudt William C → Pt-80 Pit And Plant; 1950-01-01 to 1981-09-13; source msha-controller-operator-history
- **controller_controls_operator:** Troudt William C → Troudt Sand & Gravel Company; 1950-01-01 to 1981-09-13; source msha-controller-operator-history
- **operator_operates_mine:** Central Sand & Gravel Company → Pt-80 Pit And Plant; 1981-09-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heimes Don → Central Sand & Gravel Company; 1981-09-14 to current/open; source msha-controller-operator-history