# Relationship history for MSHA mine 1200047

Current hierarchy: **Venturi Robert W → Energy Supply Inc → Marengo Quarry Division**

- 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:** Hy Rock Products Company Inc → Marengo Quarry Division; 1950-01-01 to 1984-11-25; source msha-controller-operator-history
- **controller_controls_mine:** Bowen James W → Marengo Quarry Division; 1950-01-01 to 1984-11-25; source msha-controller-operator-history
- **controller_controls_operator:** Bowen James W → Hy Rock Products Company Inc; 1950-01-01 to 1984-11-25; source msha-controller-operator-history
- **operator_operates_mine:** Energy Supply Inc → Marengo Quarry Division; 1984-11-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Venturi Robert W → Marengo Quarry Division; 1984-11-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Venturi Robert W → Energy Supply Inc; 1984-11-26 to current/open; source msha-controller-operator-history