# Relationship history for MSHA mine 1201972

Current hierarchy: **Venturi Robert W → Energy Supply Inc → Venturi Pit #17**

- 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:** Venturi Robert W → Venturi Pit #17; 1976-10-06 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Energy Supply Inc → Venturi Pit #17; 1988-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Venturi Robert W → Energy Supply Inc; 1988-12-01 to current/open; source msha-controller-operator-history