# Relationship history for MSHA mine 1000091

Current hierarchy: **Monsanto Company → Monsanto Company → Henry Mine**

- 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

- **controller_controls_mine:** Monsanto Company → Henry Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Dravo-Soda Springs → Henry Mine; 1950-01-01 to 1979-06-18; source msha-controller-operator-history
- **controller_controls_mine:** Dravo Corp & N A Degerstrom Inc → Henry Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dravo Corp & N A Degerstrom Inc → Dravo-Soda Springs; 1950-01-01 to 1979-06-18; source msha-controller-operator-history
- **operator_operates_mine:** Monsanto Company → Henry Mine; 1979-06-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Monsanto Company → Monsanto Company; 1979-06-19 to current/open; source msha-controller-operator-history