# Relationship history for MSHA mine 0301527

Current hierarchy: **Saint-Gobain → Norton Company → Norton Arkansas Operations**

- 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:** Saint-Gobain → Norton Arkansas Operations; 1982-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Washita Mountain Whetstone Company Inc → Norton Arkansas Operations; 1982-05-01 to 1989-05-01; source msha-controller-operator-history
- **controller_controls_mine:** St Peter Creamery → Norton Arkansas Operations; 1982-05-01 to 1989-05-01; source msha-controller-operator-history
- **controller_controls_operator:** St Peter Creamery → Washita Mountain Whetstone Company Inc; 1982-05-01 to 1989-05-01; source msha-controller-operator-history
- **operator_operates_mine:** Norton Company → Norton Arkansas Operations; 1989-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Saint-Gobain → Norton Company; 1989-05-02 to current/open; source msha-controller-operator-history