# Relationship history for MSHA mine 1401543

Current hierarchy: **Compass Minerals International, Inc. → North American Salt Company → North American Evaporated Salt Mill**

- 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:** Harris Chemical Group → North American Evaporated Salt Mill; 1988-03-11 to 2001-11-27; source msha-controller-operator-history
- **operator_operates_mine:** North American Salt Company → North American Evaporated Salt Mill; 1990-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harris Chemical Group → North American Salt Company; 1990-11-01 to 2001-11-27; source msha-controller-operator-history
- **controller_controls_mine:** Compass Minerals International, Inc. → North American Evaporated Salt Mill; 2001-11-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Compass Minerals International, Inc. → North American Salt Company; 2001-11-28 to current/open; source msha-controller-operator-history