# Relationship history for MSHA mine 4002082

Current hierarchy: **Harry  Pressnell → Columbia Rock Products Corp → Columbia No 2 Mine And 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

- **operator_operates_mine:** Columbia Rock Products Corp → Columbia No 2 Mine And Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harry  Pressnell → Columbia No 2 Mine And Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harry  Pressnell → Columbia Rock Products Corp; 1950-01-01 to current/open; source msha-controller-operator-history