# Relationship history for MSHA mine 2301089

Current hierarchy: **H K Porter Company Inc → Missouri Portland Cement Company → Sugar Creek Underground Garage & Storage**

- 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:** Missouri Portland Cement Company → Sugar Creek Underground Garage & Storage; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** H K Porter Company Inc → Sugar Creek Underground Garage & Storage; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** H K Porter Company Inc → Missouri Portland Cement Company; 1950-01-01 to current/open; source msha-controller-operator-history