# Relationship history for MSHA mine 4500623

Current hierarchy: **Goodfellow Brothers LLC → Columbia River Concrete → Elmer E Olson Pit**

- 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

- **operator_operates_mine:** Columbia Concrete Products → Elmer E Olson Pit; 1950-01-01 to 1981-08-10; source msha-controller-operator-history
- **controller_controls_mine:** Walter L  Foster → Elmer E Olson Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walter L  Foster → Columbia Concrete Products; 1950-01-01 to 1981-08-10; source msha-controller-operator-history
- **operator_operates_mine:** Columbia River Concrete → Elmer E Olson Pit; 1981-08-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Goodfellow Brothers LLC → Elmer E Olson Pit; 1981-08-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Goodfellow Brothers LLC → Columbia River Concrete; 1981-08-11 to current/open; source msha-controller-operator-history