# Relationship history for MSHA mine 4502723

Current hierarchy: **Lakeside Industries Inc. → B & K Paving Company Inc → Columbia River Sand & Gravel Pit #1**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Schwartz Dave & Roger Olson → Columbia River Sand & Gravel Pit #1; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Chelatchie Rock Products → Columbia River Sand & Gravel Pit #1; 1979-01-01 to 1981-02-11; source msha-controller-operator-history
- **controller_controls_operator:** Schwartz Dave & Roger Olson → Chelatchie Rock Products; 1979-01-01 to 1981-02-11; source msha-controller-operator-history
- **operator_operates_mine:** B & K Paving Company Inc → Columbia River Sand & Gravel Pit #1; 1981-02-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lakeside Industries Inc. et al → Columbia River Sand & Gravel Pit #1; 1981-02-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lakeside Industries Inc. et al → B & K Paving Company Inc; 1981-02-12 to current/open; source msha-controller-operator-history