# Relationship history for MSHA mine 0200686

Current hierarchy: **Peter Kiewit Sons' Inc → Pinal Materials Company Inc → Sand And Gravel 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Pinal Materials Company Inc → Sand And Gravel Pit; 1950-01-01 to 1981-02-03; source msha-controller-operator-history
- **controller_controls_mine:** Zink Ben → Sand And Gravel Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Zink Ben → Pinal Materials Company Inc; 1950-01-01 to 1981-02-03; source msha-controller-operator-history
- **operator_operates_mine:** Pinal Materials Company Inc → Sand And Gravel Pit; 1981-02-04 to 1983-08-08; source msha-controller-operator-history
- **controller_controls_mine:** Hastmarck Clark → Sand And Gravel Pit; 1981-02-04 to 1983-08-08; source msha-controller-operator-history
- **controller_controls_operator:** Hastmarck Clark → Pinal Materials Company Inc; 1981-02-04 to 1983-08-08; source msha-controller-operator-history
- **operator_operates_mine:** Pinal Materials Company Inc → Sand And Gravel Pit; 1983-08-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Peter Kiewit Sons' Inc → Sand And Gravel Pit; 1983-08-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Peter Kiewit Sons' Inc → Pinal Materials Company Inc; 1983-08-09 to current/open; source msha-controller-operator-history