# Relationship history for MSHA mine 4503158

Current hierarchy: **Hanson PLC → Yakima Concrete & Asphalt Company → Newland 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:** Yakima Concrete & Asphalt Company → Newland Pit; 1988-03-01 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_mine:** Koppers Company Inc → Newland Pit; 1988-03-01 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Yakima Concrete & Asphalt Company; 1988-03-01 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Yakima Concrete & Asphalt Company → Newland Pit; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Newland Pit; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Yakima Concrete & Asphalt Company; 1988-11-14 to current/open; source msha-controller-operator-history