# Relationship history for MSHA mine 0901019

Current hierarchy: **Hanson PLC → Davidson Mineral Properties Inc → Walton County Plant**

- 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

- **controller_controls_mine:** Koppers Company Inc → Walton County Plant; 1979-02-01 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Davidson Mineral Properties Inc → Walton County Plant; 1988-03-01 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Davidson Mineral Properties Inc; 1988-03-01 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Walton County Plant; 1988-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Davidson Mineral Properties Inc → Walton County Plant; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Davidson Mineral Properties Inc; 1988-11-14 to current/open; source msha-controller-operator-history