# Relationship history for MSHA mine 1512950

Current hierarchy: **Hanson PLC → Kentucky Stone Company → Harrodsburg Mine**

- 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

- **controller_controls_mine:** Koppers Company Inc → Harrodsburg Mine; 1950-01-01 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky Stone Company → Harrodsburg Mine; 1981-06-01 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Kentucky Stone Company; 1981-06-01 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky Stone Company → Harrodsburg Mine; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Harrodsburg Mine; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Kentucky Stone Company; 1988-11-14 to current/open; source msha-controller-operator-history