# Relationship history for MSHA mine 4801182

Current hierarchy: **Willis  Young; Irene  Young → Willis Young Cement & Gravel Company → Willis Young Cement & Gravel**

- 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:** Roger D  Koontz → Willis Young Cement & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Willis  Young et al → Willis Young Cement & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Harris Trucking & Construction Company → Willis Young Cement & Gravel; 1978-03-09 to 1979-04-15; source msha-controller-operator-history
- **controller_controls_operator:** Roger D  Koontz → Harris Trucking & Construction Company; 1978-03-09 to 1979-04-15; source msha-controller-operator-history
- **operator_operates_mine:** Willis Young Cement & Gravel Company → Willis Young Cement & Gravel; 1979-04-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Willis  Young et al → Willis Young Cement & Gravel Company; 1979-04-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Irene  Young et al → Willis Young Cement & Gravel Company; 1979-04-16 to current/open; source msha-controller-operator-history