# Relationship history for MSHA mine 0504237

Current hierarchy: **Wilson Galen → Wilson Excavation → Eight Mile Creek 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Holyoke Ready Mix Corp → Eight Mile Creek Gravel; 1987-06-01 to 1989-04-18; source msha-controller-operator-history
- **controller_controls_mine:** Dragoo Jerry L → Eight Mile Creek Gravel; 1987-06-01 to 1989-04-18; source msha-controller-operator-history
- **controller_controls_operator:** Dragoo Jerry L → Holyoke Ready Mix Corp; 1987-06-01 to 1989-04-18; source msha-controller-operator-history
- **operator_operates_mine:** Wilson Excavation → Eight Mile Creek Gravel; 1989-04-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wilson Galen → Eight Mile Creek Gravel; 1989-04-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wilson Galen → Wilson Excavation; 1989-04-19 to current/open; source msha-controller-operator-history