# Relationship history for MSHA mine 2103948

Current hierarchy: **Michael W  Buetow → Buetow Trucking & Excavating → Highway 61 Sand and 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:** Buetow Trucking & Excavating → Highway 61 Sand and Gravel; 2019-05-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael W  Buetow → Highway 61 Sand and Gravel; 2019-05-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael W  Buetow → Buetow Trucking & Excavating; 2019-05-24 to current/open; source msha-controller-operator-history