# Relationship history for MSHA mine 0502177

Current hierarchy: **Thomas E  Brubaker → Valco Inc → Valco Gunnison Concrete**

- 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:** Thomas E  Brubaker → Valco Gunnison Concrete; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Gunnison Ready Mix Inc → Valco Gunnison Concrete; 1950-01-01 to 1980-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Glass Fred → Valco Gunnison Concrete; 1950-01-01 to 1980-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Glass Fred → Gunnison Ready Mix Inc; 1950-01-01 to 1980-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Valco Inc → Valco Gunnison Concrete; 1980-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas E  Brubaker → Valco Inc; 1980-09-01 to current/open; source msha-controller-operator-history