# Relationship history for MSHA mine 0202170

Current hierarchy: **Calmat Company → Allied Concrete & Materials Company Inc → Val Vista**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Allied Concrete & Materials Company → Val Vista; 1950-01-01 to 1986-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Allied Concrete & Materials Company → Val Vista; 1983-10-01 to 1986-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Allied Concrete & Materials Company → Allied Concrete & Materials Company; 1983-10-01 to 1986-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Allied Concrete & Materials Company Inc → Val Vista; 1987-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Calmat Company → Val Vista; 1987-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Calmat Company → Allied Concrete & Materials Company Inc; 1987-01-01 to current/open; source msha-controller-operator-history