# Relationship history for MSHA mine 4100253

Current hierarchy: **Buzzi S p A → Alamo Concrete Products Company → Barrett Base Plt**

- 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

- **operator_operates_mine:** Barrett Industries → Barrett Base Plt; 1950-01-01 to 1991-03-21; source msha-controller-operator-history
- **controller_controls_mine:** Harold F  Mc Donald → Barrett Base Plt; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold F  Mc Donald → Barrett Industries; 1950-01-01 to 1991-03-21; source msha-controller-operator-history
- **controller_controls_mine:** Buzzi S p A → Barrett Base Plt; 1988-12-20 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Alamo Concrete Products Company → Barrett Base Plt; 1991-03-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Buzzi S p A → Alamo Concrete Products Company; 1991-03-22 to current/open; source msha-controller-operator-history