# Relationship history for MSHA mine 1400162

Current hierarchy: **Buzzi S p A → Buzzi Unicem USA → INDEPENDENCE QUARRY & MILL**

- 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:** Heidelberg Materials AG → INDEPENDENCE QUARRY & MILL; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Universal Atlas Cement Company → INDEPENDENCE QUARRY & MILL; 1950-01-01 to 1980-10-15; source msha-controller-operator-history
- **controller_controls_mine:** USX Corp (United States Steel Corp) → INDEPENDENCE QUARRY & MILL; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USX Corp (United States Steel Corp) → Universal Atlas Cement Company; 1950-01-01 to 1980-10-15; source msha-controller-operator-history
- **operator_operates_mine:** Lehigh Portland Cement Company → INDEPENDENCE QUARRY & MILL; 1980-10-16 to 1986-06-24; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Lehigh Portland Cement Company; 1980-10-16 to 1986-06-24; source msha-controller-operator-history
- **controller_controls_mine:** Buzzi S p A → INDEPENDENCE QUARRY & MILL; 1986-06-12 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Buzzi Unicem USA → INDEPENDENCE QUARRY & MILL; 1986-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Buzzi S p A → Buzzi Unicem USA; 1986-06-25 to current/open; source msha-controller-operator-history