# Relationship history for MSHA mine 3400267

Current hierarchy: **USG Corporation → H & B Gypsum Inc → H & B QUARRY**

- 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 → H & B QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** United States Steel Corp → H & B QUARRY; 1950-01-01 to 1980-10-15; source msha-controller-operator-history
- **controller_controls_mine:** USX Corp (United States Steel Corp) → H & B QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USX Corp (United States Steel Corp) → United States Steel Corp; 1950-01-01 to 1980-10-15; source msha-controller-operator-history
- **operator_operates_mine:** Lehigh Portland Cement Company → H & B QUARRY; 1980-10-16 to 1986-06-11; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Lehigh Portland Cement Company; 1980-10-16 to 1986-06-11; source msha-controller-operator-history
- **controller_controls_mine:** Donald  Boutwell → H & B QUARRY; 1986-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Heartland Cement Company-Div/Rc Cement Co Inc → H & B QUARRY; 1986-06-12 to 1995-09-10; source msha-controller-operator-history
- **controller_controls_mine:** Buzzi S p A → H & B QUARRY; 1986-06-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Buzzi S p A → Heartland Cement Company-Div/Rc Cement Co Inc; 1986-06-12 to 1995-09-10; source msha-controller-operator-history
- **operator_operates_mine:** H & B Gypsum Inc → H & B QUARRY; 1995-09-11 to 1998-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Donald  Boutwell → H & B Gypsum Inc; 1995-09-11 to 1998-12-31; source msha-controller-operator-history
- **operator_operates_mine:** H & B Gypsum Inc → H & B QUARRY; 1999-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** USG Corporation → H & B QUARRY; 1999-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USG Corporation → H & B Gypsum Inc; 1999-01-01 to current/open; source msha-controller-operator-history