# Relationship history for MSHA mine 4607091

Current hierarchy: **Heidelberg Materials AG → Hanson Aggregates Pma Inc → Dredge Thaddus Carr**

- 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:** Pittsburg Sand & Gravel Inc → Dredge Thaddus Carr; 1986-03-01 to 1991-03-07; source msha-controller-operator-history
- **controller_controls_mine:** Glenn I  Crain → Dredge Thaddus Carr; 1986-03-01 to 1991-03-07; source msha-controller-operator-history
- **controller_controls_operator:** Glenn I  Crain → Pittsburg Sand & Gravel Inc; 1986-03-01 to 1991-03-07; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Dredge Thaddus Carr; 1987-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Pioneer International Ltd → Dredge Thaddus Carr; 1989-01-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pittsburgh Sand & Gravel Inc → Dredge Thaddus Carr; 1991-03-08 to 1991-10-02; source msha-controller-operator-history
- **controller_controls_mine:** Standard Slag Company → Dredge Thaddus Carr; 1991-03-08 to 1991-10-02; source msha-controller-operator-history
- **controller_controls_operator:** Standard Slag Company → Pittsburgh Sand & Gravel Inc; 1991-03-08 to 1991-10-02; source msha-controller-operator-history
- **operator_operates_mine:** Lafarge Construction Materials → Dredge Thaddus Carr; 1991-10-03 to 1996-05-15; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Lafarge Construction Materials; 1991-10-03 to 1996-05-15; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Mid-Atlantic Inc → Dredge Thaddus Carr; 1996-05-16 to 2000-08-03; source msha-controller-operator-history
- **controller_controls_operator:** Pioneer International Ltd → Pioneer Mid-Atlantic Inc; 1996-05-16 to 2000-08-03; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates Pma Inc → Dredge Thaddus Carr; 2000-08-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Dredge Thaddus Carr; 2000-08-04 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates Pma Inc; 2000-08-04 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Dredge Thaddus Carr; 2007-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Hanson Aggregates Pma Inc; 2007-08-23 to current/open; source msha-controller-operator-history