# Relationship history for MSHA mine 3603155

Current hierarchy: **Heidelberg Materials AG → Heidelberg Materials Northeast LLC → Bloomsburg Sand & Gravel**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Bloomsburg Sand & Gravel Company Inc → Bloomsburg Sand & Gravel; 1950-01-01 to 1985-05-14; source msha-controller-operator-history
- **controller_controls_mine:** N B  Beers → Bloomsburg Sand & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** N B  Beers → Bloomsburg Sand & Gravel Company Inc; 1950-01-01 to 1985-05-14; source msha-controller-operator-history
- **operator_operates_mine:** Bloomsburg Sand & Gravel Company → Bloomsburg Sand & Gravel; 1985-05-15 to 1989-01-25; source msha-controller-operator-history
- **controller_controls_mine:** Terry W  Hock → Bloomsburg Sand & Gravel; 1985-05-15 to 1989-01-25; source msha-controller-operator-history
- **controller_controls_operator:** Terry W  Hock → Bloomsburg Sand & Gravel Company; 1985-05-15 to 1989-01-25; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Bloomsburg Sand & Gravel; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **operator_operates_mine:** Heidelberg Materials Northeast LLC → Bloomsburg Sand & Gravel; 1989-01-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Heidelberg Materials Northeast LLC; 1989-01-26 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Bloomsburg Sand & Gravel; 2007-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Heidelberg Materials Northeast LLC; 2007-08-23 to current/open; source msha-controller-operator-history