# Relationship history for MSHA mine 3003633

Current hierarchy: **Heidelberg Materials AG → HEIDELBERG MATERIALS NORTHEAST LLC → WATERFORD 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

- **controller_controls_mine:** Hanson PLC → WATERFORD SAND & GRAVEL; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Carver P  Laraway et al → WATERFORD SAND & GRAVEL; 1995-11-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → WATERFORD SAND & GRAVEL; 2007-08-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Carver Sand & Gravel LLC → WATERFORD SAND & GRAVEL; 2008-05-13 to 2025-05-22; source msha-controller-operator-history
- **controller_controls_operator:** Carver P  Laraway et al → Carver Sand & Gravel LLC; 2008-05-13 to 2025-05-22; source msha-controller-operator-history
- **operator_operates_mine:** Heidelberg Materials Northeast LLC → WATERFORD SAND & GRAVEL; 2025-05-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Heidelberg Materials Northeast LLC; 2025-05-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Heidelberg Materials Northeast LLC; 2025-05-23 to 2007-08-22; source msha-controller-operator-history