# Relationship history for MSHA mine 1901045

Current hierarchy: **CRH PLC → Tilcon Connecticut Inc → Southwick 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Tilcon Roncari Inc → Southwick Sand & Gravel; 1995-07-01 to 1996-09-08; source msha-controller-operator-history
- **controller_controls_mine:** BTR PLC → Southwick Sand & Gravel; 1995-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BTR PLC → Tilcon Roncari Inc; 1995-07-01 to 1996-09-08; source msha-controller-operator-history
- **operator_operates_mine:** Tilcon Connecticut Inc → Southwick Sand & Gravel; 1996-09-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Southwick Sand & Gravel; 1996-09-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Tilcon Connecticut Inc; 1996-09-09 to current/open; source msha-controller-operator-history