# Relationship history for MSHA mine 0504037

Current hierarchy: **CRH PLC → Mountain Gravel → CURSHER UNIT #2**

- 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

- **controller_controls_mine:** Richard  Tibbits  et al → CURSHER UNIT #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Gravel & Construction Company → CURSHER UNIT #2; 1985-05-01 to 1998-06-07; source msha-controller-operator-history
- **controller_controls_operator:** Richard  Tibbits  et al → Mountain Gravel & Construction Company; 1985-05-01 to 1998-06-07; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Gravel → CURSHER UNIT #2; 1998-06-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → CURSHER UNIT #2; 1998-06-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Mountain Gravel; 1998-06-08 to current/open; source msha-controller-operator-history