# Relationship history for MSHA mine 2800035

Current hierarchy: **CRH PLC → Tilcon New York Inc → Clifton Quarry**

- 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:** Union Building & Construction Corp → Clifton Quarry; 1950-01-01 to 1979-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Everett B  Muh → Clifton Quarry; 1950-01-01 to 1979-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Everett B  Muh → Union Building & Construction Corp; 1950-01-01 to 1979-12-31; source msha-controller-operator-history
- **operator_operates_mine:** R A Hamilton Corp → Clifton Quarry; 1980-01-01 to 1994-05-11; source msha-controller-operator-history
- **controller_controls_mine:** R A Hamilton Corp → Clifton Quarry; 1980-01-01 to 1994-09-05; source msha-controller-operator-history
- **controller_controls_operator:** R A Hamilton Corp → R A Hamilton Corp; 1980-01-01 to 1994-05-11; source msha-controller-operator-history
- **operator_operates_mine:** Dell Contractors Materials Inc → Clifton Quarry; 1994-05-12 to 1999-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Anthony J  Dellechiaie → Clifton Quarry; 1994-05-12 to 1999-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Anthony J  Dellechiaie → Dell Contractors Materials Inc; 1994-05-12 to 1999-06-30; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Clifton Quarry; 1996-09-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tilcon New York Inc → Clifton Quarry; 1999-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Tilcon New York Inc; 1999-07-01 to current/open; source msha-controller-operator-history