# Relationship history for MSHA mine 3600513

Current hierarchy: **CRH PLC → Pennsy Supply Inc → Fontana 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:** H J Smith & Son Inc → Fontana Quarry; 1950-01-01 to 1991-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Chester N  Smith → Fontana Quarry; 1950-01-01 to 1991-12-19; source msha-controller-operator-history
- **controller_controls_operator:** Chester N  Smith → H J Smith & Son Inc; 1950-01-01 to 1991-12-19; source msha-controller-operator-history
- **operator_operates_mine:** Smith Quarries Inc → Fontana Quarry; 1991-12-20 to 1993-07-20; source msha-controller-operator-history
- **controller_controls_mine:** Barbara M  Mumma → Fontana Quarry; 1991-12-20 to 1993-07-20; source msha-controller-operator-history
- **controller_controls_operator:** Barbara M  Mumma → Smith Quarries Inc; 1991-12-20 to 1993-07-20; source msha-controller-operator-history
- **operator_operates_mine:** Pennsy Supply Inc → Fontana Quarry; 1993-07-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Fontana Quarry; 1993-07-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Pennsy Supply Inc; 1993-07-21 to current/open; source msha-controller-operator-history