# Relationship history for MSHA mine 3608736

Current hierarchy: **CRH PLC → Pennsy Supply Inc → Lawton 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

- **controller_controls_mine:** CRH PLC → Lawton Quarry; 1993-07-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark  Powers et al → Lawton Quarry; 1997-03-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Powers Stone Inc → Lawton Quarry; 1998-06-01 to 2011-11-18; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Powers et al → Powers Stone Inc; 1998-06-01 to 2011-11-18; source msha-controller-operator-history
- **controller_controls_operator:** Ronald J Powers et al → Powers Stone Inc; 1998-06-01 to 2011-11-18; source msha-controller-operator-history
- **operator_operates_mine:** Pennsy Supply Inc → Lawton Quarry; 2011-11-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Pennsy Supply Inc; 2011-11-19 to current/open; source msha-controller-operator-history