# Relationship history for MSHA mine 4500764

Current hierarchy: **CRH PLC → American Rock Products → ARP Portable Crusher #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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Parker'S Sand & Gravel Inc → ARP Portable Crusher #2; 1950-01-01 to 1978-08-07; source msha-controller-operator-history
- **controller_controls_mine:** Mike  Parker → ARP Portable Crusher #2; 1950-01-01 to 2023-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Mike  Parker → Parker'S Sand & Gravel Inc; 1950-01-01 to 1978-08-07; source msha-controller-operator-history
- **operator_operates_mine:** Columbia Ready-Mix Inc → ARP Portable Crusher #2; 1978-08-08 to 2017-02-12; source msha-controller-operator-history
- **controller_controls_mine:** Lawrence  Sali  et al → ARP Portable Crusher #2; 1978-08-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lawrence  Sali  et al → Columbia Ready-Mix Inc; 1978-08-08 to 2017-02-12; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Sali  et al → Columbia Ready-Mix Inc; 1978-08-08 to 2017-02-12; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → ARP Portable Crusher #2; 1987-09-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** American Rock Products → ARP Portable Crusher #2; 2017-02-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → American Rock Products; 2017-02-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Casey  Parker → ARP Portable Crusher #2; 2024-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Casey  Parker → Parker'S Sand & Gravel Inc; 2024-01-01 to 1978-08-07; source msha-controller-operator-history