# Relationship history for MSHA mine 4202046

Current hierarchy: **Read Cliff → Park City Rock Products Inc → Park City Portable Crusher**

- 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:** Read Cliff → Park City Portable Crusher; 1988-11-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Park City Rock Products Inc → Park City Portable Crusher; 1989-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Read Cliff → Park City Rock Products Inc; 1989-04-01 to current/open; source msha-controller-operator-history