# Relationship history for MSHA mine 3503372

Current hierarchy: **Merle  Maine → Ontario Asphalt & Concrete Inc → PORTABLE CRUSHER #1**

- 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:** Merle  Maine → PORTABLE CRUSHER #1; 1983-07-29 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ontario Asphalt & Concrete Inc → PORTABLE CRUSHER #1; 1992-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Merle  Maine → Ontario Asphalt & Concrete Inc; 1992-07-01 to current/open; source msha-controller-operator-history