# Relationship history for MSHA mine 3609514

Current hierarchy: **Richard G  Simonds → Simonds Excavating Inc. → 4242 Impact 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Richard G  Simonds → 4242 Impact Crusher; 1993-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Simonds Excavating Inc. → 4242 Impact Crusher; 2007-04-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard G  Simonds → Simonds Excavating Inc.; 2007-04-27 to current/open; source msha-controller-operator-history