# Relationship history for MSHA mine 3503385

Current hierarchy: **Frischman Randy → Frischman Excavating Inc → Frischman Rock**

- 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:** Frischman Excavating Inc → Frischman Rock; 1993-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Frischman Randy → Frischman Rock; 1993-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frischman Randy → Frischman Excavating Inc; 1993-02-01 to current/open; source msha-controller-operator-history