# Relationship history for MSHA mine 4604488

Current hierarchy: **Irey Frank Jr → Steam Systems Sales & Service Inc → No 1 Strip Mine**

- 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:** Irey Frank Jr → No 1 Strip Mine; 1974-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Steam Systems Sales & Service Inc → No 1 Strip Mine; 1974-12-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Irey Frank Jr → Steam Systems Sales & Service Inc; 1974-12-30 to current/open; source msha-controller-operator-history