# Relationship history for MSHA mine 4503004

Current hierarchy: **Hyrum  Cox → Steelman-Duff Inc → PORTABLE CRUSHER #2**

- 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:** Poe Don M → PORTABLE CRUSHER #2; 1980-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Poe Asphalt Paving Inc → PORTABLE CRUSHER #2; 1983-05-01 to 1996-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Poe Don M → Poe Asphalt Paving Inc; 1983-05-01 to 1996-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Steelman-Duff Inc → PORTABLE CRUSHER #2; 1996-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hyrum  Cox → PORTABLE CRUSHER #2; 1996-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hyrum  Cox → Steelman-Duff Inc; 1996-11-01 to current/open; source msha-controller-operator-history