# Relationship history for MSHA mine 4604764

Current hierarchy: **Smeltzer Donald → Smeltzer Augering Company → Auger Machine No 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:** Smeltzer Donald → Auger Machine No 2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Smeltzer Augering Company → Auger Machine No 2; 1975-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smeltzer Donald → Smeltzer Augering Company; 1975-05-01 to current/open; source msha-controller-operator-history