# Relationship history for MSHA mine 0405262

Current hierarchy: **Donald D  Schnetzer → Schnetzer Engineering Inc → SCHNETZER PORTABLE PLANT**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Schnetzer Engineering Inc → SCHNETZER PORTABLE PLANT; 1994-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Donald D  Schnetzer → SCHNETZER PORTABLE PLANT; 1994-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Donald D  Schnetzer → Schnetzer Engineering Inc; 1994-12-01 to current/open; source msha-controller-operator-history