# Relationship history for MSHA mine 3901406

Current hierarchy: **Milt  Wendelboe; Kenny  Wendelboe → Wendelboe Construction → PORTABLE SCREENER**

- 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:** Wendelboe Construction → PORTABLE SCREENER; 1994-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kenny  Wendelboe et al → PORTABLE SCREENER; 1994-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenny  Wendelboe et al → Wendelboe Construction; 1994-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Milt  Wendelboe et al → Wendelboe Construction; 1994-11-01 to current/open; source msha-controller-operator-history