# Relationship history for MSHA mine 3003117

Current hierarchy: **David  Squires; Mark  Squires → John F & John P Wenzel Contractors Inc → Wenzel Gravel 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** John F & John P Wenzel Contractors Inc → Wenzel Gravel Mine; 1994-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wenzel John F & John P → Wenzel Gravel Mine; 1994-05-01 to 2019-12-12; source msha-controller-operator-history
- **controller_controls_operator:** Wenzel John F & John P → John F & John P Wenzel Contractors Inc; 1994-05-01 to 2019-12-12; source msha-controller-operator-history
- **controller_controls_mine:** David  Squires et al → Wenzel Gravel Mine; 2019-12-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Squires et al → John F & John P Wenzel Contractors Inc; 2019-12-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Squires et al → John F & John P Wenzel Contractors Inc; 2019-12-13 to current/open; source msha-controller-operator-history