# Relationship history for MSHA mine 3901662

Current hierarchy: **Darby E  Parsons; Wayne A  Lloyd → Prairie States Trucking Inc → Chancellor Gravel**

- 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:** Utica Gravel, Inc. → Chancellor Gravel; 2022-04-11 to 2023-11-29; source msha-controller-operator-history
- **controller_controls_mine:** Ralph  Marquardt → Chancellor Gravel; 2022-04-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ralph  Marquardt → Utica Gravel, Inc.; 2022-04-11 to 2023-11-29; source msha-controller-operator-history
- **operator_operates_mine:** Prairie States Trucking Inc → Chancellor Gravel; 2023-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Darby E  Parsons → Chancellor Gravel; 2023-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darby E  Parsons → Prairie States Trucking Inc; 2023-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wayne A  Lloyd → Prairie States Trucking Inc; 2023-11-30 to current/open; source msha-controller-operator-history