# Relationship history for MSHA mine 3503378

Current hierarchy: **Michael Ray  Hilton → Hilton Fuel & Supply → Willow Creek Aggregate**

- 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

- **operator_operates_mine:** Hilton Fuel & Supply Company → Willow Creek Aggregate; 1992-12-01 to 2018-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Michael Ray  Hilton → Willow Creek Aggregate; 1992-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael Ray  Hilton → Hilton Fuel & Supply Company; 1992-12-01 to 2018-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Hilton Fuel & Supply → Willow Creek Aggregate; 2019-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael Ray  Hilton → Willow Creek Aggregate; 2019-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael Ray  Hilton → Hilton Fuel & Supply; 2019-01-01 to current/open; source msha-controller-operator-history