# Relationship history for MSHA mine 3500758

Current hierarchy: **Shipley William → Ace Rock Inc → Ferry Creek Rock**

- 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:** Ferry Creek Rock & Concrete Inc → Ferry Creek Rock; 1950-01-01 to 1991-09-25; source msha-controller-operator-history
- **controller_controls_mine:** Curry John K → Ferry Creek Rock; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Curry John K → Ferry Creek Rock & Concrete Inc; 1950-01-01 to 1991-09-25; source msha-controller-operator-history
- **operator_operates_mine:** Ace Rock Inc → Ferry Creek Rock; 1991-09-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Shipley William → Ferry Creek Rock; 1991-09-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shipley William → Ace Rock Inc; 1991-09-26 to current/open; source msha-controller-operator-history