# Relationship history for MSHA mine 1700729

Current hierarchy: **DANIEL F  BICKFORD → FOX ISLAND GRANITE CO. INC. → FOX ISLAND QUARRY**

- 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:** FOX ISLAND GRANITE CO. INC. → FOX ISLAND QUARRY; 2002-05-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** DANIEL F  BICKFORD ET AL → FOX ISLAND QUARRY; 2002-05-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** DANIEL F  BICKFORD ET AL → FOX ISLAND GRANITE CO. INC.; 2002-05-21 to current/open; source msha-controller-operator-history