# Relationship history for MSHA mine 3503871

Current hierarchy: **Edward B Fisher → Oakridge Sand & Gravel → Angel Butte**

- 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

- **controller_controls_mine:** Edward B Fisher → Angel Butte; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Oakridge Sand & Gravel → Angel Butte; 2018-10-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward B Fisher → Oakridge Sand & Gravel; 2018-10-04 to current/open; source msha-controller-operator-history