# Relationship history for MSHA mine 0202481

Current hierarchy: **Quackenbush H E & Mike → Western Sand & Rock → Gila Bend Plant #3 (Portable)**

- 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:** Quackenbush H E & Mike → Gila Bend Plant #3 (Portable); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Western Sand & Rock → Gila Bend Plant #3 (Portable); 1989-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Quackenbush H E & Mike → Western Sand & Rock; 1989-04-01 to current/open; source msha-controller-operator-history