# Relationship history for MSHA mine 0504784

Current hierarchy: **Terry L  Helms → Quartz Creek Gravel → Quartz Creek Gravel**

- 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:** Quartz Creek Gravel → Quartz Creek Gravel; 2004-04-22 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Terry L  Helms → Quartz Creek Gravel; 2004-04-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Terry L  Helms → Quartz Creek Gravel; 2004-04-22 to current/open; source msha-controller-operator-history