# Relationship history for MSHA mine 4003504

Current hierarchy: **Avery C  York III → York and Sons Quarries → Copeland 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

- **controller_controls_mine:** Avery C  York III → Copeland Quarry; 2009-07-15 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** York and Sons Quarries → Copeland Quarry; 2018-11-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Avery C  York III → York and Sons Quarries; 2018-11-06 to current/open; source msha-controller-operator-history