# Relationship history for MSHA mine 2902320

Current hierarchy: **Arthur  Vasquez → O & A Stone Company → H. Richards 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Arthur  Vasquez → H. Richards Quarry; 2001-11-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** O & A Stone Company → H. Richards Quarry; 2006-04-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Arthur  Vasquez → O & A Stone Company; 2006-04-29 to current/open; source msha-controller-operator-history