# Relationship history for MSHA mine 4300677

Current hierarchy: **Alexander (Sandy)  Adams → E & M Maintenance → Hard Work 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

- **operator_operates_mine:** E & M Maintenance → Hard Work Quarry; 2007-08-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Alexander (Sandy)  Adams → Hard Work Quarry; 2007-08-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alexander (Sandy)  Adams → E & M Maintenance; 2007-08-07 to current/open; source msha-controller-operator-history