# Relationship history for MSHA mine 0405163

Current hierarchy: **Gordon  Vicini → Plymouth Sand & Gravel → Plymouth Sand & 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Plymouth Sand & Gravel → Plymouth Sand & Gravel; 1991-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gordon  Vicini → Plymouth Sand & Gravel; 1991-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gordon  Vicini → Plymouth Sand & Gravel; 1991-12-01 to current/open; source msha-controller-operator-history