# Relationship history for MSHA mine 3301381

Current hierarchy: **Murphy Frank B → Lancaster Asphalt Company → Alexandria 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Alexandria Material Company → Alexandria Sand & Gravel; 1950-01-01 to 1986-04-22; source msha-controller-operator-history
- **controller_controls_mine:** Hall Richard A → Alexandria Sand & Gravel; 1950-01-01 to 1986-04-22; source msha-controller-operator-history
- **controller_controls_operator:** Hall Richard A → Alexandria Material Company; 1950-01-01 to 1986-04-22; source msha-controller-operator-history
- **operator_operates_mine:** Lancaster Asphalt Company → Alexandria Sand & Gravel; 1986-04-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Murphy Frank B → Alexandria Sand & Gravel; 1986-04-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Murphy Frank B → Lancaster Asphalt Company; 1986-04-23 to current/open; source msha-controller-operator-history