# Relationship history for MSHA mine 3302517

Current hierarchy: **George S  Smith → Masons Sand & Gravel Company → Masons Sand & Gravel Company**

- 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:** Masons Sand & Gravel Company → Masons Sand & Gravel Company; 1950-01-01 to 2001-05-29; source msha-controller-operator-history
- **controller_controls_mine:** Gordon  Masteller → Masons Sand & Gravel Company; 1950-01-01 to 2001-05-29; source msha-controller-operator-history
- **controller_controls_operator:** Gordon  Masteller → Masons Sand & Gravel Company; 1950-01-01 to 2001-05-29; source msha-controller-operator-history
- **operator_operates_mine:** Masons Sand & Gravel Company → Masons Sand & Gravel Company; 2001-05-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** George S  Smith → Masons Sand & Gravel Company; 2001-05-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** George S  Smith → Masons Sand & Gravel Company; 2001-05-30 to current/open; source msha-controller-operator-history