# Relationship history for MSHA mine 3304368

Current hierarchy: **Martin  Savko Jr → Savko Materials 1, LLC → Sand and Gravel 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:** Tuffco Sand & Gravel Inc → Sand and Gravel Quarry; 1996-02-01 to 2025-04-06; source msha-controller-operator-history
- **controller_controls_mine:** Charles  Lewis → Sand and Gravel Quarry; 1996-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Charles  Lewis → Tuffco Sand & Gravel Inc; 1996-02-01 to 2025-04-06; source msha-controller-operator-history
- **operator_operates_mine:** Savko Materials 1, LLC → Sand and Gravel Quarry; 2025-04-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin  Savko Jr → Sand and Gravel Quarry; 2025-04-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin  Savko Jr → Savko Materials 1, LLC; 2025-04-07 to current/open; source msha-controller-operator-history