# Relationship history for MSHA mine 0203518

Current hierarchy: **AMS Southwest LLC; Sand River Holdings LLC → Premier Material Group LLC → Premier Materials Group -1350**

- 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

- **controller_controls_mine:** Sand River Holdings LLC et al → Premier Materials Group -1350; 2022-03-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Premier Material Group LLC → Premier Materials Group -1350; 2024-10-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sand River Holdings LLC et al → Premier Material Group LLC; 2024-10-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** AMS Southwest LLC et al → Premier Material Group LLC; 2024-10-07 to current/open; source msha-controller-operator-history