# Relationship history for MSHA mine 4105309

Current hierarchy: **Pro Frac Holding Corp → Alpine Silica, LLC → Alpine Silica-Kermit**

- 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:** Alpine Silica, LLC → Alpine Silica-Kermit; 2017-11-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wilks Brothers LLC → Alpine Silica-Kermit; 2017-11-13 to 2022-10-09; source msha-controller-operator-history
- **controller_controls_operator:** Wilks Brothers LLC → Alpine Silica, LLC; 2017-11-13 to 2022-10-09; source msha-controller-operator-history
- **controller_controls_mine:** Pro Frac Holding Corp → Alpine Silica-Kermit; 2022-10-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pro Frac Holding Corp → Alpine Silica, LLC; 2022-10-10 to current/open; source msha-controller-operator-history