# Relationship history for MSHA mine 4105224

Current hierarchy: **Kenneth R Rusty"  Simpson; Stacey M "Shelly" Simpson" → Simpson Crushed Stone, LLC → Sweetwater Buzzi Unicem**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Stacey M Shelly" Simpson et al" → Sweetwater Buzzi Unicem; 2009-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Simpson Crushed Stone, LLC → Sweetwater Buzzi Unicem; 2016-12-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stacey M Shelly" Simpson et al" → Simpson Crushed Stone, LLC; 2016-12-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth R Rusty"  Simpson et al" → Simpson Crushed Stone, LLC; 2016-12-18 to current/open; source msha-controller-operator-history