# Relationship history for MSHA mine 4801660

Current hierarchy: **Tolsa S A → Tolsa Wyoming Bentonite Corp. → Tolsa Mines**

- 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

- **controller_controls_mine:** Robert  Nolind et al → Tolsa Mines; 1999-03-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rock Springs Minerals Processing → Tolsa Mines; 2004-08-24 to 2015-02-19; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Nolind et al → Rock Springs Minerals Processing; 2004-08-24 to 2015-02-19; source msha-controller-operator-history
- **operator_operates_mine:** Tolsa Wyoming Bentonite Corp. → Tolsa Mines; 2015-02-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Tolsa S A → Tolsa Mines; 2015-02-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tolsa S A → Tolsa Wyoming Bentonite Corp.; 2015-02-20 to current/open; source msha-controller-operator-history