# Relationship history for MSHA mine 2000847

Current hierarchy: **Fairmount Santrol → Standard Sand Corp → Rosy Mound Standard Sand Corporation**

- 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:** Standard Sand Corp → Rosy Mound Standard Sand Corporation; 1950-01-01 to 2001-03-19; source msha-controller-operator-history
- **controller_controls_mine:** Cheyenne Corp → Rosy Mound Standard Sand Corporation; 1950-01-01 to 2001-03-19; source msha-controller-operator-history
- **controller_controls_operator:** Cheyenne Corp → Standard Sand Corp; 1950-01-01 to 2001-03-19; source msha-controller-operator-history
- **operator_operates_mine:** Standard Sand Corp → Rosy Mound Standard Sand Corporation; 2001-03-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Fairmount Santrol → Rosy Mound Standard Sand Corporation; 2001-03-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fairmount Santrol → Standard Sand Corp; 2001-03-20 to current/open; source msha-controller-operator-history