# Relationship history for MSHA mine 2501252

Current hierarchy: **Thomas A  Fitch; Timothy  Armstrong → Riverview Sand & Gravel, L.L.C. → Riverview Sand & Gravel, L.L.C.**

- 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:** Riverview Sand & Gravel, L.L.C. → Riverview Sand & Gravel, L.L.C.; 2008-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Timothy  Armstrong et al → Riverview Sand & Gravel, L.L.C.; 2008-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Timothy  Armstrong et al → Riverview Sand & Gravel, L.L.C.; 2008-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas A  Fitch et al → Riverview Sand & Gravel, L.L.C.; 2008-10-03 to current/open; source msha-controller-operator-history