# Relationship history for MSHA mine 1601562

Current hierarchy: **Kim  Smith; Pamela  Smith → Sierra Frac Sand, LLC → Sierra Sand Mine**

- 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

- **operator_operates_mine:** Sierra Frac Sand, LLC → Sierra Sand Mine; 2016-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kim  Smith et al → Sierra Sand Mine; 2016-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kim  Smith et al → Sierra Frac Sand, LLC; 2016-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pamela  Smith et al → Sierra Frac Sand, LLC; 2016-03-18 to current/open; source msha-controller-operator-history