# Relationship history for MSHA mine 1002180

Current hierarchy: **Keith D  Sibert; Troy D  Sibert → D and A Crushing → Portable Crusher**

- 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:** D and A Crushing → Portable Crusher; 2009-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Troy D  Sibert et al → Portable Crusher; 2009-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Troy D  Sibert et al → D and A Crushing; 2009-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keith D  Sibert et al → D and A Crushing; 2009-04-13 to current/open; source msha-controller-operator-history