# Relationship history for MSHA mine 0302002

Current hierarchy: **Steve R  Hackman → T & H Sand Company → T & H Sand Plant # 2**

- 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:** T & H Sand Company → T & H Sand Plant # 2; 2010-11-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steve R  Hackman et al → T & H Sand Plant # 2; 2010-11-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve R  Hackman et al → T & H Sand Company; 2010-11-08 to current/open; source msha-controller-operator-history