# Relationship history for MSHA mine 2402094

Current hierarchy: **Frank A  Thomas → Polson Ready Mix Concrete Inc → PRM 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

- **controller_controls_mine:** Frank A  Thomas  et al → PRM CRUSHER; 1984-05-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Polson Ready Mix Concrete Inc → PRM CRUSHER; 1996-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frank A  Thomas  et al → Polson Ready Mix Concrete Inc; 1996-06-01 to current/open; source msha-controller-operator-history