# Relationship history for MSHA mine 2902336

Current hierarchy: **Thomas G  Fisher → Fisher Sand & Gravel Company → Fisher Industries Plant 36**

- 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

- **controller_controls_mine:** Thomas G  Fisher et al → Fisher Industries Plant 36; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Fisher Sand & Gravel Company → Fisher Industries Plant 36; 2007-02-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas G  Fisher et al → Fisher Sand & Gravel Company; 2007-02-28 to current/open; source msha-controller-operator-history