# Relationship history for MSHA mine 3200912

Current hierarchy: **Leon M.  Hoyt → Leon Hoyt Construction → Pioneer Crushing Plant**

- 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:** Leon M.  Hoyt → Pioneer Crushing Plant; 2011-04-15 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Leon Hoyt Construction → Pioneer Crushing Plant; 2011-09-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Leon M.  Hoyt → Leon Hoyt Construction; 2011-09-15 to current/open; source msha-controller-operator-history