# Relationship history for MSHA mine 2200235

Current hierarchy: **Paige W  Farrish; David N  Farrish → Nelson Materials, Inc → Mitchell Pit And 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

- **operator_operates_mine:** Farrish Gravel Company Inc → Mitchell Pit And Plant; 1950-01-01 to 1982-11-08; source msha-controller-operator-history
- **controller_controls_mine:** John M  Farrish Sr → Mitchell Pit And Plant; 1950-01-01 to 1983-01-03; source msha-controller-operator-history
- **controller_controls_operator:** John M  Farrish Sr → Farrish Gravel Company Inc; 1950-01-01 to 1982-11-08; source msha-controller-operator-history
- **operator_operates_mine:** Nelson Materials, Inc → Mitchell Pit And Plant; 1982-11-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Paige W  Farrish et al → Mitchell Pit And Plant; 1982-11-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paige W  Farrish et al → Nelson Materials, Inc; 1982-11-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David N  Farrish et al → Nelson Materials, Inc; 1982-11-09 to current/open; source msha-controller-operator-history