# Relationship history for MSHA mine 1901071

Current hierarchy: **All States Materials Group → Mitchell Materials LLC → Mitchell Materials- Northfield**

- 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

- **operator_operates_mine:** Mitchell Excavating Inc → Mitchell Materials- Northfield; 1999-08-01 to 2019-12-29; source msha-controller-operator-history
- **controller_controls_mine:** Robert V  Mitchell Jr → Mitchell Materials- Northfield; 1999-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert V  Mitchell Jr → Mitchell Excavating Inc; 1999-08-01 to 2019-12-29; source msha-controller-operator-history
- **operator_operates_mine:** Mitchell Materials LLC → Mitchell Materials- Northfield; 2019-12-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** All States Materials Group → Mitchell Materials- Northfield; 2019-12-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** All States Materials Group → Mitchell Materials LLC; 2019-12-30 to current/open; source msha-controller-operator-history