# Relationship history for MSHA mine 4607077

Current hierarchy: **Grubb M W Jr → Witcher Mining Corp → Witcher Mining Corp Preporation 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Grubb M W Jr → Witcher Mining Corp Preporation Plant; 1985-04-22 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Witcher Mining Corp → Witcher Mining Corp Preporation Plant; 1985-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grubb M W Jr → Witcher Mining Corp; 1985-12-01 to current/open; source msha-controller-operator-history