# Relationship history for MSHA mine 3605721

Current hierarchy: **Nixon David → Brush Run Inc → Nixon Mine (Strip)**

- 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:** Brush Run Inc → Nixon Mine (Strip); 1975-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nixon David → Nixon Mine (Strip); 1975-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nixon David → Brush Run Inc; 1975-07-01 to current/open; source msha-controller-operator-history