# Relationship history for MSHA mine 2402636

Current hierarchy: **Ty L  Balbach; VJ  Magee → Silver Summit Narrow Vein Mining Group → Black Friday**

- 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:** Silver Summit Narrow Vein Mining Group → Black Friday; 2012-08-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ty L  Balbach et al → Black Friday; 2012-08-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ty L  Balbach et al → Silver Summit Narrow Vein Mining Group; 2012-08-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** VJ  Magee et al → Silver Summit Narrow Vein Mining Group; 2012-08-06 to current/open; source msha-controller-operator-history