# Relationship history for MSHA mine 4201578

Current hierarchy: **Shumway Kevin W → T K S Mining Company → Avalanche 13**

- 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:** Nuclear Assurance Corp → Avalanche 13; 1979-01-01 to 1987-05-05; source msha-controller-operator-history
- **controller_controls_mine:** Pennsylvania Power & Light Company → Avalanche 13; 1979-01-01 to 1987-05-05; source msha-controller-operator-history
- **controller_controls_operator:** Pennsylvania Power & Light Company → Nuclear Assurance Corp; 1979-01-01 to 1987-05-05; source msha-controller-operator-history
- **operator_operates_mine:** T K S Mining Company → Avalanche 13; 1987-05-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Shumway Kevin W → Avalanche 13; 1987-05-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shumway Kevin W → T K S Mining Company; 1987-05-06 to current/open; source msha-controller-operator-history