# Relationship history for MSHA mine 4606050

Current hierarchy: **Tyson Robert → Quanta Coal Corp → Mine No 2 Surface**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Tyson Robert → Mine No 2 Surface; 1977-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Quanta Coal Corp → Mine No 2 Surface; 1979-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tyson Robert → Quanta Coal Corp; 1979-08-01 to current/open; source msha-controller-operator-history