# Relationship history for MSHA mine 3303731

Current hierarchy: **Mc Cort Michael B → Mack Energy Company → Mack River Terminal**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Mc Cort Michael B → Mack River Terminal; 1973-12-06 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mack Energy Company → Mack River Terminal; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mc Cort Michael B → Mack Energy Company; 1979-01-01 to current/open; source msha-controller-operator-history