# Relationship history for MSHA mine 3606778

Current hierarchy: **Mc Cullough Collieries & Irwin Processing → Mc Cullough-Irwin Partnership → Westmoreland Mine**

- 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:** Mc Cullough-Irwin Partnership → Westmoreland Mine; 1978-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mc Cullough Collieries & Irwin Processing → Westmoreland Mine; 1978-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mc Cullough Collieries & Irwin Processing → Mc Cullough-Irwin Partnership; 1978-12-01 to current/open; source msha-controller-operator-history