# Relationship history for MSHA mine 4608788

Current hierarchy: **Alpha Natural Resources, Inc. → Progress Coal → Brushy Fork Cedar Grove Sur 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Massey Energy Company → Brushy Fork Cedar Grove Sur Mine; 1997-06-01 to 2011-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Progress Coal → Brushy Fork Cedar Grove Sur Mine; 1999-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Progress Coal; 1999-08-01 to 2011-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Natural Resources, Inc. → Brushy Fork Cedar Grove Sur Mine; 2011-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Natural Resources, Inc. → Progress Coal; 2011-06-01 to current/open; source msha-controller-operator-history