# Relationship history for MSHA mine 1518558

Current hierarchy: **Alpha Natural Resources Holdings, Inc → Enterprise Mining Company LLC → Big Branch**

- 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

- **controller_controls_mine:** Progress Energy Inc → Big Branch; 2002-01-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Diamond May Coal Co Inc → Big Branch; 2002-07-17 to 2006-05-04; source msha-controller-operator-history
- **controller_controls_operator:** Progress Energy Inc → Diamond May Coal Co Inc; 2002-07-17 to 2006-05-04; source msha-controller-operator-history
- **controller_controls_mine:** Amfire LLC → Big Branch; 2003-01-31 to 2003-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Natural Resources, Inc. → Big Branch; 2003-02-01 to 2016-07-25; source msha-controller-operator-history
- **operator_operates_mine:** Enterprise Mining Company LLC → Big Branch; 2006-05-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Natural Resources, Inc. → Enterprise Mining Company LLC; 2006-05-05 to 2016-07-25; source msha-controller-operator-history
- **controller_controls_operator:** Amfire LLC → Enterprise Mining Company LLC; 2006-05-05 to 2003-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Natural Resources Holdings, Inc → Big Branch; 2016-07-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Natural Resources Holdings, Inc → Enterprise Mining Company LLC; 2016-07-26 to current/open; source msha-controller-operator-history