# Relationship history for MSHA mine 1518380

Current hierarchy: **Alpha Natural Resources Holdings, Inc → Sidney Coal Company, Inc → Halfway Branch Surface 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

- **controller_controls_mine:** Massey Energy Company → Halfway Branch Surface Mine; 1984-10-04 to 2011-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Sidney Coal Company, Inc → Halfway Branch Surface Mine; 2001-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Sidney Coal Company, Inc; 2001-05-01 to 2011-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Natural Resources, Inc. → Halfway Branch Surface Mine; 2011-06-01 to 2016-07-25; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Natural Resources, Inc. → Sidney Coal Company, Inc; 2011-06-01 to 2016-07-25; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Natural Resources Holdings, Inc → Halfway Branch Surface Mine; 2016-07-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Natural Resources Holdings, Inc → Sidney Coal Company, Inc; 2016-07-26 to current/open; source msha-controller-operator-history