# Relationship history for MSHA mine 4608784

Current hierarchy: **Alpha Metallurgical Resources Inc → Delbarton Mining Company → Bias Lower Cedar Grove Mine #1**

- 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 → Bias Lower Cedar Grove Mine #1; 1998-12-22 to 2011-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Delbarton Mining Company → Bias Lower Cedar Grove Mine #1; 1999-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Delbarton Mining Company; 1999-07-01 to 2011-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Natural Resources, Inc. → Bias Lower Cedar Grove Mine #1; 2011-06-01 to 2016-07-25; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Natural Resources, Inc. → Delbarton Mining Company; 2011-06-01 to 2016-07-25; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Natural Resources Holdings, Inc → Bias Lower Cedar Grove Mine #1; 2016-07-26 to 2018-11-08; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Natural Resources Holdings, Inc → Delbarton Mining Company; 2016-07-26 to 2018-11-08; source msha-controller-operator-history
- **controller_controls_mine:** Alpha Metallurgical Resources Inc → Bias Lower Cedar Grove Mine #1; 2018-11-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alpha Metallurgical Resources Inc → Delbarton Mining Company; 2018-11-09 to current/open; source msha-controller-operator-history