# Relationship history for MSHA mine 0301976

Current hierarchy: **Southwestern Energy Co. → SWN PRODUCTION (ARKANSAS), LLC → SWN SAND COMPANY**

- 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:** Southwestern Energy Production Company → SWN SAND COMPANY; 2008-09-22 to 2014-02-19; source msha-controller-operator-history
- **controller_controls_mine:** Southwestern Energy Co. → SWN SAND COMPANY; 2008-09-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Southwestern Energy Co. → Southwestern Energy Production Company; 2008-09-22 to 2014-02-19; source msha-controller-operator-history
- **operator_operates_mine:** SWN PRODUCTION (ARKANSAS), LLC → SWN SAND COMPANY; 2014-02-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Southwestern Energy Co. → SWN SAND COMPANY; 2014-02-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Southwestern Energy Co. → SWN PRODUCTION (ARKANSAS), LLC; 2014-02-20 to current/open; source msha-controller-operator-history