# Relationship history for MSHA mine 4800154

Current hierarchy: **Natural Resource Partners LP; Ciner Resources LP → Sisecam Wyoming, LLC → Big Island Mine & Refinery**

- 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

- **operator_operates_mine:** Stauffer Chemical Company Of Wyoming → Big Island Mine & Refinery; 1950-01-01 to 1987-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Unilever United States Inc → Big Island Mine & Refinery; 1950-01-01 to 1987-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Unilever United States Inc → Stauffer Chemical Company Of Wyoming; 1950-01-01 to 1987-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Rhone-Poulenc Of Wyoming L P → Big Island Mine & Refinery; 1987-12-01 to 1996-02-29; source msha-controller-operator-history
- **controller_controls_mine:** Rhone-Poulenc S A → Big Island Mine & Refinery; 1987-12-01 to 1996-02-29; source msha-controller-operator-history
- **controller_controls_operator:** Rhone-Poulenc S A → Rhone-Poulenc Of Wyoming L P; 1987-12-01 to 1996-02-29; source msha-controller-operator-history
- **operator_operates_mine:** Sisecam Wyoming, LLC → Big Island Mine & Refinery; 1996-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Anadarko Petroleum Corp et al → Big Island Mine & Refinery; 1996-03-01 to 2013-01-22; source msha-controller-operator-history
- **controller_controls_operator:** Anadarko Petroleum Corp et al → Sisecam Wyoming, LLC; 1996-03-01 to 2013-01-22; source msha-controller-operator-history
- **controller_controls_operator:** OCI Company, Ltd.  et al → Sisecam Wyoming, LLC; 1996-03-01 to 2013-01-22; source msha-controller-operator-history
- **controller_controls_mine:** Natural Resource Partners LP et al → Big Island Mine & Refinery; 2013-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Natural Resource Partners LP et al → Sisecam Wyoming, LLC; 2013-01-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ciner Resources LP et al → Sisecam Wyoming, LLC; 2013-01-23 to current/open; source msha-controller-operator-history