# Relationship history for MSHA mine 4608674

Current hierarchy: **Cleveland-Cliffs Inc → Prime Processing, Inc. → SKYGUSTY PLANT**

- 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:** Regal Rock Inc → SKYGUSTY PLANT; 1997-11-01 to 2010-12-02; source msha-controller-operator-history
- **controller_controls_mine:** Nancy K  Preservati et al → SKYGUSTY PLANT; 1997-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nancy K  Preservati et al → Regal Rock Inc; 1997-11-01 to 2010-12-02; source msha-controller-operator-history
- **controller_controls_operator:** Richard G  Preservati et al → Regal Rock Inc; 1997-11-01 to 2010-12-02; source msha-controller-operator-history
- **controller_controls_mine:** Steven W  Haynes et al → SKYGUSTY PLANT; 2004-10-01 to 2008-06-30; source msha-controller-operator-history
- **controller_controls_mine:** ArcelorMittal → SKYGUSTY PLANT; 2008-07-01 to 2020-12-08; source msha-controller-operator-history
- **operator_operates_mine:** Prime Processing, Inc. → SKYGUSTY PLANT; 2010-12-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** ArcelorMittal → Prime Processing, Inc.; 2010-12-03 to 2020-12-08; source msha-controller-operator-history
- **controller_controls_operator:** Steven W  Haynes et al → Prime Processing, Inc.; 2010-12-03 to 2008-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Cleveland-Cliffs Inc → SKYGUSTY PLANT; 2020-12-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cleveland-Cliffs Inc → Prime Processing, Inc.; 2020-12-09 to current/open; source msha-controller-operator-history