# Relationship history for MSHA mine 2602521

Current hierarchy: **Holcim Ltd → Regal Materials, Inc. → Regal Materials Wash 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Regency Ready Mix Inc → Regal Materials Wash Plant; 2003-07-22 to 2004-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Tracy C  Hepner → Regal Materials Wash Plant; 2003-07-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tracy C  Hepner → Regency Ready Mix Inc; 2003-07-22 to 2004-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Regal Materials, Inc. → Regal Materials Wash Plant; 2005-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Industries PLC → Regal Materials Wash Plant; 2005-01-01 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → Regal Materials, Inc.; 2005-01-01 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Regal Materials Wash Plant; 2009-04-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Regal Materials, Inc.; 2009-04-30 to current/open; source msha-controller-operator-history