# Relationship history for MSHA mine 2100521

Current hierarchy: **CRH PLC → Southern MN Construction → #0521 Guaranteed 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Guaranteed Gravel & Sand Company Inc → #0521 Guaranteed Wash Plant; 1950-01-01 to 1995-10-18; source msha-controller-operator-history
- **controller_controls_mine:** Richard C  Lundin  et al → #0521 Guaranteed Wash Plant; 1950-01-01 to 1995-10-18; source msha-controller-operator-history
- **controller_controls_operator:** Richard C  Lundin  et al → Guaranteed Gravel & Sand Company Inc; 1950-01-01 to 1995-10-18; source msha-controller-operator-history
- **controller_controls_mine:** Larry V  Nurre → #0521 Guaranteed Wash Plant; 1988-07-01 to 2006-03-01; source msha-controller-operator-history
- **operator_operates_mine:** Southern Minnesota Construction Company, Inc → #0521 Guaranteed Wash Plant; 1995-10-19 to 2008-12-27; source msha-controller-operator-history
- **controller_controls_operator:** Larry V  Nurre → Southern Minnesota Construction Company, Inc; 1995-10-19 to 2006-03-01; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → #0521 Guaranteed Wash Plant; 2006-03-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Southern Minnesota Construction Company, Inc; 2006-03-02 to 2008-12-27; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → #0521 Guaranteed Wash Plant; 2008-01-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Southern MN Construction → #0521 Guaranteed Wash Plant; 2008-12-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Southern MN Construction; 2008-12-28 to current/open; source msha-controller-operator-history