# Relationship history for MSHA mine 2301597

Current hierarchy: **Quikrete Holdings Inc. → Quikrete Companys Inc → Quikrete Companys Inc.**

- 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:** Simpson Materials Company Inc → Quikrete Companys Inc.; 1950-01-01 to 2007-01-10; source msha-controller-operator-history
- **controller_controls_mine:** Michael G  Simpson et al → Quikrete Companys Inc.; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael G  Simpson et al → Simpson Materials Company Inc; 1950-01-01 to 2007-01-10; source msha-controller-operator-history
- **controller_controls_operator:** Mark T  Simpson et al → Simpson Materials Company Inc; 1950-01-01 to 2007-01-10; source msha-controller-operator-history
- **controller_controls_mine:** Quikrete Holdings Inc. → Quikrete Companys Inc.; 1998-09-11 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Quikrete Companys Inc → Quikrete Companys Inc.; 2007-01-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Quikrete Holdings Inc. → Quikrete Companys Inc; 2007-01-11 to current/open; source msha-controller-operator-history