# Relationship history for MSHA mine 4102610

Current hierarchy: **Nicolas R  Ayala → Uvalde Concrete LLC → Knippa 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:** South Texas Aggregates Inc → Knippa Plant; 1950-01-01 to 1995-02-20; source msha-controller-operator-history
- **controller_controls_mine:** William Clay  Coleman → Knippa Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William Clay  Coleman → South Texas Aggregates Inc; 1950-01-01 to 1995-02-20; source msha-controller-operator-history
- **operator_operates_mine:** Uvalde Concrete Company Inc → Knippa Plant; 1995-02-21 to 2011-10-18; source msha-controller-operator-history
- **controller_controls_mine:** Nicolas R  Ayala → Knippa Plant; 1995-02-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nicolas R  Ayala → Uvalde Concrete Company Inc; 1995-02-21 to 2011-10-18; source msha-controller-operator-history
- **operator_operates_mine:** Uvalde Concrete LLC → Knippa Plant; 2011-10-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nicolas R  Ayala → Knippa Plant; 2011-10-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nicolas R  Ayala → Uvalde Concrete LLC; 2011-10-19 to current/open; source msha-controller-operator-history