# Relationship history for MSHA mine 4102804

Current hierarchy: **Trinity Industries Inc → Transit Mix Concrete & Materials Company → Zavalla 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:** Southeast Texas Aggregates Company → Zavalla Plant; 1978-12-01 to 1981-04-01; source msha-controller-operator-history
- **controller_controls_mine:** Moore Chester → Zavalla Plant; 1978-12-01 to 1981-04-01; source msha-controller-operator-history
- **controller_controls_operator:** Moore Chester → Southeast Texas Aggregates Company; 1978-12-01 to 1981-04-01; source msha-controller-operator-history
- **operator_operates_mine:** Triple S Crushed Stone Corp → Zavalla Plant; 1981-04-02 to 1991-08-25; source msha-controller-operator-history
- **controller_controls_mine:** Bitner D E → Zavalla Plant; 1981-04-02 to 1991-08-25; source msha-controller-operator-history
- **controller_controls_operator:** Bitner D E → Triple S Crushed Stone Corp; 1981-04-02 to 1991-08-25; source msha-controller-operator-history
- **operator_operates_mine:** Triple S Crushed Stone Corp → Zavalla Plant; 1991-08-26 to 1993-12-08; source msha-controller-operator-history
- **controller_controls_mine:** Willis Gary D → Zavalla Plant; 1991-08-26 to 1993-12-08; source msha-controller-operator-history
- **controller_controls_operator:** Willis Gary D → Triple S Crushed Stone Corp; 1991-08-26 to 1993-12-08; source msha-controller-operator-history
- **controller_controls_mine:** Trinity Industries Inc → Zavalla Plant; 1992-12-15 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Transit Mix Concrete & Materials Company → Zavalla Plant; 1993-12-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Trinity Industries Inc → Transit Mix Concrete & Materials Company; 1993-12-09 to current/open; source msha-controller-operator-history