# Relationship history for MSHA mine 4102976

Current hierarchy: **Vulcan Materials Company → Vulcan Construction Materials, LLC → Helotes Quarry**

- 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

- **controller_controls_mine:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Helotes Quarry; 1950-01-01 to 2007-11-15; source msha-controller-operator-history
- **controller_controls_mine:** William Clay  Coleman → Helotes Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** D & B Materials Inc → Helotes Quarry; 1980-03-01 to 1988-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Henry L  Zumwalt → Helotes Quarry; 1980-03-01 to 1988-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Henry L  Zumwalt → D & B Materials Inc; 1980-03-01 to 1988-01-31; source msha-controller-operator-history
- **operator_operates_mine:** South Texas Aggregates Inc → Helotes Quarry; 1988-02-01 to 1990-06-12; source msha-controller-operator-history
- **controller_controls_operator:** William Clay  Coleman → South Texas Aggregates Inc; 1988-02-01 to 1990-06-12; source msha-controller-operator-history
- **operator_operates_mine:** Vulcan Construction Materials, LLC → Helotes Quarry; 1990-06-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Vulcan Construction Materials, LLC; 1990-06-13 to 2007-11-15; source msha-controller-operator-history
- **controller_controls_mine:** Vulcan Materials Company → Helotes Quarry; 2007-11-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vulcan Materials Company → Vulcan Construction Materials, LLC; 2007-11-16 to current/open; source msha-controller-operator-history