# Relationship history for MSHA mine 0900070

Current hierarchy: **Vulcan Materials Company → Vulcan Construction Materials, LLC → Norcross 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Vulcan Construction Materials, LLC → Norcross Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Norcross Quarry; 1950-01-01 to 2007-11-15; source msha-controller-operator-history
- **controller_controls_operator:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Vulcan Construction Materials, LLC; 1950-01-01 to 2007-11-15; source msha-controller-operator-history
- **controller_controls_mine:** Vulcan Materials Company → Norcross 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