# Relationship history for MSHA mine 0405490

Current hierarchy: **Vulcan Materials Company → Superior Ready Mix Concrete L P → Willow Springs Mine**

- 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:** Michael  McGrath → Willow Springs Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** J Brouwer Investments Inc Et Al → Willow Springs Mine; 1979-09-01 to 2025-04-27; source msha-controller-operator-history
- **operator_operates_mine:** C W McGrath Inc → Willow Springs Mine; 2001-07-01 to 2013-03-07; source msha-controller-operator-history
- **controller_controls_operator:** Michael  McGrath → C W McGrath Inc; 2001-07-01 to 2013-03-07; source msha-controller-operator-history
- **operator_operates_mine:** Superior Ready Mix Concrete L P → Willow Springs Mine; 2013-03-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** J Brouwer Investments Inc Et Al → Superior Ready Mix Concrete L P; 2013-03-08 to 2025-04-27; source msha-controller-operator-history
- **controller_controls_mine:** Vulcan Materials Company → Willow Springs Mine; 2025-04-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vulcan Materials Company → Superior Ready Mix Concrete L P; 2025-04-28 to current/open; source msha-controller-operator-history