# Relationship history for MSHA mine 0404937

Current hierarchy: **Vulcan Materials Company → Superior Ready Mix Concrete L.P. → DILLON ROAD PIT**

- 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

- **controller_controls_mine:** James E. Simon Co., A Wyoming Corp → DILLON ROAD PIT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** J Brouwer Investments Inc Et Al → DILLON ROAD PIT; 1979-09-01 to 2025-04-27; source msha-controller-operator-history
- **operator_operates_mine:** James E Simon Company → DILLON ROAD PIT; 1988-02-01 to 2007-01-01; source msha-controller-operator-history
- **controller_controls_operator:** James E. Simon Co., A Wyoming Corp → James E Simon Company; 1988-02-01 to 2007-01-01; source msha-controller-operator-history
- **operator_operates_mine:** Superior Ready Mix Concrete L.P. → DILLON ROAD PIT; 2007-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** J Brouwer Investments Inc Et Al → Superior Ready Mix Concrete L.P.; 2007-01-02 to 2025-04-27; source msha-controller-operator-history
- **controller_controls_mine:** Vulcan Materials Company → DILLON ROAD PIT; 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