# Relationship history for MSHA mine 0301792

Current hierarchy: **Brad  De Vazier → Crowley'S Ridge Sand & Gravel Company Inc → SMITH 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:** Brad  De Vazier → SMITH PIT; 1992-04-10 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Crowley'S Ridge Sand & Gravel Company Inc → SMITH PIT; 1998-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brad  De Vazier → Crowley'S Ridge Sand & Gravel Company Inc; 1998-02-01 to current/open; source msha-controller-operator-history