# Relationship history for MSHA mine 3000984

Current hierarchy: **Hannah L  Robinson → H. L. ROBINSON SAND & GRAVEL → UNIVERSITY GRAVEL PRODUCTS**

- 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

- **operator_operates_mine:** University Sand & Gravel, Inc. → UNIVERSITY GRAVEL PRODUCTS; 1950-01-01 to 2018-05-09; source msha-controller-operator-history
- **controller_controls_mine:** Susan  Ettinger → UNIVERSITY GRAVEL PRODUCTS; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Susan  Ettinger → University Sand & Gravel, Inc.; 1950-01-01 to 2018-05-09; source msha-controller-operator-history
- **controller_controls_mine:** Hannah L  Robinson → UNIVERSITY GRAVEL PRODUCTS; 1988-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** H. L. Robinson Sand & Gravel → UNIVERSITY GRAVEL PRODUCTS; 2018-05-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hannah L  Robinson → H. L. Robinson Sand & Gravel; 2018-05-10 to current/open; source msha-controller-operator-history