# Relationship history for MSHA mine 2003400

Current hierarchy: **Gentner Incorporated → Gentner Materials → Stone Scrubber (Ann Arbor Sand & Gravel)**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Gentner Incorporated → Stone Scrubber (Ann Arbor Sand & Gravel); 2003-06-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Gentner Materials → Stone Scrubber (Ann Arbor Sand & Gravel); 2008-04-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gentner Incorporated → Gentner Materials; 2008-04-17 to current/open; source msha-controller-operator-history