# Relationship history for MSHA mine 0203021

Current hierarchy: **Glen R  Greer → GRG Construction → GRG Santa Cruz #1**

- 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:** GRG Construction → GRG Santa Cruz #1; 2003-05-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Glen R  Greer → GRG Santa Cruz #1; 2003-05-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Glen R  Greer → GRG Construction; 2003-05-08 to current/open; source msha-controller-operator-history