# Relationship history for MSHA mine 2103925

Current hierarchy: **Kelly L  Engen → Engen Sand & Gravel → Engen 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Engen Sand & Gravel → Engen Sand & Gravel; 2018-05-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kelly L  Engen → Engen Sand & Gravel; 2018-05-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kelly L  Engen → Engen Sand & Gravel; 2018-05-08 to current/open; source msha-controller-operator-history