# Relationship history for MSHA mine 0600750

Current hierarchy: **Marguerite M  Segalla → Segalla Sand & Gravel, Inc. → Portable Powerscreen**

- 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:** Marguerite M  Segalla et al → Portable Powerscreen; 1988-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Segalla Sand & Gravel, Inc. → Portable Powerscreen; 2008-03-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marguerite M  Segalla et al → Segalla Sand & Gravel, Inc.; 2008-03-12 to current/open; source msha-controller-operator-history