# Relationship history for MSHA mine 0405591

Current hierarchy: **Frank  Dutra → Northern Aggregates Inc → Portable**

- 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:** Frank  Dutra et al → Portable; 1991-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Northern Aggregates Inc → Portable; 2004-05-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frank  Dutra et al → Northern Aggregates Inc; 2004-05-24 to current/open; source msha-controller-operator-history