# Relationship history for MSHA mine 0405707

Current hierarchy: **Steve  Norberg → DS, Inc. → Portable Operation**

- 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

- **operator_operates_mine:** Norberg Crushing, Inc. → Portable Operation; 2007-01-19 to 2022-10-18; source msha-controller-operator-history
- **controller_controls_mine:** Dana K  Ferrell et al → Portable Operation; 2007-01-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dana K  Ferrell et al → Norberg Crushing, Inc.; 2007-01-19 to 2022-10-18; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Norberg et al → Norberg Crushing, Inc.; 2007-01-19 to 2022-10-18; source msha-controller-operator-history
- **operator_operates_mine:** DS, Inc. → Portable Operation; 2022-10-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steve  Norberg → Portable Operation; 2022-10-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Norberg → DS, Inc.; 2022-10-19 to current/open; source msha-controller-operator-history