# Relationship history for MSHA mine 3200963

Current hierarchy: **Knife River Corporation → Knife River Corporation - North Central → Portable Plant #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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Bauerly Brothers Inc → Portable Plant #1; 1950-01-01 to 2001-04-25; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Portable Plant #1; 2001-04-26 to 2023-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Knife River Corporation - North Central → Portable Plant #1; 2012-09-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bauerly Brothers Inc → Knife River Corporation - North Central; 2012-09-07 to 2001-04-25; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Knife River Corporation - North Central; 2012-09-07 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Portable Plant #1; 2023-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Knife River Corporation - North Central; 2023-06-01 to current/open; source msha-controller-operator-history