# Relationship history for MSHA mine 3200776

Current hierarchy: **Knife River Corporation → Knife River Corporation-North Central → Wash 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 → Wash Plant #1; 1950-01-01 to 2001-04-25; source msha-controller-operator-history
- **controller_controls_mine:** Leo  Klein Jr → Wash Plant #1; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Construction Inc → Wash Plant #1; 2000-04-01 to 2006-09-11; source msha-controller-operator-history
- **controller_controls_operator:** Leo  Klein Jr → Pioneer Construction Inc; 2000-04-01 to 2006-09-11; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Wash Plant #1; 2001-04-26 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Wash Plant #1; 2003-07-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Construction Inc → Wash Plant #1; 2006-09-12 to 2007-12-31; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Pioneer Construction Inc; 2006-09-12 to 2007-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Knife River Corporation-North Central → Wash Plant #1; 2008-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bauerly Brothers Inc → Knife River Corporation-North Central; 2008-01-01 to 2001-04-25; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Knife River Corporation-North Central; 2008-01-01 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Wash 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