# Relationship history for MSHA mine 4503326

Current hierarchy: **Knife River Corporation → Knife River → Knife River - North West**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Valley Asphalt & Paving Inc → Knife River - North West; 1994-08-01 to 2007-05-31; source msha-controller-operator-history
- **controller_controls_mine:** William R  Thompson → Knife River - North West; 1994-08-01 to 2004-09-07; source msha-controller-operator-history
- **controller_controls_operator:** William R  Thompson → Valley Asphalt & Paving Inc; 1994-08-01 to 2004-09-07; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Knife River - North West; 1998-03-05 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Knife River - North West; 1999-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brian J  Winkler → Knife River - North West; 2004-09-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brian J  Winkler → Valley Asphalt & Paving Inc; 2004-09-08 to 2007-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Knife River → Knife River - North West; 2007-06-01 to 2009-12-31; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Knife River; 2007-06-01 to 2009-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Knife River → Knife River - North West; 2010-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Knife River; 2010-01-01 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Knife River - North West; 2023-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Knife River; 2023-06-01 to current/open; source msha-controller-operator-history