# Relationship history for MSHA mine 2103185

Current hierarchy: **Knife River Corporation → Northstar Materials Inc dba Knife River Materials → Crusher #43517**

- 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

- **controller_controls_mine:** W T  Thorson → Crusher #43517; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Thorson Inc → Crusher #43517; 1998-09-01 to 2002-03-13; source msha-controller-operator-history
- **controller_controls_operator:** W T  Thorson → Thorson Inc; 1998-09-01 to 2002-03-13; source msha-controller-operator-history
- **operator_operates_mine:** Northstar Materials Inc dba Knife River Materials → Crusher #43517; 2002-03-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Crusher #43517; 2002-03-14 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Northstar Materials Inc dba Knife River Materials; 2002-03-14 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Crusher #43517; 2023-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Northstar Materials Inc dba Knife River Materials; 2023-06-01 to current/open; source msha-controller-operator-history