# Relationship history for MSHA mine 2402312

Current hierarchy: **Knife River Corporation → Knife River Corporation → Portable Crusher #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:** MDU Resources Group Inc → Portable Crusher #1; 1999-09-01 to 2023-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Montana Portable Crushing LLC → Portable Crusher #1; 2003-02-15 to 2007-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Richard M  Sparrow → Portable Crusher #1; 2003-02-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard M  Sparrow → Montana Portable Crushing LLC; 2003-02-15 to 2007-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Sparrow Enterprises, Inc. → Portable Crusher #1; 2008-01-01 to 2026-02-05; source msha-controller-operator-history
- **controller_controls_mine:** Richard M  Sparrow → Portable Crusher #1; 2008-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard M  Sparrow → Sparrow Enterprises, Inc.; 2008-01-01 to 2026-02-05; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Portable Crusher #1; 2023-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Knife River Corporation → Portable Crusher #1; 2026-02-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Knife River Corporation; 2026-02-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Knife River Corporation; 2026-02-06 to 2023-05-31; source msha-controller-operator-history