# Relationship history for MSHA mine 4103931

Current hierarchy: **Knife River Corporation → Knife River Corporation-South → Skyhigh Pit**

- 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:** F M  Young → Skyhigh Pit; 1950-01-01 to 2003-07-10; source msha-controller-operator-history
- **operator_operates_mine:** Young Materials Corp → Skyhigh Pit; 1996-12-01 to 2005-10-09; source msha-controller-operator-history
- **controller_controls_operator:** F M  Young → Young Materials Corp; 1996-12-01 to 2003-07-10; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Skyhigh Pit; 2003-07-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Young Materials Corp; 2003-07-11 to 2005-10-09; source msha-controller-operator-history
- **operator_operates_mine:** Knife River Corporation-South → Skyhigh Pit; 2005-10-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Skyhigh Pit; 2005-10-10 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Knife River Corporation-South; 2005-10-10 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Skyhigh Pit; 2023-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Knife River Corporation-South; 2023-06-01 to current/open; source msha-controller-operator-history