# Relationship history for MSHA mine 4801535

Current hierarchy: **Knife River Corporation → Jtl Group Inc → JTL - PORTABLE NO 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:** JTL Group Inc → JTL - PORTABLE NO 1; 1990-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Jtl Group Inc → JTL - PORTABLE NO 1; 1997-01-01 to 1999-08-31; source msha-controller-operator-history
- **controller_controls_operator:** JTL Group Inc → Jtl Group Inc; 1997-01-01 to 1999-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Jtl Group Inc → JTL - PORTABLE NO 1; 1999-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → JTL - PORTABLE NO 1; 1999-09-01 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Jtl Group Inc; 1999-09-01 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → JTL - PORTABLE NO 1; 2023-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Jtl Group Inc; 2023-06-01 to current/open; source msha-controller-operator-history