# Relationship history for MSHA mine 2104045

Current hierarchy: **Mathy Construction Company → Mathy Const. Co. DBA Northland Constrs. of Duluth → K400**

- 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:** Mathy Construction Company → K400; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Northland Constructors of Duluth, Inc. → K400; 2023-02-23 to 2023-12-17; source msha-controller-operator-history
- **controller_controls_mine:** API Group Inc → K400; 2023-02-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** API Group Inc → Northland Constructors of Duluth, Inc.; 2023-02-23 to 2023-12-17; source msha-controller-operator-history
- **operator_operates_mine:** Northland Constrs. of Duluth → K400; 2023-12-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mathy Construction Company → Northland Constrs. of Duluth; 2023-12-18 to current/open; source msha-controller-operator-history