# Relationship history for MSHA mine 2103460

Current hierarchy: **Mathy Construction Company → Mathy Constr. Co. DBA Northland Constrs. of Duluth → Wash Plant**

- 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 → Wash Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James L  Holmgren → Wash Plant; 1985-08-06 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Northland Crushing, Inc. → Wash Plant; 2004-07-28 to 2014-12-04; source msha-controller-operator-history
- **controller_controls_operator:** James L  Holmgren → Northland Crushing, Inc.; 2004-07-28 to 2014-12-04; source msha-controller-operator-history
- **controller_controls_mine:** James L  Holmgren → Wash Plant; 2014-10-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Northland Constructors → Wash Plant; 2014-12-05 to 2023-12-17; source msha-controller-operator-history
- **controller_controls_operator:** James L  Holmgren → Northland Constructors; 2014-12-05 to 2023-12-17; source msha-controller-operator-history
- **operator_operates_mine:** Northland Constrs. of Duluth → Wash Plant; 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