# Relationship history for MSHA mine 2901288

Current hierarchy: **Grant County-Nm → Grant County Road Department → Grant County Screening 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

- **operator_operates_mine:** Grant County Road Department → Grant County Screening Plant; 1950-01-01 to 1986-06-17; source msha-controller-operator-history
- **controller_controls_mine:** Grant County-Nm → Grant County Screening Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grant County-Nm → Grant County Road Department; 1950-01-01 to 1986-06-17; source msha-controller-operator-history
- **operator_operates_mine:** La Paz-Bear Creek Inc → Grant County Screening Plant; 1986-06-18 to 1988-03-16; source msha-controller-operator-history
- **controller_controls_mine:** La Paz Mining → Grant County Screening Plant; 1986-06-18 to 1988-03-16; source msha-controller-operator-history
- **controller_controls_operator:** La Paz Mining → La Paz-Bear Creek Inc; 1986-06-18 to 1988-03-16; source msha-controller-operator-history
- **operator_operates_mine:** Grant County Road Department → Grant County Screening Plant; 1988-03-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grant County-Nm → Grant County Road Department; 1988-03-17 to current/open; source msha-controller-operator-history