# Relationship history for MSHA mine 0300481

Current hierarchy: **Global Industrial Technologies Inc → Harbison-Walker Refractories Company → ARKANSAS CALCINE MILL**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** A P Green Refractories Inc → ARKANSAS CALCINE MILL; 1950-01-01 to 1988-02-23; source msha-controller-operator-history
- **controller_controls_mine:** USG Corporation → ARKANSAS CALCINE MILL; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USG Corporation → A P Green Refractories Inc; 1950-01-01 to 1988-02-23; source msha-controller-operator-history
- **operator_operates_mine:** A P Green Industries Inc → ARKANSAS CALCINE MILL; 1988-02-24 to 1998-06-30; source msha-controller-operator-history
- **controller_controls_mine:** A P Green Industries Inc → ARKANSAS CALCINE MILL; 1988-02-24 to 1998-06-30; source msha-controller-operator-history
- **controller_controls_operator:** A P Green Industries Inc → A P Green Industries Inc; 1988-02-24 to 1998-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Global Industrial Technologies Inc → ARKANSAS CALCINE MILL; 1992-08-07 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Harbison-Walker Refractories Company → ARKANSAS CALCINE MILL; 1998-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Global Industrial Technologies Inc → Harbison-Walker Refractories Company; 1998-07-01 to current/open; source msha-controller-operator-history