# Relationship history for MSHA mine 1200736

Current hierarchy: **Horstman Terry → Horstman Enterprises Inc → K-2 PORTABLE 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Brudi Stone & Gravel Company Inc → K-2 PORTABLE SCREENING PLANT; 1950-01-01 to 1992-08-25; source msha-controller-operator-history
- **controller_controls_mine:** Brudi Jimmie J → K-2 PORTABLE SCREENING PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brudi Jimmie J → Brudi Stone & Gravel Company Inc; 1950-01-01 to 1992-08-25; source msha-controller-operator-history
- **operator_operates_mine:** Horstman Enterprises Inc → K-2 PORTABLE SCREENING PLANT; 1992-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Horstman Terry → K-2 PORTABLE SCREENING PLANT; 1992-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Horstman Terry → Horstman Enterprises Inc; 1992-08-26 to current/open; source msha-controller-operator-history