# Relationship history for MSHA mine 3901560

Current hierarchy: **Robert L  Jacobs → H F Jacobs & Son Construction Inc → CEC Screen 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:** Robert L  Jacobs → CEC Screen Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** H F Jacobs & Son Construction Inc → CEC Screen Plant; 2010-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert L  Jacobs → H F Jacobs & Son Construction Inc; 2010-08-02 to current/open; source msha-controller-operator-history