# Relationship history for MSHA mine 3609816

Current hierarchy: **Jerry L  Johnson → Johnson Quarries, Inc. → Johnson Portable Extec Screener #1**

- 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:** Jerry L  Johnson → Johnson Portable Extec Screener #1; 1997-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Johnson Quarries, Inc. → Johnson Portable Extec Screener #1; 2009-11-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jerry L  Johnson → Johnson Quarries, Inc.; 2009-11-24 to current/open; source msha-controller-operator-history