# Relationship history for MSHA mine 2401966

Current hierarchy: **Ernest W Johnson; Robert E  Johnson → Johnson Brothers Contracting → Screen Plant #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

- **operator_operates_mine:** Johnson Brothers Contracting → Screen Plant #1; 1992-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert E  Johnson et al → Screen Plant #1; 1992-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert E  Johnson et al → Johnson Brothers Contracting; 1992-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ernest W Johnson et al → Johnson Brothers Contracting; 1992-05-01 to current/open; source msha-controller-operator-history