# Relationship history for MSHA mine 4202755

Current hierarchy: **Steven W Richins → Richins General Engineering Co → Richins portable 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:** Richins General Engineering Co → Richins portable 1; 2023-11-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steven W Richins → Richins portable 1; 2023-11-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steven W Richins → Richins General Engineering Co; 2023-11-08 to current/open; source msha-controller-operator-history