# Relationship history for MSHA mine 3610137

Current hierarchy: **Larry L  Showman; Lynette M  Showman → Raymond D. Showman & Sons, Inc. → Powerscreen Chieftain 1400**

- 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:** Lynette M  Showman et al → Powerscreen Chieftain 1400; 1999-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Raymond D. Showman & Sons, Inc. → Powerscreen Chieftain 1400; 2015-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lynette M  Showman et al → Raymond D. Showman & Sons, Inc.; 2015-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Larry L  Showman et al → Raymond D. Showman & Sons, Inc.; 2015-03-27 to current/open; source msha-controller-operator-history