# Relationship history for MSHA mine 2003514

Current hierarchy: **Kenneth W  Norris; Nicholas W  Huyck → Con Agg Inc → Portable 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:** Kenneth W  Norris → Portable Screen Plant; 1995-05-01 to 2025-12-21; source msha-controller-operator-history
- **operator_operates_mine:** Con Agg Inc → Portable Screen Plant; 2015-09-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth W  Norris → Con Agg Inc; 2015-09-22 to 2025-12-21; source msha-controller-operator-history
- **controller_controls_mine:** Nicholas W  Huyck et al → Portable Screen Plant; 2025-12-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nicholas W  Huyck et al → Con Agg Inc; 2025-12-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth W  Norris et al → Con Agg Inc; 2025-12-22 to current/open; source msha-controller-operator-history