# Relationship history for MSHA mine 4502797

Current hierarchy: **Patricia  Riley → Riley Brothers Inc. → Portable Screening 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:** Patricia  Riley → Portable Screening Plant; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Jim Riley Excavating → Portable Screening Plant; 1980-03-01 to 2025-05-15; source msha-controller-operator-history
- **controller_controls_operator:** Patricia  Riley → Jim Riley Excavating; 1980-03-01 to 2025-05-15; source msha-controller-operator-history
- **operator_operates_mine:** Riley Brothers Inc. → Portable Screening Plant; 2025-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Patricia  Riley → Portable Screening Plant; 2025-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Patricia  Riley → Riley Brothers Inc.; 2025-05-16 to current/open; source msha-controller-operator-history