# Relationship history for MSHA mine 4407438

Current hierarchy: **Regina G Glass; Gregory D Glass → Glass Machinery & Excavation, Inc. → M&M Quarry Site**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Glass Machinery & Excavation, Inc. → M&M Quarry Site; 2025-06-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Regina G Glass → M&M Quarry Site; 2025-06-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Regina G Glass → Glass Machinery & Excavation, Inc.; 2025-06-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gregory D Glass → Glass Machinery & Excavation, Inc.; 2025-06-15 to current/open; source msha-controller-operator-history