# Relationship history for MSHA mine 3610484

Current hierarchy: **Charlton F  Dygert → TMT Gravel & Contracting, Inc. → Astec Cone (P232187)**

- 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:** Charlton F  Dygert → Astec Cone (P232187); 2010-08-20 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** TMT Gravel & Contracting, Inc. → Astec Cone (P232187); 2025-12-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Charlton F  Dygert → TMT Gravel & Contracting, Inc.; 2025-12-03 to current/open; source msha-controller-operator-history