# Relationship history for MSHA mine 3200731

Current hierarchy: **Damian  Dvorak → D & L Gravel Inc → PLANT #1**

- 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

- **operator_operates_mine:** D & L Gravel Inc → PLANT #1; 1992-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Damian  Dvorak → PLANT #1; 1992-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Damian  Dvorak → D & L Gravel Inc; 1992-06-01 to current/open; source msha-controller-operator-history