# Relationship history for MSHA mine 0405647

Current hierarchy: **Paul S  Viborg; Debbie K Sturgis-Viborg → Viborg Sand & Gravel, Inc. → Smith Sand Pit**

- 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:** Debbie K Sturgis-Viborg et al → Smith Sand Pit; 1989-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Viborg Sand & Gravel, Inc. → Smith Sand Pit; 2005-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Debbie K Sturgis-Viborg et al → Viborg Sand & Gravel, Inc.; 2005-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paul S  Viborg et al → Viborg Sand & Gravel, Inc.; 2005-07-01 to current/open; source msha-controller-operator-history