# Relationship history for MSHA mine 3401478

Current hierarchy: **Davis Carl L & Bobbi M → Davis Sand Plant → Davis Sand 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

- **operator_operates_mine:** Davis Sand Plant → Davis Sand Plant; 1984-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Davis Carl L & Bobbi M → Davis Sand Plant; 1984-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Davis Carl L & Bobbi M → Davis Sand Plant; 1984-12-01 to current/open; source msha-controller-operator-history