# Relationship history for MSHA mine 2000796

Current hierarchy: **Dave  Nieb → Nieb Concrete Product → Niles Sand & Gravel**

- 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:** Nieb Concrete Product → Niles Sand & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dave  Nieb → Niles Sand & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dave  Nieb → Nieb Concrete Product; 1950-01-01 to current/open; source msha-controller-operator-history