# Relationship history for MSHA mine 1519149

Current hierarchy: **Mona L  Smith → Smith Mechanical LLC → Sturgeon**

- 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:** Smith Mechanical LLC → Sturgeon; 2007-09-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mona L  Smith → Sturgeon; 2007-09-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mona L  Smith → Smith Mechanical LLC; 2007-09-20 to current/open; source msha-controller-operator-history