# Relationship history for MSHA mine 3503875

Current hierarchy: **Brett A Smith; Brian L Smith → Nehalem Bay Ready Mix/Mohler Sand & Gravel → Track Mounted Crusher**

- 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:** Brett A Smith et al → Track Mounted Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Nehalem Bay Ready Mix/Mohler Sand & Gravel → Track Mounted Crusher; 2018-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brett A Smith et al → Nehalem Bay Ready Mix/Mohler Sand & Gravel; 2018-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brian L Smith et al → Nehalem Bay Ready Mix/Mohler Sand & Gravel; 2018-11-05 to current/open; source msha-controller-operator-history