# Relationship history for MSHA mine 2902209

Current hierarchy: **Howard  Bartoo Jr → Bartoo Sand & Gravel Inc → BARTOO PORTABLE SCREEN #1**

- 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:** Howard  Bartoo Jr → BARTOO PORTABLE SCREEN #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bartoo Sand & Gravel Inc → BARTOO PORTABLE SCREEN #1; 2000-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Howard  Bartoo Jr → Bartoo Sand & Gravel Inc; 2000-10-01 to current/open; source msha-controller-operator-history