# Relationship history for MSHA mine 1901133

Current hierarchy: **Boston Sand & Gravel Company → FASTRACK CRUSHING COMPANY → FASTRACK CRUSHING CO**

- 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:** FASTRACK CRUSHING COMPANY → FASTRACK CRUSHING CO; 2004-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Boston Sand & Gravel Company → FASTRACK CRUSHING CO; 2004-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Boston Sand & Gravel Company → FASTRACK CRUSHING COMPANY; 2004-03-16 to current/open; source msha-controller-operator-history