# Relationship history for MSHA mine 4608424

Current hierarchy: **American Metals & Coal International Inc → Virginia Crews Coal Company → Mine No 14 Portal B**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** American Metals & Coal International Inc → Mine No 14 Portal B; 1990-12-14 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Virginia Crews Coal Company → Mine No 14 Portal B; 1994-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** American Metals & Coal International Inc → Virginia Crews Coal Company; 1994-07-01 to current/open; source msha-controller-operator-history