# Relationship history for MSHA mine 5001449

Current hierarchy: **KRC Aggregate Inc → Anchorage Sand & Gravel Company Inc → A B I Cement Plant**

- 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:** KRC Aggregate Inc → A B I Cement Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Anchorage Sand & Gravel Company Inc → A B I Cement Plant; 1983-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** KRC Aggregate Inc → Anchorage Sand & Gravel Company Inc; 1983-06-01 to current/open; source msha-controller-operator-history