# Relationship history for MSHA mine 0504496

Current hierarchy: **Rockford  Ryan → Colorado Crushing Inc → CRUSHER #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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Colorado Crushing Inc → CRUSHER #1; 1992-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rockford  Ryan  et al → CRUSHER #1; 1992-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rockford  Ryan  et al → Colorado Crushing Inc; 1992-06-01 to current/open; source msha-controller-operator-history