# Relationship history for MSHA mine 4503640

Current hierarchy: **Fred W  Hackney → Alpine Rock Walls Inc. → Mr. Rock Inc**

- 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:** Alpine Rock Inc → Mr. Rock Inc; 2007-10-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Fred W  Hackney → Mr. Rock Inc; 2007-10-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fred W  Hackney → Alpine Rock Inc; 2007-10-30 to current/open; source msha-controller-operator-history