# Relationship history for MSHA mine 3609993

Current hierarchy: **Hannah L  Robinson → H L Robinson Sand & Gravel → Eagle 1000 Serial # 30756**

- 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:** Hannah L  Robinson → Eagle 1000 Serial # 30756; 1988-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** H L Robinson Sand & Gravel → Eagle 1000 Serial # 30756; 2012-10-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hannah L  Robinson → H L Robinson Sand & Gravel; 2012-10-19 to current/open; source msha-controller-operator-history