# Relationship history for MSHA mine 1515989

Current hierarchy: **Marshall Afton → Allen & Marshall Augering Company Inc → Auger #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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Allen & Marshall Augering Company Inc → Auger #1; 1987-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Marshall Afton Et Al → Auger #1; 1987-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marshall Afton Et Al → Allen & Marshall Augering Company Inc; 1987-01-01 to current/open; source msha-controller-operator-history