# Relationship history for MSHA mine 2602029

Current hierarchy: **Graham Ronald R → Ronald R Graham → Crow 19 20 21**

- 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:** Ronald R Graham → Crow 19 20 21; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Graham Ronald R → Crow 19 20 21; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Graham Ronald R → Ronald R Graham; 1987-10-01 to current/open; source msha-controller-operator-history