# Relationship history for MSHA mine 4002090

Current hierarchy: **Roger E  West → Round Mountain Coal Company Inc → No 1 Mine**

- 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:** Round Mountain Coal Company Inc → No 1 Mine; 1976-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Roger E  West → No 1 Mine; 1976-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roger E  West → Round Mountain Coal Company Inc; 1976-07-01 to current/open; source msha-controller-operator-history