# Relationship history for MSHA mine 4406320

Current hierarchy: **Robert  Nichols → R & O Coal Company Inc → No 2**

- 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:** Robert  Nichols → No 2; 1985-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R & O Coal Company Inc → No 2; 1986-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Nichols → R & O Coal Company Inc; 1986-09-01 to current/open; source msha-controller-operator-history