# Relationship history for MSHA mine 3601883

Current hierarchy: **Keim Ralph A & George W Tallman → Ralph Keim Coal Company → Otto Bank 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

- **operator_operates_mine:** Ralph Keim Coal Company → Otto Bank No 2; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Keim Ralph A & George W Tallman → Otto Bank No 2; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keim Ralph A & George W Tallman → Ralph Keim Coal Company; 1950-01-01 to current/open; source msha-controller-operator-history