# Relationship history for MSHA mine 1511833

Current hierarchy: **Johnson Ralph → R J F Coal Company → Mine No 10**

- 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:** Johnson Ralph → Mine No 10; 1974-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R J F Coal Company → Mine No 10; 1979-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Ralph → R J F Coal Company; 1979-04-01 to current/open; source msha-controller-operator-history