# Relationship history for MSHA mine 2101251

Current hierarchy: **Ken W  Rikke → Ken Rikke Gravel → Rikke Pit & Mill**

- 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:** Ken Rikke Gravel → Rikke Pit & Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ken W  Rikke → Rikke Pit & Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ken W  Rikke → Ken Rikke Gravel; 1950-01-01 to current/open; source msha-controller-operator-history