# Relationship history for MSHA mine 1401478

Current hierarchy: **Kenneth L Nelson → Nelson Quarries Inc → Plant 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:** Kenneth L Nelson → Plant 2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Nelson Quarries Inc → Plant 2; 1985-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kenneth L Nelson → Nelson Quarries Inc; 1985-07-01 to current/open; source msha-controller-operator-history