# Relationship history for MSHA mine 1508690

Current hierarchy: **Nickell Eugene → Nickell Construction Company → No 3 Surface**

- 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:** Nickell Eugene → No 3 Surface; 1974-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Nickell Construction Company → No 3 Surface; 1975-09-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nickell Eugene → Nickell Construction Company; 1975-09-24 to current/open; source msha-controller-operator-history