# Relationship history for MSHA mine 1800500

Current hierarchy: **Shafer Olaf → White Rock Mining → No 1 Strip**

- 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:** White Rock Mining → No 1 Strip; 1973-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Shafer Olaf → No 1 Strip; 1973-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shafer Olaf → White Rock Mining; 1973-11-01 to current/open; source msha-controller-operator-history