# Relationship history for MSHA mine 3610256

Current hierarchy: **Prushnok Coal Company Inc → P & N Coal Company Inc → Mayo Operation**

- 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:** Prushnok Coal Company Inc → Mayo Operation; 1987-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** P & N Coal Company Inc → Mayo Operation; 2018-07-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Prushnok Coal Company Inc → P & N Coal Company Inc; 2018-07-19 to current/open; source msha-controller-operator-history