# Relationship history for MSHA mine 1513210

Current hierarchy: **Haywood Billy H → P & G Coal Company Inc → No 3a**

- 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:** Haywood Billy H → No 3a; 1981-02-27 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** P & G Coal Company Inc → No 3a; 1981-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Haywood Billy H → P & G Coal Company Inc; 1981-11-01 to current/open; source msha-controller-operator-history