# Relationship history for MSHA mine 1515173

Current hierarchy: **Hall Forest D → F & M Coal Company Inc → No 1 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:** Hall Forest D Et Al → No 1 Surface; 1983-08-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** F & M Coal Company Inc → No 1 Surface; 1985-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hall Forest D Et Al → F & M Coal Company Inc; 1985-04-01 to current/open; source msha-controller-operator-history