# Relationship history for MSHA mine 3607650

Current hierarchy: **Grandville Robert R → Grandstone Coal Company Inc → Grandstone Coal Co Inc**

- 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:** Grandstone Coal Company Inc → Grandstone Coal Co Inc; 1985-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Grandville Robert R → Grandstone Coal Co Inc; 1985-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grandville Robert R → Grandstone Coal Company Inc; 1985-01-01 to current/open; source msha-controller-operator-history