# Relationship history for MSHA mine 3607898

Current hierarchy: **Steimling C F → C F Steimling Inc → GREENTOWN SAND AND GRAVEL**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** C F Steimling Inc → GREENTOWN SAND AND GRAVEL; 1987-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steimling C F → GREENTOWN SAND AND GRAVEL; 1987-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steimling C F → C F Steimling Inc; 1987-06-01 to current/open; source msha-controller-operator-history