user: Question: What rank is the Silver Bell mine of Pima county?
Columns: ['Rank', 'Mine', 'County', 'Operator', 'Capacity (thousands of metric tons)']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Morenci', 'Greenlee', 'Freeport-McMoRan', '390']
SQL:

assistant: SELECT "Rank" FROM "Table" WHERE "County" = 'Pima' AND "Mine" = 'Silver Bell';