Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_79972 ( "Rank" real, "Mine" text, "County" text, "Operator" text, "Source of copper" text, "2012 Cu Production (lbs)" real )

### Question ###
What's the lowest ranking source of copper, copper ore, concentrated and leached?

### Accurate SQL ###

SELECT MIN("Rank") FROM table_79972 WHERE "Source of copper" = 'copper ore, concentrated and leached'