The column name that I have added to my csv file when importing new products from a supplier catalogue is

SUPPLIER / MINIMAL QUANTITY

The minimal quantity was imported as desired

Before we can fix the issue, can you tell us how you tried to add a new column? Given your text, I think you used openERP to create a new column 'min_qty' on the table 'product'. If so, the name of the column should be 'x_min_qty', which is forced by openERP when adding it.

Is it possible for you to see which fields are defined within postgreSQL on the table product_product and product_template? For example within webmin (on Linux), or pgadmin (linux and windows).

A better way of adding new fields to a table/model is to use custom modules, and define the fields in the python code.