Source of commodity production statistics?
I work for Quandl and on our site I can recommend two free historical databases that you may want to check out: 

The United Nations Industrial Commodities Database, I believe, shows production amounts for various commodities like steel, petroleum, glass etc. in metric tons for different countries: https://www.quandl.com/data/UINC

The United Nations Energy Statistics Database also shows production for other things like alcohol, gasoline etc. in metric tons: https://www.quandl.com/data/UENG

When you go to each database above, just search for "production" within each database. Hope this helps!