Please find below a link to the "European Commission" "Defining 'critical' raw materials" Dated 26 May 2014. (2011 to 2013)
Note Tungsten is Per the chart Tungsten has the greatest "Economic importance" and in the middle of the "Supply Risk".
One could argue that due to the current issues in Russia and China limiting supply the "Supply Risk" may have increased. This could be a factor why Warren Buffet has invested in Tungsten.
Please DYOR. I am very happy to hold but I see CNQ as a LT Buy.
Google Search. Critical raw materials - European Commission
Link http://ec.europa.eu/enterprise/policies/raw-materials/critical/index_en.htm
CNQ Price at posting:
9.2¢ Sentiment: LT Buy Disclosure: Held
A personalised tool to help users track selected stocks. Delivering real-time notifications on price updates, announcements, and performance stats on each to help make informed investment decisions.
(20min delay)