#6 RA2, April 2017 #7 RA2, March 2017 #4 RA2, February 2017 #4 RA2, January 2017 #7 RA2, November 2016 #1 RA2, September 2016 #7 RA2, August 2016 #2 RA2, July 2016 #10 RA2, June 2016 #5 RA2, February 2016 #1 RA2, January 2010 #7 RA2, March 2008
Hint: Place refineries as close to ore as possible.