CREATE TABLE table_80057 ("Year" FLOAT, "Road Opened" TEXT, "Road Closed" TEXT, "Freight Carried s Tonne" FLOAT, "Super B Capacity Reached [ citation needed ]" TEXT, "Number of Truck Loads North" FLOAT)

What is the smallest amount of freight carried on the road that closed on March 31 and reached super B capacity on February 17 after 2011?
SELECT MIN("Freight Carried s Tonne") FROM table_80057 WHERE "Road Closed" = 'march 31' AND "Super B Capacity Reached [ citation needed ]" = 'february 17' AND "Year" > '2011'
SELECT MIN("Freight Carried s Tonne") FROM "table_80057" WHERE "Road Closed" = 'march 31' AND "Super B Capacity Reached [ citation needed ]" = 'february 17' AND "Year" > '2011'