Reply #19: A different estimate:

[Make7]

Although it doesn't look like a complete pre-fabricated perimeter section (i.e. 3 columns by 3 stories), let us estimate what it might weigh if it were. The perimeter columns were approximately 14 inches square - let's just say 15 inches to be safe. And in the lower parts of the tower the thickness of the walls of the perimeter columns were 4 inches. (Obviously the steel pictured is not from the lower part of the building - but let's pretend for this exercise.) Now - each story was about 12.44 feet - multiply by 3 and we get 37.32 feet.

So we have a cross section of (15 inches x 15 inches) - (7 inches x 7 inches) = 176 square inches

Divide by 144 to get square feet = 1.22 sq. ft.

Multiply by 37.32 ft. (three stories) to get the cubic feet of steel for one column = 45.53 cu. ft.

Multiply by 3 for the numbers of columns = 136.59 cu. ft. of steel

Now - how much does a cubic foot of steel weigh? I don't know the exact type or weight of the steel pictured, so I'll just go with an approximation. The highest density for steel I found in a quick search (source) was 8.03 g/cm³ - which is 501.3 lbs./cu. ft. (For comparison the ASTM A36 steel used for the core columns had a density of 7.312 g/cm³ - source)

So - 136.59 cu. ft. of steel times 501.3 lbs./cu. ft. results in 68,473 pounds of steel. Remember this is the estimate of the maximum weight of the steel in the picture. The stated figure seems to be off by a factor of about 10. (Possibly more.) It is likely that they meant 60,000 lbs. - not 600,000 lbs. Perhaps it is just a typo.

To add to the unlikelihood of the piece pictured weighing 600,000 pounds, I would like to mention that the cranes used to erect to WTC Towers were capable of lifting 60 tons each (source). There are videos showing perimeter sections being lifted by these cranes - since the section in that picture appears to be a perimeter section - it is next to impossible that it weighs 300 tons.

- Make7