Does seem a little weird, doesn't it? Reasonably we're only picking up the pieces of the deposit that has enough ore for us to see - we're not going to know about or chance the idea that some random hunk of rock might be 2% iron. Fair enough. But... Once that ore is refined and the slag discarded, why are we losing 184kg of refined metal to make a 16kg sword? I've gotten used to hauling 400kg of metal cross-country for five minutes to make a sword but... That doesn't make it right.

That's just one of the weird quality-of-life fixes I wish they'd make. There's enough busy-work with the process of (potentially) rebuilding one's entire manufacturing process for each tier that we don't need to be mysteriously losing 9/10ths of our metal too.

...unless.

...maybe we're secretly fueling Odin's war machine and we just don't know it. What we 'lose' is being whisked away by Thor in his sky-chariot. Possibly to buy more horses.