I don't quite see why you have a problem with the difference...

I don't quite see why you have a problem with the difference between costs per tonne. The mine was designed with tonnage per year in mind. Too big and the cost to build becomes cost prohibitive and too small and they can't get their cost per tonne down low enough to compete. The whole business is designed around a figure of about 350,000 tonnes per year. (see link) 2018 was about a third of that!

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwji3fybxqjgAhXKYH0KHQsNB18QFjAAegQICRAC&url=http%3A%2F%2Fwww.syrahresources.com.au%2Finvestors%2Fdownloads%2F542&usg=AOvVaw0SBSVBliDyxGXxbJGweGbA

The closer they get to that point the cheaper their cost per tonne becomes. The same document above lists a final cost per tonne of US$300/t. That's almost half the cost per tonne to produce than the current US$550/t. 

I posted below that Syrah needs to be patient in these early days in order to avoid over supplying the market to ensure they receive decent prices per Tonne. However if they don't increase their cash-flow they will also be screwed. I see management walking a tightrope where they are making just enough to keep the wolves from the door until the supply/demand ration tips in their favour.