I think I was a little fast when programming that part. The issue is now fixed in v1.2.
Thanks for the prompt response and rectification!
If you don't mind, could you briefly go over the benefits of the arc furnace? If it takes a fuel as input like the coal furnace, I don't see why I would use it.
Edit: AH! Graphene is loaded using the Care robot. Now I understand the utility!
That, and it becomes faster as it heats up.