But it's a good point and I'm already working on a solution to calculate mined assets with a 0 cost basis.
It will be released very soon (maybe even today).
Released

You can now use the "Filter menu" to set a cost basis of 0 to all minings (and other transaction types).
Can you please explain this a little more? Either its not working correctly or I am doing it all wrong. When i go back to edit mining entries and I change the asset balance to 0 it goes back and pulls the historical value.
I'm a little new to the platform and have all my entries uploading via API. What or where is the "filter menu" for this update?
Thank you!