There is no guidance on when to recognize mining income kendog77 - I think the IRS will ultimately say it is taxable at time of receipt of the coinbase and valued  using a reasonable valuation method (pull it from coindesk?) either on the date the block is included in the blockchian, the date it has sufficient confirms (6?) so as not to be considered an orphan or the date it reaches the 99 confirms required for it to be spendable.  I think any convention on timing of the three is supportable, but once you select a method you will have to stick with it for other income from the same mining operation.

You might choose to report it on disposition or sale of the BTC but you may need to consider disclosing what you are doing on the return to avoid significant penalties.

Now how you tax it - ordinary income, capital gain, etc., will be more of a conversation between you and your accountant.  They may also disagree with what I state above.... the 'right' answer is not entirely clear and I have spent several hours on mining income recognition.....

Note if you are in a pool or mining as a group the above may be quite different as the mining pool structure will impact how the income is recognized.........

my two cents.