Well what im wondering is if you just only mine, never put $$ into it, it doesnt seem you would ever have to pay capital gains? From what I understand, capital gains are only if you purchased the product.. What do you guys think? Seeing as I didnt "invest" but rather "produced" the product?
Talk to a real accountant/lawyer. But it seems likely to me that the cost basis would be the price at the time the block was mined / share paid out.
Cost basis would be your cost to produce.