Okay, the lawyer in me is coming out, but seriously, why not just tax crypto-mining the same commodity trades are taxed. They say Bitcoin is the new gold for safe haven assets. So, tax it like a commodity. For the curious, and those not familiar with the tax code, 60% of the profits made from trading commodities are taxed as long-term capital gains (i.e. 15%) and the reaming 40% as short-term capital gains (ordinary income tax rate). Otherwise, just tax all profits made as regular income.
Given the number of the illegal mining Tom's Hardware has reported, I suspect some miners in the US are not exactly honest enough to accurately report income to the IRS every April. I also suspect some may never bothered learning how to report income from mining. Heck it is not like Turbo Tax has page for reporting gains from crypto mining. Consequently, enforcement will be problem.