@virtualgrowth my personal opinions on whether or not STEEM mined should be taxed aside, the Internal Revenue Service guidance issued on March 25, 2014 (Internal Revenue Notice IR-2014-36 IRS Virtual Currency Guidance) already laid out regulatory guidance that virtual convertible currency (cryptocurrencies) are considered to be property and are subject to the general tax rules associated with property. Also, Title 26 Internal Revenue Code specifies the income subject to the tax code is the taxpayer's worldwide income. There are some extensive sections on the taxation of property, receiving compensation in the form of property and how to value it for tax purposes.

Unfortunately legal precedent in the US Tax courts would disagree with your position.