I'd like a few others to chime in on a hypothetical example which tries to apply the new IRS ruling for miners (or hashrate providers per se).

A miner buys a mining device for 5 BTC @ $100/BTC ($500 cost), the expected life of which is well under 1 year.

The mining device uses $100 in electricity over the year ($100 cost)

The device generates 2 BTC @ $200/BTC and 2 BTC $250/BTC over the year ($900 income)

The miner spends the 4 BTC in 4 transactions:

1 BTC @ $200/BTC
1 BTC @ $300/BTC
1 BTC @ $400/BTC
1 BTC @ $500/BTC

The total gross income is $900

The total cost of the income is $600 ($500 + $100 Electricity)

So the net income is $300.

For capital gains, the basis is:

2 BTC @ $200
2 BTC @ $250

and to consume those 4 BTC via FIFO:

1 BTC $200 from 1 BTC @ $200 => $0 Gain
1 BTC $300 from 1 BTC @ $200 => $100 Gain
1 BTC $400 from 1 BTC @ $250 => $150 Gain
1 BTC $500 from 1 BTC @ $250 => $250 Gain
------------------------------------------------------
4 BTC         from 4 BTC                 $500 Gain.

So the owed taxes are calculated from:

$300 taxed as income plus $500 taxed as capital gains (short term in this example).

Sound right?