I don't know. There is a lot that is still unclear.
If you used the bitcoin to get cash, then that's a taxable event (a $12,000 capital gain, based on your numbers.)
Likewise, if you used the bitcoin to buy a car, gold coins, or any other tangible asset, you have a $12,000 capital gain, because you have converted the virtual currency into something real. The sales price of the bitcoin for capital gains purposes would be treated as being the value of whatever real thing you acquired for it. (Such as, if you bought a $15,000 car because the deal discounted the bitcoin, your capital gain would be $10,000 even though the value on a currency exchange might have been higher.)
If you used $US to buy shares in a gold mine, that would be treated as an investment, and if you took your gold mining share dividend and bought more shares that's a reinvestment.
The issue here is that you are using something virtual to buy something else that is virtual. And the IRS only taxes virtual things when they become real. So I don't know whether you really have a capital gain that you have to realize and pay taxes on, but my guess is that you don't report a capital gain. But you do report the mining income, and if you sell the contract to someone else for more than your $5000 original investment, then you have a capital gain on the contract.
But I am not a CPA so if you find an expert in cryptocurrency you should probably rely on them. (Well, rely on them if you hire them for advice and they have errors and omissions insurance if they are wrong. I would not necessarily rely on someone I knew socially who happens to be a CPA, unless you actually pay for their advice.)
