To price the CO2 emissions of miners, you don't try to track the miners themselves. You tax CO2 emissions at the source (i.e. the coal-fired power plant the miners are plugged in to), and then the miners pay for it through higher electricity costs. If they use solar or wind instead then their electricity prices wouldn't reflect that tax. If they use a mix, the price will partially reflect that tax.

If you can price in the consequences at their origin then the rest just works itself out, whether it's LEDs or cars or bitcoin mining.