and anyway i'm sure that if you run a big business the simple thing of buying many miners mean that you invested a lot of money and you need to declare those money
Depends on what they consider the income or investment. To be honest I would be interested to hear a CPA on it. At one time I thought I wanted to be one of those...... but went a different path. So I'm not going to throw out wrong info.
A business would definitely have some. I think a lot will come down to if it's seen as a hobby or enough to be over a hobby. A CPA could do a lot better though at classifying it and be able to tell exact numbers.