I don't know exactly (need to ask a professional), but in Latvia a company registration number seems to be not the same as VAT number. The second is being assigned separately after request and review of the company and let to claim VAT returns (inspectors can visit the place where you operate your business to check that it is real and trustworthy). These rules were imposed to prevent fraudulent VAT returns which are rather common in Latvia. Bitcoin is not regulated in Latvia at all, so I very doubt that our state's revenue service will ever assign VAT number to the Bitcoin mining company.
May be you know more about it, e.g. other EU counties that allow easier ways to get VAT number?
Describe yourself as a data centre hosting computer processors and providing/using calculation power rather than saying a "mining company".