So why were the miners seized then? if this situation revolved solely around marijuana, and past marijuana offenses got him here, and the warrant was specifically for drugs and more specifically marijuana what purpose was there to confiscate anything having to do with bitcoins, mining equipment, and what they referred to as "Physical" bitcoins.
I don't know about the law there so I can only speculate:
1)Mining equipment:suspicious looking, unknown machinery (I doubt this cops would recognise a mining rig beforehand) that may be relevant to the illegal activity.Possibly they thought it was contained some data(if they mistaken it for some server/computer) on contacts.
2)Physical bitcoin: it it even looked like casascius coin it could be mistaken for token/chips that hold monetary value used in the illegal transaction, akin to how authorities seizes drug money and assets.