Infusers don't use up any crystals which makes miners pretty useless.
Most likely a bug, but in case it's not, I would suggest changing it.
Edit:
Same problem with animators.
It is not a bug, each worker is meant to only affect it's own resource. Crystals and Mana have uses later in the game beyond just making other resources.
P.S. I can't remember what was put into this version of the build I uploaded, Crystals definitely have their first extended use implemented, Mana has it's use implemented in the development version but I don't know if that has yet made it into the build. The four basic resources are intended to be used for other purposes many times over throughout the game. As this game is in development not all of the purposes are fully functional or even implemented yet.