I really hope someone can take the time to help me with this odd query.

I have be offered a large cider milling stone (approx. mass = 2,000,000g & r = 1.5m).

I would like to put the stone back into use (only utilized seasonally) and ideally harness water power as the driving force. My hope is we can store rainwater in a large enough quantity to turn the mill wheel for short bursts (total run time <5 hrs per year).

So my questions are what initial torque would be require to accelerate the wheel to 0.25m/s over 60s? And what mass of water does that relate to in a quarter (approx. water catchment area) of a waterwheel. Finally what flow would be required to keep the stone turning at 0.25m/s.

At this point I would be happy to treat the system as if my waterwheel and mill stone are one though obviously this won't be implementable. In the end product I would be able to implement a very basic gearing.

I've attached a diagram of the intended implementation

http://archive.willfaulds.com/2009/watermill.jpg