If it came from a sponsor in Canberra then it is very cool *8-) The answer is that yes it can be done and there is several methods to do it.
The old fashioned method is to use a large single phase 240V motor to drive a 3 phase motor as a generator to make the 415V. Clunky cumbersome bulkky and very reliable.
Second method is to buy a 240V input 415V variable speed drive. You might pick up one at an electrical disposals place cheap or it will cost you a pretty penny new. Neat and tidy and variable speed but potentially expensive.
Third option is to repower the grinder with a Cap Start Cap Run (high torque) 240V motor, while this is an engineering fiddle and will require maching of shafts etc. I have done this with pumps in the past and grinders are much the same as some of those. Most likely still the cheapest option in spite of the engineering.
4th option is just to polish it up and admire it *:)