how long was the ballarat mile

The Ballarat Mile is a running race. Having freed himself from Squizzy's service, Charlie throws his energy into training for the Ballarat mile race and spending time with his mother, Alice, and Norman. Charlie and Mr. Redmond take a train to Ballarat, where Charlie decides he will bet the twenty-three pounds he earned from Squizzy on himself to win the race. To make his odds greater, Charlie runs the first heats barefoot. In the last race, Charlie takes first place and wins 1,200 pounds.

I mean i assume it's a mile?!