Taken initially to Hawke's Bay Hospital in a critical condition, she was then transferred to Wellington Hospital where she is due to undergo surgery today.
"She should get through what's expected to be two surgeries - it will be a long recovery but her injuries are repairable," Ms Pottinger said.
Ms Dolan was conscious while waiting for the rescue services to arrive, and was very brave throughout, she added.
Earlier this month, Ms Dolan, who has worked for Ms Pottinger part-time for the last two years, competed at the Horse of the Year event in Hastings, where she won the Youth Rider of the Year and Paced and Mannered Pinto of the Year.
A part-time extramural student at Massey University, Ms Dolan had just started working part-time at Farmlands in Hawke's Bay.
Ms Pottinger said it was a freak accident that could not have been prevented.
"It was no-one's fault - she had been on the horse for 10 minutes before it happened - it's just one of those things."