On the morning of 4th April I drove from home off Pikiwahine Road to the location in which we were to ride our horses in a bush area located on Waihui Road, Waihui north of Dargaville we set off around 11 am and at approximately 11:30 am, mum was thrown from her horse when the horse was unable to climb a small bank due to rock face that was not visible to us at the time. Myself and 2 other riders were at the scene, the male phoned for help while the female took care of the horses. Two ambulances had attempted to get in to us however they were unable to. I set off the locator beacon as we were aware that it was not possible to get assistance to our location as we were on the side of a hill surrounded by trees. It was approximately 50 minutes from the time of the accident to the point in which the rescue helicopter arrived where mum was air lifted to the Auckland Hospital. After mum was air lifted away myself and the two that we were with rode out horses out of the bush, from there I went down to Auckland Hospital with my Father.