By the time emergency services arrived, shortly before 6pm, the man's co-workers had removed the dirt. St John Ambulance and Fire Service staff climbed through the pipes to treat the man.
"He had injuries to his pelvic region and he was in a lot of pain," said Mr McRae.
Paramedics gave the man pain relief and fire crews hooked up a rope system.
"[Fire staff] assisted St John to put the guy into a Stokes basket - an orange plastic stretcher - and we connected lines and pulled him along the pipe to the bigger opening at the end.
St John did some more stabilising of him then we lifted him up the pipe and got him to the top."
He was taken to Middlemore Hospital in a serious condition, St John spokeswoman Olive Taylor said.