For 13 years, Sharon Walkington has been a dinosaur hunter, surveying in the field, digging up dino bones, preparing them in the lab. But she's not a professional paleontologist — and she's not doing any illegal poaching.

Walkington, Salt Lake City, is one of the volunteers working with the Utah Museum of Natural History to uncover the state's distant prehistory, with fossils dating back 75 million years to 150 million years. Now the museum is inviting others to join the volunteers for training, preparation work and, eventually, digging in the field under professional supervision.

A series of classes for volunteers starts Wednesday at the museum, 2 p.m. to 5 p.m., according to a press release. The museum is located on the University of Utah campus at 1390 E. Presidents Circle (200 S.).

Most of the volunteers do not have backgrounds in paleontology, according to the museum.

The training and volunteer work are "actually something relatively unique to this museum," Mike Getty, collections manager for paleontology, told the Deseret Morning News. There are some other programs like this one but not many.

Following the lessons on fossil preparation, volunteers eventually can help at digs as well, he said. "Once they do this, they can go on and actually get training in the field aspects of our program."

Training and preparation take place in the museum's first-floor laboratory behind a glass partition. Museum visitors are able to watch as volunteers painstakingly chip away the rock matrix from ancient fossil bones.

"They (the volunteers) will be a little bit like a fish in a bowl," he said.

Getty, who has trained "well over 200 volunteers" in the last five years or so, said 50 to 70 are active at any one time. "Once they do the training they can pretty much come in on their own time," he said.

For every hour of field work at a dinosaur site, an estimated five or 10 hours of lab work is needed. "It requires a vast amount of labor to clean and stabilize the specimens for research and display."

Besides removing rock from bone, the volunteers use adhesives and other material to hold the fossils together. And they may find themselves working on other animals that were contemporaries of the dinosaurs such as fossil turtles and crocodiles, he said.

"We completely depend on them. With the amount of labor that would be involved, we don't have enough staff."

Walkington said she volunteers three or four times a week, putting in perhaps 10 or 12 hours weekly.

"But that's unusual. Most people don't do that much," she said.