MINE HILL - A Morris County homeowner must pay about $10,000 to fix two massive sinkholes in his backyard.

One of the holes in Andrew Kauff's Mine Hill yard is 19 feet deep, which officials say is about 15 truckloads of caved-in soil.

"I get sick to my stomach to be honest.  I think what next, how am I going to resolve this?  It's always on my mind,” Kauff says.

Kauff says that he discovered the huge hole after coming home from work on Dec. 30. At about 4 a.m. the next morning, he says he woke up to a loud thud. The hole had gotten even bigger, and a second hole had been created.

Insurance will not cover the sinkholes because they are considered “earth movement.”

Mine Hill Mayor Sam Morris tells News 12 New Jersey that this is the seventh sinkhole he’s had to deal with during his tenure as mayor.

“This one gets the prize,” he says. “This is the biggest and scariest one that we found.”

Experts say the problem of sinkholes may be an issue through the state. There are over 400 mines in New Jersey. The state provided many of the metals used during the Revolutionary War, and experts say that the ground has become unstable over the centuries.

"If you build something over the ground that's been turned into Swiss cheese, settlement happens,” says Sterling Hill Mining Museum president William Kroth. “When you mine, you generally put supports in and those supports would be steel, iron, wood and you get temporary support.”

However, Kroth says that after time the support is lost due to deterioration. “Gravity is always there and you get a sinkhole,” he says.

Kroth says that he's been seeing more sinkholes around the state. Decades ago, New Jersey opted out of a federal program that would have helped homeowners pay for sinkholes that develop on their properties.

A spokesman for the Mine Hill Public Works Department says that Kauff’s sinkhole is safe now and should not cave in.