The bad news keeps piling up for the mining industry.

Amid the second-best jobs report in 16 years, released Friday, mining shed another 7,500 jobs in December and posted a decline of 129,000 positions in 2015. That means one in seven mining-related jobs in America disappeared in the past 12 months.

In Minnesota, the industry's struggles are showing up at ports on Lake Superior, where fewer tons of iron ore are leaving on ships for Chicago, Detroit or Gary, Ind.

Iron ore shipments on the Great Lakes fell 24 percent in 2015 compared to 2014, and shipments from Duluth fell 63 percent, according to the Lake Carriers' Association, a Cleveland-based group that represents Great Lakes ships with U.S. flags. Shipments from Two Harbors and Silver Bay also fell.

"It's discouraging," said Peter Kakela, a Michigan State University professor and expert on the taconite industry.

A glut of iron ore production combined with a slowdown in China has sent the price of iron ore tumbling, forced the idling of several taconite plants in Minnesota and has caused the layoffs of more than 2,000 workers. The latest news came from Essar Steel Minnesota, which is laying off 100 people at the taconite site it is revamping near Nashwauk. On Thursday, Magnetation said it will idle its Bovey, Minn., iron ore plant on Jan. 18.

Huge iron ore firms in Australia and Brazil can still turn a profit at current prices, Kakela said, and they are not slowing production, which only compounds the problem for smaller producers in North America, which has become a relatively small player in the global iron ore market.

"International iron ore demand is down, but the big three — the two Australian and the Brazilian — are going strong," Kakela said. "That's a big concern to me."

Kakela believes iron ore production on the Great Lakes will return but that restoration will be delayed by increased turmoil in Chinese markets and China's economy.

"I was looking at the second quarter of 2016 as the recovery period," he said. "But now the recovery period seems a longer ways off."