WARSAW (Reuters) - The number of miners missing after an earth tremor struck KGHM Polska Miedz’s mine near the Polish town of Rudna, 70 miles east of the German border, fell to one from nine, the copper producer said on Twitter on Tuesday.

Earlier KGHM spokesperson Anna Osadczuk told Reuters the miners were missing after the tremor hit the mine early this afternoon 770 meters below the earth’s surface.

Eleven teams took part in the rescue operation, finding all but one of the missing miners. Originally 14 were missing, but some were rescued within several hours of the tremor.

In 2016, eight miners died after a tremor caused rockfalls deep underground at the mine, which is Europe’s largest copper mine.