Sinkhole to be filled in by LUN.Canadas Lundin Mining is planning to fill in a giant mystery sinkhole near its copper mine in Chile, an ambitious plan that will also see it attempt to pump out water that has seeped into the mine, a senior company executive told Reuters on Thursday. The huge 36-metre-diameter sinkhole that opened up in late July in the Tierra Amarilla commune, around 665 kilometers north of capital Santiago, drew widespread global attention and saw charges by authorities against Lundin. Studies to determine the causes of the sinkhole are already in decisive stages and a technical body is already receiving all the information to be able to draw conclusions, Luis Sanchez, president of a local unit of Lundin, told Reuters.