DETROIT (AP) — Federal officials have awarded a contract to remove copper mine waste from a Lake Superior harbor, where it threatens to damage crucial fish spawning habitat more than a century after companies dumped it into the water.

The U.S. Army Corps of Engineers said Petersen Companies Inc. of Minocqua, Wisconsin, will dredge about 27,500 cubic yards of material known as “stamp sands” from in and around Grand Traverse Harbor.

The company also will dredge 80,000 cubic yards of the waste from the ancient riverbed area north of Buffalo Reef.

Officials say the dredging will buy time to develop a long-term plan for dealing with an estimated 15 million cubic yards of stamp sands that endanger the reef.