MENOMINEE COUNTY, MI -- Tribal officials are "disappointed" Michigan regulators gave final approval to a proposed open pit mine they argue endangers burial grounds, wetlands and the health of the Menominee River in the Upper Peninsula.

"Our Tribe maintains our stance against this open pit mine project, and we made our objection throughout the permitting process," Menominee Indian Tribal Chairman Douglas Cox said in a statement.

"We are not surprised by the issuance of the wetlands permit by Michigan Department of Environmental Quality, but we are surprised that many of the concerns raised by the public, tribes, and EPA were not addressed. Michigan Department of Environmental Quality has made minimal efforts to communicate with the Tribe on our concerns of tremendous impact to our cultural resources."

On Monday, June 4, the Michigan Department of Environmental Quality issued a conditional, final permit for the proposed Back Forty mine about 28 miles southeast of Iron Mountain.

The controversial gold, zinc and copper mine owned by Toronto-based Aquila Resources would tap the mineral-rich Penokean Volcanic Belt. Conventional drilling and blasting would extract sulfide ore from rock. Metals would be extracted from the ore through a process that generates acidic leachate.

The tribe's statement didn't specify what concerns went unaddressed. Cox and tribe officials could not be reached for further comment.

During a public comment period which closed earlier this year, DEQ received 3,420 written comments and heard from 88 people in person about the proposed mine.

Some comments raised concerns that burial grounds, ceremonial sites and ancient agricultural sites significant to the tribe are located within the Back Forty site and could be jeopardized or disturbed by mining operations.

The DEQ seemingly agrees, according to a statement included in the final permit which grants Aquila the ability to dig up and build on wetlands.

"Cultural, historical, and/or archaeological artifacts are known to occur in or near regulated areas of the project authorized by this permit and may be impacted by the permittee's activities," DEQ stated.

Aquila says tribal burial mounds, while on company land, aren't where the pit would be. Before the Canadian company begins work, they're required to submit a plan to deal with any unanticipated discoveries of cultural and historical artifacts, including human remains.

Any discoveries must be reported to Michigan's state archaeologist.

Environmentalists and tribal members have also critiqued the project as a potential polluter of neighboring Menominee River.

Wastewater, including product laced with cyanide, will be treated on-site before being discharged into the Menominee River, according to Aquila's website.

In issuing the final permit, the DEQ required Aquila to plan safeguards and responses to any contamination spill.

"Aquila will also be required to develop state-of-the-art controls aimed at spill prevention and response to potential pollution releases from the mining operations, including chemicals used and stored on site, and the storage and disposal of mine tailings," the DEQ stated.

Aquila expects to pull 532,000 ounces of gold, 721 million pounds of zinc, 74 millions pounds of copper, 4.6 million ounces of silver and 21 million pounds of lead from the Back Forty site at a construction cost of $261 million.

Constructions for the operation include a 700-foot deep, 83-acre open pit mine, about five miles of roads, and surface buildings for fuel storage, equipment washing, water supply and distribution, wastewater treatment and power supply.

The operation involves excavating 980,820 cubic yards of ground within 5.31 acres of wetland and placing 803,453 cubic yards of fill within 5.91 acres of wetland, according to the DEQ permit.

About 17 acres of wetland will be impacted from reduced surface waters, DEQ estimates. Aquila must mitigate the loss of at least 28.4 acres of wetland.

Aquila plans to close the mine after seven years of operation. DEQ ordered the company produce a closure plan which eliminates any contamination to surface and ground water from returning waste rock to the pit.