The 25-year permit for Seabridge’s KSM, the world’s largest undeveloped gold-copper project by reserves, regulates all structures and activities situated on waters straddling the border with the US, the firm said in a statement.

Canada’s minister of the environment approved KSM during the final days of 2014. The federal and provincial environmental assessment process took nearly seven-years and KSM was only the second metal mine in five years to receive the green-light from authorities.

Today’s approval, said Seabridge Gold chairman and CEO, Rudi Fronk, further validates the permits obtained to date, which concluded that the KSM Project would not result in any “significant impacts” to the environment, including those waters which flow into Alaska.

During its first seven years of operation, the mine is expected to have an annual gold output of 1 million ounces and life of mine annual production is estimated at 592,000 ounces of gold, 286,000 pounds of copper and 2.8 million ounces of silver.

Construction costs, however, have soared lately, with the most recent preliminary study showing that building the mine would cost $5 billion, or over 20% of the total market capitalization of Barrick Gold, the world’s No.1 producer by output.