Seabridge Gold is a Toronto-based North American resource exploration company. It owns Kerr Sulphurets Mitchell (KSM), a copper-gold-silver-molybdenum porphyry project in northern British Columbia. KSM's proven-probable reserves amount to 38.2 million ounces of gold, 191 million ounces of silver, 9.988 billion pounds of copper and 213 million pounds of molybdenum. Gold reserves at the Courageous Lake deposit total 6.5 million ounces. The property is part of a bigger deposit containing another gold project known as Snowfield (Pretium Resources); the entire deposit is the largest undeveloped gold deposit in North America. The KSM project will cost more than $4.7 billion to build but funding is not yet in place.

The 100% owned KSM project located in north-western British Columbia has proven and probable reserves of 38.2 million ounces of gold and 9.9 billion pounds of copper (2.16 billion tonnes averaging 0.55 gpt gold and 0.21% copper), making it the largest gold reserve in Canada and one of the largest in the world. The project's EA Application received provincial government approval in July, 2014. The 100% owned Courageous Lake project located in Northwest Territories contains one of the largest undeveloped gold deposits in Canada.

The company was initially incorporated as Chopper Mines Incorporated on September 14, 1979. It was renamed Dragoon Resources Ltd on November 9, 1984, and then Seabridge Resources Ltd on May 20, 1998, before adopting its current name on June 20, 2002.

In June 2000 Seabridge purchased the Kerr Sulphurets Mitchell (KSM) property from Placer Dome for 500,000 common shares and royalty payments capped at C$4.5 million. The project consisted of two contiguous claim blocks in the Iskut-Stikine region in British Columbia, approximately 20 kilometres (12 mi) southeast of the Eskay Creek Mine. When Seabridge acquired it, the project hosted two distinct deposits which were modelled separately by Placer Dome (CLA) Limited. At the two deposits, Placer Dome had estimated an historical indicated gold resource of 2.1 million ounces, with an additional 1.3 million ounces of gold in the inferred resource category as well as 2.8 billion pounds of copper resources. KSM's resources stand at 38.2 million ounces of gold, 191 million ounces of silver, 9.988 billion pounds of copper and 213 million pounds of molybdenum.

In May 2002, Seabridge purchased 100% of its second largest gold property, Courageous Lake in the NWT from Newmont Mining and Total Resources for $5.5 million plus a 2% NSR royalty. The project at that time reported an historical resource of 5.9 million ounces of gold.

Seabridge began exploring KSM in 2006. After five years of drilling, Seabridge reported a new NI 43-101 compliant resource estimate in February 2012 which estimated measured and indicated resources totalling 49.0 million ounces of gold, 12.7 billion pounds of copper, 261 million ounces of silver and 304 million pounds of molybdenum in 2.8 billion tonnes grading 0.55 gpt gold and 0.21% copper. An updated Preliminary Feasibility Study released on May 14, 2012 reported reserves of 38.2 million ounces of gold, 9.9 billion pounds of copper, 191 million ounces of silver and 213 million pounds of molybdenum in 2.2 billion tonnes grading 0.55 gpt gold and 0.21% copper. The new PFS included engineering changes designed to increase the production rate, facilitate permitting and enhance economics. NPVs, IRRs and capital paybacks substantially improved over the 2011 PFS. Base case life of mine cash operating costs fell significantly to $141 per ounce of gold produced (see executive summary). Further core drilling in August, 2013 discovered a very large, high-grade core zone at Deep Kerr. An initial NI 43-101 compliant resource estimate was released for the new Deep Kerr deposit which confirmed an inferred resource of 515 million tonnes grading 0.53% copper and 0.36 g/T gold for 6.1 billion pounds of copper and 5.9 million ounces of gold.

The KSM Project is undergoing a joint harmonized environmental assessment review as outlined by the British Columbia Environmental Assessment Act and the Canadian Environmental Assessment Act. In February, 2013 Seabridge submitted its EA/EIS Application to the provincial and federal regulatory authorities and the Application was accepted into the formal review process in June, 2013 after meeting the requirements of the screening process. In July, 2014 the project received its Environmental Assessment Certificate from the provincial authorities. Seabridge also expects to receive final federal approval in 2014.

In November 2016 Seabridge received a licence from the Government of Canada required for the construction, operation and maintenance of the Water Storage Facility and associated ancillary water works for KSM.

At Courageous Lake, after six years of work, an updated PFS completed in July, 2012 estimated proven and probable reserves of 6.5 million ounces of gold (91.1 million tonnes grading 2.2 gpt), an average annual production of 385,000 ounces at an average cost of $780 per ounce and a mine life of 15 years. An $8.5 million exploration program in 2012 focused on finding a second major deposit along the Greenstone Belt. This program discovered the Walsh Lake deposit. An initial resource for the Walsh Lake deposit was announced in early 2014 totalling 4.62 million tonnes grading 3.24 g/T and containing 482,000 ounces of gold, all inferred.

Red Mountain (Stewart, British Columbia) – Acquired in 2001 from North American Metals Corp. for 800,000 common shares.

Quartz Mountain (Oregon) – Acquired December 2001. This project has been optioned to Alamos Gold for a total consideration of $21 million.