The KSM project consists mainly of four, gold-copper porphyry deposits: the Kerr (104B 191), Sulphurets (104B 182), Mitchell (104B 103) and Iron Cap (104B 173) deposits. All deposits are related to the Early Jurassic (~194 Ma; Margolis, 1993) Texas Creek intrusions. The Sulphurets-Mitchell Creek area is underlain by rocks of the Lower-Middle Jurassic Unuk River Formation, Hazelton Group. These rocks include green to grey volcanic epiclastics and a sequence of dominantly fine-grained marine sediments. A third sequence of massive red and green volcanic sandstones and conglomerates form the highest peaks capping the stratigraphic sections.

The Kerr deposit is a strongly-deformed copper-gold porphyry, where copper and gold grades have been upgraded due to remobilization of metals during later and/or possibly syn-intrusive deformation. Alteration is the result of a relatively shallow, long lived hydrothermal system generated by intrusion of monzonite. Subsequent deformation along the Sulphurets Thrust Fault (STF) was diverted into the Kerr area along pre-existing structures. The mineralized area forms a fairly continuous, north-south trending, west-dipping irregular body measuring about 1,700 metres long and up to 200 metres thick. Deep drilling since 2012 has identified two sub-parallel, north-south trending, steep west-dipping mineralized zones that appear to coalesce near the topographic surface.

The Kerr Zone is centered on a north-south trending, steep westerly dipping, tabular intrusive complex that drilling demonstrates has a horizontal extent of 2,400 metres and a vertical extent of at least 2,200 metres. The complex includes an east and west limb that may coalesce near the current surface. The west limb is up to 500 metres thick, and the east limb is up to 300 metres thick. There are several distinct intrusive phases, the earliest of which are fine grained diorites with 5 per cent to 60 per cent quartz-sulphide vein stockworks, and these appear to contribute the majority of metals. Later phases envelope and sometimes invade the earlier phase, and are characterized by coarser textures, less veining, and lower metal contents. The intrusions are hosted by an Early Jurassic sequence of rhythmically bedded siltstones, sandstones, conglomerates, and debris flows that have been altered adjacent to the intrusions, but generally contain marginal metal grades.

Mineralization occurs mainly in feldspar and hornblende porphyritic diorite (PAND1) of the Mitchell Intrusive Suite intrusion and the IBX unit consisting of a mixed complex of altered and sheared host rocks, dikes, and breccias; however it may extend into the adjacent late PAND2 intrusion and wall rock sediments. The PAND2 is similar to PAND1, but is a later intrusive phase.

The dominant copper mineral is chalcopyrite, which typically occurs as isolated grains about 0.2 to 2 millimetres across, disseminated and clustered in quartz veins, fractures, and surrounding haloes. Bornite is present almost exclusively in the north half of the east leg, within a phase containing over 50 per cent crackled quartz veins, accompanied by coarse grained chalcopyrite and minor tennantite. Tennantite is rare, but widely distributed in late quartz-carbonate veins, mostly in wall rocks, along with minor sphalerite, rare galena, and arsenopyrite. Dark, arseniferous pyrite is associated with these minerals. Molybdenum is a minor constituent, mostly contained within the PAND1 and IBX units and closely associated with copper. Visible gold has not been observed except under microscopic examinations, where it is observed as less than 100 µm inclusions within sulphides, mainly chalcopyrite, and sulphide grain boundaries.

Little or no information is given in recent industry documents on other individual zones defined in the 1980s and documented in MINFILE as: Kerr A (104B 194), Kerr C (104B 188), Kerr D, (104B 099), Kerr F (104B 198) and Kerr L (104B 192), Kerr P (104B 181)). However, Seabridge's website maps show the greater Kerr zone deposit outline to encompass all or most of the area where the individual zones are plotted.

WORK HISTORY

From 1982 to 1983, the Alpha Joint Venture began prospecting and soil geochemical surveys of the Kerr gossan focusing on gold.

From 1984 to 1985, Brinco optioned the Kerr project and completed some geologic surveys and drilled 3 holes.

From 1987 to 1989, Western Canadian Mines optioned Kerr and completed 59 drill holes and recognized copper-gold porphyry.

From 1989 to 1992, Placer Dome (Placer) acquires Kerr property in 1989 and follows up with delineation drilling of Kerr deposit at 50 metre centers by drilling 82 holes.

From 1992 to 1996, Placer estimated resources (non NI 43-101), metallurgical testing, and scoping studies. Unclassified reserves at Kerr are 135 million tonnes grading 0.34 gram per tonne gold and 0.76 per cent copper (Sharon Gardner (Placer Dome), personal communication, 1993).

From 1996 to 2000, the project was dormant

In 2000, Seabridge Gold acquired a 100 per cent interest in Kerr from Placer Dome. The Kerr deposit has been modelled by Placer Dome as a copper-gold porphyry system with total measured, indicated and inferred resources estimated at 140.8 million tonnes grading 0.75 per cent copper and 0.36 gram of gold (1.6 million ounces of gold) per tonne at a 0.40 per cent copper grade cut-off (Seabridge Resources Inc., Press Release, June 6, 2000; Northern Miner, June 26, 2000). Approximately 52 per cent of the total Kerr resource is within 50 metres of a drill intercept and has been classified by Placer Dome as drill-indicated.

In 2002, Noranda Inc. acquired an option from Seabridge with the right to earn up to a 65 per cent interest in Kerr.

From 2003 to 2004, Noranda undertook various exploration surveys.

In 2006, Seabridge Gold purchased Falconbridge's option (formerly Noranda) and conducts drilling programs on Mitchell and Sulphurets deposits (9,098.8 metres in 29 holes, operated by Falconbridge).

In 2007, Seabridge Gold puchased Arbee prospect from D. Ross. Drilling at the KSM (Kerr-Sulphurets-Mitchell) project was undertaken within and peripheral to the Mitchell zone. A total of 15,294 meters of core drilling in 37 holes were completed.

In February 2008, a mineral resource of 206.272 million tonnes indicated grading 0.25 gram per tonne gold and 0.45 per cent copper and 51.387 million tonnes inferred grading 0.21 gram per tonne gold and 0.45 per cent copper was reported, using a 0.50 gram per tonne gold equivalent cut-off grade, for the Kerr deposit (Lechner, M.J. (2008-02-29): Kerr-Sulphurets Technical Report).

In March 2009, an updated mineral resource of 225.300 million tonnes indicated grading 0.23 gram per tonne gold and 0.41 per cent copper with an additional 69.900 million tonnes inferred grading 0.18 gram per tonne gold and 0.39 per cent copper was reported, using a 0.50 gram per tonne gold equivalent cut-off grade, for the Kerr deposit (Lechner, M.J. (2009-03-30): Updated KSM Mineral Resources).

In 2009, Seabridge drilled 7 holes totalling 1,159 metres and conducted metallurgical testing and permit work. In 2010 Seabridge drilled 4 holes totalling 1,453 metres and conducted metallurgical testing and permit work.

In January 2010, an updated mineral resource of 237.500 million tonnes indicated grading 0.26 gram per tonne gold and 0.48 per cent copper with an additional 76.100 million tonnes inferred grading 0.20 gram per tonne gold and 0.30 per cent copper was reported, using a 0.50 gram per tonne gold equivalent cut-off grade, for the Kerr deposit (Lechner, M.J. (2010-01-25): January 2010 Updated KSM Mineral Resources).

In March 2010, Seabridge Gold released updated reserves for the KSM property. The Probable reserves for the Kerr Zone are 125.1 million tonnes grading 0.28 gram per tonne gold, 0.48 per cent copper, and 1.26 grams per tonne Ag (Stockwatch News Release March 31, 2010).

In March 2011, an updated mineral resource of 241.200 million tonnes indicated grading 0.25 gram per tonne gold, 0.47 per cent copper and 1.2 grams per tonne silver with an additional 91.500 million tonnes inferred grading 0.23 gram per tonne gold, 0.30 per cent copper and 0.7 gram per tonne silver was reported, using a 0.50 gram per tonne gold equivalent cut-off grade, for the Kerr deposit (Lechner, M.J. (2011-03-29): March 2011 Updated KSM Mineral Resources).

In 2011, a total of 20,718 metres of NQ core was drilled by Seabridge Gold on the KSM project in 2011. Of the sixty-three holes drilled, nine were drilled at the Kerr Zone, forty-one at the Sulphurets Zone, six at the Mitchell Zone, and seven at areas outside of the mineralized zones.

Pretium Resources Inc signed two agreements with Seabridge Gold Inc regarding their Brucejack-Snowfield and KSM projects, respectively. The two companies agreed to mutual access in the proposed Mitchell and Snowfield pits allowing both operators to conduct stripping activities across the claim boundary. A mutual cooperation and confidentiality agreement was signed to enable the efficient preparation of an engineering study combining KSM and Snowfield projects as a single mine operation. Combined, the KSM, Snowfields and Brucejack deposits comprise the largest in-ground gold resource identified to date in North America. Potential quantities of metals within reserve, measured, indicated and inferred categories across the six projects approach 13.7 million tonnes copper and 4.7 million kilograms gold (Fieldwork 2011).

In 2012, Seabridge drilled 5 exploration holes totalling 3730.6 meters. Two holes testing the new Deep Kerr zone yielded significantly higher grades than currently in the Kerr Zone reserves. These were the first holes put down on the Deep Kerr zone which occurs below the Kerr zone. Seabridge Gold Inc. released results of an updated preliminary feasibility study which included updated reserves of 476 million tonnes Proven grading 0.67 gram per tonne gold, 0.17 per cent copper, 3.05 grams per tonne silver and 60.9 parts per million molybdenum; 1.688 billion tonnes Probable grading 0.51 gram per tonne gold, 0.22 per cent copper, 2.65 grams per tonne silver and 40.1 parts per million molybdenum. Proven reserves include the Mitchell zone and Probable reserves include Mitchell, Iron Cap, Sulphurets and Kerr zones (Seabridge Gold Inc. News Release May 14, 2012).

A July 24, 2012, resource estimate update for the Kerr deposit at 0.50 gram per tonne gold equivalent cut-off grade as follows: Measured plus Indicated - 270,400,000 tonnes grading 0.24 gram per tonne gold, 0.46 per cent copper and 1.1 grams per tonne silver; Inferred - 85,000,000 grading 0.24 gram per tonne gold, 0.28 per cent copper and 0.9 gram per tonne silver (http://www.seabridgegold.net).

In 2013, Seabridge drilled 23,822.4 metres in 29 resource definition holes totalling on the Deep Kerr zone. They also completed induced polarization and down-hole geophysical surveys.

In March 2014, an undiluted inferred resource for the Deep Kerr deposit was reported at 514.667 million tonnes grading 0.53 per cent copper, 0.36 gram per tonne gold, 1.8 grams per tonne silver and 0.003 per cent molybdenum, using a $20 per tonne cut-off grade (Lechner, M.J. (2014-03-31): NI 43-101 Technical Report on Initial Deep Kerr Resource).

In 2014, Seabridge drilled 16 resource definition holes totalling 15,909.6 metres and completed magneto-telluric and gravity geophysical surveys. Depth extension tests associated with the 2014 drilling program confirmed that the Deep Kerr Zone plunges west-northwest and continues to at least 1,350 metres below the topographic surface.

In November 2014, an updated mineral resource for the Kerr deposit was reported at 270.400 million tonnes indicated grading 0.24 gram per tonne gold, 0.46 per cent copper and 1.1 grams per tonne silver with an additional 85.000 million tonnes inferred grading 0.24 gram per tonne gold, 0.28 per cent copper and 0.9 gram per tonne silver, using a 0.50 gram per tonne gold equivalent cut-off grade (Huang, J. (2014-11-11): 2012 KSM (Kerr-Sulphurets-Mitchell) Prefeasibility Study).

In 2015, Seabridge Gold Inc. continued to expand their fully permitted KSM copper-gold porphyry deposit and identify higher average grades than those for the presently defined 2.16 billion tonnes of Reserves. 2015 was the third successful year of testing deeper, higher grade cores of the Texas Creek intrusive suite hosting the Kerr, Sulphurets and Mitchell deposits. At the Deep Kerr deposit, nine holes tested the down-dip continuity of higher copper-gold grades for zones amenable to underground block-cave mining. Results indicate the west limb of the deposit extends over 450 metres along strike and 400 metres down dip and remains open (Exploration in BC 2015, page 130).

In 2016, Seabridge Gold Inc. continued work on their KSM copper-gold porphyry deposit. Exploration drilling at Deep Kerr totalled 8,514.8 metre. Results indicate that copper-gold mineralization extends down dip of the known resources on the east and west limbs of the deposit. Mineralization defined for the Kerr deposit now extends nearly 2 kilometres along strike, and over 1.5 kilometres in vertical extent.

In 2016, Seabridge delivered two comprehensive technical reports: 1) a Preliminary Feasibility Study based on updated Mineral Reserves; and 2) a Preliminary Economic Assessment (PEA) that incorporated Inferred Mineral Resources into a conceptual project design. The PEA envisions a milling rate of 170,000 tonnes per day for the initial 20 years followed by 130,000 tonnes per day for 15 years, reduced to 77,000 tonnes per day for 12 years and finally reduced to 28,000 tonnes per day for 3 years. Total mine life would be 51 years.

On March 8, 2016, Seabridge Gold Inc. provided an updated independent mineral resource estimate for the Deep Kerr deposit at its KSM project. The deposit now contains an inferred resource of 1.01 billion tonnes grading 0.53 per cent copper and 0.35 gram per tonne. (Seabridge Gold Inc, News Release, March 8, 2016).

In October 2016, Seabridge Gold published a combined Proven and Probable Reserve for the Kerr Open Pit given as 276 million tonnes grading 0.22 gram per tonne gold, 0.43 per cent copper, 1.0 gram per tonne silver and 0.0034 per cent molybdenum (Ghaffari, H. (2016-10-06): 2016 KSM (Kerr-Sulphurets-Mitchell) Prefeasibility Study Update and Preliminary Economic Assessment).

Also at this time, a Measured and Indicated Mineral Resources at KSM are estimated at 2.9 billion tonnes grading 0.54 gram per tonne gold, 0.21 per cent copper and 2.7 grams per tonne. An additional 2.7 billion tonnes are estimated in the Inferred Resource category grading 0.35 gram per tonne gold, 0.32 per cent copper and 2.0 grams per tonne silver (Seabridge Gold Inc, News Release, October 6, 2016).

In 2017, Seabridge Gold Inc. released an updated independent mineral resource estimate for the Deep Kerr deposit at its 100-per-cent-owned KSM project. The new inferred resource now totals 1.92 billion tonnes grading 0.41 per cent copper and 0.31 gram per tonne constrained by conceptual block cave shapes (Seabridge Gold Inc, News Release, February 16, 2017). The project consists of four porphyry gold-copper deposits: Kerr, Sulphurets, Mitchell, and Iron Cap. The deposits represent what may be the largest undeveloped copper-gold camp in the world (by reserves). In 2017, Seabridge completed 10,383 metres of drilling in 11 holes at the Iron Cap deposit.

In September, 2018, 5 holes were cited to confirm mineral reserves in those areas where production would likely begin. Drill holes in the Mitchell, Sulphurets and Kerr deposits confirmed block grades comparable with model predictions (Results in Seabridge Gold Inc., News Release, Sept.24, 2018). A total of eight drill holes oriented into the margins of the Mitchell and Sulphurets deposits have been completed and an additional four holes were planned for a total of 4,919 metres. These holes were designed to test an updated block model of waste types on the margins of the deposits. Eight exploration drill holes at Iron Cap have been completed and the final five are in progress, totalling about 16,700 metres of drilling. The exploration drill program was designed to continue testing the core zone of the Iron Cap deposit down-plunge to the west. Initial indications are that the deposit approaches near vertical continuity to depth of at least 1,800 metres. Nine geotechnical drill holes have been completed during the current season, totalling 3,609 metres of drilling. The work focused on evaluating the material properties of fractures and faults on the planned pit high-walls. Results will be used to plan additional work for the Mitchell and Sulphurets deposits.

In 2018 and 2019, work by Seabridge Gold on their KSM project was focused on Iron Cap (104B 173).

In December 2019, Seabridge Gold Inc. released an updated mineral resource for the KSM project (Kerr [MINFILE 104B 191], Sulphurets [MINFILE 104B 182], Mitchell [MINFILE 104B 103] and Iron Cap [MINFILE 104B 173]) totalling 3 038 000 000 tonnes measured and indicated grading 0.52 gram per tonne gold, 2.8 grams per tonne silver, 0.21 per cent copper and 0.0048 per cent molybdenum plus an additional 4 599 000 000 tonnes inferred grading 0.38 gram per tonne gold, 2.2 grams per tonne silver, 0.32 per cent copper and 0.0029 per cent molybdenum (Threlkeld, W.E., Ghaffari, H. [2020-04-30]: KSM (Kerr-Sulphurets-Mitchell) Prefeasibility Study and Preliminary Economic Assessment Update, NI 43-101 Technical Report). For a complete summary of each deposit refer to the above cited report.

Refer to Iron Cap (104B 173), Mitchell (104B 180), Snowfield (104B 179) and West (104B 193) for related details.