Seabridge Gold’s FAT (felsic ash tuff) deposit in the Courageous Lake Greenstone Belt (CLGB) is a rare example of a well-preserved epithermal gold system in Archean rocks. CLGB is one of several Archean greenstone belts in the Slave Province. This greenstone belt is part of the Yellowknife Supergroup of the Central Slave Province, NWT, that contains large gold deposits like the past producing Giant, Con, Lupin and Salmita mines. The CLGB is made up of cyclical volcanic eruptions that formed an 1800m thick succession of mafic flows that gave way to a discrete rhyolite tuff series and is host to the FAT deposit. This volcanic stratigraphy is overlain by a thick turbidite sedimentary package.  Multiple metamorphic events have affected the CLGB, tilting the strata to near vertical and producing a mid-greenschist metamorphic mineral assemblage. 

Felsic volcanic textures of the rocks within the FAT deposit are well preserved, generally representing sub-aerial lapilli tuff and ash tuff laid down during eruptions. Placed between the eruptive events are aqueously reworked volcanoclastic beds.  There are eight recognized eruptions forming the felsic volcanic pile that is host to the FAT deposit.  At the top of several discrete eruptions are well developed, stratabound chert beds that contain most of the gold-arsenopyrite mineralization.  Mineralized volcanic units stretch north-south for about 2,000m. Overall thickness of the volcanic zone is 920m with individual mineral zones between 30m and 65m wide.  Drilling has evaluated the mineral system vertically to about 650m.  Narrow shear structures cut the stratigraphy at an acute angle, remobilizing and redepositing the gold-arsenopyrite.  The FAT deposit is refractory with most of the gold found as small inclusions within the arsenopyrite.

The scientific and technical information in respect of the KSM Project herein was derived from the technical Report entitled KSM (Kerr – Sulphurets – Mitchell) Prefeasibility Study and Preliminary Economic Assessment dated effective August 8, 2022. This information was prepared by leading consulting firms and their Qualified Persons (as defined in NI 43-101), all of who are independent of Seabridge and are listed below along with their areas of responsibility:
(i) Tetra Tech, Inc. under the direction of Hassan Ghaffari P.Eng (surface infrastructure, capital estimate and financial analysis), John Huang P.Eng. (metallurgical testing review, permanent water treatment, mineral process design and operating cost estimation for process, general and administrative (“G&A”) and site services, and overall report preparation)
(ii) Wood Canada Limited, under the direction of Henry Kim P.Geo. (Mineral Resources)
(iii) Moose Mountain Technical Services under the direction of Jim Gray P.Eng. (open pit Mineral Reserves, open pit mining operations, mine capital and mine operating costs, MTT and rail ore conveyance design, tunnel capital costs)
(iv) N. Brazier Associates Inc. under the direction of W.N. Brazier P.Eng. (Electrical power supply, energy recovery plants)
(v) ERM Consultants Canada Ltd. under the direction of Rolf Schmitt P.Geo. (environment and permitting)
(vi) Klohn Crippen Berger Ltd. under the direction of David Willms P.Eng (design of surface water diversions, diversion tunnels, tailing management facility, water treatment dam and RSF and tunnel geotechnical)
(vii) BGC Engineering Inc. under the direction of Derek Kinakin P.Geo., P.L.Eng., P.G. (rock mechanics, geohazards and mining pit slopes)
(viii) WSP Golder Inc., under the direction of Ross Hammett P.Eng (Block Cave mining)