Mining Intelligence and News

KSM Project

Click for more information



Mine TypeOpen Pit
  • Gold
  • Copper
  • Silver
  • Molybdenum
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
SnapshotThe Kerr-Sulphurets-Mitchell (KSM) is the world's largest undeveloped project by gold and copper resources.

The KSM mine development has been evaluated as a Prefeasibility Study (2022 PFS) using open pit mining of the Mitchell, East Mitchell and Sulphurets deposits. A Preliminary Economic Assessment (2022 PEA) is a stand-alone mine plan that has been undertaken to evaluate a potential future expansion of the KSM mine to the Iron Cap and Kerr deposits after the 2022 PFS mine plan has been completed.


Seabridge Gold Inc. 100 % Indirect
All claims and leases are in good standing under the Mining Tenure Act of BC and are recorded as owned 100% by KSMCo.

KSM Mining ULC (KSMCo) is a wholly owned subsidiary of Seabridge Gold Inc.



- subscription is required.

Deposit type

  • Porphyry


The KSM deposits display many diagnostic features of porphyry Cu ± Au ± Mo systems. The deposits are centered on intrusive complexes composed of Early Jurassic, Texas Creek suite porphyry stocks and dykes. The Kerr, Mitchell, East Mitchell, and Iron Cap zones display the typical lateral and vertical zoning sequence of alteration assemblages observed in many porphyry systems: deep central potassic alteration, peripheral propylitic alteration, and shallow sericitic alteration. Mineralization is associated with stockwork quartz veinlets and arrays of sheeted quartz veinlets, with vein density decreasing in later intrusive phases. Host rocks may be mineralized for up to several hundred meters from the intrusions. The Kerr, Mitchell, and East Mitchell zones also feature small remnants of advanced argillic alteration. The structurally complex Sulphurets deposit does not feature the same clear alteration zoning patterns observed at the other three deposits, due to its dismembered and fragmental nature. However, the Lower Panel fault block at Sulphurets, which hosts the bulk of the mineralization, features potassic alteration and mineralization typical of porphyry Cu ± Au ± Mo systems.

KerrR Zone
The Kerr Zone is centered on an Early Jurassic, north-south trending, steep westerly dipping, tabular intrusive complex. Drilling demonstrates that the Kerr Zone has an extent of 2,400 m along strike, a width of roughly 800 m, and a vertical extent of at least 2,200 m. The flattened and elongated modern morphology of Kerr is highly unusual for porphyry copper-gold deposits, which typically display roughly cylindrical morphologies. The flattened morphology and relatively elevated copper:gold ratio of the Kerr Zone distinguishes Kerr from the other deposits in the district. The surface expression of the Kerr deposit is a large and elongated, northerly trending, pyritic gossan, primarily exposed in a cirque on the northern flank of Kerr peak.

The Kerr intrusive complex is composed of a suite of northerly-striking and steeply westdipping dykes and intrusions emplaced into a sequence of rhythmically bedded siltstones, sandstones, conglomerates, and debris flows belonging to the Lower Jurassic Hazelton Group. Wall rocks adjacent to the intrusions have been hornfelsed and hydrothermally altered, but generally contain marginal metal grades. The complex is composed of an east and west limb separated by a thin wedge of intensely altered sedimentary wall rock. The west limb is up to 500 m thick, and the east limb is up to 300 m thick.

The dominant copper mineral is chalcopyrite, which typically occurs as isolated grains about 0.2 mm to 2 mm 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 QABX zone containing >50% crackled quartz veins, and is accompanied by coarse grained chalcopyrite and minor tennantite. Tennantite-tetrahedrite is rare, but widely distributed in late quartz-carbonate veins, mostly in wall rocks, along with minor sphalerite, rare galena, and arsenopyrite. 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.

Sulphurets Zone
The Sulphurets Zone is situated between the Kerr and Mitchell deposits, immediately to the north of the valley hosting Sulphurets Lake. The main body of the Sulphurets deposit has a lensoidal geometry, dipping approximately 30 degrees northwest. It has a horizontal extent of 2,200 m, down dip extent of 550 m, and true thickness of up to 330 m. Copper and gold grades gradually diminish towards the limits of the known resource area, but the extent of anomalous copper and gold grades has not been completely delineated down dip or in the southwest direction.

Sulphurets is a structurally complex deposit, intersected by numerous east-vergent faults associated with the mid-Cretaceous Skeena fold and thrust belt. The deposit is composed of stacked thrust fault panels made up of Upper Triassic Stuhini Group and Lower Jurassic Hazelton Group volcano-sedimentary strata intruded by several dykes and stocks.

Late, discontinuous veins, breccias, shear fillings, and patchy replacements similar to those in the Upper Panel occur throughout the Lower Panel fault block. A higher density of these late mineralized structures is reflected in average arsenic, lead, antimony and zinc concentrations being roughly two to three times those of the Upper Panel. Scattered, sub-meter to centimeter scale quartz and sulphide veins, breccia veins, shear fillings, patchy discontinuous clots or replacements and disseminations occur in all rock types except late dykes, but are most abundant in brecciated and crackled zones. They include coarse pyrite, carbonate, chlorite, quartz, occasionally with minor chalcopyrite, sphalerite, arsenopyrite or galena, and traces of tennantite. Native gold is rare but has been observed as sub-millimeter blebs and stringers in quartz-carbonate-sulphide veins, and chlorite-pyrite-carbonate breccia matrix fillings.

A small number of very thin, volumetrically insignificant post-mineral dykes with meterscale widths cut all other lithologies at Sulphurets. These include northwesterly-dipping, fine-grained diabase dykes with aphanitic chilled margins and pervasive chlorite alteration, and two fine-grained, unaltered, black lamprophyre dykes dipping westnorthwest. Similar post-mineral dyke sets are observed in the Kerr, Mitchell, and Iron Cap zones.

Mitchell Zone
The Mitchell Zone represents the footwall portion of an Early Jurassic gold-coppermolybdenum porphyry deposit that was cleaved in two by the MTF during the midCretaceous. The upper portion of the deposit, termed the East Mitchell Zone, was transposed approximately 1,600 m towards the east southeast during the development of the Skeena fold and thrust belt.

The Mitchell Zone crops out in Mitchell Valley, through an erosional window exposing the footwall of the MTF. The zone is a roughly cylindrical gold-copper-molybdenum deposit, dipping ~60° to the northwest, with approximate true dimensions of 1,600 m in strike, 1,500 m down dip, and up to 850 m in thickness. It remains open down dip and along strike to the northeast at depth. Recent glacial melt back has provided exceptional surface exposure of a gold-coppermolybdenum porphyry system. A zone of intense quartz and sulphide veining (“Sheeted Quartz Vein Zone”) forms resistant bluffs in Mitchell Valley. However, the higher-grade core area is mostly covered by talus and moraine west of the bluffs. Active oxidation and leaching of sulphides has produced prominent gossans and extensive copper sulphate precipitates at the surface.

The Mitchell deposit features many characteristics typical of gold-enriched calc-alkaline porphyry copper deposits: calc-alkaline syn-mineral intrusions; hydrothermal alteration assemblages that include deep potassic, peripheral propylitic, and extensive shallow sericitic alteration; and abundant quartz veining. Metals, chiefly gold and copper (in terms of economic value), are generally at low concentrations, finely disseminated, stockwork or sheeted veinlet controlled, and pervasively dispersed over dimensions of hundreds of metres. Grades diminish slowly over large distances; sub-economic grades are encountered at distances of several hundreds of metres beyond the interpreted centre of the system. This is distinct from the Sulphurets and Kerr zones, where there are more abrupt breaks in grade due to higher structural complexity and juxtaposition of weak and moderate grade domains by faulting, both syn-mineral structures controlling breccia contacts, and post-mineral faulting and displacements.

East Mitchell Zone
The East Mitchell Zone, found in the hanging wall of the MTF, is the displaced upper portion of the Mitche



- subscription is required.

Mining Methods


- subscription is required.


Crushers and Mills


- subscription is required.



- subscription is required.


CommodityProductUnitsAvg. AnnualLOM
Gold Metal in conc./ doré koz 1,02733,900
Gold Metal in doré koz 10,521
Copper Metal in concentrate M lbs 1785,872
Silver Metal in conc./ doré koz 2,96697,890
Silver Metal in doré koz 33,195
Molybdenum Metal in concentrate M lbs 4.2140
Molybdenum Concentrate kt 127
Copper-Gold Concentrate kt 11,180

Operational metrics

Daily ore mining rate  ....  Subscribe
Daily processing rate  ....  Subscribe
Annual processing rate  ....  Subscribe
Stripping / waste ratio  ....  Subscribe
Ore tonnes mined  ....  Subscribe
Waste tonnes, LOM  ....  Subscribe
Total tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2022 study.

Production Costs

Cash costs Gold USD  ....  Subscribe
All-in costs Gold USD  ....  Subscribe
Assumed price Molybdenum USD  ....  Subscribe
Assumed price Copper USD  ....  Subscribe
Assumed price Silver USD  ....  Subscribe
Assumed price Gold USD  ....  Subscribe
* According to 2022 study / presentation.
** Net of By-Product.

Operating Costs

OP mining costs ($/t milled) USD 3.31 *  
Processing costs ($/t milled) USD  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2022 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
Total OpEx $M USD  ......  Subscribe
Income Taxes $M USD  ......  Subscribe
Mining Taxes $M USD  ......  Subscribe
Total Taxes $M USD  ......  Subscribe
Royalty payments $M USD  ......  Subscribe
Gross revenue (LOM) $M USD  ......  Subscribe
Net revenue (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
Pre-tax NPV @ 5% $M USD  ......  Subscribe
Pre-tax NPV @ 8% $M USD  ......  Subscribe
After-tax NPV @ 5% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe
Pre-tax payback period, years  ......  Subscribe
After-tax payback period, years  ......  Subscribe

Required Heavy Mobile Equipment


- subscription is required.


Mine Management

Job TitleNamePhoneProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Aug 8, 2022
....................... Subscription required ....................... Subscription required ........... Subscription required Aug 8, 2022
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2024

Total WorkforceYear
...... Subscription required 2022


- subscription is required.