Sudbury Basin holds 249,000 kilograms of platinum group metals (PGE) in the U.S. Geological Survey's world inventory, all of it recovered as a by-product of nickel and copper mining rather than as a primary PGM target. The Ontario, Canada deposit formed roughly 1.85 billion years ago, when an asteroid impact melted crust and mantle rock into the Sudbury Igneous Complex, a genesis that sets it apart from every reef or conduit-type PGE deposit on the planet. What does that impact-melt origin mean for the metal it produces? Sudbury Basin's geology, grade, metal split and the company that reports its ore follow below.
What Is Sudbury Basin?#
Sudbury Basin is an impact-melt nickel-copper-PGE deposit in Ontario, Canada, hosted by the Sudbury Igneous Complex, which has no parent intrusion of its own: it ranks as a top-level, named entry in its own right in the U.S. Geological Survey's world PGE inventory. The complex formed 1,850 ± 1 million years ago, a date from Corfu and Lightfoot (1996) cited in the USGS's Professional Paper 1802-N, when an asteroid strike melted rock into an impact sheet across an original crater roughly 130 kilometers (81 miles) across. Platinum, palladium and gold occur only as by-products of the nickel and copper sulfide ore the complex hosts, a genetic pathway distinct from the magmatic reef and conduit deposits that supply most of the world's PGE.
Sudbury's ore-forming minerals also carry a few mineralogical firsts. Sperrylite (PtAs2), the most widespread platinum mineral in the world, was first identified here and named for Francis Lewis Sperry, a chemist of Sudbury, Ontario, while michenerite (PdBiTe) and sudburyite ((Pd,Ni)Sb) both take their discovery or their name from the district, according to the Handbook of Mineralogy.
| Property | Value |
|---|---|
| Deposit type | Impact-melt complex (Sudbury Igneous Complex) |
| Host country | Canada (Ontario) |
| Parent complex/intrusion | None; Sudbury ranks as its own top-level intrusion in the USGS world inventory |
| Age | 1,850 ± 1 million years (Corfu and Lightfoot, 1996, via USGS PP 1802-N) |
| PGE+Au grade | 2.36 g/t (USGS PP 1802-N Table N10, Vale S.A. data, 2012) |
| PGE status | By-product of nickel and copper mining |
Sudbury Basin Geology and Grade#
Sudbury Basin's ore sits in four distinct structural settings around and beneath the Sudbury Igneous Complex, and grades 2.36 g/t combined platinum, palladium and gold (PGE+Au) across the properties the USGS compiled from Vale S.A. in 2012. The four deposit styles are listed below.
- Contact deposits, at the margin of the Complex, associated with footwall breccia.
- Offset dyke deposits, in radiating dykes that extend outward from the Complex.
- Footwall deposits, in Cu-Ni-PGE ore beneath the Complex, where bisulfide complexes are the documented transport mechanism that concentrated platinum, palladium and gold hydrothermally, one of the best-documented cases of hydrothermal PGE remobilization in a magmatic deposit (Wood, 2002, cited in USGS PP 1802-N).
- Sudbury breccia deposits, hosted in Sudbury breccia, a rock unit distinctive to the impact structure.
Pyrrhotite, pentlandite and chalcopyrite are the ore minerals that carry the metal, and platinum, palladium and gold ride along as by-products rather than as the mined commodity. That 2.36 g/t figure sits well below the 5 to 15 ppm grade typical of ore mined primarily for PGE elsewhere (USGS PP 1802-N), a gap that reflects Sudbury's status as a nickel and copper mine that also yields platinum group metals, not a dedicated PGM operation. The grade table below breaks out each element from the USGS's 2012 compilation.
| Element | Grade |
|---|---|
| Nickel (Ni) | 1.2% |
| Copper (Cu) | 1.5% |
| Platinum (Pt) | 0.916 g/t |
| Palladium (Pd) | 1.06 g/t |
| Gold (Au) | 0.387 g/t |
| PGE+Au total | 2.36 g/t |
| Tonnage | 110 million tonnes |
Sudbury-Vale properties, USGS PP 1802-N Table N10 (Vale S.A. data, 2012).
PGM Content and Metal Split at Sudbury Basin#
Palladium marginally outweighs platinum in Sudbury Basin's ore, at a Pd:Pt ratio of 1.16:1 derived from the USGS's Vale S.A. grade data. Of the 2.36 g/t PGE+Au grade, palladium accounts for about 44.9%, platinum 38.8% and gold 16.4% by mass, each metal's grade divided by the total. The USGS's cited dataset does not report a rhodium, ruthenium, iridium or osmium grade for Sudbury, so those four metals' shares are not established in the sources this page draws on.
That near-even split places Sudbury toward the middle of the world's PGE deposits, nowhere close to the strongly platinum-dominant Bushveld reefs or the strongly palladium-dominant Noril'sk-Talnakh ore, as the comparison below shows.
| Deposit | Pd:Pt ratio | Character |
|---|---|---|
| Merensky Reef, western Bushveld | 0.44 | Strongly platinum-dominant |
| UG2, eastern Bushveld | 0.84 | Platinum-dominant, approaching parity |
| Panton, Australia | 1.09 | Near parity |
| Sudbury Basin, Canada | 1.16 | Palladium-dominant (marginal) |
| Noril'sk-1, Russia | 2.48 | Strongly palladium-dominant |
Ratios derived from USGS PP 1802-N Table N10 grade data.
Mines and Operators at Sudbury Basin#
Vale S.A. is the operating company behind the ore grade and tonnage the USGS reports for Sudbury Basin, whose 2012 compilation draws on Vale's own property data for the deposit's 110 Mt resource base. Ore processed at Sudbury enters the same platinum group metals market that Bushveld Complex and Noril'sk-Talnakh producers supply, though Vale reports its output as nickel and copper production with platinum, palladium and gold credits rather than as a standalone PGM figure.
The four deposit styles described above correspond to different mining targets: contact ore worked at the Complex margin, offset dyke ore followed along radiating structures, footwall ore mined at depth where hydrothermal activity concentrated platinum, palladium and gold, and Sudbury breccia ore worked within the impact-related host rock. Individual mine and shaft names, current ownership shares and mining depths for each are not established in the geology reference this page draws on; readers seeking that operating detail are better served by Vale's own disclosures.
Sudbury's production history reaches back further than any other named PGE by-product source: the district supplied approximately 80% of the world's nickel in the first half of the 20th century (Prevec, 1997, cited in USGS PP 1802-N), and Canada had become the world's leading PGE producer by 1934 on the strength of that output.
That by-product status also sets the economics of the operation. The USGS classifies Canadian PGE production, alongside Russia's, as "a byproduct" of base-metal mining, in contrast with South Africa's mines, where platinum is the primary product the ore is worked for. Vale's output of platinum, palladium and gold from Sudbury therefore rises and falls with its nickel and copper mine plans and with nickel and copper prices, not with the platinum or palladium price on its own, a structural difference from every Bushveld or Great Dyke operator named elsewhere on this site.
Resources and Reserves at Sudbury Basin#
Sudbury Basin holds 110 million tonnes of Ni-Cu-PGE ore at 2.36 g/t PGE+Au in the USGS's 2012 compilation of Vale S.A.'s reported properties, the same assessment year behind every grade figure on this page. The USGS's separate district-wide ranking of the world's 14 largest PGE-holding intrusions lists the Sudbury Complex slightly differently, at 105 Mt for the same 2.36 g/t grade, containing 249,000 kilograms of PGE, or 0.24% of world identified PGE resources.
That 0.24% share puts Sudbury 11th among the 14 intrusions that together hold more than 97% of the world's identified PGE resources, a list topped by the Bushveld Complex at 73%. World PGE resources sit in a long tail: the top 10% of deposits hold more than 80% of the total, and the bottom half hold less than 1% between them (USGS PP 1802-N), which places Sudbury as a minor but still ranked source rather than an unranked, negligible one. The table below sets Sudbury's resource inventory against that USGS-ranked context.
| Measure | Value |
|---|---|
| Vale-reported properties (Table N10) | 110 Mt at 2.36 g/t PGE+Au |
| District-wide inventory (Table N5) | 105 Mt at 2.36 g/t PGE+Au |
| Contained PGE | 249,000 kg |
| Share of world identified PGE resources | 0.24% |
| World rank among 14 major PGE intrusions | 11th of 14 |
USGS Professional Paper 1802-N, Tables N5 and N10, resources as of 2012.
No newer, company-specific resource or reserve statement for Sudbury is cited in the reference this page draws on, so the 2012 USGS assessment is the only dated figure this page states.
Where This Page Stops#
This page reports Sudbury Basin's PGM geology, grade and by-product mining economics, not the impact-crater science, meteorite history or district tourism that dominate general search results for the name. Craterexplorer.ca, NASA's Sudbury Impact Structure page and Northern Ontario tourism coverage answer questions about the crater itself. This page carries no investment advice, share-price target or stock recommendation on Vale, and no salary or hiring commentary on Sudbury mining jobs.
Other PGM Deposits#
Sudbury Basin is one of just 14 intrusions that together hold more than 97% of the world's identified PGE resources, a list it shares with Canada's other major PGE source, Lac des Iles. The deposits below span three deposit types and four countries, each with its share of world resources from the same USGS assessment.
| Deposit | Country | Deposit type | Contained PGE | Share of world total |
|---|---|---|---|---|
| Bushveld Complex | South Africa | Contact and reef | 75,200,000 kg | 73% |
| Noril'sk-Talnakh | Russia | Conduit | 10,100,000 kg | 10% |
| Stillwater Complex | USA (Montana) | Reef (sulfide) | 2,240,000 kg | 2.2% |
| Sudbury Basin | Canada | Impact-melt | 249,000 kg | 0.24% |
| Lac des Iles | Canada | Atypical, pipe-like | 207,000 kg | 0.20% |
USGS Professional Paper 1802-N, Table N5, resources as of 2012.
Frequently Asked Questions#
Where is the Sudbury Basin? Sudbury Basin sits in Ontario, Canada, within the Sudbury Igneous Complex that gives the district its name. The complex formed 1,850 ± 1 million years ago, dated by Corfu and Lightfoot (1996) and cited in the USGS's Professional Paper 1802-N.
Why is there so much nickel in Sudbury? Nickel, copper and platinum group metals concentrate at Sudbury because the district is an impact-melt sheet. An asteroid strike roughly 1.849 billion years ago melted crust and mantle rock into a sheet in which pyrrhotite, pentlandite and chalcopyrite crystallized, the sulfide minerals that carry the metal.
Was Sudbury hit by a meteor? Yes. The Sudbury Igneous Complex formed from an asteroid impact approximately 1.849 billion years ago that left an original crater roughly 130 kilometers across, dated by Corfu and Lightfoot (1996) and cited in the USGS's Professional Paper 1802-N.