Though nowhere near last year’s record highs, palladium is still trading at three times the historical range, and that bodes well for a group of companies exploring for platinum-group-metal (PGM) deposits near Sudbury, Ont.
Exploration in the region came to a head in mid-1999, when
River Valley covers the northwestern margin of the layered magmatic intrusion after which it is named. The intrusion is one of several in the so-called Huronian-Nipissing magmatic belt, a 200-km-long arcuate corridor of Proterozoic-aged intrusive bodies and related volcanics.
Most of the activity in the Sudbury region (or, for that matter, throughout northern Ontario) is focused on the anorthositic-gabbroic intrusions of the belt, of which River Valley is one. A lesser effort is being spent on the younger Nipissing gabbro, though both ages of rocks are known to carry platinum and palladium.
Generally, companies are confining their search to the margins of the intrusions, where palladium appears to be enriched relative to platinum. For example, Amplats and Pacific North West outlined two near-surface deposits at River Valley hosting a combined 12.7 million tonnes grading 1.04 grams palladium and 0.35 gram platinum per tonne, plus gold, nickel and copper.
The in situ resource remains open in several directions, prompting Amplats set the 2002 exploration budget at $2.3 million. Drilling got under way last fall, with 20,000 metres planned in all.
Drilling is primarily focusing on the Dana Lake and Lismer’s Ridge zones, which host current resources. The former, which sits 2 km northwest of the latter, is more defined, though both show similar spatial and mineralogical characteristics.
Amplats can increase its interest to 60% by funding all exploration required to complete a feasibility study and to 65% by financing the project to production.
Last summer, Amplats broadened the original agreement to include the Agnew Lake property, southwest of Sudbury. The property covers most of the Shakespeare-Dunlop anorthositic-gabbroic intrusion and had been explored by Pacific North West under an option agreement with
To earn a 49.5% stake, Amplats must spend $6 million on exploration over three years. It can increase this to 57% by tabling a positive feasibility study and to 60% by carrying its partners through to production. Pacific North West and New Millennium would each be left with a 19.5% participating interest, with the remaining 1% reserved for the underlying property vendor.
As at River Valley, exploration at Agnew Lake is focused along the intrusion’s margin, along which sampling has returned up to 8.4 grams combined platinum and palladium in magmatic breccias. The geological setting is said to be comparable to Dana Lake and Lismer’s Ridge.
A $1.2-million program that includes drilling got under way last August. No results have been released yet.
Not far from Agnew Lake,
Recently, Ursa sank two holes in surface showings of a sill. Both intersected anomalous platinum and palladium near the intrusion’s base, with a best result of 1.7 grams palladium, 0.16 gram and 0.09 gram gold over half a metre.
Shakespeare
No further exploration is planned here, but the high palladium tenor leaves Ursa hopeful for its adjacent Shakespeare property. Last fall, Ursa found several sub-angular boulders that ran up to 1.02% copper and 0.46% nickel but just 0.67 gram palladium and 0.48 gram platinum. The boulders lie 450 km southwest of the western end of the historic, low-grade Shakespeare deposit and coincide with an induced-polarization anomaly.
Falconbridge discovered the Shakespeare deposit several decades ago but considered it too low-grade to warrant follow-up work. Inferred resources stand at 1.9 million tonnes averaging 0.36% nickel, 0.42% copper, 0.44 gram palladium, 0.4 gram platinum and 0.23 gram gold.
Ursa plans to raise $2 million by June through a private placement, after which exploration will begin. The junior must raise that amount to complete a separate agreement whereby it can acquire several PGM properties in Wyoming and Minnesota.
The Minnesota property is in the Duluth complex, adjacent to the Birch Lake project, which is being explored by Impala Platinum (IMPAY-Q). The major can earn a 60% interest from the underlying vendors by spending US$5 million over five years.
Meanwhile, back at the River Valley intrusion, partners
The olivine gabbronorite layer has been traced by geochemical sampling and drilling for 1.2 km. So far, mineralization appears to be enriched in this layer, running up to 5 grams palladium and 3 grams platinum over narrow intervals.
Mustang owns more than 28 km of the intrusions’s northern and southern margins. Impala can acquire a 60% interest by spending $6 million on exploration over five years.
Mustang has also renewed drilling at the East Bull Lake intrusion, which lies due north of Shakespeare-Dunlop and is similar in composition. The junior controls more than 90% of the intrusion and has granted
East Bull Lake is the largest intrusion in the Huronian-Nipissing belt. Earlier work there was carried out by
Trenching
Recently, Mustang and Falconbridge dug 17 trenches to expose more than 1,000 metres of bedrock and extract 1,036 channel samples. The best results came from the Kid, Central and Parisien showings, each of which extends for more than 1 km and remains open.
The best results at Kidd were 4 metres averaging 2.43 grams combined platinum, palladium and gold, 7 metres averaging 1.81 grams, and 24 metres grading 1.05 grams. Several higher-grading sub-intervals are noted.
The Central zone yielded the best results of all three, with 15.7 metres grading 1.92 grams, 15 metres grading 1.62 grams and 24 metres grading 1.01 grams. Again, each section is enriched in places.
Results from the Parisien zone include 0.84 gram over 21 metres, including 1.36 grams over 6 metres.
Drilling is set to begin shortly and will mainly target the Central showing.
Falconbridge can earn its half-stake by covering $5 million worth of exploration over four years. Of that, $1 million must be spent by the fall.
Meanwhile, in the Sudbury basin itself, South African-based
This is the first time a company of Lonmin’s size — the company is the Western World’s third-largest platinum producer, after Anglo and Impala — has got a toehold in a basin long monopolized by Falconbridge and Inco.
The agreement requires Lonmin to provide US$4.5 million for exploration over the next two years, followed by US$1 million in annual expenditures thereafter. Once a resource has been established on a property, Lonmin can vest a 50% interest and become the project’s operator.
As part of the agreement, Lonmin can increase its intere
st in any property to 65% by tabling a feasibility study. Should the major advance the project to production, it must share the ensuing cash flows with Wallbridge on a 65-35 basis.
Like Amplats and Impala, Lonmin pulls its metals from the famous Bushveld igneous complex. Production in the complex accounts for two-thirds of the world’s platinum supply and a significant portion of its palladium supply.
Other newcomers to the Sudbury complex include partners
Fort Knox
Earlier this year, Inco granted Fort Knox the right to earn 100% interests in the properties by spending $14 million over the next 16 months and another $16 million by 2006. The junior subsequently teamed up with Dynatec, which will cover half of the first tranche of exploration expenditures and 25% of the rest.
Under terms of their agreement, Fort Knox is managing exploration while Dynatec assumes development and mining responsibilities. All of the properties were formerly mined by Inco and are thus considered highly prospective for new discoveries or extensions of mined-out deposits.
Inco retains a right of first refusal if any property is sold and can re-acquire a 51% interest in any new discovery containing more than 2,723 tonnes nickel. The major also retains processing rights, or, in the event of third-party processing, can elect to receive a 2% net smelter return royalty for nickel, copper and cobalt and a 2.5-5% NSR for precious metals.
Be the first to comment on "Sudbury PGM play enters new phase"