Vancouver — The lacklustre performance of most traditional metals has induced several junior companies to begin exploring for tantalum in earnest.
Global demand for tantalum has accelerated dramatically over the past few years, hitting 2,200 tonnes in 2000. The major producers are Western Australia, Brazil, Ethiopia, Canada, and several countries in Eastern and Central Africa.
Fuelling the increased demand is growth in the electronics industry. Demand for the miniaturization of electronic goods with more complex circuitry has led to a greater reliance on the efficiency of tantalum capacitors. The growth in the consumption rate of integrated circuits has averaged 12% per year over the past eight years, and demand for tantalum and ceramic capacitors averaged 34% in the same period.
According to UK-based Roskill Information Services, demand for tantalum has grown by an average of 10% per year since 1992, and this trend is expected to continue for the next few years. A study by NRJ Investment Group compares tantalum and copper prices between 1955 and 1993, and demonstrates that tantalum is two to 10 times more volatile than copper. The volatility is a result both of the metal’s rarity and its erratic supply.
It is believed that, if a predictable supply of tantalum were put into place, tantalum usage would increase and tantalum pricing would gradually stabilize.
Prices for tantalum rose to about US$150 in 2000 from US$3.40 per lb. in 1955. In early 2001, spot prices reached a peak of US$454 per lb., with long-term contracts negotiated between US$110 and US$140 per lb. Since then, prices have drifted down because of slackening of demand and a slowing economy. Recent spot prices were quoted at US$40 per lb. Ta2O5.
Tantalum is not traded on any organized market, so there is no way to get reliable price quotes. The most common quotes are based on the Ta2O5 content of a mineral concentrate, and these are quoted in U.S. dollars per pound of Ta2O5 contained in the concentrate. (Note: Ta2O5 is about 80% Ta by weight.) The market quote is usually for a concentrate with at least 60% contained Ta2O5.
Tantalum, is a good conductor of heat and electricity. It is also resistant to corrosion by acids and has a high melting point of about 3,000C. Tantalum is used primarily in the production of electronic components, especially tantalum capacitors. Applications include portable telephones, pagers, computers, instruments and controls for aircraft, missiles, ships, and weapons systems. When alloyed with other metals, tantalum is used to produce super-alloys for aerospace structures, jet engines and carbide tools. Its corrosion-resistant properties make it ideal for use in the chemical industry, where applications include heat exchangers, condensers, pumps, and liners for tanks and reactors. Tantalum is also bio-compatible and is used in implant materials for humans.
There are five geological types of tantalum deposits: granitic pegmatites; “acidic” (lithium-fluorine) granites; alkaline granites and metasomatites; carbonatites; and placer deposits.
Rare metal granitic pegmatites are traditionally the main source of tantalum ores in the Western World. Grades of Ta2O5 in economic pegmatitic deposits vary from 200 to 2200 grams per tonne (commonly 300-600 grams per tonne).
Acidic lithium-fluorine granites are a major source of tantalum in Russia and China. These deposits host economic concentrations of tantalum, beryllium, lithium and tin, as well as fluorine and other industrial and ceramic raw material. Grades of Ta2O5 in the best deposits average 120-300 grams per tonne.
Alkaline Granites and metasomatite-type deposits are typically large bodies of syenite that were subjected to cracking. As a result, trapped fluids were allowed to permeate the intrusive body. These late fluids can be rich in concentrated rare metal minerals, including tantalum, forming either pegmatite-like bodies within the syenite or a host body enriched in the rare metal minerals.
Carbonatites are igneous rocks composed of more than 50% carbonate minerals and are generally exploited for rare earth elements, niobium, vermiculite, fluorite, iron, copper and phosphate. Only about 20% of the known carbonatites contain economic concentrations of tantalum, and, to date, no pyrochlore-bearing carbonatite sources of tantalum have been developed. Pyrochlore can contain radioactive isotopes of thorium-232 and uranium-238.
Tantalum exists exclusively as an oxide, Ta2O5, known as tantalum pentoxide. Although tantalum can be extracted as a byproduct from the melting of cassiterite, SnO2, or from columbite (Fe, Mn)(Nb, Ta)2O6, the primary source is commercially mined tantalum ores, the principle mineral of which is tantalite. The quality of ore varies among regions in terms of Ta2O5 concentration and the level of specific impurities. Both these factors can influence the ore benefication costs.
At present, world tantalum production is dominated by the Wodgina and Greenbushes mines in Australia. These mines, owned by Australian-based Sons of Gwalia, are classified as pegmatite deposits; they produce about a quarter of the world’s tantalum. The Greenbushes operation hosts total reserves (proven and probable) of 27 million tonnes grading 298 grams Ta2O5 per tonne, and Wodgina hosts total reserves of 27 million tonnes grading 420 grams Ta2O5 per tonne.
The only operating tantalum mine in Canada is Tanco (Tantalum Mining Corporation of Canada), which is 180 km northeast of Winnipeg. Tanco is owned by U.S.-based Cabot Corp., which does not report reserve or production statistics. The preproduction tantalum reserves for the deposit are believed to be 2.1 million tons grading 0.216% Ta2O5.
Tantalum exploration
At Thor Lake, Navigator has entered into an option agreement with Calgary-based
Thor Lake is 100 km southeast of Yellowknife. Previous work by Placer Development on the Lake zone outlined a preliminary resource of 63.5 million tonnes grading 0.03% Ta2O5 and 0.4% Nb2O5. Thor lake represents an “alkali-syenite” body.
The tantalum mineralization was found to be relatively fine-grained and could not be concentrated by gravity separation techniques. Navigator is investigating the possibility of producing salable-grade tantalum concentrates, as well as achieving good recoveries from newly developed mineral flotation processes.
Recently, the junior collected a 300-kg metallurgical sample from archived drill core on the Lake zone and sent it to Lakefield Research for testing. Results are expected shortly. The overall head grade of the composite sample derived from the drill holes was 0.05% Ta2O5.
Navigator stands to earn a 75% interest in seven tantalum projects in the Yellowknife-Hearne Channel area from New York, N.Y.-based G&S Trading. Navigator is required to spend $3 million on the properties by 2005.
726 ppm
The prospects (encompassing more than 4,800 hectares) cover tantalum occurrences in pegmatite dykes that were discovered in the 1940s. Only limited exploration has been performed since the 1950s.
The focus of this year’s exploration program was the collection of more then 4,000 samples. As a result, three new tantalum-bearing pegmatites were discovered. The best result to date from these new discoveries averaged 726 parts per million tantalum from a grab sample (0.088% Ta2O5). In addition, the sampling results suggest that the properties may host other unexposed pegmatites with the potential for tantalum mineralization.
In June,
or before Dec. 1, 2003. Chapleau can increase its stake to 60% by spending an additional US$500,000 by 2004. The underlying vendor is entitled to receive a 5% net smelter return royalty (NSR) at the start of commercial production.
In the early 1980s, Ananconda Mineral Co. explored the Kougarok property for its tin potential. The company spent US$5.5 million on exploration, including 1,100 metres of bulldozer trenching and about 10,000 metres of diamond drilling. The effort was ceased in the mid-1980s as a result of low tin prices. Previous trenching and diamond drilling suggest a resource of 217,000 tonnes grading 1.4% tin and 99,000 tonnes grading 2.3% tin.
The 55-sq-km property is in the north-central Seward Peninsula, 112 km north-northeast of Nome.
A paved road extends from Nome to within 50 km of the property. A 1-km-long airstrip on site can accommodate multi-engine aircraft.
Main Plug
Geologically, the Kougarok property contains a large magmatic-hydrothermal system that contains tantalum-tin mineralized greisens within a fluorine-lithium granite. The main mineralized system, dubbed the Main Plug, has been defined geologically and geochemically over a surface area of 1.2 by 1 km. Based on previous drilling, it is a flat-lying body of granite measuring 100-150 metres thick and lies at a depth of 200-400 metres below surface.
Chapleau and Navigator are exploring the property, having already check-assayed archived drill core and performed rock geochemical sampling and limited prospecting. Recently, the partners discovered the Hill Top showing in a previously unmapped area. Grab samples of this material returned results that ranged from 218 to 341 grams Ta2O5.
The partners believe that the Hill Top showing — 500 metres east of, and 145 metres above, Anaconda’s chief drill target, the Main Plug — may represent a significant, near-surface target for tantalum mineralization. Follow-up trenching is planned. Seven grab samples were taken from the Hill Top showing, three of which returned high tantalum pentoxide values of 218 grams, 238 grams and 341 grams per tonne.
Check assays of archived drill core confirmed the widespread occurrence of tantalum mineralization around the Main Plug area. Sample results from three of the better drill holes include: 67.1 metres grading 0.025% Ta2O5; 52 metres of 0.022% Ta2O5, and 27.4 metres of 0.026% Ta2O5.
The 45-sq.-km Mac property features a tantalum prospect that is associated with a lithium-rich, albite-spodumene dyke complex, referred to as the Little Nahanni Pegmatite group. These granitic bodies are of economic interest for their tantalum and tin content, as well as for spodumene, a high-grade lithium-bearing mineral. Previous exploration focused on the area’s lithium potential.
The road-accessible property is 250 km north of Watson Lake, B.C., in the Northwest Territories, near the Yukon border. The Cantung mine and mill facility are roughly 45 km from the central portion of the claim block. All-weather and winter roads, which service the Cantung mine as well as the Howards Pass lead-zinc deposit, pass within a few kilometres of the claim block.
The Little Nahanni Pegmatite group hosts numerous individual dykes and dyke concentrations that are exposed over a northwesterly trending belt that strikes for 12 km and is 2.5 km wide. Mapping has identified six steeply dipping, northwest-trending, dyke swarms that range from 40 to 500 metres in width and are individually traceable for up to 5 km along strike. The dyke swarms generally show good continuity, and War Eagle states that individual dykes often merge along strike or downdip.
Enhanced grades
The company’s first phase of exploration identified two broad areas within the dyke complex that contain enhanced grades of tantalum and tin. Lithium, tin and tantalum mineralization can be found in all of the pegmatite dykes; however, the central portion of the complex hosts more lithium-rich dykes. War Eagle has discovered that the northern and southern parts of the complex appear to have higher concentrations of tin and tantalum.
A chip sample from a 0.27-metre talus block on the northern portion of the complex returned 1,023 grams Ta2O5 per tonne and an excess of 0.8% tin.
A channel sample that was sourced from the “Climbing Wall” dyke swarm, on the southern part of the dyke complex, returned 200 grams Ta2O5 and 0.07% tin across a true width of 6 metres. War Eagle says the sample was taken near the plateau of the local ridge and that there may be more than 300 metres of vertical relief on this dyke.
Some higher-grade tantalum and tin assays from mineralized float samples in the central part of the dyke system include: 526 grams Ta2O5 and 2% tin; 720 grams Ta2O5 and 1.88% tin; 768 grams Ta2O5 and 2.15% tin; and 800 grams Ta2O5 and 1.82% tin. In total, 270 samples were taken and sent to ALS Chemex in North Vancouver for analysis. Results are pending.
Next year, War Eagle will drill targets in the anomalous areas that were discovered in 2001.
The property is 75 km east of Cochrane, Ont., and Platinova stands to earn a 100% interest in it from a private company by making cash payments totalling $219,000, issuing 700,000 special shares and spending $500,000 on exploration by the end of 2003. The property is subject to a 2% NSR.
The tantalum-bearing zones on the property are hosted in two pegmatite dykes that occur within a large granitic body. These dykes have been tested over a strike length of 150 metres and to a maximum depth of 70 metres. All zones remain open along strike and downdip.
North dyke
The North dyke measures up to 10 metres wide and has been traced on surface for 110 metres. The Main dyke measures up to 30 metres wide and has been traced on surface for more than 300 metres. Both dykes have barren quartz-rich cores which measure up to 10 metres in the Main dyke and 2 metres in the North dyke. The two bodies are separated by 15-20 metres of granite and extend in both directions under the overburden.
This year, Platinova conducted surface mapping and channel sampling, as well as diamond drilling. Results returned an average grade of 0.024% Ta2O5 over 8.8 metres in the Main dyke (this is the weighted average of three channel samples and seven drill cores over 8.8 metres of mineralizaton). The barren zone was excluded from the average.
The North dyke was tested by two channel samples and five drill holes. These samples extended over 120 metres of strike and to a depth of 35 metres below the surface. The grade of mineralized intersections varies from 0.011% Ta2O5 over 1 metre to 0.032% over 7.7 metres. The average of all the mineralized intersections from the North Dyke is 0.035% Ta2O5 over an average of 4.5 metres.
Platinova is now performing metallurgical tests on the pegmatite. If these are positive, the company will carry out definition drilling.
At the Lamaune property, north of Lake Nipigon in northwestern Ontario, Platinova kicked off a program of prospecting and sampling. The company tested a shallow-dipping pegmatite dyke. Twelve grab samples from outcrop and 35 float samples were collected and analyzed. The average value for the outcrop samples was 0.021% Ta2O5, whereas the overall average for the 47 samples was 0.012% Ta2O5. Platinova plans to drill the property later this year. The junior can earn a 100% interest in the property from the vendors, subject to a 2% NSR, through payments totalling $70,000 and the issuance of 200,000 special shares by October 2004.
Platinova can acquire a 75% interest in the
Zigzag property from
The property is 15 km west of Platinova’s Lamaune project and is in the Falcon Lake pegmatite trend. Previous work identified five sub-parallel pegmatites that measured 5-20 metres in width and were exposed over a strike length of 800 metres. Trench samples returned values of 0.37% Ta2O5 over 1 metre, 0.21% Ta2O5 over 2.5 metres and 0.05% Ta2O5 over 8.5 metres.
Commerce Res.
Commerce intends to delineate the grade and tonnage of available tantalum, niobium and phosphate deposits within the Verity-Paradise carbonatite complex, as well as the Fir Carbonatite. The carbonatites are well-situated with respect to railway, roads and power.
The Verity carbonatite is up to 70 metres thick and has been traced intermittently along a strike length of 7,000 metres. The Fir carbonatite measures up to 75 metres thick and is a nearly flat-lying body that was previously traced along a strike length of about 400 metres.
The Verity Carbonatite contains an inferred resource of 3.1 million tonnes averaging 196 grams Ta2O5 and 645 grams Nb2O5 per tonne, plus 3.2% P2O5. The Fir Carbonatite contains the highest reported tantalum grades. It has been intersected by four drill holes and traced, on surface, along a strike length of about 400 metres. A resource has yet to be delineated by an independent third party.
In August 2001, Commerce drilled five holes into its Verity Carbonatite. All five holes intersected varying widths of the main carbonatite sill. Highlights from the are as follows:
Hole 1 cut 24 metres grading 141 grams Ta2O5, 794 grams Nb2O5 and 2.96% P2O5 starting 34.0 metres down-hole. This included a 10-metre interval that averaged 164 grams Ta2O5, 824 grams Nb2O5 and 2.79% P2O5.
Hole 2 intersected 38 metres grading 152 grams Ta2O5, 696 grams Nb2O5 and 2.99% P2O5 starting 55.0 metres down-hole. This included a 6-metre section that averaged 208 grams Ta2O5, 873 grams Nb2O5 and 3.16% P2O5.
Fir carbonatite
At the Fir carbonatite, which is about 10 km south of Verity, Commerce Resources has completed three holes and has decided to drill an additional three more. Assays are still pending.
Meanwhile, ongoing reconnaissance work in the region has identified other tantalum exploration targets. Several stream-sediment samples returned highly anomalous values of tantalum and niobium (up to 1,300 grams Ta2O5 and 2.42% Nb2O5).
Commerce has retained International Metallurgical & Environmental to develop a beneficiation process for the treatment of tantalum, niobium, and phosphate from its Verity and Fir carbonatites. Two bulk samples, one from each carbonatite, were collected for testing. Geochemical, mineralogical and petrological work on the Verity carbonatite reveals that the dominant tantalum-bearing mineral is pyrochlore.
A few other juniors have flocked to the Blue River area and acquired ground near Commerce’s ground.
First Narrows
Back in Ontario,
The Raleigh Lake property is one of three tantalum projects Avalon is exploring under a joint-venture agreement with Global Canada. The other two are Lilypad Lakes, near Pickle Lake, Ont., and East Braintree, near Falcon Lake in southeastern Manitoba. Global can earn a half-stake in any of the three properties by spending $5 million on any one property by 2003. Global can increase its interest to 75% by arranging all financing to production.
At the Lilypad pegmatite property, assay results from a 15-hole, 2,786-metre program of diamond drilling indicate that the Rubellite and Pollucite dyke targets increase in grade and thickness at depth. Highlights include a 22-metre section from the Rubellite dyke that averaged 0.038% Ta2O5 and a 10-metre section from the Pollucite dyke that ran 0.040% Ta2O5 and 2.892% Cs2O.
Rubellite dyke
The Rubellite dyke has now been traced over a strike length of 100 metres and to a vertical depth of 250 metres, while the Pollucite dyke has been traced over a strike length of 60 metres and to a vertical depth of 300 metres.
The 4,700-ha East Braintree property hosts two known, but little-explored, rare metal pegmatites known as Lucy and Artdon. The pegmatite system on the East Braintree program is extensive, with a minimum strike length of 1.5 km. Economic-grade tantalum mineralization appears to be situated northeast of the Lucy pegmatites, in an area completely covered by overburden. Future work will include drill testing the extension of the Lucy pegmatites.
Avalon also drilled a 12-holes, or 1,401 metres, to test tantalum targets located peripheral to the Big Whopper petalite deposit, near Kenora, Ont. The junior also performed a check assay program to re-evaluate tantalum grades and distribution within the Big Whopper itself. Results indicate tantalum enrichment on the eastern and western margins of the deposit, with grades ranging from 0.009% to 0.022% Ta2O5. The new data are being used to map tantalum distribution within the Big Whopper and define the limits of the higher-grade tantalum sub-zones for mine planning purposes.
The company also holds the Coldwell tantalum property, near Marathon, Ont., and the Shatford Lake tantalum property, near Bernic Lake, Man.
The Coldwell property covers 2,512 ha and hosts tantalum occurrences in syenites of the Coldwell alkaline intrusive complex, whereas Shatford Lake hosts a buried Tanco-type tantalum-lithium-cesium-rubidium pegmatite. The property is just 6 km southwest of the Tanco mine, which is North America’s only current producer of tantalum.
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