Zinc, Lead, Silver

Content maintained by David Huston and Keith Porritt

• Zinc, Lead, Silver
• Resources
  • Zinc
  • Lead
  • Silver
• Accessible EDR
• JORC Reserves
• Exploration
• Production
• World Ranking
• Industry Developments

Zinc (Zn) is the 23rd most abundant element in the Earth’s crust and the 4th most common metal in use after iron, aluminium and copper. The construction, transport and appliance manufacturing industries use large amounts of zinc, mainly as anti-corrosion coatings (galvanizing) on sheet steel, steel beams, vehicle panels, chain-link fencing, guard rails and light posts. World-wide, around four million tonnes (Mt) of zinc is used annually to protect around 100Mt of steel, representing almost half of the world’s total consumption of zinc. The widespread use of zinc as a protective coating is due mainly to its resistance to normal weathering. This is an electrochemical reaction known as galvanic action. Zinc is more reactive than iron or steel and consequently attracts almost all local oxidation. A protective surface layer of oxide and carbonate forms as the zinc corrodes. Zinc is used also in brass (almost 20% zinc), alloys (16%) such as for die cast precision components, pigments, salts, as oxide additives to rubber and for agricultural chemicals as well as for wrought or rolled products. Zinc metal is produced in Australia at Sun Metals’ Townsville refinery in Queensland (Qld) and at Nyrstar NV’s Hobart refinery in Tasmania (Tas).

The widespread occurrence of lead (Pb), its relatively simple extraction and a combination of desirable properties have made it useful to humans since at least 5000 BC. In deposits mined today, lead, mainly in the form of galena (PbS), is usually associated with zinc, silver (Ag) and sometimes copper (Cu) and is extracted as a co-product of those metals. The largest use is in batteries for vehicles, which accounts for 80% of modern lead usage. The remaining 20% of applications include underwater cable sheathing, solder, casting alloys, chemical compounds, ammunition, glassware and radiation protection. Uses for lead could increase in the future in large storage batteries used for load-levelling of electrical power and in electric vehicles. The growing popularity of electric bikes, particularly in China, has led to the e-bike now consuming more than 8% of world lead production. More than half of the lead currently used is from recycling rather than from mining. Lead recycling plants jointly owned by Nyrstar NV and the Sims Group are in Melbourne, Victoria (Vic) and in Sydney, New South Wales (NSW). Nyrstar NV’s Port Pirie smelter in South Australia (SA) is the world’s largest primary lead smelting facility and a leading global silver producer.

The relative scarcity, attractive appearance and malleability of silver make it suitable for use in jewellery, ornaments and household silverware. Its extensive use in coins throughout history has declined over the past 50 years. In Australia, the 1966 50 cent piece was the last coin in general use to contain silver (80% Ag, 20% Cu). Silver is mined and produced mainly as a co-product of lead, zinc, copper and, to a lesser extent, gold (Au). Currently, jewellery, photographic paper and film, followed by electronics and tableware, are the most important users of silver. Other applications include coatings for mirrors, for biocide and bacteriostatic activity in plastic and textiles formulations and as an anti-bacterial agent in areas such as water treatment including, for example, as an ioniser with copper in domestic swimming pools.

Australia’s total resources of zinc, lead and silver rose significantly in 2010. Total identified resources of zinc rose from 85Mt in 2008 to 94Mt in 2009, lead rose 6Mt to 61Mt and silver rose 7 kilotonne (kt) to 126kt.

Australia’s Economic Demonstrated Resources (EDR) of zinc increased by 7Mt to 65Mt and accounts for around 25% of world economic resources and is the world’s largest holding. Queensland continued to hold the largest resource with 35Mt, or 54% of national EDR, predominantly at the George Fisher, Mount Isa, Century and Dugald River deposits in Qld. The Northern Territory (NT) had the second largest EDR with 19Mt, or 29% of national EDR, all at the McArthur River deposit. Following was NSW with 5Mt EDR, up from 4Mt in 2009 and mostly at the Broken Hill and Endeavor deposits. Then, Western Australia (WA) with 3Mt, mostly at the Golden Grove, Sulphur Springs and Jaguar-Bentley deposits. Total inferred zinc resources increased to 24Mt in 2010.

Australia’s EDR of lead increased by 4Mt in 2009 to 35Mt of contained lead and constituted 57% of Australia’s total identified lead resources (61Mt). Australia also accounts for the largest share of world economic resources for lead at 39%. Queensland retained the top ranking with its EDR increasing from 18Mt in 2009 to 19Mt in 2010, which represents a 56% share of national EDR. The NT lead EDR ranks second with 8Mt or 24% of the national total, almost all of which is at the McArthur River mine. New South Wales recorded an increase in EDR from 3Mt in 2009 to 4Mt. Australia’s Paramarginal Demonstrated Resources of lead decreased by 1Mt to 4Mt, which is 7% of total Identified Resources, as more of the older resources are re-drilled and re‑estimated under the Joint Ore Reserve Committee (JORC) Code. Total Inferred Resources of lead increased slightly in 2010 to 21Mt.

EDR for silver is 77kt which is 15% of world economic resources. Queensland has 44kt or 57% of Australian EDR, mainly in the Cannington, Mount Isa, George Fisher, Dugald River and Century deposits. Most other silver EDR occurs in SA (11kt), the NT (8kt), NSW (8kt), WA (3kt) and Tas (3kt). In SA, most silver EDR is at Olympic Dam with some at Prominent Hill, while in the NT silver EDR is nearly all at McArthur River. In NSW it is mostly at Broken Hill and Endeavor, while in WA it is predominantly at Golden Grove, Spinifex Ridge and Jaguar-Bentley.

All zinc, lead and silver EDR is accessible.

Of Australia’s EDR of zinc, 33% occurs in the JORC Code ore reserves categories. The remaining EDR is made up of those measured and indicated resources as reported by mining companies and which Geoscience Australia considers will be economic over the long term. The zinc resource life using national EDR divided by annual production is 44 years, but using the ore reserve and dividing by annual production gives a resource life of only 14 years.

Of Australia’s EDR of lead, 34% occurs in the JORC Code ore reserves categories. For lead, the national EDR/production ratio is 49 years, but if the ore reserve/production ratio is used it is 17 years. For silver, JORC Code reserves account for around 36% of EDR and resource life is 41 years for EDR or 15 years for JORC Code reserves.

In 2010, exploration spending on zinc, lead and silver was $67 million, 39% higher than in 2009. The 2010 expenditure was 12% of the total base metal expenditure of $563 million compared to 13% in 2009. Expenditure on exploration for the three commodities made up only 2.7% of all mineral exploration of $2.49 billion (excluding petroleum), and compared to 2% in 2009.

According to the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES), 2010 Australian mine production of zinc, lead and silver was 1.480Mt, 0.712Mt and 1.88kt, respectively. Compared to 2009, production in 2010 increased by 15%, 26% and 15% for zinc, lead and silver respectively. The majority of production was from Qld which contributed 994kt, or 67% to national zinc production during 2010 (up 179kt on 2009) along with 474kt or 67% of lead (up 66kt) and 1.60kt or 85% of silver. Western Australia produced 99kt of zinc and 31kt of lead with both increasing over the 2009 production levels. The large increase in lead production in WA resulted from reopening of the Magellan mine (see below). Elsewhere, NSW produced 102kt zinc and 75kt lead, the NT 180kt zinc and 31kt lead and Tas 86kt zinc and 28kt lead. In all of these states production of zinc and lead was similar to that in 2009.

The Century zinc mine, which is located close to the Gulf of Carpentaria about 250 kilometres (km) north of Mount Isa in northwest Qld, ranks in the top few globally in zinc production. Century produced 511kt of zinc and 38.7kt of lead as metal-in-concentrate in 2010. The Cannington mine, also located in northwest Qld, is the world’s largest and lowest cost single mine producer of both silver and lead as well as a significant producer of zinc. Cannington produced 256kt of lead, 1.2kt of silver and 59.7kt of zinc in 2010. Also in Qld are Xstrata’s Mount Isa operations which produced 355kt of zinc, 144kt of lead and 6.8kt of silver (including 1.6kt in silver from purchased concentrate) in 2010.

The value of Australia’s exports of zinc concentrates and refined zinc in 2010 totalled $2376 million, 32% more than the $1804 million in 2009 and 1% of the value of total merchandise exports. The amount of zinc exports increased by 5% to 1.5Mt in 2009. The average price for zinc in 2010 was $2419 a tonne, 8% higher than the average of $2233 a tonne in 2009. The 2010 December quarter average price was slightly higher than for the December quarter in 2009.

Exports of lead totalled 661kt in 2010, up 2% on 2009. The value of the 2010 exports was 17% higher at $1938 million compared to $1651 million in 2009. The average price for lead was 10% higher at $2631 a tonne compared to the average of $2376 a tonne in 2009. However, lead prices were 5% lower when comparing December quarters. For silver, the average price was 9% higher at $695 a kilogram (kg) compared to the average of $589/kg in 2009 with a 39% December on December increase. The value of Australia’s mine production of silver was $1311 million in 2010, up 36% on 2009.

Based on United States Geological Survey (USGS) data for other countries, Australia has the world’s largest economic resources of zinc (25%), lead (39%) and silver (15%). In terms of production, Australia ranks third for zinc after China and Peru, second for lead after China and fourth for silver after Peru, Mexico, and China.

Mount Isa (Qld): Mount Isa zinc-lead operations commenced production in 1931 and were acquired by Xstrata Plc in 2003. Operations currently comprise the George Fisher underground mine, the open cut mines of Black Star and Handlebar Hill, an eight million tonnes per annum (Mtpa) capacity zinc-lead concentrator, a lead smelter and a zinc filter plant. During 2009 there was extensive restructuring of Mount Isa operations, resulting in a 40% reduction in costs. This restructuring flowed on to major increases in production in the Mount Isa operations. Ore treated increased by 15%, from 7.42Mt in 2009 to 8.57Mt in 2010. Underground production at George Fisher was at record levels at 3.3Mt, while production at the Black Star open cut was 4.5Mt, 32% higher than in 2009. However, the head grades were slightly lower. Overall this resulted in increases in zinc and lead in concentrate of 10% and 14%, respectively. Together, the cost savings and increased zinc and lead volumes contributed to a profit of $270 million for Xstrata’s Australian zinc operations, including McArthur River (see below), compared to $192 million in 2009. Smelter production of lead in bullion of 140kt was 4% lower than in 2009, mainly as a result of a decrease in third-party concentrate supply.

During 2010 and the 2011, a number of announcements were made by Xstrata regarding expansion of the Mount Isa operations. Expansions of the Black Star open cut and the George Fisher underground mines were made in March and September 2010 respectively. The Black Star Deeps development will extend its life to 2015, and the George Fisher development will increase production 28% by 2013. In addition, a pre-feasibility study was commissioned in the latter half of 2011 into the development of a large open cut zinc-lead-copper mine at Mount Isa. If developed, this project will extend the life of the combined zinc-lead and copper operations until 2060. Finally, following purchase of the remaining 25% stake in the Lady Loretta deposit from Cape Lambert Resources in February, Xstrata approved a $246 million development in July 2011, with immediate development of a decline. The ore will be trucked 140km to the Mount Isa milling operations.

McArthur River (NT): Underground mining at McArthur River began in 1995, with open cut mining beginning in 2009. The conversion to open cut mining combined with a concentrator expansion increased production capacity to 2.5Mtpa in 2009. Actual ore treated increased slightly (3%) to 2.23Mt in 2010. Higher zinc grades resulted in an increase in zinc in concentrate of 10% to 184kt, but lower lead grades resulted in a decrease in lead in concentrate of 15% to 31.6kt. In March 2011 Xstrata announced a $270 million plan to more than double concentrate production from McArthur River. The increase in production is seen as critical for the viability of the mine by decreasing unit production costs. However, this development necessitates the installation of proprietary hydrometallurgy technology in company smelters in Europe and improvements to the Brunswick smelter in North America to allow processing of the bulk zinc-lead concentrates produced from McArthur River. If the development plan is successful, mine life will be extended by six years to 2033.

Century (Qld): The Century mine is one of the world’s three largest zinc mines, producing 4% of global production. Minerals and Metals Group (MMG), a Chinese-owned corporation, acquired the Century, Rosebery and Golden Grove mines, amongst others, in early 2009. During 2010, production of zinc in concentrate from the Century operation increased by 42% over 2009, and lead in concentrates increased by 138%. Total silver production was 95.5 tonnes, an increase of 222% over 2009. The increase in production was due to resolution of the failure of the zinc-transporting pipeline to port at Karumba and the lack of the major rain events which disrupted production in 2009. The much higher relative increases in lead and silver production is the result of mining ore with twice the grades of lead and silver as that mined in 2009. At current rates of production, mine life extends to 2015. An 18-month exploration program in 2009-10 failed to identify new resources at the mine, or in adjacent exploration leases.

Cannington (Qld): The Cannington deposit in northwest Qld was discovered in 1990 by BHP-Billiton, with mining operations commencing in 1997. Production in 2010 increased on that achieved during 2009 by 14% and 13% for silver and lead respectively. This increase in production was the result largely of higher silver and lead grades (up 11.7% and 10.2%, respectively) and a small (2.8%) increase in ore milled. A slight decrease in zinc grades offset the increase in ore milled so that 2010 zinc production was similar to that of 2009.

Rosebery (Tas): In 2010, metal in concentrate produced at the Rosebery operations of MMG was 86.2kt of zinc, 27.0kt of lead, 2.3kt of copper, 1.09t of gold and 78.3t of silver. This production is broadly similar to that achieved in 2009. Ore from the nearby South Hercules mines is expected to be delivered to the Rosebery mill on a trial basis in the 2011 December quarter. Near-mine exploration is targeting deep targets below the Rosebery orebody and a new mineralised horizon identified to the north of the mine at the Jupiter prospect. Rosebery currently has a mine life beyond 2020.

Golden Grove (WA): MMG's Golden Grove operation consists of the Scuddles and Gossan Hill underground mines and the Scuddles processing plant. In 2010, a greater emphasis was place on zinc production, with a commensurate increase in zinc-in-concentrate and lead-in-concentrate production of 29% to 73.3kt and 78% to 7.75kt. Silver-in-concentrate and gold-in-concentrate production also increased substantially by 38% to 59.2 a tonne and by 25% to 1.13 a tonne, respectively. Copper-in-concentrate production increased marginally to 33.3kt. These increases in production were on the basis of a 46% increase in the tonnage of zinc ore milled to 580kt, although at lower grades (13.9% in 2010 compared with 16.8% in 2009). The amount of copper ore milled, 1017kt, was similar to 2009, but at a slightly higher grade (3.9% in 2010 compared with 3.4% in 2009). The Scuddles mine was on care and maintenance through 2010, re-opening in April 2011. In the first half of 2011, approval was granted for development of a shallow copper resource at Gossan Hill. Near-mine exploration targeted down-plunge extensions of the Scuddles and Gossan Hill ore bodies and testing of near-mine prospects south of Golden Grove. Work on an additional tailings storage facility with a 15-year life was completed in September. At current production rates, the Golden Grove reserves will support mining operations until 2016.

Broken Hill (NSW): In 2010 Perilya Limited increased ore production from their Southern Operations at Broken Hill, treating a total of 1.64Mt, compared with 1.4Mt in 2009. However, the processing of lower grade ore resulted in decreased production of metal-in-concentrate. Relative to 2009, zinc production, at 63.6kt, and lead production, at 51.2kt, each decreased 10%. Silver production was 44.7 tonnes, down from 56 tonnes in 2009. In December Perilya reported an 18% increase in ore reserves for its Southern Operation to 15.26Mt at 5.3% Zn, 4.0% Pb and 42 grams per tonne (g/t) Ag and a 13% increase in total mineral resources to 23.7Mt at 9.4% Zn, 7.3% Pb and 89g/t Ag. These reserves provide for at least 10 years of production at the Southern Operations. Perilya’s three other developments, North Mine, North Mine Deeps and the Potosi project remained on care and maintenance throughout 2010.

In 2010, CBH Resources Limited continued to push towards production at its Rasp development, which had been placed on care and maintenance in June 2008. Approval from the New South Wales Department of Planning for development was gained in January 2011 and development was approved by the Toho Board (see below) in February. Full scale production is now expected in mid 2012. Current mineral resources stand at 16.5Mt at 6.6% Zn, 5.1% Pb and 89g/t Ag (reported on 1 July 2009). At an annual production of 0.75Mt, annual production would be 48kt of zinc, 39kt of lead and 72 tonnes of silver over 15 years. In September 2010, CBH Resources was taken over by Toho Zinc Company Limited of Japan.

Endeavor (NSW): Because of the takeover of CBH Resources by Toho Zinc in September 2010, production figures for zinc and lead at the Endeavor mine near Cobar in NSW are available for the March and June quarters only. Production during this period was 14.8kt of zinc and 9.0kt of lead, which was 11.3% and 6.2%, respectively, lower than the corresponding period in 2009. Silver production at Endeavor during 2010 was reported by Couer d'Alene Mines Corporation, which owns silver production, at 18.2 tonnes (566134 ounces).

Angas (SA): Operations began at Terramin Australia Ltd’s underground Angas mine in July 2008 at a setup cost of $71 million. The mine reached nameplate production capacity of 0.4Mtpa in the second half of 2009. Production for 2010 was 19.3kt of zinc, 8.4kt of lead, 145 tonnes of copper, 7.7 tonnes of silver and 0.108 tonnes of silver, all as metal in concentrate. Production of all metals in 2010 exceeded production in 2009. On 31 December 2010, Angas had reserves of 1.69Mt at 6.95% Zn and 2.80% Pb, which are sufficient for a further four year operation at current production rates. Terramin is undertaking both near-mine and regional exploration, including at many nearby historic mine sites which have not been the subject of modern exploration. More regionally, successful exploration at the Meninnie zinc prospect (SA), 450km northwest of Adelaide, has doubled the resource, which now stands at 7.7Mt grading 3.1% Zn, 2.6% Pb and 27 g/t Ag.

Mungana (Qld): Kagara Limited’s zinc interests are centred on the Mount Garnet-Chillagoe region of north Qld and include mines at Mungana, Mount Garnet and Balcooma and ore processing facilities at Mount Garnet (separate facilities for copper and polymetalic ores) and Thalanga. The Thalanga facility was refurbished in 2010, converting it from a copper-only circuit to a polymetallic facility with a capacity for oxide ores. This facility was commissioned in October using ores from the Vomacka deposit. Zinc in concentrate production in 2010 across Kagara’s north Qld operations was 38kt, similar to that in 2009, but copper and lead production decreased by 26% and 10% to 17.8kt and 1.2kt respectively. Silver and gold production was 15.8t and 106kg respectively. Production was impacted by a prolonged wet season, delays in mining of the Vomacka deposit, road closures and plant down time.

Jaguar – Bentley (WA): The Jaguar project consists of three high grade deposits, Jaguar, Teutonic Bore, and Bentley, located approximately 300km north of Kalgoorlie. Perth-based Jabiru Metals Limited began operations at Jaguar in 2007 and production in 2010 was 20.2kt of zinc and 9.66kt of copper from 0.362Mt of ore. Although copper production was similar to 2009, zinc production was 39% lower because of lower grades. In late 2008, Jabiru discovered the Bentley deposit, 4km to the south and of a similar size to Jaguar. The total pre-mining mineral resource at Bentley stood at 3.038Mt grading 9.8% Zn, 2.7% copper, 139 g/t Ag and 0.7 g/t Au (including ore reserves of 2.45Mt grading 8.6% Zn, 1.5% Cu and 106 g/t Ag). Production began in June 2011, with ore being processed through the Jaguar concentrator. Jabiru Metals Ltd was taken over by Independence Group in February 2011.

Que River and Hellyer – Fossey (Tas): Following cessation of Bass Metals mining activities at the Que River mine in September, the last shipment of ore was made in October to the MMG Rosebery mill. A total of 31.4kt of ore grading 14.7% Zn, 8.2% Pb, 0.3% Cu, 261 g/t Ag and 3.9 g/t Au was mined during 2010. Metals-in-concentrate from the Que River ore are included in the Rosebery operations described above.

During 2010, most of Bass Metals activities were directed towards starting the Hellyer Mining Project, which includes development of the Fossey and Fossey East deposits, discovered in 2007 and 2010 respectively, along with extraction of remnant ore and resuming re-treatment of tailings from the historical Hellyer Mine. The last activity involves developing methods of extracting metallurgically refractory gold from the Hellyer tailings. Work to develop a decline to access the Fossey deposit and refurbish the Hellyer mill began in January. First ore production from Fossey was achieved in March 2011. Under an off-take agreement Bass has committed 100% of zinc and lead concentrate to Nyrstar NV.

Magellan (WA): Magellan Metals Pty Ltd, which is a wholly owned subsidiary of Toronto-listed Ivernia Inc, totally owns the Magellan deposit, 30km west of Wiluna. Lead production at this deposit, which is the largest known carbonate lead deposit in the world, began in October 2005, with concentrates sold overseas and shipped initially from the Port of Esperance. However, because of lead contamination at the port, shipping was suspended and the mine was placed on care and maintenance in April 2007. Mine production re-commenced in February 2010 following revision of concentrate transport procedures with the concentrate being shipped through the Port of Freemantle. However, production ceased again in early January 2011 following a stop order on the transportation of lead carbonate and the mine was placed on care and maintenance. Total production at Magellan in 2010 was 44.1kt of lead-in-concentrate, but no zinc or silver were produced.

Other zinc-lead-silver developments: There are several zinc-lead-silver prospects at various stages of development which could come on line in the next decade. The most significant of the zinc-lead projects is the Dugald River deposit (Qld), which is owned by MMG. This deposit, the first zinc deposit discovered in the Mount Isa region, was the subject of a feasibility study in 2008, which was updated in 2010. The feasibility study indicated a mine life of 23 years based on a resource of 53Mt grading 12.5% Zn, 1.9% Pb and 36 g/t Ag. Progress on this project is continuing, with an environmental impact statement released in March 2011 for public comment and a decision to proceed expected in the latter part of 2011.

After Dugald River, the most advanced project is the Independence Group's Stockman project (Vic) which includes the Wilga and Currawong volcanic-hosted massive deposits with a combined resource of 12.69Mt grading 4.4% Zn, 0.7% Pb, 2.1% Cu, 39 g/t Ag and 1.0 g/t Au. At the time of writing this report, a defensible feasibility study and an environmental effects statement for this project were being prepared. Another project for which a defensible feasibility study was completed is YTC Resource's Hera project near Cobar in NSW. Based on a global resource of 2.44Mt grading 3.8% Zn, 2.8% Pb, 0.2% Cu, 16.7g/t Ag and 4.1g/t Au, the feasibility study indicated a financially and technically robust project with a minimum 7.3 year mine life. This result would be enhanced by a significant resource at the nearby Nymagee prospect.

Venturex Pt Ltd has consolidated many of the zinc-lead resources in the Pilbara region (WA) into its Pilbara VMS Copper-Zinc Project. The project includes the Whim Creek, Mons Cupri, Salt Creek, Evelyn and Sulphur Springs deposits,. Current resources for the consolidated project total 26.274Mt grading 3.0% Zn, 0.3% Pb, 1.2% Cu, 19.8 g/t Ag and 0.1 g/t Au. The company is conducting a bankable feasibility study, which began in February 2011.

The Myrtle project (NT) is located about 40km south of the MacArthur River deposit in the same host succession. The owner of this project, Rox Resources, has attracted Teck Australia as a joint venture partner. This project is still at the exploration stage, but has a total resource of 43.6Mt grading 4.09% Zn and 0.95% Pb, with a higher-grade resource of 15.3Mt grading 5.45% Zn and 1.40% Pb.

At Kagara's Admirals Bay deposit in the Canning Basin (WA), a pre-feasibility study identified mineral resources of 72Mt grading 3.1% Zn, 2.9% Pb, 18 g/t Ag and 20% barite. However, this deposit is located more than a kilometre below the surface and requires a large injection of money to bring the project to bankable feasibility status.

Silver: One of the more interesting developments over the past few years in the zinc-lead-silver sector has been the interest in projects in which silver is the main commodity, with zinc and lead as by-products or co-products. This activity is occurring in NSW and Qld, particularly in the New England and Lachlan Orogens, and includes a producing mine at Twin Hills (Qld), an advanced project at Wonawinta (NSW) and several other projects at various stages of development. At its Texas Project, Alcyone Resources Ltd began re-commissioning the Twin Hills mine in February this year, with irrigation of historic heap leach stockpiles beginning in April and the first silver production in June. At the time of writing this report, mining had not commenced, but Alcyone has identified mineral resources at Twin Hills deposit of 3.642Mt grading 83g/t Ag and 0.08g/t Au and 2.347Mt at the nearby Mount Gunyan grading 77g/t Ag  and 0.09g/t Au.

At the Wontawinta deposit, in the Cobar mineral field, Cobar Consolidated Resources Ltd completed a bankable feasibility study in December 2010, with a decision to mine taken in June 2011. At present the project is based on an ore reserve of 4.6Mt grading 97g/t Ag and 1.4% Pb within a mineral resource of 21.9Mt grading 72g/t Ag and 1.0% Pb. A small resource has also been identified at the nearby De Nardi deposit. First production in the Wonawinta project is expected in December 2011.

Other silver projects in early stages of development include Argent Mineral's Kempfield project (NSW), Kingsgate Consolidated Bowdens project (NSW), which are the subject of feasibility studies due in early 2012. At Kempfield, oxide/mixed and sulphide resources of 5.8Mt grading 58g/t Ag and 0.1g/t Au and 14.4Mt grading 49g/t Ag, 0.1g/t Au, 1.2% Zn and 0.6% Pb, respectively. In addition, the deposit contains large amounts of barite. At Bowdens, a total resource of 58.2Mt grading 52.9g/t Ag, 0.40% Zn and 0.30% Pb has been defined. Other less advanced silver project include Silver Mines Ltd's Webbs project (NSW) and White Rock Minerals' Mount Carrington project (Qld). In addition, silver is a significant component of polymetallic projects at Mount Carlton (Qld; Conquest Mining) and Kangiara (NSW; Paradigm Metals).

Takeovers and mergers: A final trend in the zinc-lead-silver sector during the past few years is the number of takeovers and mergers. Although in several cases this involved the takeover of a junior to mid-sized Australian company by a major Chinese company, other takeovers and mergers involved Japanese and other Australian companies. The most significant Chinese takeovers include Abra Mining by Hunan Nonferrous Metals, and Meridian Metals by Northwest Nonferrous International Investment Company. CBH Resources was taken over by Japanese zinc and lead smelting company, Toho Zinc. Jabiru Mining was taken over by the Australian company, Independence Group, while Conquest Mining and Catalpa Resources merged into Evolution Mining.