An analysis of historic production trends in Australian base

An analysis of historic production trends in Australian

base metal mining

Gavin M.Mudd ?

Department of Civil Engineering,Institute for Sustainable Water Resources,Monash University,Clayton,Victoria 3800,Australia

Received 22August 2005;accepted 29May 2006

Available online 19January 2007

Abstract

The base metal mining sector,including copper,lead –zinc –silver and nickel,has been a prominent and critical feature of the Australian minerals industry.The various mines and fields have been producers of world significance,including Broken Hill,Mt Isa,Mt Lyell,Olympic Dam,Cobar and Kambalda.The long-term production trends in the base metal sector governing these historic fields remain relatively undocumented.This includes trends in ore grades,mining technique (open cut versus underground),solid wastes produced (tailings and waste rock),technology (e.g.,milling)and known economic resources.This paper presents these results for the Australian base metals sector —arguably the first such systematic compilation undertaken.A historical overview is discussed for each major commodity to outline the principal developments and changes for that commodity,followed by the presentation of mining and milling trends.Overall,the key trends are declining ore grades versus increasing metal production and ore milled,and increased open cut mining and associated waste rock (though this latter aspect remains significantly under-reported).The extent of known economic resources has steadily increased for all commodities analysed,principally due to the inclusion of lower grade ores and/or difficult to treat ores (such as nickel laterites)or new deposit discoveries.Based on present mine plans and proposals,future metal production will increasingly shift towards lower ore grades and larger open cut mines to maintain production levels.There are sufficient known economic resources for about three decades or more,providing a basis to sustain the existing base metal industry but beyond this timeframe is difficult to predict.These trends point to the need to accurately report complete data on base metal mining and milling as key inputs into quantifying mineral resource trends as well as the environmental aspects of “sustainable mining ”.

?2007Elsevier B.V .All rights reserved.

Keywords:Base metals;Australia;Sustainable mining;Nickel;Copper;Lead –zinc –silver

1.Introduction

The history of base metal mining in Australia is

indeed extensive and the industry would appear to be

well positioned for the future.Many such mineral fields

are well known in Australian history —including

Moonta –Wallaroo,Mt Lyell,Broken Hill,Mt Isa,

Cobar,Rosebery,among many others.The continuing and steady growth in the mining and milling of base metal ores in Australia,however,is less well known.In order to better predict future trends in the Aus-tralian mining industry (a discipline now termed “sustainable mining ”),it is important to analyse the available historical record.Historical trends can be used for a variety of purposes —research to highlight the effect of significant mineral discoveries (or their deple-tion),social impacts (e.g.,strikes,wars),the advent

of Ore Geology Reviews 32(2007)227–

aa4c0ffc19e8b8f67c1cb9e7/locate/oregeorev

?Tel.:+61399051352;fax:+61399054944.

E-mail address:Gavin.Mudd@aa4c0ffc19e8b8f67c1cb9e7.au .

0169-1368/$-see front matter ?2007Elsevier B.V .All rights reserved.

doi:10.1016/j.oregeorev.2006.05.005

new techniques and technologies,or economic analyses. The extent to which data exist as well as its relative availability(ignoring the effort required to synthesize such a large data set)is quite surprising.

This paper presents the results of such a study on the history of base metal ore mining and metal production in Australia,namely copper(Cu),lead–zinc–silver(Pb–Zn–Ag)and nickel(Ni).The structure includes a review of the survey methodology adopted,together with principal references used,followed by a section for each principal base metal ore,namely Cu,Pb–Zn–Ag and finally Ni.An historical account of events for each sector is included to discern the principal effects that can be identified in the presented data sets and graphs.This historical annotation is not intended to be a thorough economic,scientific or engineering analysis of that sector—it is purely intended as a guide to the compiled data sets and graphs.

This paper presents,arguably for the first time,the best available data sets for Australian totals of the quantities of ore milled,average ore grades,metal production,the extent of open cut and underground mining,waste rock (overburden)produced,as well as known economic re-sources over time.These trends should prove a valuable basis for further historical insight of the present and possible future scale of the minerals industry in Australia, especially concerning the key issues of mineral resource and environmental sustainability.

2.Methodology

A detailed annual data set of inpidual mines was compiled to calculate Australian totals for mining and milling of Cu,Pb–Zn–Ag and Ni ores.All sourced data have been compiled and converted to metric units—namely ore mined,ore grades,metal production,mining technique(open cut or underground mining),waste rock (overburden)and known economic resources.The waste rock,where available data permits,was compiled for both underground and open cut mining to facilitate comparison of the total solid wastes produced for a given metal production.All references used for inpidual mines/fields are detailed in the Appendix.A location map showing major mines/fields across Aus-tralia is given in Fig.1.

There are a number of historical periodic or regular reports published with data on the Australian mining industry.These include:

?Annual Mineral Industry Review(Years1948–1987) by the(former)Bureau of Mineral Resources(BMR) (now Geoscience Australia)(BMR,various years);?Australian Commodity Statistics(Years1995–2005) by Australian Bureau of Agricultural and Resource Economics(ABARE)(ABARE,various years-a,b);?Australian Mineral Statistics(Years1988–2005) ABARE Quarterly Journal(ABARE,1988);?mining industry statistical periodicals—Jobson's Mining Year Book(Years1957–2004)(Riddell,various years),Register of Australian Mining(Years1980–2004)(RIU,various years),and Australian Mines Handbook(Years1976–2004)(LP and Minmet,various years);

?State Department of Mines(their current equivalents)—annual reports,industry statistical reviews, research reports,geological bulletins and the like (e.g.,Andrews,1911a;NSWDM,various years; WADoIR,various years);

?The Mineral Industry:Its Statistics,Technology and Trade(Years1892–1940)published by McGraw Hill (Anonymous,various years);

?BMR's Australian Mineral Industry:Production and Trade,1842–1964(Kalix et al.,1966);?numerous mining company annual and quarterly reports and/or supplied data;

?numerous mining profession and scientific monographs and publications,covering mining,metallurgy,geolo-gy,engineering or history(e.g.,Dunkin,1953;Hooper and Black,1953;Knight,1975;Woodcock,1980; Hughes,1990;Woodcock and Hamilton,1993;Berk-man and Mackenzie,1998).

The following rules were applied in compiling and assessing reported data:

?company data takes precedence over other sources;?calendar year was adopted where possible,otherwise financial year data was applied in the year it was reported(e.g.,1987/1988would be recorded in1988; considered sufficient for overall trends over time-scales of decades);

?assayed ore grade was sought,with yield data correc-ted for recovery(if known);

?co-product or by-product mines with significant production have been incorporated into each specific commodity(e.g.,a Cu–Zn mine would be included in both sectors);

?in cases where sources conflicted,the data considered closest to or most consistent with a company source was adopted.

The inclusion of co-products and by-products into each commodity introduces a small degree of double accounting.It was considered important to do this to

228G.M.Mudd/Ore Geology Reviews32(2007)227–261

assess the true extent of ore processed to produce that

metal.In general,it is clear that a mine should be

included (e.g.,Golden Grove in Cu and Pb –Zn –Ag),

while for others it is somewhat subjective (e.g.,Broken

Hill in Pb –Zn –Ag and Cu).Overall,the amount of

metals produced from co/by-product mines is small (e.g.,

～5%for Cu).This does,however,become a major issue when comparing the gold (Au)sector with other metal sectors or assessing the total ore throughput for the whole metals sector of the Australian mining industry.The extent and quality of data vary considerably across publications while reporting of data is not always consistent,such as metal yield versus assayed ore grade,metal or concentrate versus ore.Discrepancies can exist for the same years between different publications.For much of the data from the 1800s a key issue is that

not Fig.1.Note :Mt Morgan (1),Clonclurry Field (2),Ernest Henry (3),Mt Isa (Cu)(4),Gunpowder-Mt Gordon (5),Osborne (6),Selwyn Field (7),Cobar Field (8),Cadia Hill (9),Ridgeway (9),Northparkes (10),Mt Lyell (11),Moonta-Wallaroo (12),Burra (13),Mt Gunson-Cattlegrid (14),Olympic Damc (15),Kanmantoo (16),Nifty (17),Telfer (18),Tennant Creek (19),Century Zinc (20),Cannington (21),Mt Isa (PbZnAg)(22),Thalanga (23),Herberton-Chillagoe (24),Mt Garnet-Surveyor (25),Broken Hill (26),Elura-Enterprise (27),Woodlawn (28),Captain ’s Flat (28),Yerranderie (29),Rosebery-Hercules (30),Zeehan Field (31),Hellyer (32),Beltana-Aroona (33),Northampton Field (34),Golden Grove (35),Teutonic Bore (36),Cadjebut-Pillara (37),Magellan (38),McArthur River (39),Woodcutters (40),Kambalda Field (41),Scotia (41),Nepean (41),Carr Boyd (41),Redross (41),Spargoville (41),Leinster-Agnew (42),Forrestania (43),Radio Hill (44),Sally Malay (45),Mt Keith (46),Murrin Murrin (47),Black Swan (48),Cawse (49),Bulong (50),Emily Ann (51),Greenvale-Brolga (52-53),Yabulu refinery (54),Rum Jungle (55),Peak Downs (56),Thackaringa-Silverton (57),Wingellina-Blackstone Ranges (58),Windarra (59),Honeymoon Well (60),Cosmos (61),Rav8(62),Ravensthorpe (63),Yakabindie (64),Eloise (65),Girilambone (66),Cobar-CSA (67),Benambra (68),Abra (69),Lady Loretta (70),Sorby Hills (71),Highway-Reward (72),Prominent Hill (73).

229

G.M.Mudd /Ore Geology Reviews 32(2007)227–261

all production was reported to State Mines'Departments

(despite the urging to do so for posterity),including

some ores or concentrates exported overseas with no

records.For other aspects,such as waste rock or the

sourcing of ore from open cut or underground,there is

commonly no reporting of data.

In order to assess the degree to which the data set

represents its specific sector,the calculated production is

graphed as a percentage of reported production.The ‘calculated production’is derived by the summation of all inpidual mine production from the compiled data

set.The reported production is the official annual

production of that metal.Thus,for each metal a value of N90%would suggest that the data presented effectively covers that metal sector for that given year.Given the variable data sources,it is possible that the proportion of production could be N100%.This could be due to a variety of factors,including errors in inpidual mine production,rounding errors,financial versus calendar year,and/or incorrect reported Australian production.

The extent of Australian economic base metal

resources is published by Geoscience Australia and

includes data from1975to2004for most minerals(GA,

various years).All pre-1975resources data is obtained

by collating inpidual mines.It should be noted that the

formal basis for reporting ore resources has changed

considerably over time,say1900to2004(e.g.,the Joint

Ore Reserves Code or‘JORC’;AusIMM et al.,2004).

However,given the generally small number of major

mines reporting resources prior to1975,it is considered

useful to compare the different data to assess the

magnitude of changes in economic reserves over this

period.

Overall,there is a minor degree of uncertainty in the

assembled data sets.When different data sources for

specific mines are compared,the correlations are very

close.The net effect on trends in the data is therefore

considered to be negligible.For examining trends over

temporal scales up to two centuries,this uncertainty is not

significant as the overall trends show larger change than

the uncertainty in the data(e.g.,Cu ore was～15–25%Cu

in the mid-1800s but is presently0.2–3%Cu).For most of

the time period presented,the compiled data represents

more than90%of base metal production in Australia. 3.Copper

3.1.History

Copper mines hold an important place in Australian

mining history,as they were the first base metal deposits

to be discovered and worked on a notable scale from 1842,almost a decade before the gold rush began in

1851.

The1840s saw several Cu discoveries in South

Australia(SA)close to Adelaide at Kapunda,Montacute,

and Burra followed in1861by the Moonta–Wallaroo

field on the Yorke Peninsula.The SA mines,especially

Burra,contained exceedingly rich ore ranging from15to

25%Cu—rapid development led to the construction of

mines,smelters and soon boom towns became established

(O'Neil,1982).The total SA output,dominated by the

Burra mine,saw SA become widely known as the “Copper Kingdom”and supplied about10–20%of world production(Dickinson,1990;Bampton and Taylor,

2000).In the early1870s the Burra mine trialled open

cut mining but converted back to underground mining just

before closure in1877(Dickinson,1942;Higgins,1956;

Drexel,1982).The low Cu prices prevailing between

1875and1900,together with increasingly difficult

mining conditions,led to the closure of almost all mines

except the Moonta–Wallaroo field,which merged their

previously independent operations in1889to stay

profitable(O'Neil,1982).

The dominance of SA also started to be challenged by

the eastern states.The rich Peak Downs Cu mine in central

Queensland(QLD)opened in1862.In1867the

Clonclurry Cu–Au field was discovered in remote wes-

tern QLD while the Cobar Cu–Au field was discovered in

northern New South Wales(NSW)in1869.These fields

rapidly proved to be of major importance,though they

suffered from the tyranny of distance,lack of abundant

water resources,economic fuel supplies and the want of

capital(e.g.,Brooke,1975;Brooks,1990).Similarly to

SA,these mines initially exploited rich oxidised Cu ores

grading some15%Cu or higher.

By the late1800s,however,some major structural

changes were being forced on Australia's Cu industry

(Brown,1908;Carne,1908).Most importantly,the

prolonged depressed Cu price forced the closure of

many smaller mines,leaving only large companies and

fields surviving.Another major issue was the exhaus-

tion of the rich oxidised ores and the need to process and

smelt the more abundant but lower-grade sulphide ores.

By the1890s,both the Moonta–Wallaroo and Cobar

fields had declined in ore grade to～4.3%Cu.This

created serious challenges for the industry,which

worked even harder to maintain production.A major

aspect of their success in this regard was the increasing

mechanisation of the mines and smelters.

The development of the Mt Lyell Cu–Au–Ag mine

in1894on Tasmania's(TAS)west coast heralded a new

era in Australian mining,even globally,as the first Cu

mine to successfully implement pyritic smelting—

230G.M.Mudd/Ore Geology Reviews32(2007)227–261

thereby negating the need for coke to fuel the smelters.Mt

Lyell was arguably Australia's largest and most complex

mining project by this time,involving the construction of

the Abt rack-and-pinion railway system to traverse the

steep terrain,large flux quarries,the first pyritic smelters

in the world and another Australian first with the famous ‘Iron Blow’mine at Mt Lyell being developed through large-scale open cut mining(the previous attempt at open

cut mining at Burra was small in comparison and

unsuccessful).The Mt Lyell field was still in production

in2005with significant ore resources remaining(29.4Mt

at 1.37%Cu;2005Edition,TDM,various years).

However,the field has caused severe environmental

damage locally and downstream due to the generation of

acid mine drainage(AMD)from tailings and waste rock

discharged to the Queen and King Rivers reaching the

Macquarie Harbour(Koehnken,1997).

The early1900s continued to prove challenging for

various Cu mines.The ongoing complexities of World

War I,labour disputes,declining ore grades and increa-

sing costs versus depressed prices led to the effective

complete closure of the Moonta–Wallaroo and Cobar

fields by1923—only small numbers of tributers

continued mining.

The only significant new Cu mine developed around

the early20th Century was the1906entry of the

Mt Morgan Au mine as a Cu–Au producer.Ore pro-

duction was through a mixture of underground and open

cut mining.Mt Morgan faced a strenuous decade in the

1920s as economic problems coupled with a major fire

destroyed the mine in1925.Mt Morgan was redeve-

loped as a dedicated large-scale open cut operation in

1931,remaining in production until1982with tailings

re-processing until1990(Parbo,1992).Similarly to Mt

Lyell,the Mt Morgan mine has caused significant envi-

ronmental impacts on the Dee River due to AMD(Sul-

livan et al.,2005).

The mid-to-late20th Century produced a variety of

new Cu fields and deposits,especially between1975

and2000.Until Mt Isa started large-scale Cu production

in1953,most Cu was produced as a co-product with Au

and/or Ag at Mt Lyell,Mt Morgan and the Cobar field.

A major trend throughout the latter half of the20th

Century was the use of open cut mining.Most Cu mines

have been associated with Au and/or Ag production,

while some Pb–Zn–Ag mines also produce(or have

produced)Cu as a co/by-product(e.g.,Broken Hill,

Captain's Flat,Rosebery,Woodlawn,Thalanga).

A chronology of Cu mines from1940includes:?1948—Discovery and development of the Tennant Creek Cu–Au field;?1953—Mt Isa starts large-scale Cu production(in parallel to existing Pb–Zn–Ag operations);?1964—CSA Cu–Ag underground mine in the Cobar field is re-developed into a major producer(including small by-products of Pb–Zn);

?1960s–1970s—old SA mines are re-worked by open cut,such as Kanmantoo,Burra and Mt Gunson, including the newly discovered Cattlegrid deposit;?1988—Olympic Dam Cu–U–Au–Ag underground mine,northern SA,is bought on-stream;

?1990s—Re-development of many small to moderate scale Cu mines across the Clonclurry field,including major new mines at Osborne(underground,1995), Gunpowder–Mt Gordon(underground/open cut), Eloise(1996),Ernest Henry(open cut,1997);?1993—Nifty Cu open cut mine,east of the Pilbara, northern Western Australia(WA);?1994—Northparkes Cu–Au open cut/underground mine,central NSW;

?1998—Cadia Hill Cu–Au open cut mine,central NSW;

?2000—Ridgeway Cu–Au underground mine, adjacent to Cadia Hill.

The discovery of the giant Olympic Dam deposit in 1975by Western Mining Corporation(WMC)heralded a previously unrecognised style of mineral deposit,that of iron oxide copper–gold or‘IOCG’deposits,and has enabled a major advance in mineral resource explora-tion.The Olympic Dam deposit is also highly unusual in its metal association consisting of Cu,uranium(U),Au, Ag and rare earths.Significant greenfields Cu deposits are still being discovered(e.g.,Prominent Hill,SA), though most known Cu resources are lower grade than current operations,broadly average around1%Cu or lower and are,at present,commonly proposed as open cut mines.By2005,Australia had produced17.81Mt Cu,of which11.18Mt Cu(63%)was produced from 1985to2005.

3.2.Production results

The compiled statistics for Cu mining are shown in Figs.2–6,with total production from major Cu mines/ fields in Table1(important co/by-product Cu mines/ fields are given in the Pb–Zn–Ag and Ni production sections,Tables2and3,respectively).

The ore milled,average ore grade,estimated extent of open cut mining and waste rock(as reported)are shown in Fig.2.For pre-1890data,there is a lack of historical annual data on which to complete the graph. As shown later in Fig.5,there is a major gap in

231

G.M.Mudd/Ore Geology Reviews32(2007)227–261

calculated production for this period,though some sparse data exist which has been incorporated into Fig.2.The proportion of open cut mining between 1872to 1875,based on data compiled for Burra,is clearly an over-estimate due to the low extent of data for this period (data represents only 6to 17%of Cu production).Assuming an average grade of 17.5%Cu for these years leads to an estimate of the proportion of between 3and 4%ore derived from open cut mining compared to the 20to 50%shown.

Despite the lack of comprehensive pre-1890data,it is certain,based on numerous historical works and mining/geological overview publications,that the period from 1842to the mid-1870s saw very rich Cu ore mined in the range of 15–25%Cu (e.g.,Burra,SA;Peak Downs,QLD;see Brown,1908;Carne,1908;Dickinson,1942;Dickinson,1944).By around 1890,ore grades had declined to about 4.3%Cu,from which time excellent data are available.

The impact of closing down open cut mining at Mt Lyell during the 1920s,along with the forced closure of Mt Morgan,is clearly visible in Fig.2as this led to an increase in average ore grade during the 1920s (i.e.,North Lyell underground ore).However,with the re-sumption of large-scale open cut mining at both sites in the 1930s the average ore grade rapidly declined to-wards 1%Cu,reaching a historic low of 0.53%Cu in 1947.In 2005average ore grade was 1.10%Cu,declining from a recent historic high of 2.58%Cu in 1991.

The waste rock data in Fig.2is a minimum since the respective companies have not publicly reported

such

Fig.2.Copper ore grade,ore milled,waste rock open cut mining over time.Note (?):Burra's trial of open cut mining 1872to 1875is an over-estimate due to the paucity of data for Cu mining in Australia during these years;true values are likely to be of the order of 3–4%.

232G.M.Mudd /Ore Geology Reviews 32(2007)227–261

data for several major open cut mines.This primarily

relates to the period 1995–2005,with additional annual

waste rock possibly of the magnitude of 25to 60Mt.

There is only sparse data on waste rock for underground

mines.It can be observed that the reported quantity of waste rock,since the mid-1990s,is significantly higher than the quantity of ore milled.This is important since it is the waste rock at several Cu mines which has been primarily responsible for long-term environmental im-pacts (e.g.,Mt Lyell,Rum Jungle,Mt Morgan).

At

Fig.4.Copper production by state

(fraction).Fig.3.Copper production by state.

233

G.M.Mudd /Ore Geology Reviews 32(2007)227–261

present there are proposals being investigated for con-verting the underground mines of Olympic Dam and Mt Isa to large open cut mines,potentially producing ～40Mt/year of ore,giving renewed emphasis on the need to report waste rock data.

The relative dominance of inpidual states changing over time is evident from Figs.3and 4,with SA,QLD and TAS each leading Australian Cu production at va-rious times.

The degree of completeness for the ore mined and milled,in terms of calculated versus reported Cu pro-duction or the fraction of Australian Cu production,Fig.5,is low and quite variable prior to about 1890.From 1890data becomes more widely available and reported annually,especially by state agencies,with calculated production generally representing more than 85%of Australian Cu production.The years where the fraction of Cu production exceeds 100%can only be attributed to inconsistencies between mine production and reported Australian production.

Australian Cu production versus economic resources,Fig.6,indicates sustained growth in both Australian production and resources over the latter half of the 20th Century (1950–2000).As of December 2004,it is esti-mated that Australia has 42.1Mt Cu in economically demonstrated resources,with an additional 4.9and 29.9Mt Cu of sub-economic and inferred resources,respectively (2005Edition,GA,various years ).This compares to estimated global economic Cu resources of 490Mt Cu (2005Edition,GA,various years ).

The Cu resources of probable future mines,as well as re-development projects,include:

?Mt Isa potential open cut,277Mt at 1.0%Cu (Wallis,2005);

?Olympic Dam proposed open cut,3980Mt at 1.1%Cu (2004Edition,WMC,various years-b );

?Roseby,QLD,103Mt at 0.7%Cu (UR,2004);

?Cadia East,NSW,830Mt at 0.35%Cu (2005Edition,Newcrest,various years );

?Telfer Au –Cu open cut project,WA,with 527Mt at 0.18%Cu (2005Edition,Newcrest,various years );?Prominent Hill,SA,with 101Mt at 1.5%Cu (Oxiana,2005).

Based on presently known economic resources and 2005production of 918kt Cu,there are sufficient re-sources to maintain existing Australian Cu production for approximately 45years.As noted above,known Cu ore resources are commonly lower grade than

present

Fig.5.%Copper production —reported versus

calculated.

Fig.6.Copper production versus economic resources.

234G.M.Mudd /Ore Geology Reviews 32(2007)227–261

operations and proposed as open cut mines,keeping downward pressure on ore grades and upward pressure on environmental aspects such as solid wastes,energy, water and pollutant emissions per Cu produced(e.g.,t CO2/t Cu).

Overall,the compiled data give an excellent repre-sentation of Cu mining and milling in Australia from the 1840s to2005.The cumulative production,resources and ore grades over time for Mt Isa and Mt Lyell are shown in Figs.7and8,respectively.Although similar

Table3

Major nickel mines/fields—production statistics

Mine/field Principal

operating

period Metals

mined

Mine

type

%

Ore

open

cut

Ore

milled

Mt

Ore grade Production Waste rock

Mt

%Ni%Cu%Co kt Ni kt Cu kt Co

Kambalda(41)1967–2004a Ni–Cu–Co UG–42.07 3.13～0.25～0.061166.7》60》10No data

Scotia(41)1970–1977Ni–Cu–Co UG–0.823 2.140.15～0.0418.62 1.20～1No data

Nepean(41)1970–1987Ni UG– 3.15～3.3––33.6––No data

Carr Boyd(41)1973–1975Ni–Cu–Co UG–0.178 1.560.48– 1.950.74–No data

Redross(41)1973–1978Ni–Cu–Co UG–0.403 3.37～0.2–13.0～1–No data

Spargoville(41)1975–1980Ni–Cu–Co UG–0.601 2.37～0.15–12.58～1–No data

Windarra(59)1974–1991Ni–Cu UG/OC～308.08 1.56～0.15–93.45》2.2–～21

Forrestania(43)1992–999Ni UG/OC～25 3.81 2.0––55.2～1–No data

Leinster–Agnew(42)1978–2004a Ni UG/OC b N533.05 2.12––566.2––No data Mt Keith(46)1994–2004a Ni OC100104.510.61––422.6––No data

Emily Ann(51)2001–2004a Ni UG–0.847 3.02––20.26––No data

Rav8(62)2000–2004a Ni UG/OC45.10.417 3.45––12.77––No data

Black Swan(48)1997–2004a Ni UG/OC 5.1 2.244 5.26––105.3––No data

Radio Hill(44)1998–2004a Ni–Cu–Co UG– 1.00 2.78 1.940.16421.515.3 1.20No data

Cosmos(61)2000–2004a Ni OC/UG66.00.6578.35––52.5––No data

Sally Malay(45)2004a Ni–Cu–Co OC1000.261 1.310.580.07 2.70 1.470.15～5.13

Murrin Murrin c(47)1999–2004a Ni–Co OC100～11.75～1.36–～0.09125.3～18.22No data

Cawse(49)1998–2000d Ni–Co OC100 1.128 1.32–0.16510.44– 1.79No data

Bulong(50)1999–2002Ni–Co OC100 1.233 1.79–0.13917.15– 1.02～7

Greenvale–Brolga(52–53)1974–1995Ni–Co OC10031.45 1.43–0.125324.6–14.4～35(total)

a Still operating at the end of2004.

b No data is known to estimate the proportions of ore derived from underground and open cut mining.

c Murrin Murrin does not report actual ore mille

d nor or

e grades(only metal production);all values above estimated from the only available data in quarterly and annual reports.

d Caws

e was originally closed in early2001and later re-opened under a new process operating regime though no data is available since late

2000.

Fig.7.Mt Isa copper production plus remaining resources,ore grades.237

G.M.Mudd/Ore Geology Reviews32(2007)227–261

graphs could be developed for other major Cu mines,Mt Isa and Mt Lyell are good examples of the long-term changes at major mineral fields and the associated cu-mulative trends in production,ore grades and economic resources.

The principal events in the evolution of the Australian Cu industry are clearly discernable in Figs.2–8—the early dominance of SA,the emergence of QLD,NSW and TAS,the start and temporary closure of open cut mining at Mt Lyell and Mt Morgan,the development of Mt Isa,and the near exponential increase in production in the period from 1950to the present.Overall,total pro-duction is dominated by Mt Isa (6.70Mt Cu),Mt Lyell (1.49Mt Cu)and Olympic Dam (1.96Mt Cu)with ～5%of Cu being sourced as a co/by-product from Pb –Zn –Ag and Ni operations.4.Lead –zinc –silver 4.1.History

Following on from the Cu,Au and tin booms of the previous decades,the 1880s was the decade for lead –silver (Pb –Ag),and later zinc (Zn)from the 1900s.It is the 1880s to which can be attributed,directly and indi-rectly,the establishment of the majority of Australia's foremost mining companies —the Broken Hill Propri-etary Company Ltd (BHP,now BHP Billiton Ltd),Zinc Corporation,North Broken Hill Ltd (NBH),Broken Hill South Ltd (BHS)and Pasminco Ltd (now Zinifex Ltd)—the Broken Hill field has been particularly dominant in this regard.Through Broken Hill,Australia became world-renowned as a major producer of Ag,Pb and Zn.Throughout the mid-1800s there were minor attempts at mining Pb –Ag ores,such as Glen Osmond near Adelaide in 1841,the Northampton field of central western WA from 1852,the small Yerranderie and Captain's Flat fields in eastern NSW in the 1870s,and the Chillagoe field in northern QLD towards the end of the 1870s (Legge and Haslam,1990).In general these early mines were of a relatively small and commonly unprofitable nature (or at least very limited periods of profitable working).

General interest in Pb –Zn –Ag mining was low-Cu,Au and tin were the minerals of proven abundance and profitability.In the 1880s several major new fields were discovered —Thackaringa –Silverton in 1876(but not confirmed until 1880)and Broken Hill in 1883in far western NSW,Zeehan of western TAS in 1882,and Lawn Hill of north-western QLD in 1887.

The confirmation of the Thackaringa –Silverton field led to a small rush,especially following discovery of the Umberumberka deposit.In the end the rush was relatively short-lived and failed to deliver significant profits but led prospectors to the real prize nearby.In September 1883,boundary rider Charles Rasp dis-covered what he thought was a prominent outcrop of ‘tinstone ’—which turned out to be Pb –Ag ore and the Broken Hill ‘line of lode ’was on its way to world renown.

The Broken Hill Proprietary Company Ltd (BHP)was registered on 10August 1885and the development of mining,milling and smelting operations aa4c0ffc19e8b8f67c1cb9e7ter in 1885,the northern end was taken up by the Broken Hill North Silver Mining Company Ltd (later North Broken Hill Ltd or NBH)while the southern end

was

Fig.8.Mt Lyell copper production plus remaining resources,ore grades.

238G.M.Mudd /Ore Geology Reviews 32(2007)227–261

pegged by the Broken Hill South Silver Mining Com-pany Ltd(BHS).Remaining areas along the line of lode were soon pegged by numerous hopeful companies, most backed by British investors eager to participate in the latest Australian mineral rush.By the end of the decade Broken Hill was a world-renowned Ag field with increasingly important Pb production.At this stage there was no interest in Zn—the focus was squarely on the rich Ag grades being mined from oxidised ore in the weathered zone by BHP and others(Jaquet,1894; Andrews,1922).

Over the following two decades the Broken Hill field had to solve two critical challenges—the decline of readily mineable and easily smelted oxidised ore and the Zn problem(i.e.,no economic recovery technology and limited market interest in Zn relative to Pb–Ag).The early mining of the oxide ore lead to easy milling and smelting but the rapidly declining Ag grades of this ore forced the field to address the challenge of future ore sources(Jaquet,1894;O'Malley,1988).By this stage there was known to be very large resources of deeper sulphide ore(mainly within the NBH and BHS leases) but there was no method at that time for economic milling.Engineers and metallurgists set to work and developed an array of processes for concentrating the sulphide minerals from fresh ore(e.g.,the Wilfley Table)(Raggatt,1968;O'Malley,1988;Parbo,1992).

In order to continue improving economic efficiency on the Broken Hill field,the zinc problem then had to be solved.In1904it was estimated that the tailings dumps contained6.69Mt grading6%Pb,19%Zn and184g/t Ag(Woodward,1965)—but there was no known method for efficient Zn recovery.Metallurgical exper-tise was again mobilised and the method of flotation was invented with great success,including key variants of the method(Raggatt,1968).The technology was applied to the Zn-rich tailings by the British-backed Zinc Corpo-ration(ZC)in1905,among other companies,and later modified to a froth flotation technique for fresh ore.The use of flotation went on to revolutionise the milling of numerous sulphide ores around the world(O'Malley, 1988;Lynch,1992;Bear et al.,2001).By1910the future again seemed assured for coming decades.

The Broken Hill field saw a20month-long strike from 1919,which,when combined with the economic impacts of World War I and a disastrous fire at the Port Pirie smelter in1921,caused great economic pain for the field and most of its companies due to the loss of production(this period is clearly evident in the figures)(Andrews,1922).

The Broken Hill ethos of continually evolving mining and metallurgical practices has helped to underpin the profitability of several companies(Raggatt,1968).Many of the companies who started life in the Broken Hill field have gone on to invest in and/or develop many other mines or industries across Australia.For example (Woodward,1965;Raggatt,1968;Griffiths,1998):?Large smelting centres at Port Pirie,SA,and Cockle

Creek,NSW;

?BHP initiated iron ore mining in SA in1903,initially for flux at the Port Pirie Pb smelters but later steel production at Newcastle in1915(primarily as a way to provide for its future beyond Broken Hill);?Many Broken Hill company directors,engineers and metallurgists went on to important roles in guiding other mining companies and ventures to prosperity;?The1916creation of the Electrolytic Zinc Company of Australasia Ltd(EZ)to establish a Zn refinery near Hobart,TAS(initially partly-owned by most Broken Hill companies);

?BHS developed the CSA mine at Cobar in the mid-1960s;

?The Zinc Corporation formed the Consolidated Zinc Corporation,which in1962was merged with UK's Rio Tinto Zinc(RTZ)to form Conzinc Riotinto Australia Ltd or‘CRA’(now fully integrated with RTZ to form Rio Tinto Ltd/Plc,a dual-listed Anglo-Australian company);BHS and NBH were taken over by CRA/Rio Tinto in1980and2000,respectively.

The ties with the Broken Hill field have now been effectively closed by all companies.The exit of the founding BHP occurred in1939,while the operations of North Broken Hill and the Zinc Corporation(which included BHS from1980)were merged into a single independent company in1987called Pasminco Ltd (now Zinifex,who sold the operation to Perilya Ltd in 2002).The ore resources at Broken Hill as of March 2005are,remarkably,17.73Mt grading5.9%Pb,9.9% Zn and63g/t Ag(2005Edition,Perilya,various years). Despite an air of inevitability there remains some opti-mism for the great lode(e.g.,Plimer,2004).

In northwest QLD in February1923,to the west of the Clonclurry Cu field,the Mt Isa Pb–Zn–Ag field was discovered by John Campbell Miles.However,the field's potential was slow to be realised,due primarily to the lower ore grades compared to Broken Hill,the more difficult nature of the finer grained ore to mill and smelt,the small quantity of easily treatable oxidised ore and Mt Isa's sig-nificant remoteness(Berkman,1996).Unlike Broken Hill, however,the entire field was quickly amalgamated into a single operating company by late1925—Mt Isa Mines Ltd(MIM)(Raggatt,1968)(MIM was recently taken over by Swiss-based Xstrata Ltd in mid-2003).

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The complete control by MIM soon proved to be a significant advantage—the field needed intensive capital to finance it into production.Operations at Mt Isa required completely new infrastructure on a large-scale, including roads,a long-distance railway,a new town,as well as major mining and metallurgical facilities(Rag-gatt,1968).The development of Mt Isa in the late1920s was arguably Australia's first mega-scale and planned mining and smelting project(Mt Lyell,though signif-icant for its time,was much smaller in scale relative to Mt Isa).The pioneering effort was based on a1928ore resource of21.2Mt grading6.1%Pb,8.2%Zn and 115g/t Ag(Legge and Haslam,1990).For comparison, in1928the Broken Hill field milled1.2Mt at14.3%Pb, 11.2%Zn and205g/t Ag while known ore resources were of the order of15Mt at13.7%Pb,12.1%Zn and 186g/t Ag(based on data compiled).

When Mt Isa began production in1931the world Pb market was effectively collapsing.By1932the price of Pb had fallen by more than half,forcing MIM to continue to seek further financial assistance and again in 1939.MIM delivered a small profit for1936/37,but it was not until after World War II and the development of a large Cu operation that MIM finally delivered ongoing profits.In1947–1948the Hilton and George Fisher Pb–Zn–Ag deposits were discovered20km north of Mt Isa(Legge and Haslam,1990).As of June2005,the total Pb–Zn–Ag ore resources at Mt Isa,including Hilton,George Fisher,Black Rock and potential‘Isa open cut’resources,were467Mt grading4.7%Pb,7.4% Zn and95g/t Ag(2005Edition,Xstrata,various years).

Throughout the latter half of the1900s numerous, and often significant,discoveries of Pb–Zn–Ag or similar ores have been made,including:

Lead–zinc–silver Copper–zinc–silver ?1955—McArthur River-HYC,

NT;

?1978—Benambra,VIC;

?1964—Woodcutters,NT;?1979—Golden Grove,WA.?1966—Beltana–Aroona,SA;

?1970—Lady Loretta,QLD;Lead–Zinc–Silver–Copper–

Gold

?1971—Sorby Hills,WA;?1969—Woodlawn,NSW ?1972—Elura,NSW;?1974—Que River,TAS;?1976—Abra,WA;?1975—Thalanga,QLD;?1978—Cadjebut–Blendevale,

WA;

?1983—Hellyer,TAS.

?1989—Century Zinc,QLD;

?1990—Cannington,QLD;

?1991—Magellan,WA.

The McArthur River-HYC deposit(the HYC stands for“Here's Your Chance”)was discovered by MIM geologists in1955.Ore resources were effectively as large as the Broken Hill or Mt Isa fields with strong Zn grades but of a lower overall Pb–Ag grade and con-taining very finely disseminated sulphides—making the ore very difficult to treat(Beattie and Leung,1993). Prior to development in the mid-1990s resources were estimated at227Mt grading4.1%Pb,9.2%Zn,41g/t Ag and0.2%Cu(Logan et al.,1990).The milling problems took MIM some decades of research to overcome,inventing new‘Isamill’grinding technology in the process(Enderle et al.,1997;Pease et al.,2006)to produce a saleable mixed Pb–Zn concentrate(as oppo-sed to separate concentrates from standard Pb–Zn–Ag operations).Commercial operations started in1995.

Most of the above-listed deposits have now been developed.Some higher grade mines,such as McArthur River and Century Zinc(high Zn)and Cannington (high Pb–Ag)have made considerable contributions to production and stabilising or even increasing average Australian Pb–Zn–Ag ore grades in the short-term(see Fig.9).

Although the original emphasis at Broken Hill was on Ag and then quickly shifting to Pb,the primary profitability and overall importance in the Pb–Zn–Ag sector is now placed on Zn production,which is now more than double the production of Pb.Based on pre-sently known resources,future Pb–Zn–Ag production will be derived,like Cu,from generally lower grade ores and proposed larger open cut mines(see next section). By2005,Australia had produced36.1Mt Pb and 44.4Mt Zn,with34%and51%,respectively,being produced between1985and2005.

4.2.Production results

The compiled statistics for Pb–Zn–Ag mining are shown in Figs.9–15,with total production from major Pb–Zn–Ag mines/fields given in Table2.The long-term trends of ore milled and ore grades(Figs.9and10),are dominated by Broken Hill for most of the period presented.The data for the Northampton field(WA) from1850to1883is not included since it is was a very small production and only beneficiated concentrate data are available—not as-mined ore grades.Prior to1913 the annual data for the Broken Hill field was not reported consistently,though data for some years and some companies are available either from NSWDM(various years)or the online archives of the NSW Department of Mines(the‘DIGS’system).Due to the changing milling and smelting sites of this period,and the fact that a considerable degree of the mined metals were refined in states other than NSW(e.g.,SA or exported to Europe), there is some confusion over the extent of Broken Hill-

240G.M.Mudd/Ore Geology Reviews32(2007)227–261

derived production (hence the variability in calculated

versus reported production until about 1900).The period

1883–1912is therefore based on approximate data.This

early period is also based on effective metal yields from

the ore,whereas from 1913onwards,full reporting by

NSWDM (various years)is based on actual assayed ore

grades and inpidual mine production.The drop in ore

milled,ore grades and production for 1920is related to

the prolonged strike at Broken Hill.

The high variability in Zn grades until 1910is related

to the problem of Zn extraction.As data prior to 1913is commonly based on yield and not assay grade,only the payable Zn quantity in concentrates is available and the true Zn grade therefore remains unknown.From the 1890s,given the shift to sulphide ores and the published assay grades of ore resources for some of the major Broken Hill companies (e.g.,BHP,NBH,BHS),it is most likely that true Zn grades were comparable to Pb of around 20%Zn (e.g.,the tailings dump by 1904contained 19%Zn),as marked on Fig.9.The short-term decline in Zn grades from 1930to 1935is due the start up of Mt Isa in 1931,which focused on

higher Fig.9.Lead –zinc –silver ore grades.

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G.M.Mudd /Ore Geology Reviews 32(2007)227–261

grade Pb –Ag ore (～10.5%Pb,～170g/t Ag)in its early years with lower Zn grades (～4%)while Zn production began in 1935from combined Pb –Zn –Ag ore (～8.3%Pb,～10.5%Zn,～200g/t Ag).Further peaks in Zn grades are related to temporary mining of higher grade ores,deposit variability,and/or the start and expansion of new mines (e.g.,Rosebery,TAS,in 1936).

With respect to open cut mining there are two major issues —early open cuts at Broken Hill and waste rock data.Firstly,there is only minimal data shown for open cut mining prior to about 1960.To overcome the geo-technical stability problems of underground mining at Broken Hill,some open cut mining was undertaken to relieve underground rock stresses.The data to estimate the fraction of ore derived from this work is approximate only,with open cut ore reaching ～10%in the late 1890s.No significant further open cut mining is understood to have occurred.Secondly,there is no waste rock data included due to the fact that the respective companies

have not publicly reported such data.This is despite several open cut mines being developed since 1970,including Woodlawn (NSW),Woodcutters (NT),Cen-tury Zinc (QLD),Blackwoods,Potosi and others at Broken Hill as well as minor open cuts at Rosebery –Hercules (TAS).For the new Black Star open cut at Mt Isa (started in 2005),the waste:ore ratio is 4(Wallis,2005).The Century Zinc project has a total mine life waste:ore ratio of ～5.5(QNRME,2000).At present,like Cu,there are proposals being investigated for con-verting the underground mines of McArthur River and Mt Isa to large open cut mines,again reinforcing the need to report waste rock data.

There is no data on waste rock for underground mines.An important example in this regard is that it is possible to generate AMD impacts from waste rock at underground mines,with Captain's Flat in NSW being a prominent example.

The long-term trends in the proportion of Pb –Zn production,Fig.11,show a clear,sustained shift towards greater Zn than Pb (as noted by Legge and Haslam,1990).This is also facilitated by the development of the Cu –Zn mine at Golden Grove or Zn-dominant ores such as Century Zinc and McArthur River.Further comment on this issue is provided in the discussion section.

The Pb –Zn production by mine/field is shown in Figs.12and 13.The dominance of Broken Hill for nearly a century is clearly visible,as well as the strong con-tribution of Mt Isa and other recent mines in the latter decades of the 20th Century.In a similar pattern to Cu,there have been numerous Pb –Zn –Ag mines developed in the past few decades,including some mines with higher than average grades such as Cannington (high Pb –Ag)and Century Zinc and McArthur River (high Zn).A common feature of several of the mines/fields is the by-products produced,especially Cu and Au (see Table 2

).

Fig.10.Lead –zinc –silver ore milled and open cut

mining.

Fig.11.Lead –zinc production (fraction).

242G.M.Mudd /Ore Geology Reviews 32(2007)227–261

The degree of completeness for the ore mined and

milled,in terms of calculated versus reported production

or the fraction of Australian Pb –Zn production (Fig.14),is generally excellent and very close to 100%.As discussed above,prior to 1913full data was not reported plus there was confusion over the extraction of metals

in Fig.12.Lead production by mine/field.Note:minor producers includes Zeehan Field (1893–1922),Woodlawn (1978–1998),Thalanga (1990–1999)and Woodcutters (1985–

1999).

Fig.13.Zinc production by mine/field.Note:Minor producers includes Captains Flat (1939–1962),Thalanga (1990–1999),Woodcutters (1985–1999)and Cannington (1997–2005).243

G.M.Mudd /Ore Geology Reviews 32(2007)227–261

NSW versus that of interstate or overseas.Due to the

dominance of Broken Hill,and available data for Mt Isa,

from 1913to about 1988the data represents very close to 100%for Pb and Zn.From 1988to 2005the calculated production is more variable but still generally N

90%.

Fig.14.%Lead and %Zinc production —reported versus

calculated.

Fig.15.Australian lead –zinc production and economic resources.244G.M.Mudd /Ore Geology Reviews 32(2007)227–261

Australian Pb–Zn production versus economic resources(Fig.15),indicates sustained growth in both production and resources,though Pb has not grown to the same degree as Zn.As of December2004,it is estimated that Australia has22.9/41.0Mt Pb/Zn in economically demonstrated resources,an additional 12.2/23.4Mt Pb/Zn of sub-economic resources as well as21.6/25.2Mt Pb/Zn inferred resources,respectively (2005Edition,GA,various years).The estimated global economic Pb–Zn resources are70/222Mt Pb/Zn, respectively(2005Edition,GA,various years).

The Pb–Zn–Ag resources of potential future mines include the Mt Isa proposed open cut,314Mt at3.2%, 4.0%and70.7g/t Pb,Zn Ag,respectively(Wallis, 2005);McArthur River proposed open cut,42.8Mt at 10.4%Zn(Pb–Ag grades not stated,but for the global mineral resource are～5.7%Pb and57g/t Ag), including an estimated waste:ore ratio of～4.3(URS and MRM,2005).Resources at existing mines are generally of similar grades to production to date.

Based on presently known economic resources and 2005production of767kt Pb and1.37Mt Zn,there are sufficient resources to maintain existing Pb–Zn–Ag production for approximately25years.As noted above, known Pb–Zn–Ag ore resources,like Cu,are mostly all lower grade than present operations and proposed as open cut mines,keeping downward pressure on ore grades and upward pressure on environmental aspects such as solid wastes,energy,water and pollutant emissions per unit metal produced(e.g.,t CO2/t Cu).The ore milled and grades over time for Broken Hill and Mt Isa are shown in Figs.16and17,respectively,with cumulative production plus resources for Mt Isa shown in Fig.18.Overall,the compiled data give an excellent representation of Pb–Zn–Ag mining and milling in Australia.

5.Nickel

5.1.History

The large-scale production of nickel(Ni)is one of Australia's most recent additions to its mining indus-try—and has filled an important gap in the nation's mineral self-sufficiency.The earliest production of Ni was from the Zeehan field of western TAS.Approxi-mately585t of Ni were produced intermittently between 1910and1938from about10,000t of ore Ni–Cu sulphide ore from the Five Mile group of small mines. The ore graded8to17%Ni and5to14%Cu,though only half of the ore was sold in1913and1914.Despite broad Ni interest,the difficulty in mining these small deposits and the collapse of the Zeehan field around this time led to no further activity for several decades (McIntosh Reid,1925;Hughes,1965

). Fig.16.Broken Hill ore milled and ore grades.245

G.M.Mudd/Ore Geology Reviews32(2007)227–261

Between1953and1965,a number of important Ni prospects were discovered,namely(Marston,1984; Pratt,1996):

?1953—Claude Hills–Wingellina prospects in the Tomkinson and Blackstone Ranges of the remote corner region of north-west SA(bordering WA);?1955—Beaconsfield Ni laterite prospect,north-east TAS;

?1957—Greenvale Ni laterite prospect,northern QLD;

?1965—Marlborough Ni laterite prospects,central QLD.

However,these prospects were extremely isolated (Claude Hills–Wingellina)and/or very difficult to mill (Ni laterites).They occurred at a time,however,when world Ni demand and production was growing significantly.

In late January1966Western Mining Corporation (WMC)discovered a2.7m intersection of8.3%Ni sulphide ore from145.7m depth—indicating an important Ni prospect at Kambalda,south of Kal-goorlie,WA(Woodall and Travis,1979).Exploration sufficiently proved up Kambalda and WMC announced their discovery and intention to proceed with develop-ment on4April1966(Raggatt,1968;Parbo,1992

).

Fig.18.Mt Isa Pb–Zn production plus remaining

resources.

Fig.17.Mt Isa ore milled and ore grades.

246G.M.Mudd/Ore Geology Reviews32(2007)227–261

The Kambalda region,in Archaean geology,had not been considered prospective for Ni sulphide deposits and the global significance of the find was immediately realised—and Australia's Ni boom began(Woodall and Travis,1979).It is perhaps curious that the numerous indications of Ni mineralisation in the broader region had been missed for some decades in a major mining centre such as Kalgoorlie(Raggatt,1968).By the end of1966WMC announced an ore reserve of 1.93Mt grading4.15%Ni containing81kt Ni—a considerably higher grade than Canadian mines though smaller in size(at this time,Canada was the world's major Ni producer,averaging236kt Ni/year from ore grading～1.2%Ni;see CDEMR,various years). Kambalda ore,like Canadian ores,commonly contains around0.2and0.35%Cu.The WMC management moved quickly to capture the strong Ni market and began construction of a new mine/mill at Kambalda while exploration was still continuing(Marston,1984).

The Kambalda mill came on-stream in mid-1967and by the end of the year had produced2.1kt Ni from ore averaging4.6%Ni.The project was in a state of almost continuing expansion for many years.Perhaps the most important aspect of the unprecedented rapid develop-ment of Kambalda,especially with hindsight,was that the major Canadian Ni mines underwent protracted labour strikes from1966to1969—thereby facilitating WMC's access to supply the world market and strong profitability in the critical early years(Marston,1984). The ongoing exploration efforts proved the Kambalda region to be very rich in Ni deposits,with WMC's Kambalda reserves by1975estimated at24.55Mt at 3.23%Ni plus the7.69Mt at3.4%Ni already processed (Marston,1984).

The Kambalda discovery ignited a Ni exploration boom across Australia,but particularly WA.By1970, numerous Ni deposits had been discovered of varying economic potential,with some already in the process of development,including(Marston,1984;Pratt, 1996):

?1968—Kambalda field—Scotia,Nepean,Redross, Wannaway,and others in the Widgiemooltha–Spar-goville belt south of Kambalda;?1969—further Kambalda discoveries,Mt Windarra near Laverton,Mt Keith near Wiluna,Carr–Boyd Rocks;

?1970—Yakabindie and further low-grade deposits near Wiluna;Black Swan high-grade Ni sulphide deposit north-east of Kalgoorlie;?1971—Perseverance deposit near Agnew(now called Leinster);the Forrestania Ni field260km

south-west of Kalgoorlie(on the edge of the south-west WA wheatbelt);

?1972—Sherlock Bay Ni deposit in the western Pilbara.

The pace of discovery and delineation of Ni resources,especially in WA,is perhaps unparalleled. By June1976WA Ni sulphide resources had been estimated at85.6Mt of ore at2.4%Ni and a further 755Mt of ore at0.6%Ni,containing2.1and4.8Mt Ni, respectively(Woodall and Travis,1979).By the mid-1970s an integrated Ni industry had been developed in Australia.This included several mines in WA,Kwinana refinery south of Perth(1970),Kalgoorlie smelter (1972)and the Greenvale Ni laterite mine and associated Yabulu refinery in QLD(1974).The Ni sulphide mines were mostly very profitable for their owners,especially WMC,although Greenvale–Yabulu took some years before proving profitability.Production and develop-ment stabilised from the mid-1970s,with the difficult market conditions for Ni in the1980s dampening industry expansion(Marston,1984;Pratt,1996).

Due to WMC selling all of their Kambalda mines to junior companies(operating the Kambalda mill on a toll basis),an exact resource position remaining on the field is now somewhat difficult.Prior to this strategy,WMC stated total ore resources of17.3Mt of ore grading 3.26%Ni,containing564kt Ni(1999Edition,WMC, various years-b).Based on exploration results since this time and an analysis of numerous junior miners'annual reports,Ni ore resources are still likely to be of the same magnitude and grade.

From the early1990s the Ni industry has undergone a major expansion,bought about by a stronger Ni market, the development of new milling technology for difficult laterite deposits and several new mines coming on-stream:?1994—WMC's Mt Keith mine,WA,processing10–11Mt/year of0.6%Ni sulphide ore;?1997—high-grade Black Swan Ni sulphide mine, WA(～4.5–9%Ni);

?1999—Cawse and Bulong Ni laterite mines,WA, using new‘high pressure acid leach’(HPAL) technology(reviewed by Whittington and Muir, 2000);

?2000—Murrin Murrin Ni laterite mine,WA,using HPAL technology;

?2000—high-grade Cosmos Ni sulphide mine,WA (～7–9%Ni);

?1998–2004—Rav8(2000)and Emily Ann(2001)Ni sulphide mines,WA,plus Radio Hill(1998)and Sally Malay(2004)Ni–Cu–Co mines,WA.

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