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Australia Region

Gold Fields’ mining assets in the Australia region include a 100% interest in the St Ives, Agnew, Darlot and Granny Smith mines in the Yilgarn area of Western Australia and a 50% interest in the Gruyere project with Gold Road.

Australia
Operations

Mineral Resources

15.5Moz

Mineral Reserves

5.8Moz
  • The Mineral Resource for operations post depletion grew by 7% and with Gruyere included, the region grew by 37%
  • The Mineral Reserve for operations grew by 13% and with Gruyere included, the region grew by 62% after mining depletion of 943koz
  • Ongoing multi-year investment in brownfield exploration is imperative to realise each mine’s geological endowment potential given the orogenic style of mineralisation in the Yilgarn (US$76.3m 2016 and US$68.1m 2015)
  • The regional exploration strategy is supported by a dedicated team of geologists with broad expertise to support the sites and ensure a fully integrated approach to target generation, prospectivity mapping and exploration stage gating
  • Exploration discovery and resource extension programmes are in place at all operations, in conjunction with resource conversion drilling campaigns, aimed at replacing depletion and growing quality, high-margin reserves
  • The Proved and Probable Mineral Reserves as at 31 December 2016, do not reflect the potential inherent to the Inferred Resource and advancing exploration projects at each site

Agnew/Lawlers Gold Mine

Mineral Resources

2.1Moz

Mineral Reserves

0.5Moz

  • The FBH underground ore body now dominates production at Waroonga as the Kim lode advances to maturity and geotechnical depth constraints
  • The year-on-year reduction in Reserves post depletion has accelerated the identification of incremental opportunities to maintain mill feed, while the assessment of Waroonga North as a potential new mining front is completed
  • A dedicated team is systematically reviewing all potential to improve the resource to reserve conversion focused on mine extensional work at Waroonga North, FBH Lower, Kath Lower, Kim South Lower, while at New Holland prospects include Sheba South, Genesis 600 Series, NH Upper and Cinderella extensions
  • Maiden reserve reported at Waroonga North
  • Strong focus on exploration in prospective Cinderella Trend east of New Holland and across wider tenement package
  • LoM, based on current Mineral Reserves, extends to 2020 (four years)

Agnew has continued its focus on defining new ore sources at New Holland and Waroonga, with brownfield exploration programmes also testing targeted areas across the broader tenement package.

These include Waroonga North extensions, FBH Link and the under-explored Cinderella Trend. Agnew’s short-to medium-term focus is on maximising value from the existing resource base and its extensions to supplement mill feed while balancing efforts on discovering new mining fronts that will take over from Kim, FBH and current mining in New Holland. Mining in the FBH area and development of the Waroonga North project at Waroonga underground has continued, and extensions to FBH and profiling the full potential at Waroonga North remain priorities in 2017.

Asset fundamentals

  Asset fundamentals  
  General location     Agnew is situated at latitude 27° 55’ S and longitude 120° 42’ E in the Norseman-Wiluna Greenstone Belt. It is located 23km west of the town of Leinster in Western Australia, which is 375km north of Kalgoorlie and approximately 870km north-east of Perth. Well-established power, access roads and supporting infrastructure are in place.  
  Licence status and holdings     The Agnew Gold Mining Company Proprietary Limited (AGMC), ACN 098-385-883, was incorporated in Australia in 2001 as the legal entity holding and conducting mining activity on the Agnew mineral leases. The Gold Fields Limited Group holds 100% of the issued shares of AGMC through its 100% holding in the issued shares of Orogen Holding (BVI) Limited. Agnew controls exploration and mineral rights over a total area of 72,236ha (total of granted, inclusive of miscellaneous and non-managed tenements) and has security of tenure for all current exploration and mining leases that contribute to future Mineral Reserves.  
  Operational infrastructure     Agnew currently operates two underground mines, Waroonga and New Holland. At Waroonga, ore is sourced from the Kim South, FBH and Main North lodes that are accessed via declines. New Holland mining occurs in four primary areas: Genesis, New Holland, Cinderella and Sheba. These are accessed via declines. There are also centralised administrative offices, as well as engineering workshops at both Waroonga and New Holland and one active CIP processing plant (1.3Mtpa capacity).  
  Climate     No extreme climate conditions are experienced that may affect mining operations.  
  Deposit type     Orogenic greenstone gold deposits hosted in a number of different styles of lodes. Although all of the Agnew deposits broadly occur at the intersections between structures and stratigraphy, there are subtle differences in alteration and mineralisation, which are controlled in part by the local host rock chemistry.  
  LoM     Extensional and brownfields exploration continues, which could increase the LoM given the modelled endowment potential and under explored sections of the tenements. It is estimated that the current Mineral Reserves will be depleted in 2019 (4 years).  
  Environmental, health and safety     Agnew continues to be certified to OHSAS 18001 and ISO 14001. During 2014, the New Holland operations were amalgamated under these certifications. The mine was recertified compliant with the International Cyanide Management Code (ICMC) in September 2016.  

Brief history of Agnew

Paddy Lawlers’ prospecting party were responsible for the discovery of gold at Lamehorse Soak in 1894, approximately 10km south of Agnew. The Great Eastern and Donegal leases were pegged in the same year and mining commenced. The discovery and subsequent mining of the Waroonga, Glasgow Lass, New Holland and Cinderella areas all commenced before 1899. East Murchison United commenced the mining of nine underground levels at Main Lode in 1935 and the mine was operational until 1948.

In 1976, Western Mining Corporation (WMC) purchased the Waroonga leases and in 1984 Forsayth NL purchased the Great Eastern leases and modern open pit mining commenced at both Waroonga (450 South) and Lawlers in the mid-1980s. Additional discoveries at Redeemer (1985), Cox-Crusader (1987) and Genesis (1990) ensured that both the Emu and Lawlers mills operated at capacity while additional open pit discoveries at New Holland (1991) and Fairyland (1997) were made before underground mining commenced at New Holland in 1998.

The Lawlers operation was purchased by Plutonic Resources from Forsayth in 1992 and was subsequently acquired by Homestake in 1998. During 2001, Barrick merged with Homestake and Gold Fields acquired Agnew from WMC. The Kim South lode at Waroonga was discovered in 2002, as was Songvang OP, with production commencing in 2002 and 2004 respectively. Further discoveries were made at Fairyland UG (2009) and FBH in 2012. Gold Fields concluded the acquisition of the neighbouring Lawlers Mine from Barrick in October 2013. Access development was completed in 2015 for the FBH lodes (Fitzroy, Bengal and Hastings) at Waroonga with the commencement of mining at Cinderella and the release of a maiden reserve for Waroonga North in 2016.

Key developments and material issues

  • Drilling at Waroonga North successfully increased the Mineral Resource and defined a maiden Mineral Reserve in 2016
  • Underground production commenced at Cinderella in H2 2016
  • Focused resource definition drilling down plunge of Waroonga North is planned for 2017
  • Extensional and infill drilling at FBH has increased confidence and definition in the geology mode
  • Continued ramp-up of early stage on-lease exploration activities across the tenements and targeted near mine brownfields exploration is planned for 2017
  • Further assessment of the site open pit potential, including DobraSerica, Hidden Secret, Cinderella, Leviathan North and Claudius is scheduled for 2017
  • Establishment of a dedicated team to assess all incremental and value accretive opportunities to contribute to short to medium term mill feed

Plan of the Agnew/Lawlers mining area

Agnew

 

Darlot Gold Mine

Mineral Resources

0.22Moz

Mineral Reserves

0.06Moz

  • Continued to be cash generative with planned gold output maintained in 2016
  • Well established mining in the Lords South Lower areas with extensions, provided consistent grade and volumes in 2016
  • Conversion drilling of the CDA Oval resource completed, access development to CDA finished with first ore intersected December 2016
  • Exploration in 2016 focused on replacing production depletion, reserve growth, and the evaluation of multiple alternative mining areas to maintain critical mass and mining flexibility
  • Development and construction of an integrated 3D structural model for the mine and regional tenement areas
  • Geochemical multi-element map combined with hyper spectral analyses compiled for tenement area to supplement multi-faceted exploration platform
  • A detailed surface 3D seismic survey to bolster confidence in target generation commenced at Darlot in late 2016
  • Near mine and regional tenement package remains under explored and highly prospective

Darlot continues to strive for LoM extension beyond a one-year plan and is balancing near-term mine production and cash-flow with the assessment of exploration opportunities.

During the year, the surface and underground exploration strategy, process and methodologies were reviewed and a number of new initiatives were implemented. Work commenced with the development and construction of an integrated 3D geological structure model for the mine and broader tenement areas to define the major regional structural damage zones and fault architecture that is a controlling factor in mineralisation. This was supplemented with a resampling programme of all historical drill hole residue samples to compile a detailed geochemical multi-element map combined with hyper spectral analyses. This was used to determine regional metamorphism trends, hydrothermal fluid vectors and distinguish mafic lithologies to identify high potential ore forming areas and targets.

Sustained mining and extensions to the underground Lords South Lower (LSL) area were achieved, which was brought into full production in 2016, while ongoing extensional and conversion drilling at the Centenary Oval ore body delivered an initial Indicated Mineral Resource. In late 2016, acquisition of a detailed surface 3D seismic programme commenced at Darlot within a 1km radius of the existing mine used to generate a 3D seismic cube to map out potential geological structures that could have played a role in ore deposit placement. The emphasis here is on assessing near mine targets and the potential for a Centenary Depth Analogue (CDA), which is viewed as a potential replication of the ore body mined in the Centenary Deposit.

The exploration budget increased to A$11.0m in 2016 (A$9.6m 2015). Exploration activities are focused on both underground and surface prospecting and assessing and converting extensional and lease endowment opportunities to extend Darlot’s life.

Brief history of Darlot

Gold was first discovered in the Lake Darlot region in an alluvial field in late 1894. Initial exploration and production focused on readily extractable gold from the alluvial deposits, however, production from these areas is poorly documented.

The discovery of high-grade quartz vein hosted deposits and the depletion of the alluvial fields changed the exploration focus in the area. Mines at the time included King of the Hills, Saint George, Monte Christo and Zangbar. These were all located within the current Darlot tenement M37/155.

In 1935, a syndicate undertook limited drilling of the Zangbar and Monte Christo quartz lodes. The high-grade lateritic gold section of Monte Christo was mined by open pit in the 1950s.

Modern exploration commenced in the project area in the late 1970s and focused on a re-evaluation of historical mining camps, as well as extensions and repetitions of known mineralised veins. Interest in the area was renewed in the mid-1980s. From 1986 to 1988, Sundowner Minerals NL undertook an aggressive exploration programme around the Monte Christo area and successfully delineated sufficient resources to commence open-cut mining at Monte Christo and Darlot in 1988. In December 1992, Plutonic Resources Group acquired Sundowner Minerals NL. Open-cut mining continued until December 1995 and yielded approximately 400,000oz of gold.

Continued exploration confirmed down-dip extensions to the Darlot lodes. This work culminated with underground development and mining of the Darlot lodes, which began in October 1995.

During August 1996, a drill hole intersected a 33m section grading 8.0g/t of gold. This discovery drill hole for the Centenary ore body was approximately 1.2km east of the Darlot open pit. Underground development to the Centenary ore body from the Darlot workings was initiated during December 1996.

In May 1998, Homestake Mining Company acquired Plutonic Resources Group and in June 2001 Barrick merged with Homestake. In October 2013, Gold Fields acquired the Darlot mine and tenement package from Barrick.

Key developments and material issues

  • Continued to be cash generative with gold output maintained in 2016
  • Established mining in the Lords South Lower areas and extensions delivered consistent grade and volumes in 2016
  • Conversion drilling of the CDA Oval resource finished and access development to CDA completed with first ore intersected in December 2016
  • Exploration focused on replacing production depletion, reserve growth and the evaluation of multiple alternative mining areas to maintain critical mass and mining flexibility
  • Development and construction of an integrated 3D geological structure model for the mine and regional tenement areas
  • Acquisition of a detailed surface 3D seismic programme commenced at Darlot in late 2016
  • Near mine and regional tenement package remains highly prospective in the long term
  • In accordance with GFI’s portfolio management strategy, the decision has been made to sell Darlot

Plan of the Darlot mining area

Darlot

 

Granny Smith Gold Mine

Mineral Resources

6.5Moz

Mineral Reserves

1.7Moz

  • Substantial 0.4Moz increase (+29%) in the Wallaby underground Mineral Reserve, post depletion
  • Significant 1.2Moz increase (+24%) in Mineral Resource, post depletion
  • Initial Inferred Resource (770koz) declared for Wallaby Zone 135 re-enforces ore body consistency at depth
  • Exploration continues to grow the Wallaby lodes laterally and at depth
  • Regional exploration, outside of Wallaby, delivering encouraging early stage results
  • Improved geology and estimation model supported by favourable drill results for the Granny Smith ore body (open pit and underground) has resulted in a total resource of 544koz and a potential mining front outside of Wallaby
  • LoM based on current Mineral Reserves extends to 2025 (nine years)

The Granny Smith Mineral Resource ounces increased by 24% (+1.2Moz) in 2016 post depletion, as a result of a successful resource definition and extensional drilling campaign at the flagship Wallaby underground mine, where a new Inferred Resource of 770koz has been declared for Zone 135.

The Mineral Reserve ounces also increased by 29% (+0.4Moz) in 2016, post depletion, following a very fruitful Mineral Resource to Mineral Reserve conversion programme at Wallaby. Early stage exploration drilling down to Zone 150 indicates consistency in the gross geology and mineralisation, which supports the positive outlook for the deposit at depth. There is a strategic requirement to assess potential outside of Wallaby underground to increase overall site flexibility and leverage mill throughput given the current campaign milling. Studies are progressing with an improved geology and estimation model at Granny Smith (OP and UG), supported by favourable drill results that will bolster the Goanna OP resource for a potential cutback and a second lode is being targeted at Granny Smith UG. Regional exploration across the tenement package is delivering very promising early stage results.

Mineral Reserves, net of production depletion, have grown incrementally for the last three years since acquisition, from 838koz to the current 1,693koz. A trend that is testament to the ongoing investment in discovering and developing new and extensional high-quality ounces at Wallaby underground mine.

Asset fundamentals

Asset fundamentals  
General location     Granny Smith is situated within the Yilgarn Craton at an elevation of 400m amsl and located at latitude 28°51’09” south and longitude 122°18’35” east, and is located approximately 400km north-east of the town of Kalgoorlie in the eastern Goldfields of Western Australia in the Laverton District.  
Licence status and holdings     GSM is owned by GSM Mining Company Pty Ltd, a wholly owned subsidiary of GFI. This entity came into being on 1 October 2013, following Gold Fields’ acquisition of the asset from Barrick Corporation. GSM controls exploration and mineral rights over a total area of 63,947ha, plus another 8,263ha miscellaneous and non-managed tenements (a total of 86 tenements) and has security of tenure for all current exploration and mining leases that contribute to future Mineral Reserves.  
Operational infrastructure     Granny Smith is currently mining four lenses from the Wallaby ore body (Z70, Z80, Z90 and Z100), accessed from a single decline. Mining administration and maintenance is located at the Wallaby mine. Ore is processed at the Granny Smith CIP processing plant under campaign milling conditions and is located 15km east of the Wallaby underground mine.  
Climate     The climate is semi-arid and temperatures vary from an average minimum of 4° C in June to an average maximum of 36° C in January. The average annual rainfall total is 220mm. No extreme climate conditions are experienced that materially affect mining operations.  
Deposit type     Orogenic greenstone gold deposits hosted in a number of different styles of lodes. The Granny Smith lodes comprise vein stock works localised by a northerly trending shear at the margin of a granodiorite. The Wallaby lodes are flat lying alteration zones hosted within magnetite amphibole altered conglomerate.  
LoM     Ongoing extensional and brownfields exploration continues, which will sustain an extended LoM well beyond current reporting. It is estimated that the current Mineral Reserves will be depleted in 2025 (nine years) or six years at current levels of production.  
Environmental, health and safety     Cyanide Code recertified in 2014, ISO 14001 and OHSAS 18001 recertification completed. GSM is in compliance with all environmental legislation.  

Brief history of Granny Smith

The Goanna and Granny Smith deposits were discovered in 1979 by CSR Ltd. In 1988, Placer Pacific acquired CSR’s 60% interest with the remaining 40% held by Delta Gold NL.

In 1989, mining at GSM commenced in the Granny Smith pit and continued in subsequent years with the development of the Goanna pit, the Windich pit and nearby satellite pits. First gold was poured in 1990.

In 1992, the Keringal and Sunrise deposits were discovered 18km and 34km south of Granny Smith respectively, with ore production from both commencing in 1994. The Wallaby deposit was discovered in 1998, 11km south-west of Granny Smith, with first ore delivered to the mill in November 2001.

Barrick acquired 100% of Placer Dome shares on 20 January 2006. The Wallaby open pit was mined from October 2001 until December 2006 and produced 13.6Mt at 3.44g/t Au for 1.5Moz of gold. Underground mining at Wallaby commenced in December 2005 and is ongoing.

Gold Fields acquired 100% of the Granny Smith gold mine on 1 October 2013 as part of the purchase of the Yilgarn South operations.

Ongoing exploration drilling has expanded the Mineral Resource footprint of the Z100 and Z110/120 lodes and outlined significant mineralised zones at Z135 and Z150, with Z135 reporting a maiden Inferred Resource of 770koz in 2016.

Key developments and material issues

  • Exploration drilling continues to discover, extend and convert high-margin resource ounces from the Wallaby ore body which remains open both at depth and laterally
  • Ongoing exploration drilling has expanded the Mineral Resource footprint of the Z100 and Z110/120 lodes and outlined significant mineralised zones at Z135 and Z150, with Z135 reporting a maiden Inferred Mineral Resource of 770koz
  • The resource development strategy will continue to focus on identifying the potential of the Wallaby system down to the Z150 level, including geotechnical modelling and metallurgical response testing
  • Consolidation of the Granny Smith underground (0.4Moz) and open pit (0.14Moz) resources in 2016 from enhanced geological models
  • Early stage surface exploration over the greater tenement package has continued to return a large number of aircore anomalies, some of which occur over a 2km strike length
  • Several target areas have been identified over the tenement package for initial drilling and follow up during 2017
  • Ongoing plant upgrades and refurbishment during 2016 has continued to improve metal recovery
  • Current LoM is viewed conservative given Wallaby resource extension programmes and highly prospective early stage brownfield exploration

Plan of the Granny Smith mining area

Granny Smith

 

St Ives Gold Mine

Mineral Resources

3.3Moz

Mineral Reserves

1.7Moz

  • A 13% increase in Mineral Reserve and 5% improvement in Mineral Resource ounces reflects a return on ongoing investment in exploration
  • Discovery accounted for 464koz mainly from Invincible Pit, Invincible UG, Invincible South and Neptune
  • Invincible open pit mining continued to perform well through 2016 and is now the mainstay for open pit production
  • Invincible underground exploration and down dip resource growth continued in 2016 and development for underground mining will start in 2017. Intensified exploration continues, targeting discovery of the next generation of mines, with exploration focused at Invincible underground, Invincible South, Speedway Trend, Eastern Causeway and the Kambalda West tenements
  • Several new areas with multiple highly prospective targets are emerging from generative work and exploration conducted in 2016
  • Development and ore production from Stage 2 Neptune continued in 2016 with Stage 3 development commencing toward the end of 2016
  • Definition and drill testing of the near surface extensive palaeochannel network across tenements commenced to define the extent of the mineralised system
  • LoM based on current Mineral Reserves extends to 2021 (five years)

At St Ives, the multi-year investment in exploration and project development is paying dividends, with increases to the Mineral Resource and Mineral Reserve in 2016. New discovery accounted for the bulk of the increased Resource base, mainly from Invincible Pit, Invincible UG, Invincible South and Neptune. Invincible OP continued to perform well in 2016 and the footprint will be extended with the start of development for Invincible underground in 2017.

With the focus on securing new mines to sustain the current LoM, the open pit opportunities in the Central Corridor/Playa area will be advanced in 2017, along with pre-resource opportunities at the Invincible Deep, Yacht Club and the Speedway Shear prospects. The palaeochannel gold project will be advanced in 2017 aimed at refining the geological modelling and resource block models and to generate an initial scoping study, covering mining and processing options.

Asset fundamentals

Asset fundamentals  
General location     The St Ives mining operations extend from five to 25km south south-west of the town of Kambalda in Western Australia, approximately 630km east of Perth at latitude 31° 12’ S and longitude 121° 40’ E. The nearest major settlement is the town of Kalgoorlie situated 80km to the north, with well-established power grids, access roads and supporting infrastructure.  
Licence status and holdings     St Ives controls exploration and mineral rights over a total area of 112,092ha, which is the total of the managed granted tenements and has security of tenure for all current exploration and mining leases that contribute to future Mineral Reserves (two additional tenements (291ha) are non-managed).  
Operational infrastructure and mineral processing     St Ives currently operates one underground mine, which is accessed via a decline, and three open pits, a centralised administrative office, an engineering workshop and a 4.7Mtpa CIP processing plant.  
Climate     St Ives is situated in an area of arid bush land. While occasional storm activity may cause minor delays to open pit mining operations, the climatic conditions do not materially impact the normal operations of the site.  
Deposit type     Archaean orogenic greenstone gold hosted in a number of different styles of mineralisation. Lode, supergene and palaeoplacer-style deposits characterise the range of ore body types.  
LoM     Ongoing extensional and brownfields exploration continues and could increase the LoM given the prevailing Inferred Resource and strengthening exploration pipeline. It is estimated that the current known Mineral Reserves will be depleted in 2021 (five years).  
Environmental, health and safety     The mine maintained OHSAS 18001 Occupational Health and Safety Management System certification and ISO 14001 Environmental Management System certification. St Ives was certified as fully compliant with the ICMC in 2013. In late-2016, St Ives was found to be non-compliant to the code. Strenuous efforts are being made to attain certification, which is expected in early-2017.  

Brief history of St Ives

Gold was discovered at Kambalda Red Hill camp in 1897 and during the following 10 years, other gold-bearing locations, such as Victory, were discovered with an estimated total production of 31koz, mostly from the Red Hill group of mines.

Iron-nickel sulphides were discovered near the old Red Hill mine. Western Mining Corporation (WMC) acquired ground and developed a mining and milling operation. From 1966 to 1996, the region produced approximately 34.0Mt of ore at an average grade of 3.1% nickel.

In 1981, the Victory-Defiance complex (Leviathan area) was discovered. Gold production commenced at St Ives using a 0.5Mtpa treatment plant (later expanded to 1.2Mtpa) located at the Kambalda Nickel Concentrator site. In 1988, a new 3.1Mtpa CIL facility was constructed 25km south of Kambalda at St Ives.

During 2001, a 2.0Mtpa heap leach facility was commissioned during the period when Gold Fields Limited acquired St Ives. In 2004, the 4.8Mtpa Lefroy mill was constructed and fully commissioned in early 2005.

An aggressive exploration programme was started in 2006, with full field aircore drilling, and in 2007, the Cave Rocks and Belleisle underground mines were established. Initiation of the consolidated Leviathan open pit area commenced in 2008.

The Athena-Hamlet deposit was discovered in 2009. This was followed by continued discovery and growth of the Hamlet deposit and commencement of the Athena mine with the first ore intersected in May 2010. Athena reached commercial levels of production in September 2011. Hamlet development intersected first ore in October 2011 as part of a new mine development programme.

During 2012, stoping commenced at Hamlet and Cave Rocks LoM was extended, as well as an early-stage discovery of a new camp (Invincible deposit). In addition, conversion to open pit, owner mining was completed and heap leach processing stopped.

Production from the Neptune palaeochannel open pit commenced in 2013. Following a hiatus in 2015 while reserves were expanded, production recommenced in 2015 and continued through 2016 into 2017.

The ongoing exploration strategy delivered the Invincible camp and group of deposits in 2013, which remains the mainstay of LoM production. First production was achieved at Invincible in Q1 2015. Further depth and lateral extensions to the Invincible deposits will be actively explored as part of the 2017 exploration programme.

Key developments and material issues

  • Reversed four-year downward trend in Mineral Resources and Mineral Reserves
  • Continued investment in the promising mine extensional and regional exploration project pipelines
  • Sustained cornerstone production from the Invincible open pit
  • The Invincible camp has achieved Mineral Resources in excess of 1.4Moz and open pit and underground Mineral Reserves of 362koz and 453koz respectively
  • Maiden Invincible South underground reserve of 188koz, with a total Mineral Resource for Invincible South of 368koz, which is open down-plunge
  • Exploration of early stage targets along the highly prospective Invincible (Speedway) trend and Eastern Causeway are providing encouraging results with an initial Mineral Resource declared for the Justice deposit
  • Drill testing of the extensive palaeochannel network across tenements to define the extent of the mineralised system commenced
  • Athena completed mining of final stopes in Q1 2016
  • In-pit tailing disposal commenced at Leviathan in Q4 2016

Plan of the St Ives mining area

St Ives

 

Gruyere Project – 50% attributable to GFI

GFI’s 50% ownership is held by Gruyere Mining Co Pty Ltd and will be reported as managed, unless otherwise stated

A long-life, low-cost, undeveloped gold project in the eastern Yilgarn, Western Australia

Mineral Reserve

1.76Moz gold

Mineral Resource

3.31Moz gold

Gruyere is under first time reporting for Gold Fields as part of the Gruyere Project Joint Venture (JV) with Gold Road Resources Limited (Gold Road). Mineral Resources and Ore Reserves are reported as at the time of the JV deal and match the figures in the Gold Road 7 November 2016 ASX announcement.

The feasibility study for the open pit project on the Gruyere deposit, generated a ~13-year LoM and the Ore Reserves are based on mining and processing parameters from the feasibility study. The mine will be developed and operated under Gold Fields management and the JV committee.

Asset fundamentals

Asset fundamentals  
General location     The Gruyere deposit, centered at latitude 27° 59' south and longitude 123° 50' east, within the Yamarna Terrane of the eastern Yilgarn, Western Australia. Gruyere is located 200km east of Laverton and 1,000km north-east of Perth.  
Licence status and holdings     St Ives controls exploration and mineral rights over a total area of 112,092ha, which is the total of the managed granted tenements and has security of tenure for all current exploration and mining leases that contribute to future Mineral Reserves (two additional tenements (291ha) are non-managed).  
Deposit type     Archaean orogenic greenstone gold hosted in a number of different styles of mineralisation. Lode, supergene and palaeoplacer-style deposits characterise the range of ore body types.  
LoM     Ongoing extensional and brownfields exploration continues and could increase the LoM given the prevailing Inferred Resource and strengthening exploration pipeline. It is estimated that the current known Mineral Reserves will be depleted in 2021 (five years).  

Brief history of Gruyere Project

Gold Road discovered the mineralisation at Gruyere in August 2013 with interface rotary air blast drilling. To date, a total of 87,066m have been drilled from 470 holes on the project [357 reverse circulation (RC) holes for 41,264m, 73 holes with RC pre-collars for 14,694m RC and 16,506m diamond core tail, and 40 full diamond drill holes (DDH) for 14,603m].

The Gruyere Project is 50% owned by Gold Fields Limited after forming a joint venture with Gold Road in November 2016. Gold Fields also has acquired a 50% joint-venture position over a further three resources within the Yamarna Terrane (Attila, Alaric, and Central Bore), comprising 144km2 of exploration and mining tenure.

Geology

The Gruyere deposit is located on a flexure point of the regional scale Dorothy Hills Shear Zone within the Dorothy Hills Greenstone Belt, where the shear zone changes from a northerly direction to a north-northwest direction. Orogenic gold mineralisation is hosted within the steep easterly dipping Gruyere Porphyry, a medium-grained quartz monzonite porphyry that has intruded the country rocks, elongated in the direction of the shear zone. The host Gruyere Porphyry averages around 90m in horizontal width through the deposit with a maximum width of 190m in the centre of the deposit and tapering to around 5m to 10m width at the northern and southern extremities. The entire Gruyere Porphyry is variably altered and gold grade is related to variations in style and intensity of alteration, structure, veining and sulphide species. Zones containing higher grade gold mineralisation above 1.2 grams per tonne (g/t) gold generally have strong albite ± sericite ± chlorite ± biotite alteration and are associated with a sulphide assemblage of pyrrhotite + pyrite ± arsenopyrite, weak to moderate foliation, common micro-fracturing and steeply dipping quartz veining. Gold mineralisation at Attila, Alaric and Central Bore comprises steeply dipping shear hosted gold in volcaniclastic sequences, with gold associated with zones of albite ± sericite ± chlorite ± pyrite mineralisation.


Plan of the Gruyere Project mining area

Gruyere Project