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Tarkwa Gold MineTechnical Short Form Report31 December 2011
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 3
Salient features
¨ Mineral Resources at 15.1 Moz (including underground).
¨ Mineral Reserves at 10.3 Moz.
¨ Solid anchor for growth in the West Africa Region.
¨ Owner-operated, high-volume, grade-driven surface operation.
¨ A well-understood predictable ore body.
¨ Focus on maintaining high mining fleet efficiencies.
¨ Life of Mine extends to 2024 (13 years).
West Africa is host to world-class gold deposits and is a premier mining destination. The Gold Fields brand is strong in the region and Tarkwa is ideally positioned to fulfil the
Gold Fields vision “To be the global leader in sustainable gold mining”.
TarkwaMining Lease
Tamale
Kumasi
Tarkwa
Accra
Takoradi
Geographic location
1
Geographic location IFC
1. Overview Page 1
2. Key aspects Page 2
3. Operating statistics Page 3
4. Geological setting and mineralisation Page 4
5. Mining Page 6
6. Projects Page 7
7. Mineral processing Page 8
8. Sustainable development Page 9
9. Mineral Resources and Mineral Reserves Page 10
10. Regulatory codes Page 13
11. Competent Persons Page 13
12. Key technical staff Page 14
13. Brief history Page 17
Tebe
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1. OverviewGold Fields Ghana Limited (GFGL) was incorporated in Ghana in 1993 as the legal entity holding the Tarkwa concession mining rights. Gold Fields Ghana Holdings Limited now holds 90% of the issued shares of GFGL after acquiring the indirect 18.9% of the issued shares belonging to IAMGold and its affiliates. The government of Ghana holds a 10% free carried interest, as required under the mining law of Ghana. The Tarkwa Gold Mine operates under seven mining leases covering a total area of approximately 20,825 hectares.
The Tarkwa Gold Mine is located in south-western Ghana near the southern end of what is commonly referred to as the Tarkwa Basin, 300 kilometres by road west of Accra, the capital of Ghana, and is easily accessible with an established infrastructure.
The open pit surface operation exploits narrow, tabular auriferous conglomerates similar to those mined in the Witwatersrand Basin of South Africa. Mining is currently taking place from six pits, Pepe, Atuabo, Mantraim, Teberebie, Akontansi and Kottraverchy and the mine utilises a conventional CIL plant as well as a heap leach facility. In the twelve months ending December 2011, Tarkwa produced 717 koz of gold from the milling and heap leach operations at a cash cost of US$552/oz.
This Technical Short Form Report reflects the latest Life of Mine plan input parameters, coupled with an updated Mineral Resource and Mineral Reserve statement, as at 31 December 2011. All Mineral Resource and Mineral Reserve figures reported are managed unless otherwise stated and Mineral Resources are inclusive of Mineral Reserves.
Cover image:
Night shift blast hole drilling operations
Note: For abbreviations refer to page 28 and for glossary of terms refer to page 29 – “Mineral Resources and Mineral Reserves Overview 2011”.
1
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 2
2. Key aspects
Independent audit Figures reported in this declaration are as reviewed by independent external consultants as at 31 December 2011 [Optiro Pty Ltd for Mineral Resources and Snowden Mining Industry Consultants (Pty) Ltd for Mineral Reserves]. Gold Fields has been informed that the audit identified no material shortcomings in any process by which the Tarkwa Mineral Resources and Mineral Reserves were evaluated
Prepared by Gold Fields Limited in compliance with the SAMREC Code (2007 edition)
Effective date 31 December 2011
Source of information This Technical Statement is a summary of the internally sourced document entitled C2011 Tarkwa Competent Persons Report
Personal inspection Personal inspection is conducted by the Competent Persons as listed, who are full-time employees of Gold Fields Limited
General location Tarkwa is located in south-western Ghana approximately 300 kilometres by road west of Accra, the capital, at a latitude 5° 15’ N and longitude 2° 00’ W. The Tarkwa Gold Mine is located four kilometres west of the town of Tarkwa with good access roads and an established infrastructure. The mine is served by a main road connecting to the port of Takoradi some 60 kilometres to the south on the Atlantic coast
Climate Although there may be minor disruptions to operations during the wet season, there are no long-term constraints on production due to climate
Licence status and holdings
The Tarkwa mine operates under mining leases covering a total area of approximately 20,825 hectares. Five mining leases, dated 18 April 1997, cover the Tarkwa property, while two mining leases, dated 2 February 1988 and 18 June 1992 respectively cover the Teberebie property. The Tarkwa concession mining leases expire in 2027 and the Teberebie property mining leases expire in 2018. All necessary statutory mining authorisations and permits are in place for the Tarkwa Mine Lease and GFGL is entitled to mine all material falling within the lease
Operational infrastructure The existing surface operation currently exploits narrow auriferous conglomerates, similar to those mined in the Witwatersrand Basin of South Africa. Following a feasibility study in 2004, the deposit is mined on an owner operated basis, and processing from 2004 to December 2011 utilised a conventional carbon-in-leach (CIL) plant as well as a heap leach facility
Deposit type The open-pit surface operation currently exploits narrow, tabular auriferous conglomerates from six open pits, Pepe, Atuabo, Mantraim, Teberebie, Akontansi and Kottraverchy
Life of Mine (LoM) It is estimated that the current Mineral Reserves will be depleted in 2023 with processing extending the mine life to 2024
Environmental/Health & Safety
Tarkwa retained its ISO14001:2004 environmental management system and certification following an external audit during the year. The mine also retained its full compliance to the ICMI Cyanide Management code
Reporting codes Gold Fields reports its Mineral Resources and Mineral Reserves in accordance with the South African Code for The Reporting of Exploration Results, Mineral Resources and Mineral Reserves (2007 SAMREC Code), and other relevant international codes such as SEC Industry Guide 7, JORC Code and NI 43 – 101. The Mineral Resources and Mineral Reserves are underpinned by an appropriate Mineral Resource management process and protocol to ensure adequate corporate governance in respect of the intent of the Sarbanes-Oxley Act
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3. Operating statistics
UnitsDec
2011Dec
20101 June2010
June2009
June2008
Open pit mining
Total mined kt 117,156 67,063 134,131 132,585 113,341 – Waste mined kt 94,927 56,008 111,051 109,906 91,960 – Ore mined kt 21,876 10,840 22,716 21,273 22,035
Mined grade g/t 1.2 1.2 1.2 1.2 1.2
Strip ratio (tonnes) waste : ore 4.4 5.2 5.2 5.1 4.7
Processing – Mill tonnes kt 11,426 5,639 11,182 7,733 5,571 – Heap leach tonnes kt 11,713 5,857 11,534 13,540 16,464
Total tonnes kt 23,138 11,496 22,716 21,273 22,035 – Mill head grade (CIL) g/t 1.4 1.4 1.4 1.4 1.5 – Heap leach head grade g/t 0.9 0.9 0.9 0.9 1.0
Total head grade g/t 1.2 1.0 1.0 1.1 1.2 – Mill yield (CIL) g/t 1.4 1.4 1.4 1.4 1.5 – Heap leach yield g/t 0.5 0.7 0.6 0.6 0.7
Combined yield g/t 1.0 1.0 1.0 0.9 0.9
Plant recovery factor
Mill % 97 97 97 97 97
Heap leach % 61 65 70 68 71
Gold produced – Mill koz 518 261 503 314 267 – Heap leach koz 199 101 218 299 379
Total gold producedkoz 717 362 721 612 646
kg 22,312 11,261 22,415 19,048 20,095
Gold sold koz 717 362 721 612 646
Financials
Surface Operating cost US$/oz 608 575 521 523 431
Total cash cost US$/oz 552 562 536 521 430
Capital expenditure US$ million 219 117 149 201 212
Notional cash expenditure (NCE) US$/oz 913 889 743 881 766
General
Employees (TEC) number 4,024 4,153 4,377 4,107 3,833
Mineral Reserves Mt 264.8 235.3 244.2 270.0 285.0
Mineral Reserves g/t 1.2 1.2 1.3 1.2 1.2
Mineral Reserves Moz 10.3 9.3 9.9 10.7 11.3
Expected Life of Mine years 13 12 12 13 141 Figures shown represent the six months to 31 December 2010. Rounding off of figures presented in this report may result in minor computational discrepancies. Where this
occurs it is not deemed significant.
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Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 4
Group Series Thickness (m) Lithology
Tarkwaian (youngest) Huni 1,370 Quartzites, minor phyllites
Tarkwa Phyllite 120 – 400
Chloritic and sericitic phyllites and schists
Banket 120 – 160Quartzites, grits and conglomerates
Major unconformity Kawere 250 – 700Quartzites, grits and conglomerates
Birimian (oldest) BirimianMeta-volcanics, volcaniclastics and sediments
The Tarkwa operation exploits narrow auriferous conglomerates, similar to those mined in the Witwatersrand Basin of South Africa and currently mines from six open pits; Pepe, Atuabo,
Mantraim, Teberebie, Akontansi and Kottraverchy.
4
The Tarkwa ore bodies are located within the Tarkwaian System, which forms a significant portion of the stratigraphy of the Ashanti Belt in south-west Ghana. The Ashanti Belt is a north-easterly striking, broadly synclinal structure made up of Lower Proterozoic sediments and volcanics underlain by the metavolcanics and metasediments of the Birimian System. The contact between the Birimian and the Tarkwaian is commonly marked by zones of intense shearing and is host to a number of significant shear-hosted gold deposits.
The Tarkwaian unconformably overlies the Birimian and is characterised by lower intensity metamorphism and the predominance of coarse-grained, immature sedimentary units.
Local geologyThe local geology at Tarkwa is dominated by the Banket Series, which can be further subdivided into a footwall and hangingwall barren quartzite, separated by a sequence of mineralised conglomerates and pebbly
4. Geological setting and mineralisation
quartzites. The stratigraphy of the individual quartzite units is well established with auriferous reefs interbedded with barren immature quartzites. The units thicken to the west and current sedimentology flow parameters indicate a flow from the east and north-east. Structurally, the Tarkwaian belt has been subject to moderate folding, and at least five episodes of deformation are recognised. The original deposition occurred in a district basin environment with associated low to steep-angle normal faulting. Subsequent
compression and folding led to development of thrust faults and reversing of previous normal faults. The final stages involved further thrusting in a south-west direction.
Sedimentological studies of the detailed stratigraphy within individual A and A footwall reef units have led to the recognition of both lateral and vertical facies variations. The modelling of these has resulted in the recognition of a cycle of events from initial channel formation and rapid down-cutting of the central channel, through a period of uplift and reworking. Finally, a period of meandering channel bars and flow reduction led to the development of low-grade conglomerates with silty interbeds. The period of uplift and reworking has been recognised as being the principal episode of gold deposition and concentration within these reefs. The C, E and G reefs style of sedimentation differs from that of the channelised, incised A reefs to a more localised sheet-flood-dominated alluvial fan deposit.
The mineralised and potentially economic conglomerate reefs are identified below from the base upwards (younging):
¨ AFc – up to three metres thick, only occurs in the west and subcrops against the A1 in the east. Well sorted with rounded clasts of quartzite and visible gold;
¨ A1 – between two and seven metres thick, moderately to poorly sorted conglomerate and thin quartzites with occasional visible gold;
¨ A3 – up to seven metres thick, moderately sorted thin
Geo
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-wes
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Gha
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« Tarkwa
Recent coastal sediments
Tertiary sediments
Dahomeyan metamorphic terrane
Togo Series Sediments
Volta Basin Sediments
Dikes
Faults
Birimian basin sediments
Tarkwaian sediments
Basin intrusives
Belt intrusives
Mafic Volcanics
Trend lines
Concession
1º 0º 1º3º
9º
8º
7º
9º
8º
7º
100 km
5
discontinuous conglomerate lenses within a package of cross-stratified quartzites, visible gold is rare;
¨ B2 (or B) – up to three metres thick, very coarse quartzites with thin lags of subrounded pebble conglomerate does not occur in the Akontansi Ridge or Kottraverchy areas;
¨ CDE – up to eight metres thick and can be subdivided into the lower C reef and upper E reef, both of which are conglomeratic and are separated by the D reef quartzite;
¨ F2 – a variably developed polymictic gravel up to two metres thick, essentially a marker horizon, except in the east where it carries low grades; and
¨ G – varies from a two to six metres thick poorly sorted conglomerate with clasts of quartzite and phyllite.
Exploration and drillingThe bulk of the Tarkwa open-pit palaeoplacer Mineral Resource has been drilled to the Measured and Indicated Mineral Resource categories at current costs and a gold price of US$1,450/oz. A regional prospectivity study conducted in 2004 did not reveal any further economic palaeoplacer nor
significant hydrothermal gold targets on the Tarkwa lease area.
Tarkwa is now a mature mine with the focus having shifted from exploration to optimising the extraction of the current Mineral Resource. The current diamond drilling programme is guided by the “unconstrained” Whittle® pit optimisations which indicate the potential for economically viable extraction of pay shoots down-dip in
some parts of the current pits. The increase in resource gold price to US$1,450/oz has resulted in an infill down dip diamond drilling programme to increase resource definition to upgrade the Mineral Resource category ahead of mining and to provide detailed information for assessment of alternative select mining cuts of the reef packages.
Sur
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Min
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Str
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the
Tark
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ore
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MAP TO BE
SUPPLIED
Intrusive Faults/Folds/Lineaments
Dompim Phyllite Roads
Huni Tarkwa Lease Boundary
Tarkwa Phyllite Open pit resource outline
Banket Hangingwall Underground stope
Banket Reef Town and villages
Banket footwall
Kawere
KOTTRAVERCHY AKONTANSI AKONTANSI (E) PEPE MANTRAIM
0
100
200
Met
res
Immature Quartzite
Submature Quartzite
Mature Quartzite
Unconformity
Horizontal, not to scale
West East
Subcrops OverPepe Roll Over
AnticlinalStructure
FW
FW
G
F
CDE
B
A3
A2
A1
Afd
Afc
AfbAfa
G
F
CDE
B
A3
A2
A1
Afd
Afc
Afb
Afa
G
F
B
A3A2A1
15000N
7500N
15000N
22500E
15000E
22500E
15000E
N ESW
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 6
5. Mining
The mine is owner operated having its own load and haul fleet of 14 excavators, ranging from 120 to 295 tonnes, 51 dump trucks with a payload of 146 tonnes, as well as ancillary equipment. Twenty-four owner-operated drill rigs are used for blast hole drilling. Maintenance of the Caterpillar fleet is carried out by Gold Fields Ghana Limited, maintenance of the excavators and blast hole rigs is carried out by contractors. In 2012, Tarkwa plans to mine a total of 136 million tonnes of material at a stripping ratio of 5.3 to 1.
Mining methodsTarkwa utilises a proven and highly selective mining methodology. The location of the mining areas is defined through the long-term planning process. The boundaries of the pits are pegged out by survey and the area is cleared of bush and topsoil. The topsoil is relocated for rehabilitation purposes. After clearing, reverse circulation grade control drilling is carried out, and geological models constructed. The short-term plans and forecasts are updated with this grade control information prior to the commencement of mining. From the highest point in the pit, material is free-dug or blasted to the first blasting reference level. Currently fresh rock and transitional zones are drilled and blasted in six-metre lifts, with excavation in three-metre flitches.
Fourteen (14) backhoe excavators are used to select waste from the ore, and vice versa, along the sedimentary horizons to an average accuracy of 30 centimetres on the hangingwall and 20 centimetres on the footwall of a reef. Pit geologists and geotechnicians supervise all digging and mineral material is classified as either RoM, delivered to one of two primary crushers, or low grade, which is stockpiled close to the primary crushers. Waste material is hauled to the nearest waste dump.
Blasting currently utilises relatively close patterns and small diameter holes, typically a 3.4-metre by
3.8-metre grid with a hole diameter of 118 millimetres and a powder factor of 0.75 kg/BCM. Larger diameter holes and an increased grid size will be utilised in the partially weathered material, while decreased grid sizes will be utilised in harder material. The small-diameter holes are used to preserve, as far as possible, the integrity of the ore/waste contacts for selective mining purposes.
Mine planning and schedulingIn general, all mine design and scheduling is undertaken using Surpac®, Datamine®, Whittle®, Xeras®, Xpac® and in-house computer software and a resource estimation model termed the indirect conditioning recoverable model (ICR). The planning cycle commences with the ratification of key input parameters, prior to producing a compliant Mineral Resource statement adjusted for all Mineral Resource depletions.
On completion of the Mineral Resource update, the planning process commences incorporating a corporate decision on macro-economic parameters, development of a two-year operational plan and the roll-out of the operational plan into an LoM plan which forms the basis of Tarkwa’s annual Mineral Reserve declaration.
Standard software is utilised to derive the optimal pit shell designs at a variety of cut-off grades. The detailed engineering and design work on the optimised pit shells and scheduling is carried out using these software packages.
A cut-off grade strategy is used in the Mineral Reserve estimation process. The cut-off defines the ore/waste segregation, and a cut-over grade defines mill/heap leach segregation. A third cut-off, termed the optimal
Tarkwa is a large, established open-pit gold mine that utilises selective surface mining methods to optimise the extraction of the sedimentary mineral deposits.
Sel
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7
Each of these initiatives are aimed at improving the profitability of the operation.
Hig
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(HP
GR
)
cut-off/cut-over, is also derived, which can be applied to increase the grade and therefore cash flow in the initial years of the LoM plan. Material between the optimal cut-off/cut-over and the process cut-off is stockpiled for treatment at the end of the LoM.
For all operational plans, a detailed (two-year) operating and capital cost budget is produced and, where appropriate, extended for the LoM production schedule. Zero-based
costing is used to formulate the two-year plan. Historic productivity data and operating costs are utilised as the basis from which the operational budget is benchmarked. All capital projects are ranked and prioritised to maximise capital efficiency and return on investment.
The gold dissolution trends show a significant decline at the heap leach facility due to reduced porosity and increased hardness of the feed ore,
which has negatively impacted the recoveries. The C2012 LoM plan is based on replacing the North Heap Leach facility with a new CIL plant.
The expansion is planned to comprise a new treatment plant with a capacity of 8 Mtpa, which will replace the current North Heap Leach facility within 36 months. This will result in the ore being treated in a more efficient way, resulting in gold recovery rates increasing from 62% to 97%.
6. Projects
The key elements in terms of optimising Tarkwa’s assets are in the areas of organic growth, efficiency and productivity. Business improvement is core to optimising the assets with the High Pressure Grinding Roll (HPGR) R&D project being a good example in point. This technology trailed on the South Heap has so far improved recoveries by up to 5%.
Tarkwa has also embarked on a pre-feasibility level study known as the “Tarkwa Expansion Project Phase Six” (TEP6) subsequent to recommendations from a “Tarkwa Options Trade-Off Study” (TOTOS) that focused on delivering a high-value strategic direction for Tarkwa. The TOTOS study recommended the installation of a conventional milling/leach circuit to offset the impact of increasing hardness and declining recoveries of the ore currently being processed through the North Heap Leach.
Other projects that were initiated in C2011 and planned to be evaluated in C2012 are:
¨ Optimising the LoM waste stripping schedule by utilising narrower cutbacks and 100 metre minimum mining widths;
¨ Evaluating alternative waste dumping and tailings disposal strategies, including co-disposal;
¨ Improvement of Heavy Mining Equipment infrastructure to support the expanded LoM mining fleet; and
¨ A scoping study to reassess if there is a realistic opportunity for ultimate economic extraction of the underground Mineral Resources at Tarkwa, is planned for 2012.
Recent re-interpretation work over the entire tenement holding has highlighted a number of conceptually prospective target areas. Target definition and initial drilling activities are planned
for 2012 to test the highest ranking.
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 8
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7. Mineral processing
Since 1999, all ore has been sourced from open-pit mining operations and is currently processed at the 9.8 Mtpa North Heap Leach facility and the 12.3 Mtpa CIL plant. A third facility, the South Heap Leach facility was closed in December 2008.
The ore is a free-milling conglomerate with negligible sulphide content. Weathering has affected rocks near the surface and a higher degree of weathering is associated with increased porosity and increased heap leach dissolution and recovery. The North Heap Leach was commissioned in 1998 to process the initial high porous ore. Phase V heap leach pad construction was completed in 2009 and a further three phases of heap leach pad construction have been accounted for in the LoM plan. As the mine gets deeper, so the percentage of weathered ore amenable to heap leaching decreases. This justified the construction of the CIL plant in 2004 and its subsequent expansion that was commissioned in January 2009. The CIL milling process provides a 97% recovery which is not possible when using heap leaching for the harder, unweathered ore, the percentage of which increases over the LoM.
The North Heap Leach employs three stages of crushing prior to agglomeration. RoM ore is directly tipped by dump trucks or reloaded by front-end loaders into a 50” x 65” Sandvik Superior primary gyratory crusher. The crushed product (100% passing 250mm and 80% passing 150mm) gravitates to a 1.83m x 6.82m D4 Jacques A Terex apron feeder, which feeds two secondary screens via a conveyor.
The oversize from the two 2.44m x 7.32m Nordberg double deck scalping screens of aperture sizes 50mm and 32mm for the upper and lower deck respectively feed two Superior gyratory secondary crushers (S6000). The undersize joins the final product to the agglomeration stockpile via a series of overland conveyors.
Secondary crushing product is fed to the tertiary hopper via series of conveyors. Ore withdrawn from this hopper is fed by six 0.75m x 1.80m Nordberg Vibratory feeders to six 2.44m x 7.32m Nordberg double deck scalping screens operating in closed circuit with six tertiary H4000 hydrocone crushers. The oversize from the upper and lower decks (32mm and 22mm respectively) feed the tertiary crushers and the discharge from the tertiary crushers is conveyed back to the tertiary bin. The undersize from the tertiary screens join the final crushing product to the agglomeration stockpile.
The agglomeration process involves the addition of 4 kg/t of cement to the crushed rock to bind the fine material and produce an agglomerate that remains stacked and porous on the heap leach pads. Following agglomeration, the ore is transferred by conveyor and stacked on the leach pads by a stacking conveyor. The heaps are irrigated with a cyanide solution which dissolves the gold as it percolates through the heaps. The pregnant solution is collected on the layer of geotextile that lines the base of the heaps and is pumped through a series of ponds to the adsorption/desorption/recovery (ADR) plant where the gold is adsorbed onto activated carbon, removed from the carbon by
acid wash, and recovered using electrowinning. The North facility has a smelt house with diesel-fired furnaces to smelt all gold produced at the North facility.
The CIL process route has a 54” x 75” Gyratory crusher that feeds two crushed ore stockpiles that have a live capacity of 45,000 tonnes (30 hours). Underneath each stockpile is a reclaim tunnel, with apron feeders that feed onto a conveyor belt, which in turn feeds the milling circuit. The milling circuit consists of a SAG and ball mill with recycle crushing in closed circuit with the SAG mill. The SAG mill has an effective grinding length of 42” with an internal diameter of 27” and 14 MW of installed power (2 x 7,000 kW twin-drive motors). The ball mill has an effective grinding length of 36’ with an internal diameter of 26” and 14 MW of installed power (2 x 7,000 kW twin drive motors) and is in close circuit with the cyclone cluster. The milling circuit is operated at a capacity of 1,450 tph. The CIL circuit consists of two trains of eight tanks in series fed from a common leach tank. The loaded carbon passes into a 15-tonne acid wash column. The gold is recovered from the loaded carbon in two 15-tonne elution circuits. Gold is recovered from solution by electro-winning and smelted in the CIL smelt house in an induction furnace.
Production ounce profile expected to grow primarily due to the planned CIL plant expansion and the installation of a secondary crusher.
Crusher pocket
Crusher
CV01 CV114 CV02 CV03
CV115
CV161
Eluted carbonscreen
2 x Regeneration kilns
2 x elutioncolumn Loaded carbon
screenAcid
column
CIL 2 tanks
CIL 1 tanks
Electrowinningcells
Pregnant solutiontank
Tailingsscreens
Gold bullionFurnace
Tailings tank
Tailings tank
Tailings 1 storage facility
Tailings 2 storage facility
Tailings screens
3 x ThickenerCarbon sizing
screens
Scats stockpile
4 x Trash screens
Mill returntank Process water
pond
Milldischarge
screen
Cyclones
SAG mill
Ball mill
CV162
Stockpile
CV04
Auxiliarystockpile
CV116
9
8. Sustainable development
Tarkwa manages risk to control and, where possible, eliminate hazards in the working environment. Tarkwa strives to achieve and maintain an outstanding health and safety performance through the participation of all employees and the application of safe, innovative processes and technologies, within a framework of OHSAS 18001 and full compliance. A comprehensive external audit of Tarkwa’s full compliance health and safety management system has been undertaken annually since 2005 and certification retained to date.
The OHSAS 18001 system is in alignment with Gold Fields Limited’s “Full Compliance Health and Safety Management System”, which is the Groupwide standard for the management of occupational health and safety in Gold Fields. This aims to achieve:
¨ The elimination of all fatal accidents at all Gold Fields operations;
¨ A 50% reduction in all accident rates over five years; and ¨ Maintain a safe and healthy working environment at all
times through quality training, effective communication and employee commitment.
The initiative has the broad support of all labour unions and associations, individual employees and management. Tarkwa operates a comprehensive employer HIV/Aids programme comprising Informed Consent Voluntary Counselling and Testing (ICVCT), disease prevention and health promotion programmes.
Tarkwa appointed an HIV/Aids Co-ordinator, who drives and oversees the implementation of an HIV/Aids programme with the full co-operation of the employee representative bodies and according to the international Labour Organisation and Gold Fields Group standards. The Co-ordinator has incorporated HIV/Aids into the induction programme on the mine for both employees and contractors. Peer educators facilitate discussions on HIV/Aids during health and safety meetings as well as providing formal counselling and training to both on-site and off-site communities.
During 2011, Gold Fields Ghana won the Global Business Coalition’s 2011 Business Action on Health Award for Workforce/Workplace Engagement – with a particular focus on HIV/Aids management, in New York, U.S.A.
Cyanide is managed under the framework of the International Cyanide Management Code. Tarkwa Gold Mine was certified as ICMC compliant in June 2008. Under the Cyanide Code, all suppliers and transporters of cyanide to the mine must comply
with the code to ensure the safe use of cyanide. Strict use of cyanide on site is continually monitored and necessary changes are incorporated into operational procedures.
Environmental management at Tarkwa is conducted within the framework of an ISO 14001:2004 certified environmental management system. Tarkwa operations are operated in accordance with Ghanaian environmental requirements, as administered by the Environmental Permitting Agency (EPA), and hold the required environmental permits and valid environmental certificates. Tarkwa complies with the EPA requirements and provides monthly monitoring returns, an annual environmental report and an update of the EMP at intervals of three years. An Environment Impact Study (EIS) for the Tarkwa expansion project was submitted to the Ghana EPA in March 2007. The document was approved on 27 May 2007.
Tarkwa is currently awaiting its certificate from the EPA for the period 2010 to 2013.
Safety statisticsClass Units June 2008 June 2009 June 2010 Dec 20101 Dec 2011
Fatalities (No) 3 0 0 1 1
Fatality rate (per mmhrs) 0.2 0 0 0.1 0.1
LDIFR (per mmhrs) 0.3 0.3 0.4 0.4 0.21 For six months to December 2010.
Tarkwa retained its ISO 14001:2004 environmental management system and certification following an external audit during 2011. The mine also retained its full compliance to the
ICMI Cyanide Management code.
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Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 10
Stockpile tonnage and grade estimates are based on accumulations of estimated tonnage and grades trucked throughout the history of the mine, and are therefore considered to be reasonably accurate. However, the grades and tonnages are discounted by 5% for processing purposes as experience has shown that this is realistically achievable when reclaiming a stockpile. Run of Mine (RoM) stockpile tonnages were reconciled to survey volumes in December 2011.
Unless otherwise stated, all Mineral Resources and Mineral Reserves are quoted as 100% and are not attributable with respect to ownership.
Mineral ResourcesMineral Resources are quoted at an appropriate in situ economic cut-off grade with tonnages and grades based on the resource block model. They also include estimates of any material below the cut-off grade required to be mined to extract the complete pay portion of the Mineral Resource.
This declaration is based on the premise that a new 8 Mtpa milling/CIL facility will be installed and commissioned by 2014 to process ore that is currently being processed through the North Heap Leach facility. The total CIL processing capacity for Tarkwa will increase to 20 Mtpa by end 2014.
Mineral Resourceclassification
Tonnes (Mt) Grade (g/t) Gold (’000 oz)
Dec 2011
Dec 2010
June 2010
Dec 2011
Dec 2010
June 2010
Dec 2011
Dec 2010
June 2010
Open pit and underground
Measured 112.0 123.5 124.3 1.5 1.5 1.5 5,361 5,798 5,940
Indicated 167.5 125.1 173.4 1.2 1.3 1.2 6,694 5,186 6,705
Inferred 33.6 14.3 26.0 2.8 3.4 3.1 2,985 1,580 2,569
Total open pit and underground 313.1 262.8 323.7 1.5 1.5 1.5 15,041 12,565 15,214
Surface stockpiles
Measured 3.4 3.3 4.2 0.8 0.7 0.7 83 77 100
Total surface stockpiles 3.4 3.3 4.2 0.8 0.7 0.7 83 77 100
Grand total 316.5 266.1 327.9 1.5 1.5 1.5 15,123 12,642 15,314
* December 2011 includes underground Inferred Mineral Resources of 22.8 Mt @ 3.53 g/t
9. Mineral Resources and Mineral Reserves
The post depletion Mineral Resources and Mineral Reserves have increased by 20% and 12% respectively as a result of the gold price increase and the new CIP plant, which will replace the
North Heap Leach within 36 months.
Modifying factors ¨ The Measured and Indicated Mineral Resources are
inclusive of those Mineral Resources modified to produce Mineral Reserves;
¨ All Mineral Reserves are quoted in terms of run-of-mine (RoM) grades and tonnages as delivered to the metallurgical processing facilities and are therefore fully diluted; and
¨ Mineral Resources and Mineral Reserves undergo both internal and external audits during the year and any issues identified are rectified at the earliest opportunity during the current reporting cycle.
Mineral Resource parameters
Dec2010
Dec2011
Mineral Resource gold price US$/oz 1,100 1,450
Cut-off for heap leach g/t 0.29 0.25
Cut-off for mill feed g/t 0.40 0.36
Cut-off for underground g/t 2.59 – 3.38 2.62 – 3.27
Mineral Reserve parametersDec
2010Dec
2011
Mineral Reserve gold price US$/oz 1,000 1,300
Cut-off for heap leach g/t 0.30 0.30
Cut-off for mill feed open pit g/t 0.42 0.40
Strip ratio waste:ore 4.90 5.30
Dilution (open pits) % 11 11
Plant recovery factor fresh ore % 97 97
Plant recovery factor oxide ore % 97 97
Heap leach recovery factor % 62 62
CIL Processing capacity Mtpa 12.3 12.3
Heap leach capacity Mtpa 9.8 9
Mine Call factor % 100 100
11
Grade tonnage curve
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Open pits
Cut-off grade (g/t)
0
50
100
150
200
250
300
350
— A
vera
ge g
rade
abo
ve c
ut-o
ff (g
/t)
— T
onne
s (m
illio
ns)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Mineral ReservesThe Mineral Reserve estimate for Tarkwa Gold Mine is based on development of appropriately detailed and engineered LoM plans. All design and scheduling work is undertaken to an appropriate level of detail by experienced engineers using appropriate mine-planning software. The planning process incorporates appropriate modifying factors and the use of cut-off grades and other technical-economic investigations.
Mineral Reserve statements include only Measured and Indicated Mineral Resources modified to produce Mineral Reserves, and contained in the LoM plan.
Mineral Reserveclassification
Tonnes (Mt) Grade (g/t) Gold (’000 oz)
Dec 2011
Dec2010
June 2010
Dec 2011
Dec2010
June 2010
Dec 2011
Dec2010
June 2010
Open pit
Proved 118.1 122.5 132.9 1.3 1.3 1.3 4,943 4,982 5,602
Probable 143.6 109.5 107.3 1.2 1.2 1.2 5,328 4,192 4,165
Total open pit 261.7 232.1 240.2 1.2 1.2 1.3 10,271 9,174 9,767
Surface stockpiles
Proved 3.2 3.3 4.0 0.7 0.7 0.7 74 75 90
Total surface stockpiles 3.2 3.3 4.0 0.7 0.7 0.7 74 75 90
Grand total 264.8 235.3 244.2 1.2 1.2 1.3 10,345 9,249 9,857
Mineral Reserve classified per mining area
Proved Probable Total Mineral Reserve
Tonnes(kt)
Grade(g/t)
Gold(koz)
Tonnes(kt)
Grade(g/t)
Gold(koz)
Tonnes(kt)
Grade(g/t)
Gold(koz)
Open pit
Akontansi 36.2 1.2 1,396 106.1 1.1 3,783 142.3 1.1 5,179
Kottraverchy 13.1 1.5 629 – – – 13.1 1.5 629
Pepe/Mantraim 30.4 1.2 1,180 10.3 1.1 375 40.7 1.2 1,555
Teberebie 38.4 1.4 1,738 27.2 1.3 1,170 65.6 1.4 2,908
Surface stockpiles 3.2 0.7 74 – – – 3.2 0.7 74
Grand total 121.3 1.3 5,017 143.6 1.2 5,328 264.9 1.2 10,345
Fold
ing
(D2)
at K
ottr
aver
chy
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 12
Factors that affected Mineral Resource reconciliation:
¨ Increased gold price;
¨ Minor changes to the Pepe-Atuabo-Mantraim-Teberebie Resource model;
¨ Depletion by mining (RoM and low grade ore); and
¨ Increase in gold price outstripped the increased cost inputs and, together with losses due to production depletion and minor resource model changes, accounts for the net increase of the Mineral Resource.
Exc
lusi
ons
Gol
d pr
ice
Mod
ellin
g
Cos
t
Dep
letio
n
Sur
face
mat
eria
l
Dec
embe
r 20
10
Dec
embe
r 20
11
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Change in Mineral ResourcesDecember 2010 to December 2011
Gol
d (M
oz)
0.812.6
15.1
0.01
0.6 0.0
5.8
1.8
Chart Data Layout
Chart Data Layout
Mineral Reserve SensitivityThe Mineral Reserve Sensitivity has been derived from the application of the relevant cut-off grades to individual grade tonnage curves of the optimised pit shells for the open pits. The Mineral Reserve sensitivities are not based on detailed depletion schedules and should be considered on a relative and indicative basis only. The following graph indicates the Managed Mineral Reserve sensitivity at -10%, -5%, Base (US$1,300), +5%, +10% and +25% to the gold price.
(Base)
Managed Mineral Reserve Sensitivity
Gol
d (M
oz)
(-10%) (-5%) (+5%) (+10%) (+25%)
Gold price (US$/oz)
1,300
15
10
5
0
9.29.9 10.3 10.8
11.312.0
Factors that affected Mineral Reserve reconciliation:
¨ Increased gold price;
¨ Depletion by mining (RoM and low grade);
¨ Minor changes to the Pepe-Atuabo-Mantraim-Teberebie Resource model; and
¨ Improved CIP plant recovery (vs. heap leach) driving optimal pit shell design and schedule.
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Change in Mineral Reserves December 2010 to December 2011
Gol
d (M
oz)
Incl
usio
ns/
Exc
lusi
ons
Res
ourc
em
odel
ling
Cos
t
Sch
edul
ing
gain
Dep
letio
n
Gol
d pr
ice
and
new
CIP
Pla
nt
Dec
embe
r 20
10
Dec
embe
r 20
11
0.79.2
10.3
0.0
3.00.6
0.6
0.1
Mineral Resources and Mineral Reserves reconciliation year-on-year
Aer
ial v
iew
of t
he T
eber
ebie
ope
n pi
t
13
10. Regulatory codes
SAMRECThis technical statement has been prepared in compliance with the South Africa Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (2007 SAMREC Code).
JSEThis technical statement has been prepared in compliance with the Listings Requirements of the JSE Limited (JSE), South Africa, specifically Section 12.
Sarbanes-Oxley ActMineral Resources and Mineral Reserves are underpinned by an appropriate Mineral Resource Management process and protocol to ensure adequate corporate governance in respect of the intent of the Sarbanes-Oxley Act.
EnvironmentalTarkwa has an environmental management team who are supported by specialists from the corporate office in Johannesburg. The systems, procedures, training, etc. are at international leading practice levels.
11. Competent Persons
Competent Persons
Mr Robert van der Westhuizen BSc (Hons) (Geology); MSc (Mining) (MAusIMM; Registration number 223783). Mr R van der Westhuizen has 32 years’ experience in the mining industry and is responsible for the overall correctness, standard and compliance of the Life of Mine planning, scheduling, reserve statement and financial analysis for Tarkwa.
Mr John A Searra: Chief Resource GeologistBSc (Hons) (Geology); MSc (Engineering). Mr JA Searra has over 26 years’ experience in the mining industry and is responsible for sampling, geology, exploration and resource estimation for Tarkwa.
Mrs Lucette Hugo, Chief Strategic Planning EngineerBSc (Mineral Exploration and Mining Geology) (MAusIMM; Registration number 992541). Mrs L Hugo has 14 years’ experience in the mining industry and is responsible for the Life of Mine planning, scheduling and financial analysis for Tarkwa.
Internal technical reviews have been conducted by the Competent Persons as listed, who are full-time employees of Gold Fields Limited.
Nig
ht v
iew
of T
arkw
a C
IL p
lant
fine
ore
sto
ckpi
les
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 14
Post Incumbent Qualifications Years Key responsibilities
General Manager Michiel van der Merwe
BEng (Extractive Metallurgy) 15 Responsible for overall strategic direction, leadership and management
Manager Mining Stephen Osei Bempah
BSc (Mining Engineering) 28 Full operational management
Mineral Resources Manager
Godfred Baba Avane
MSc Geological Engineering 16 Mineral resource management
Financial Manager Hein Muller BCom Accounting 23 Financial reporting and compliance
Human Resources Manager
Mohammed Abubakari
MPA, BA Hons Economics, ACCA 16 Human resource management
Metallurgy Manager HL
Casper Dzomeku MSc Minerals Engineering, MCSM, Exec. MBA
27 Mineral processing and metallurgy heap leach
Metallurgy Manager CIL
George Nutor BSc Mineral Engineering 18 Mineral processing and metallurgy CIL
Engineering Manager – Process
H. de Beer Diploma Mechanical Engineering Government Certificate of Competency
28 Process engineering, logistics and infrastructure management
Safety Manager D. Pienaar NADSAM (M+3) 23 Health and safety
Environmental Manager
Ben Addo BSc (Chemistry), MSc (Environmental management)
18 Environmental management
12. Key technical staff
Tark
wa
min
e vi
llage
Tark
wa
Gol
d M
ine
Pla
n sh
owin
g w
orki
ngs
and
infra
stru
ctur
e as
at 3
1 D
ecem
ber 2
011
Gha
na N
atio
nal G
rid
Co
-ord
inat
e S
yste
m
Nat
iona
l Ro
ad t
oK
umas
i/B
og
oso
/Pre
stea
1K
ottr
aver
chy
Wes
t W
aste
Dum
p
2K
ottr
aver
chy
Pit
3K
ottr
aver
chy
Sou
th E
ast
Was
te D
ump
4K
ottr
aver
chy
Eas
t W
aste
Dum
p
5TS
F 1
6TS
F 2
7C
IL P
lant
8N
orth
Prim
ary
Cru
sher
9A
kont
ansi
Pit
10A
kont
ansi
Was
te D
ump
11B
ridge
Was
te D
ump
12P
ytho
n N
eck
Was
te D
ump
13W
est
Hill
Was
te D
ump
14M
erve
Was
te D
ump
15B
lue
Rid
ge P
ad
16W
est
Pad
Ext
.
17W
est
Pad
18S
outh
Pad
19Te
ber
ebie
/ M
antr
aim
Pit
20A
irstr
ip W
aste
Dum
p
21A
tuab
o W
aste
Dum
p
22A
tuab
o P
it
23M
akul
u P
it
24P
epe
Pit
25P
apa
Was
te D
ump
26B
amb
oo W
aste
Dum
p
27N
orth
Pad
28P
hase
5 P
ad
29A
ir S
haft
30C
leav
er S
haft
31S
wan
zy S
haft
32B
isho
ps
Sha
ft
3029
31
32
1 2
3
45
6
27
28
25
24
23
22
21
20
11
1213
1419
17
1615
18
78
9
26
10
Min
ing
Leas
e ...
......
......
......
......
......
......
......
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...
Taili
ngs/
Hea
p Le
ach
pads
.....
......
......
......
......
......
......
......
..
Dam
ang
has
the
area
from
sur
face
to 3
0m b
elow
.....
..
Tark
wa
has
the
area
bel
ow 3
0m...
......
......
......
......
......
......
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te D
ump
......
......
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Ope
n P
it ...
......
......
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iona
l Roa
d ...
......
......
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......
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Nat
iona
l Rai
lway
.....
......
......
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......
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......
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......
......
.
Tow
ns ..
......
......
......
......
......
......
......
......
......
......
......
......
......
.....
Ove
rlap
Are
a
No
. 2 S
haft
Min
e V
illag
e
Nat
iona
l Rai
lway
to P
rest
ea
Sam
ahu
Ab
oss
o T
ow
n
Tark
wa
Tow
n
Ret
read
Fac
tory
So
uth
Pri
mar
y C
rush
er
Min
e O
ffice
s
Abo
sso
Dee
ps
RE
FER
EN
CE
Cin
nam
on B
ippo
Sha
ft
1K
ottr
aver
chy
Wes
t W
aste
Dum
p
2K
ottr
aver
chy
Pit
3K
ottr
aver
chy
Sou
th E
ast
Was
te D
ump
4K
ottr
aver
chy
Eas
t W
aste
Dum
p
5TS
F 1
6TS
F 2
7C
IL P
lant
8N
orth
Prim
ary
Cru
sher
9A
kont
ansi
Pit
10A
kont
ansi
Was
te D
ump
11B
ridge
Was
te D
ump
12P
ytho
n N
eck
Was
te D
ump
13W
est
Hill
Was
te D
ump
14M
erve
Was
te D
ump
15B
lue
Rid
ge P
ad
16W
est
Pad
Ext
.
17W
est
Pad
18S
outh
Pad
19Te
ber
ebie
/ M
antr
aim
Pit
20A
irstr
ip W
aste
Dum
p
21A
tuab
o W
aste
Dum
p
22A
tuab
o P
it
23M
akul
u P
it
24P
epe
Pit
25P
apa
Was
te D
ump
26B
amb
oo W
aste
Dum
p
27N
orth
Pad
28P
hase
5 P
ad
29A
ir S
haft
30C
leav
er S
haft
31S
wan
zy S
haft
32B
isho
ps
Sha
ft
17
13. Brief history
The history of Tarkwa
1935:Amalgamated Banket Area Limited (ABA) acquired the Abontiakoon concession. Sinking of the Abontiakoon vertical shaft.
1936 – 1940: Construction of new central mill with a capacity of 30 ktpm.
Late 1900s: Several small mining companies operated the Abontiakoon concession.
1960: All workings abandoned and allowed to flood.
1961: Production restarted under the State Gold Mining Corporation.
1963: The Tarkwa mines renamed Tarkwa Goldfields Limited.
1973 – 1976: Apinto Shaft sunk to access additional ore sources.
1993: GFGL signed a management contract with the Ghanaian government to operate the mine.
1996: Feasibility study completed by GFGL on an open pit/heap leach operation.
1998:Initial Tarkwa Phase I development completed for an open pit operation mining 14.5 Mtpa including 4.7 Mtpa of heap leach feed ore.
1999:Tarkwa Phase II expansion completed to increase mining rate to 20.7 Mtpa and heap leach feed ore production to 7.2 Mtpa. All underground operations and associated processing plant ceased production.
2000: GFGL acquired northern area of Teberebie. Mining production pushed to 36 Mtpa.
2004:Tarkwa implemented owner mining in July 2004 and commissioned a CIL plant with a “name plate” capacity of 4.2 Mtpa in October 2004.
2008: South Heap Leach facility ceases crushing in December 2008.
2009:Expanded CIL plant commissioned in January 2009, design throughput of 12.3 Mtpa achieved in September 2009. HPGR 1 Mt plant scale test to be started at South Heap Leach facility in last quarter of the year.
2010:Conversion to owner maintenance has been completed, with the inherent cost savings and productivity gains expected to materialise in C2011.
2011:Gold Fields Ghana Limited acquired the 18.9% IAMGold interest in Tarkwa and now holds 90% with the remaining 10% held by the Ghanaian government.
Tark
wa
Nor
th H
eap
Leac
h P
hase
V p
ad
18
Structural and evaluation confirmation drilling at Kottraverchy
Tarkwa Mineral Resource and Mineral Reserve Classification
Boreholes12500N
12000N
11500N
11000N
10500N
10000N 2000
E
2500
E
3000
E
3500
E
4000
E
4500
E
5000
E
5500
E
6000
E
6500
E
7000
E
7500
E
EXPLORATIONRESULTS
MINERALRESERVES
MINERALRESOURCES
Reported as in situmineralisation estimates
Consideration of mining, metallurgical, economic, marketing, legal,environmental, social and governmental factors (the ‘modifying factors’)
316.5 Mt @ 1.5 g/t15.1 Moz
264.8 Mt @ 1.2 g/t10.3 Moz
143.6 Mt @ 1.2 g/t5.3 Moz
121.2 Mt @ 1.3 g/t5.0 Moz
33.6 Mt @ 2.8 g/t3.0 Moz
167.5 Mt @ 1.2 g/t6.7 Moz
115.4 Mt @ 1.5 g/t5.4 Moz
Reported as mineableproduction estimates
Incr
easi
ng le
vel o
f geo
scie
ntifi
c kn
owle
dge
and
confi
denc
e
MEASURED PROVED
PROBABLEINDICATED
INFERRED
US$1 300/0z pit shell
Indicated MineralResource boundary
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011
Notes
Pol
ymic
tic c
ongl
omer
ates
at T
arkw
a
Imbr
icat
e ol
igom
ictic
con
glom
erat
es a
t Tar
kwa
This Technical Short Form Report (“the Report”) contains information as at 31 December 2011 (“the Effective Date of this Report”). The statements and information set out in this Report speak only as of the Effective Date of this Report. Shareholders and other interested and affected parties are therefore urged to review all public disclosures made by Gold Fields after the Effective Date of this Report, as some of the information contained in the Report may have changed or have been updated. Gold Fields does not undertake any obligation to update publicly or release any revisions to statements and information set out in this Report to reflect events or circumstances after the Effective Date of this Report or to reflect the occurrence of unanticipated events, unless obliged to do so pursuant to law or regulation. In such event, Gold Fields does not undertake to refer back to any information contained in this Report.
Gold Fields: Tarkwa Gold Mine – Technical Short Form Report 2011 1
“If we cannot mine safely, we will not mine”
Gold Fields Safety Value
Registered Office South Africa:150 Helen RoadSandownSandton, 2196 JohannesburgGautengPrivate Bag X30500Houghton, 2041 South Africa
Website: http://www.goldfields.co.za Telephone: +27 (0) 11 562 9700Facsimile: +27 (0) 11 562 9838