|
| Driefontein Gold Mine
Technical Short Form Report
Driefontein Gold Mine is a large, well-established shallow to ultra-deep level gold mine with
workings that are accessed through eight shaft systems that mine various gold bearing
reefs from open ground and pillars that occur at depths between 600 and 3,300 metres
below surface. The shaft systems include five sub-vertical shafts and two tertiary shafts. Ore
extracted from the gold bearing reefs is processed at three metallurgical plants. Annual mill
throughput of approximately 6 million tons of ore is mined to produce approximately 830 koz
of gold.
This Technical Short Form Report reflects the latest Life of Mine plan, coupled with an updated
Mineral Resource and Mineral Reserve statement, as at 30 June 2009. The geological and
evaluation models have been updated to reflect the latest available data. These models are
coupled with an integrated and holistic mine design and schedule that is based on current
performance levels and endeavours to take cognisance of the inherent risks associated with
deep level mining.
Driefontein has undertaken a review of the safe extraction of all remnant pillar mining and
consequently selected higher risk remnants and/or pillars have been excluded from the plan.
Significantly increased power, consumables and labour costs have offset the increased gold
price revenues, with the effect that paylimits show only nominal reductions year-on-year
despite increased gold prices for Mineral Resources and Mineral Reserves respectively.
All Mineral Resource and Mineral Reserve figures reported are managed unless otherwise
stated and Mineral Resources are inclusive of Mineral Reserves.
Salient Features
- World class orebody with long life Mineral Resources of 52.8 Moz
(excluding Tailing Storage Facility ounces).
- Mineral Reserves of 18.2 Moz.
- Underground uranium models have been generated for Driefontein.
- Focus on safe steady state production driving volume, value and quality.
- 4 Shaft pillar extraction to commence during Q4 F2010.
- Long-life franchise asset anchoring gold production to 2040 (31 years).
Driefontein Gold Mine is located in the Far West Rand Goldfields, situated in the geologically unique
and world renowned Witwatersrand Basin, which remains the most significant gold depository
in the history of mining. Geologically the mine is positioned within the richest formations of the
Carbon Leader and Ventersdorp Contact Reefs ever found in South Africa.
West Driefontein Gold Mine was registered in March 1945 and ultimately became recognised
as one of the most prolific gold producers in the country. The contiguous East Driefontein was
registered in May 1968 and merged with West Driefontein during July 1981 to form a new
company, Driefontein Consolidated Limited. Each mine however continued to manage its lease
area separately until September 1999 when they amalgamated, pooling their resources to form
one mine, the Driefontein Gold Mine, that extends for 12.5 km along strike and 8.5 km on dip. |
Key Features
|
Independent Audit |
|
Figures reported in this declaration are as reviewed and approved by independent external consultants as at 30 June 2009 |
|
Prepared by |
|
Gold Fields Limited |
|
Effective date |
|
30 June 2009 |
|
Source of Information |
|
This Technical Statement is a summary of the internally sourced document entitled F2010 Driefontein 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 |
|
Driefontein is situated some 70 km west of Johannesburg at latitude 26º 24’ S and longitude 27º 30’ E near Carletonville in the Gauteng Province of South Africa. The site is accessed via the N12 highway between Johannesburg and Potchefstroom |
|
Licence Status and Holdings |
|
Driefontein is entitled to mine all declared Mineral Resources and Reserves and has all the necessary statutory mining rights in place. The Mine has a new order mining right in respect of the mining area totalling 8,561 hectares. GFI Mining South Africa (Proprietary) Limited (GFIMSA) holds a 100% interest in Driefontein. Gold Fields Limited holds a 100% interest in GFIMSA |
|
Operational Infrastructure |
|
Driefontein is a large, well-established shallow to ultra deep level gold mine that is accessed from surface through a number of shafts to 50 level (the lowest working level) some 3,300 m below surface. It comprises eight producing shaft systems that mine different contributions from pillars and open ground, and three gold plants |
|
Climate |
|
No extreme climatic conditions are experienced that may affect mining operations |
|
Deposit Type |
|
Gold mineralisation occurs within laterally extensive quartz pebble conglomerate horizons called reefs, which are developed above unconformable surfaces within a depositional system near the basin margin. Driefontein exploits three primary reefs namely the Carbon Leader Reef (CL), Ventersdorp Contact Reef (VCR) and Middelvlei Reef (MR) with the CL representing the majority of the current Mineral Reserves |
|
Life of Mine (LoM) |
|
It is estimated that the current Mineral Reserves will be depleted in 2040 |
|
Environmental |
|
Driefontein systems, procedures, training etc. are at international best practice levels. ISO 14001:2004 certification has been obtained for this operation. The Safety Management System was certified by Bereau Veritas in F2009 for OHSAS 18001. The mine has full compliance status for the International Cyanide Management Code with certification awarded in September 2009 |
|
Regulatory 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 a sufficient Mineral Resource Management process and protocol to ensure adequate corporate governance in respect of the intent of the Sarbanes-Oxley Act |
Gold Fields has
stated that: “If we cannot mine
safely, we will not
mine”. This principle
is embedded at
Driefontein. |
Operating Statistics
|
Main development |
km |
|
20.1 |
|
27.5 |
|
28.0 |
|
27.4 |
|
27.8 |
|
|
Main on-reef development |
km |
|
4.1 |
|
5.8 |
|
5.3 |
|
4.2 |
|
3.8 |
|
|
Main on-reef development value |
cm.g/t |
|
926 |
|
1,242 |
|
1,307 |
|
1,454 |
|
1,837 |
|
|
Area mined |
’000 m2 |
|
530 |
|
579 |
|
653 |
|
680 |
|
661 |
|
|
Tons milled (Underground & Surface) |
‘000 tons |
|
6,217 |
|
5,981 |
|
6,652 |
|
6,867 |
|
6,694 |
|
|
Source of ore |
|
|
|
|
|
|
|
|
|
|
|
|
|
– Underground |
’000 tons |
|
3,137 |
|
3,273 |
|
3,812 |
|
3,867 |
|
3,794 |
|
|
– Yield |
g/t |
|
7.5 |
|
8.1 |
|
7.6 |
|
8.1 |
|
8.3 |
|
|
– Stockpile (Surface) |
’000 tons |
|
3,080 |
|
2,708 |
|
2,840 |
|
3,000 |
|
2,900 |
|
|
– Yield |
g/t |
|
0.7 |
|
0.8 |
|
1.0 |
|
1.4 |
|
0.7 |
|
|
– Average yield |
g/t |
|
4.2 |
|
4.8 |
|
4.8 |
|
5.2 |
|
5.4 |
|
|
– Gold produced (Underground & Surface) |
kg |
|
25,814 |
|
28,865 |
|
31,618 |
|
35,755 |
|
36,162 |
|
|
|
’000 oz |
|
830 |
|
928 |
|
1,017 |
|
1,150 |
|
1,163 |
|
|
Operating cost |
|
|
|
|
|
|
|
|
|
|
|
|
|
– Underground |
R/ton |
|
1 044 |
|
830 |
|
653 |
|
579 |
|
609 |
|
|
– Surface |
R/ton |
|
83 |
|
79 |
|
65 |
|
60 |
|
60 |
|
|
– Total |
R/ton |
|
568 |
|
490 |
|
402 |
|
352 |
|
371 |
|
|
– Gold sold |
kg |
|
25,814 |
|
28,865 |
|
31,618 |
|
35,755 |
|
36,162 |
|
|
– Cash cost |
US$/oz |
|
448 |
|
412 |
|
348 |
|
315 |
|
330 |
|
|
|
R/kg |
|
129,837 |
|
96,293 |
|
80,457 |
|
64,870 |
|
65 884 |
|
|
– Capital expenditure |
Rm |
|
1 034 |
|
1,016 |
|
815 |
|
543 |
|
184 |
|
|
– NCE |
R/kg |
|
176,838 |
|
136,806 |
|
110,269 |
|
82,872 |
|
– |
|
|
Number of employees |
|
|
16,955 |
|
17,210 |
|
17,122 |
|
16 644 |
|
17 018 |
|
|
Expected Life-of-Mine |
years |
|
31 |
|
33 |
|
28 |
|
27 |
|
28 |
|
|
Mineral Reserves |
million tons |
|
75.2 |
|
80.4 |
|
80.4 |
|
94.6 |
|
100.0 |
|
|
Head grade of Mineral Reserves |
g/t |
|
7.5 |
|
7.6 |
|
8.3 |
|
7.4 |
|
7.3 |
|
Rounding off of figures presented in this report may result in minor computational discrepancies. Where this occurs it
is not deemed significant.
Geological Setting and
Mineralisation
Driefontein is located in the West Wits Line that
forms part of the Far West Rand Goldfields of
the Witwatersrand Basin. Exploration in the
area dates from 1898 and mining from 1945
when West Driefontein Gold Mine began sinking
the 1 and 2 Shafts. Driefontein exploits three
primary reefs namely the Ventersdorp Contact
Reef (VCR) located at the top of the Central
Rand Group, the Carbon Leader Reef (CL)
near the base of the Group and the Middelvlei
Reef (MR), which occurs stratigraphically some
50 m to 75 m above the CL.
![Driefontein 2 Shaft ground works, 16 September 1945](images/pg3_graphic.jpg) |
Driefontein 2 Shaft ground works, 16 September 1945 |
Local geology
Several large dykes contribute to dividing the
West Wits Line into a series of compartments,
while the west dipping normal Bank Fault
defines the eastern limit of both the CL and
the VCR at Driefontein. The faulting in the
area is characterised by easterly striking,
strike slip faults with horizontal displacements
of up to 450 metres. Pilanesberg, Bushveld
and Ventersdorp age dykes are also present,
striking in a northerly direction, with the
exception of some of the latter dykes, which
strike in an easterly direction.
In certain areas a fourth reef (Erosion Channel
Reef) has been exploited and forms part of an
erosion channel in the northern part of the Mine.
This channel eliminates the CL but sometimes
contains a conglomerate which is mined as a
secondary reef. For reporting purposes, the
Erosion Channel Reef is grouped with the CL
and is not reported separately.
The vertical separation between the VCR
and CL increases east to west from zero m
to over 1,300 m on the western boundary.
This is a result of the relative angle of the VCR
unconformity surface to the regional CL strike
and dip. The CL strikes west-southwest and
dips to the south at approximately 25°.
The VCR strikes east-northeast and has
a regional dip of approximately 21° to the
south-southeast. Local variations in dip are
largely due to the terrace-and-slope palaeotopographic
surface developed during VCR
deposition.
The CL is generally a high grade reef and
represents approximately 81% of the current
Mineral Reserve, the VCR 17% with the
remaining 2% comprising mainly MR.
![Driefontein 2 Shaft ground works, 16 September 1945](images/pg4_map.gif) |
Typical section through the Driefontein orebody |
Ventersdorp Contact Reef
The VCR represents the final phase of
sedimentation prior to the extrusion of
the lavas of the Klipriviersberg Group and
unconformably overlies the underlying strata
of the Witwatersrand Supergroup. This
erosional feature, in conjunction with the
structural effects of the Bank Fault, results in
the elimination of the CL and MR in a V-shaped
area closing to the south in the eastern portion
of the mine. The VCR, from west to east,
overlies progressively older strata, from the
Kimberley Conglomerate Formation in the
west to the Jeppestown Subgroup in the east.
The VCR is dated at approximately
2.7 billion years and is an auriferous palaeoplacer,
consisting of several complex, intercalated
gravel types (facies). Lavas of the
Klipriviersberg Group lie conformably on the
gravels (conglomerates) and thus preserved
unique characteristics of the sediments and
the geomorphology. The sediments have been
subdivided into five major facies types, which
consist of a complex series of intercalated
oligomictic and polymictic conglomerates of
varying thicknesses and differing average gold
grades.
The VCR is most extensively developed in the
east of Driefontein. The subcrop line of the VCR
against the Black Reef and overlying dolomites
trends south-west and consequently restricts
the area to the west that is underlain by VCR.
Middelvlei Reef
The MR is correlated with the South Reef of
the Central Rand Goldfields. It occurs some
50 m above the CL over most of the lease area,
except where eliminated by the VCR erosion
surface, and is made up of a number of well-packed,
large pebble conglomerate bands.
The pebbles are usually up to 30 mm in
diameter, although pebbles up to 60 mm in
diameter are occasionally present.
In some areas the MR assemblage is as much
as 6 m thick with well developed Top, Middle
and Bottom Bands, separated from each
other by quartzite partings. The pebbles are
well-rounded and are generally of vein quartz.
The MR subcrops against the Black Reef just
south of the northern boundary of Driefontein.
The MR in general has well defined “pay shoots”
which are limited in extent and therefore difficult
to project or explore. The Bottom Band is most
exclusively the economic horizon of the MR,
ranging from a single pebble lag to a maximum
thickness of 80 cm.
Carbon Leader Reef
The CL correlates with the Main Reef of the
Central Rand Goldfields and is the principal
reef mined at present and varies in thickness
from a mere carbon streak to a solid seam
of carbon 7 mm thick, to a multiple band
medium pebble conglomerate, on average
some 200 cm thick. The CL is the deepest
reef and is present all over the mining area
except where eliminated by the erosive
surface at the base of the VCR in the central
parts of the mine and by the Erosion Channel
in the north. Four facies of CL are present
on the mine: a carbon seam (CSCLR) and a
single band conglomeratic (SCLR) facies in
the west, a multiple band (MCLR) facies in the
central parts and a single band conglomeratic
facies in the east. Geostatistically the east
and west single band facies differ markedly
in their average gold content and channel
widths.
The CL has a low angle of unconformity.
The footwall consists of a package of
conglomerates, usually referred to as the
“Footwall bands of the CL” (also the “North
Leader Zone”) and this zone is characterised
by lenses of conglomerates, separated by
yellowish grey argillaceous quartzite. The basal
conglomerate band of this zone is called the
North Leader (NL).
The hangingwall of the CL consists of a
siliceous grey quartzite overlain by the Green
Bar, a chloritoid shale occurring over most of
the Witwatersrand Basin.
The CSCLR is a carbon streak or seam
in quartzite, grits or conglomerates, or a
mixture of these sediments. In its more typical
development it forms a thin footwall seam
of soft friable carbon-rich quartzite, well
mineralised with pyrite. On this seam rests a
variable layer of pebbles, often with the layer
of pebbles partly embedded in the carbon-rich
material. The pebbles are well-rounded quartz
vein material and are seldom more than 3 cm
in diameter. This facies mostly occurs in the
10 Shaft area, which is now mostly mined out
except for some small pillars.
The SCLR is defined sedimentologically as
a single conglomerate band containing no
internal quartzite bands. The width thereof
can vary from a single pebble band (or in
extreme cases only a pyrite stringer) up to a
metre thick. There appears to be a relationship
between reef thickness and gold grade with
reefs thinner than 50 cm containing the higher
grades. The gold content of the SCLR is lower
than that of the CSCLR.
The MCLR is defined sedimentologically as a
reef containing more than one conglomerate
band separated by internal quartzite bands.
The internal quartzite is similar in appearance
to that forming the hangingwall of the CL.
The channel width of the MCLR varies from
as little as 10 cm to more than 420 cm and
the number of conglomerates is highly variable
because of their lenticular nature. The gold
grade of the MCLR is generally lower than that
of the SCLR facies but, because of its channel width, their gold accumulation (cm.g/t) is often
similar. Carbon seams are also known to occur
in these reefs accompanied by an increase in
gold content.
![VCR C facies](images/pg5_graphic1.jpg) |
|
![Middelvlei Reef (Bottom Band)](images/pg5_graphic2.jpg) |
VCR C facies |
|
Middelvlei Reef (Bottom Band) |
![Carbon Leader (Carbon Seam facies)](images/pg5_graphic3.jpg) |
|
![Carbon Leader (Multiple Band facies)](images/pg5_graphic4.jpg) |
Carbon Leader (Carbon Seam facies) |
|
Carbon Leader (Multiple Band facies) |
Exploration and drilling
The exploration strategy constitutes the
following:-
- Improve confidence in the orebody;
- Multi-disciplinary approach;
- Integrated 3D seismic surveys;
- Underground fan drilling;
- Timeous prospect development; and
- Proactive geology modelling.
A continuous Mineral Reserve definition
programme is in place and is aligned to
facilitate better planning and optimisation,
with appropriate lead time, to ensure robust
geological and evaluation models, that will
underpin the resource definition of the CL,
VCR and MR. The programme will confirm the
orebody potential in all areas of Driefontein,
including secondary minerals such as uranium
and sulphur. Exploration activities are focused
on the extension of existing orebodies and
the identification of new orebodies both
at existing sites and at undeveloped sites.
Once a potential area has been discovered,
exploration is extended and intensified in
order to enable clearer definition of the orebody
and the potential portions to be mined.
Geological techniques are constantly refined to
improve the economic viability of prospecting
and mining activities.
A selective cut strategy is being applied to the
MCLR directed by advanced framework drilling
conducted from the cross-cuts. The preferred
mining cut improves stope grades (g/t Au)
and mitigates the geotechnical risk linked to
exposing incompetent hangingwall quartzites.
An extensive drilling programme on the old
tailings dams in order to quantify the gold,
uranium and sulphur content has been
completed during F2009. Surface drilling of the
historic tailings was completed in March and
evaluation activities in the middle of April 2009.
A full project feasibility is currently underway
and is planned for completion during F2010.
![Tailings drilling activities](images/pg5_graphic5.jpg) |
Tailings drilling activities |
Rock Engineering
The rock engineering practices are aimed
at reducing risks and thus improving safety
associated with gravity and seismic related
rockfall and rockburst incidents through
implementing the recommendations from the
risk assessment department, testing of highyield
elongate support units and continuous
assessment of the seismic systems. Rock
engineering risk factors associated with pillar
mining are detailed in the Mine Planning and
Scheduling Section.
Mining
Driefontein is a large, established shallow
to deep level gold mine that is accessed
from surface via eight shaft systems to
50 level (currently the lowest working level)
some 3,300 m below surface. Driefontein
comprises eight producing shafts that mine
different contributions from pillars and open
ground. The shafts vary in diameter, depth and
hoisting capabilities.
Mining methods
Access to orebodies (auriferous reefs) is
provided through vertical, inclined and declined
shaft systems. If additional depth is required
to fully exploit the reef, and it is economically
feasible, then secondary (sub-vertical) or
tertiary shafts are sunk from the underground
levels. Horizontal development at various
intervals of a shaft, known as levels, extend
access to the horizon of the reef to be mined.
On-reef development then provides specific
mining access.
The mining methods employed at Driefontein
vary between shafts and can be subdivided as
follows:
- Breast mining with dip pillars in the shaft
pillar extraction at 1 Sub-Vertical;
- Breast mining with dip pillars at 1 Tertiary
and 5 Sub-Vertical Shafts;
- Pillar extraction and scattered mining at
2 Shaft;
- Mini-longwall mining, scattered mining, shaft
pillar and pillar extraction at 4 Sub-Vertical
Shaft;
- Pillar extraction and scattered mining at
6 Sub-Vertical Shaft;
- Pillar extraction and scattered mining at
8 Shaft; and
- Reclamation and vamping at 6 Tertiary and
10 Sub-Vertical Shaft.
Driefontein is also mining old surface rock
dumps containing gold. The dumps are loaded
and screened to smaller fractions and then
processed exclusively at 2 and 3 Plants.
![Remote loader used by SPH at Driefontein in the mining of a surface rock dump in an area where sinkholes occur](images/pg6_graphic.jpg) |
Remote loader used by SPH at Driefontein in the mining of a surface rock dump in an area where sinkholes occur |
Mine planning and scheduling
Mine design and scheduling at Driefontein
is done in Cadsmine©, forming part of
the seamless MRM Integrated Resource
and Reserve Information System (IRRIS).
All designs are based on two and three
dimensional resource models.
Designs and schedules are done in consultation
with production and other technical personnel.
Production efficiencies are based on past
experience and production models describing
activities for the different mining combinations.
The LoM plan schedule will remain at
approximately the current levels of some
50,000 m˛ per month (280 ktpm) from
underground until F2017, whereafter it
will decrease until the 9 Shaft production
comes on line. In the LoM profile the above
infrastructure Mineral Reserves will be
depleted in 2027 and thereafter production
will be sourced solely from below the current
infrastructure until 2040.
In accordance with the updated Pillar Mining
Code of Practice, the F2010 operational
plan was reviewed to provide assurance that
Driefontein has not planned to mine any high
risk pillars. The protocol to plan remnant
extraction is based on an internal document
which takes cognisance of a stringent safe
remnant extraction practice.
The rock engineering risk factors (risk matrix)
associated with remnant extraction were
identified as Energy Release Rate, Average
Pillar Stress, Shape, Width-to-Height Ratio and
the presence of seismically active geological
structures. Additional pillars and remnants
have also been excluded from Driefontein’s F2010 Mineral Reserves.
Reserve development will continue to be a key
performance indicator going forward and will
be accelerated further in appropriate areas.
The following table details the development
advanced for the last 12 months to June 2009.
A total of 20.1 km was developed with 4.1 km
driven on-reef.
Development results
|
Advanced (m) |
10,260 |
|
4,033 |
|
5,781 |
|
|
On-reef (m) |
2,128 |
|
1,472 |
|
520 |
|
|
Sampled (m) |
1,926 |
|
1,239 |
|
375 |
|
|
Channel Width (cm) |
62 |
|
63 |
|
58 |
|
|
Average grade (g/t) |
20.2 |
|
7.7 |
|
12.7 |
|
|
Average value (cm.g/t) |
1,248 |
|
481 |
|
738 |
|
1Carbon Leader Reef, 2Middelvlei Reef, 3Ventersdorp
Contact Reef
Projects
The 9 Sub-Vertical Shaft Deepening Project
was approved in F2007, and the pre-sinking
operations were completed early in 2008.
The reduction in the amount of power supply
to Driefontein, following the Eskom crisis,
led to the postponement of the shaft, with
sinking delayed until 2012 when there should
be sufficient power available to continue with
the project. The shaft is currently at a depth of
3,059 m below surface. The completed shaft
will be 4,121 m deep, making it the deepest
mine in the world. The project will extend Driefontein’s Life of Mine by mining an additional
8.1 million ounces of Mineral Reserves. During
F2010 a mine design, planning and financial
comparison will be undertaken between
sinking 9 Shaft and developing declines below
5 Shaft.
Mineral Processing
Driefontein operates three gold processing
plants. A centralised elution and carbon
treatment facility, capable of processing carbon
from all three of the Driefontein plants, was
installed in August 2001. The benefits of this
centralisation are better recovery rates, giving
reduced dissolved gold losses and operating
cost, as well as improved security. Gold bullion
produced is dispatched to the Rand Refinery
to further process it to a saleable quality of
99,9% fineness.
The 1 Gold Plant was commissioned in 1972
as a three stage crushing, two stage milling,
filtration and zinc precipitation operation.
The Plant was initially designed and installed
to treat 100 kt of ore per month, but this
has been gradually increased to a monthly
throughput of 240 kt. The mineral processing
technology in the Plant is based on SAG milling
circuit followed by cyanide leaching. The SAG
milling circuit was commissioned in September
2003 and replaced the conventional crushing
and milling circuit while the filtration and zinc
precipitation processes were replaced by the
state of the art carbon in pulp (CIP) plant.
The first gold pour at 2 Gold Plant was
in 1952 with ore obtained from the now
defunct 11 shaft. In 1962 the collapse of the
entire Carbon Leader plant occurred as a
result of sinkhole activity, and the current 2
Plant was erected in less than 12 months.
Currently 2 Plant is only treating surface
waste rock material at 200 kt per month.
It is delivered by rail from rock dumps to the
plant feed bunkers. The plant flow sheet
incorporates two SAG mills and a ball milling
circuit, cyanide leaching and a carbon in pulp
(CIP) plant. Loaded carbon is transported to
the central Elution Circuit at 1 Plant.
Originally a uranium plant, 3 Gold Plant was
converted in 1998 to a surface low-grade
waste rock treatment facility. The Plant was
constructed using a combination of new as
well as existing equipment on site. This Plant
has the capacity to treat 115 kt per month of
rock material reclaimed from the waste rock
dumps located on the Mine.
![1 Processing Plant, Driefontein](images/pg7_graphic.jpg) |
1 Processing Plant, Driefontein |
Sustainable Development
Gold Fields has embraced Sustainable
Development as a business imperative, which
is reflected in its Vision, Values and Strategy.
Through this, Gold Fields has introduced
structures that encourage a networked
interface between disciplines like Safety,
Health, Environmental Engineering, Natural
Environment, Risk, Stakeholder Engagement,
Legal and Communication. This approach has
allowed Gold Fields to capitalise on synergies
and to avoid duplication. In this regard,
several Key Performance Indicators (KPIs)
are monitored and utilised to make informed
business decisions.
The serious injury frequency rate for F2009
was 3.0 serious injuries for every million
hours worked, reflecting an improvement as
compared to the serious injury frequency rate
of 4.4 for F2008. The fatal injury frequency rate
improved from 0.26 in F2008 to 0.16 fatalities
for every million hours worked in F2009.
The lost day injury frequency rate improved
from 7.0 lost time injuries for every million hours
worked for F2008 to 4.9 in F2009, with about
a third of incidents caused by falls of ground, which remains the major source of incidents
in the mine.
Gold Fields is designing a safety management
system called the Safe Production
Management System, to address outstanding
issues identified and to assist Driefontein
to improve health and safety to best
practice levels. The Mine continued with the
Masiphephe safety programme, which targets
elements of the Safe Production Management
System during the year. On June 12, 2009, the
Mine recorded in excess of 2.85 million fatality
free shifts, which is a record achievement for
the Mine and set a new benchmark for deep
level gold mining.
In terms of community involvement, Driefontein
has continued to support the Living Gold
project that results in high quality roses being
exported and which creates employment for local community members. Driefontein
has also recently built a primary school that
has been made available to 1,600 children
from the local community. A bakery was also
introduced by Driefontein within the local
community and is currently fully operational,
which provides bread to the mine and
surrounding communities and is owned by
representatives of the local community. Other
projects include waste management and the
production of building materials like “ready
mix” for construction.
Driefontein’s environmental initiatives are
focused on reducing the environmental
footprint so as to reduce the impact that the
mine may have on the receiving environment
through concurrent rehabilitation and
responsible water management. All potential
sources of pollution like the water discharges
are monitored and sampled on a regular basis.
F2009 |
|
|
Fatalities |
(No) |
10 |
|
15 |
|
13 |
|
13 |
|
7 |
|
|
Fatality Rate |
(per mmhrs) |
0.2 |
|
0.3 |
|
0.3 |
|
0.3 |
|
0.2 |
|
|
LDIFR |
(per mmhrs) |
17.2 |
|
14.7 |
|
12.1 |
|
7.0 |
|
4.9 |
|
Production and hoisting
capacities
|
1 Shaft |
|
|
|
1 |
|
105,000 |
|
|
|
|
|
|
1 SV |
|
105,000 |
|
|
|
|
58,520 |
|
1T |
|
120,000 |
|
|
2 Shaft |
|
18,951 |
|
2 |
|
165,000 |
|
|
4 Shaft |
|
39,978 |
|
4 SV |
|
107,000 |
|
|
5 Shaft |
|
|
|
5 |
|
42,000 |
|
|
|
|
102,006 |
|
5 SV |
|
150,000 |
|
|
6 Shaft |
|
|
|
6 |
|
96,000 |
|
|
|
|
6,589 |
|
6 SV |
|
77,000 |
|
|
8 Shaft |
|
48,816 |
|
8 |
|
96,000 |
|
|
9 Shaft** |
|
47,085 |
|
9 |
|
200,000 |
|
|
10 Shaft |
|
7,342 |
|
10 SV |
|
62,000 |
|
* 5 year average; **5 year average starting F2018
SV: Sub Vertical; T: Tertiary
![](images/pg8_map.gif)
Plant capacities
|
1 |
240,000 |
|
|
2 |
200,000 |
|
|
3 |
115,000 |
|
Mineral Reserves per mining area
|
1 Shaft |
3,2 |
|
7,4 |
|
749 |
|
7,3 |
|
8,4 |
|
1,978 |
|
|
2 Shaft |
1,8 |
|
6,4 |
|
369 |
|
0,8 |
|
6,4 |
|
160 |
|
|
4 Shaft |
3,6 |
|
10,8 |
|
1,247 |
|
1,9 |
|
8,0 |
|
478 |
|
|
5 Shaft |
3,9 |
|
7,9 |
|
999 |
|
8,7 |
|
10,0 |
|
2,814 |
|
|
6 Shaft |
0,5 |
|
6,1 |
|
89 |
|
0,0 |
|
4,1 |
|
1 |
|
|
8 Shaft |
4,6 |
|
4,7 |
|
694 |
|
1,4 |
|
3,4 |
|
150 |
|
|
9 Shaft |
– |
|
– |
|
– |
|
27,4 |
|
9,2 |
|
8,097 |
|
|
10 Shaft |
0,0 |
|
15,5 |
|
12 |
|
0,5 |
|
9,5 |
|
154 |
|
|
Total Mineral Reserves underground |
17,6 |
|
7,4 |
|
4,157 |
|
48,0 |
|
9,0 |
|
13,832 |
|
|
Total Mineral Reserves surface |
– |
|
– |
|
– |
|
9,6 |
|
0,7 |
|
213 |
|
|
Grand Total |
17,6 |
|
7,4 |
|
4,157 |
|
57.6 |
|
7,6 |
|
14,045 |
|
Mineral Resources and Mineral Reserves
The Mineral Resources are classified as defined and described in the 2007 SAMREC Code and are consistent with the approach
used at other Witwatersrand deep level gold operations. An updated resource model provides an effective platform for realistic
mine design with the application of appropriate mining methods. Driefontein’s Mineral Resources and Mineral Reserves are reported
within its mining right and are adjusted to show the split between above (AI) and below (BI) current shaft infrastructure as defined by
50 level. The F2010 Mineral Resource includes dip pillars from the areas where breast mining with dip pillars is the mining method employed.
Mineral Resources
Mineral 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.
June 2009 |
|
June 2009 |
|
June 2009 |
|
|
Underground |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Measured |
50.2 |
|
38.4 |
|
37.7 |
|
10.5 |
|
12.9 |
|
13.1 |
|
16,887 |
|
15,926 |
|
15,840 |
|
|
Indicated (AI) |
24.9 |
|
20.3 |
|
24.2 |
|
12.7 |
|
14.5 |
|
13.0 |
|
10,177 |
|
9,430 |
|
10,127 |
|
|
Inferred (AI) |
17.4 |
|
|
|
|
|
5.9 |
|
|
|
|
|
3,343 |
|
|
|
|
|
|
Total (AI) |
92.5 |
|
58.7 |
|
61.9 |
|
10.2 |
|
13.4 |
|
13.0 |
|
30,407 |
|
25,356 |
|
25,967 |
|
|
Indicated (BI) |
43.2 |
|
43.5 |
|
49.7 |
|
12.4 |
|
13.5 |
|
11.8 |
|
17,262 |
|
18,847 |
|
18,771 |
|
|
Inferred (BI) |
25.9 |
|
|
|
|
|
5.9 |
|
|
|
|
|
4,899 |
|
|
|
|
|
|
Total underground |
161.6 |
|
102.2 |
|
111.6 |
|
10.1 |
|
13.5 |
|
12.5 |
|
52,568 |
|
44,203 |
|
44,738 |
|
|
Surface stockpile |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Indicated surface |
9.6 |
|
9.1 |
|
6.0 |
|
0.7 |
|
0.7 |
|
0.9 |
|
213 |
|
197 |
|
181 |
|
|
Total surface stockpiles |
9.6 |
|
9.1 |
|
6.0 |
|
0.7 |
|
0.7 |
|
0.9 |
|
213 |
|
197 |
|
181 |
|
|
Grand Total |
171.2 |
|
111.3 |
|
117.6 |
|
9.6 |
|
12.4 |
|
11.9 |
|
52,781 |
|
44,400 |
|
44,919 |
|
Notes: AI = Above Infrastructure and BI = Below Infrastructure.
The Mineral Resource estimate for underground uranium and the gold and uranium in the Tailings Storage Facilities (TSF), are included in the
figures below:
June 2009 |
|
June 2009 |
|
June 2009 |
|
|
Underground |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Inferred (scheduled) |
50.2 |
|
|
|
|
|
0.096 |
|
|
|
|
|
10.545 |
|
|
|
|
|
|
Total underground |
50.2 |
|
|
|
|
|
0.096 |
|
|
|
|
|
10.545 |
|
|
|
|
|
|
Surface tailings |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Measured tailings |
150.9 |
|
|
|
|
|
0.064 |
|
|
|
|
|
21.444 |
|
|
|
|
|
|
Indicated tailings |
|
|
77.4 |
|
|
|
|
|
0.067 |
|
|
|
|
|
11.380 |
|
|
|
|
Inferred tailings |
13.8 |
|
- |
|
|
|
0.027 |
|
|
|
|
|
0.811 |
|
- |
|
|
|
|
Total surface tailings |
164.7 |
|
77.4 |
|
|
|
0.061 |
|
0.067 |
|
|
|
22.255 |
|
11.380 |
|
|
|
|
Grand Total |
214.9 |
|
77.4 |
|
|
|
0.069 |
|
0.067 |
|
|
|
32.800 |
|
11.380 |
|
|
|
June 2009 |
|
June 2009 |
|
June 2009 |
|
|
Surface tailings |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Measured tailings |
150.9 |
|
|
|
|
|
0.3 |
|
|
|
|
|
1,703 |
|
|
|
|
|
|
Indicated tailings |
|
|
77.4 |
|
|
|
|
|
0.5 |
|
|
|
|
|
1,167 |
|
|
|
|
Inferred tailings |
13.8 |
|
|
|
|
|
0.2 |
|
|
|
|
|
102 |
|
|
|
|
|
|
Total TSFs |
164.7 |
|
77.4 |
|
|
|
0.3 |
|
0.5 |
|
|
|
1,805 |
|
1,167 |
|
|
|
Modifying factors
- The Measured and Indicated Mineral
Resources are inclusive of those Mineral
Resources modified to produce Mineral
Reserves;
- All Mineral Resources and Mineral Reserves
are quoted as at 30 June 2009;
- Unless otherwise stated, all Mineral
Resources and Mineral Reserves are quoted
as 100% (managed) and not attributable
with respect to ownership;
- All Mineral Reserves are quoted in terms
of Run-of-Mine (RoM) grades and tonnage
as delivered to the metallurgical processing
facilities and are fully diluted;
- Mineral Reserve statements include only
Measured and Indicated Mineral Resources,
modified to produce Mineral Reserves and
contained in the LoM plan; and
- Mineral Resources and Mineral Reserves
undergo both internal and external audits
either during the year, yearly or biannually,
and any issues identified are rectified at
the earliest opportunity – usually during the
current reporting cycle.
|
Mineral Resource Gold Price |
US$/ oz |
1,000 |
|
|
Exchange Rate |
ZAR:US$ |
8.95:1 |
|
|
Mineral Reserve Gold Price |
US$/ oz |
800 |
|
|
Mineral Resource Paylimit |
cm.g/t |
920 |
|
|
Mineral Reserve Paylimit |
cm.g/t |
1,170 |
|
|
Mined Value |
cm.g/t |
1,823 |
|
|
Mine Call Factor |
% |
91 |
|
|
Block Factor |
% |
100 |
|
|
Shortfall |
% |
14 |
|
|
Stoping Width |
cm |
151 |
|
|
Mill Width |
cm |
196 |
|
|
Plant Recovery |
% |
97.0 |
|
Grade tonnage curve
This grade tonnage curve represents undiluted grade (at block
width) and tons within the total Mineral Resource. Underground
Mineral Resources make provision for minor faulting and minor
geological losses.
![Grade tonnage curve](images/pg9_graph.gif)
![1 Processing Plant, Driefontein](images/pg9_graphic.jpg) |
1 Processing Plant, Driefontein |
Mineral Reserves
The estimation of Mineral Reserves at Driefontein is based on surface drilling, underground drilling, surface three-dimensional reflection seismics,
orebody facies, structural modelling, underground channel sampling and geostatistical estimation. The reefs are initially explored by drilling from the
surface on an approximate 500 to 2,000 m grid. Once underground access is available, drilling is undertaken on an approximate 30 by 60 m grid.
Underground channel sampling perpendicular to the reef is undertaken at 3 m intervals in development areas and at 5 m intervals in stope faces.
June 2009 |
|
June 2009 |
|
June 2009 |
|
|
Underground |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Proved |
17.6 |
|
19.7 |
|
21.1 |
|
7.4 |
|
7.6 |
|
8.4 |
|
4,157 |
|
4,834 |
|
5,691 |
|
|
Probable (AI) |
20.6 |
|
19.3 |
|
22.2 |
|
8.7 |
|
9.7 |
|
9.8 |
|
5,735 |
|
6,003 |
|
6,995 |
|
|
Total (AI) |
38.2 |
|
39.0 |
|
43.3 |
|
8.1 |
|
8.6 |
|
9.1 |
|
9,892 |
|
10,837 |
|
12,686 |
|
|
Probable (BI) |
27.4 |
|
32.3 |
|
31.1 |
|
9.2 |
|
8.3 |
|
8.5 |
|
8,097 |
|
8,668 |
|
8,488 |
|
|
Total underground |
65.6 |
|
71.3 |
|
74.4 |
|
8.5 |
|
8.5 |
|
8.9 |
|
17,989 |
|
19,505 |
|
21,174 |
|
|
Surface stockpiles |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Probable surface |
9.6 |
|
9.1 |
|
6.0 |
|
0.7 |
|
0.7 |
|
0.9 |
|
213 |
|
197 |
|
181 |
|
|
Total surface stockpiles |
9.6 |
|
9.1 |
|
6.0 |
|
0.7 |
|
0.7 |
|
0.9 |
|
213 |
|
197 |
|
181 |
|
|
Grand Total |
75.2 |
|
80.4 |
|
80.4 |
|
7.5 |
|
7.6 |
|
8.3 |
|
18,202 |
|
19,702 |
|
21,355 |
|
Notes: AI = Above Infrastructure and BI = Below Infrastructure.
Mineral Resources and Mineral Reserves Reconciliation year-on-year
Mineral Resource
Factors that affected Mineral Resource reconciliation:
- Increase in gold price by US$200/oz, which resulted in an
additional 10.9 Moz.
- Decrease by 1.1 Moz due to pillar and fault loss exclusions.
- Decrease due to mining operations
Change in Mineral Resource F2009 to F2010
![Change in Mineral Resource F2009 to F2010](images/pg10_graph1.gif)
Mineral Reserve
Factors that affected Mineral Reserve reconciliation:
- Depletions refer to ounces delivered to the plant during the
past financial year
- Exclusions are mainly due to exclusion of remnants and pillars
at 1, 2, 8 and 10 Shafts, and changes in dip pillar layouts at
9 Shaft.
Change in Mineral Reserve F2009 to F2010
![Change in Mineral Reserve F2009 to F2010](images/pg10_graph2.gif)
Mineral Reserve sensitivity
The following graph indicates the Mineral Reserve sensitivity at
–10%, -5%, base, +5%, +10% and +25% to the gold price.
The Mineral Reserve sensitivities are not based on detailed
depletion schedules and should be considered on a relative and
indicative basis only.
Managed Mineral Reserve Sensitivity
![Managed Mineral Reserve Sensitivity](images/pg10_graph3.gif)
Regulatory Codes
SAMREC
This 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).
JSE
This Technical Statement has been prepared in compliance with the listing requirements of the JSE Securities Exchange, South Africa (JSE),
specifically Section 12 – Issue 11.
Sarbanes-Oxley Act
The Mineral Resource and Mineral Reserve is underpinned by an adequate Mineral Resource Management process and protocol to ensure adequate
corporate governance in respect of the intent of the Sarbanes-Oxley Act.
Environmental
Driefontein has an environmental management team who are supported by specialist assistance from the South Africa regional office in Johannesburg.
The systems, procedures and training are at international best practice levels. Gold Fields has produced a Sustainability Report in 2009 and intends
reporting annually in accordance with the Global Reporting Initiative.
Competent Persons
GJJ van Vuuren: Manager – Mine Planning and Resource Management
MBA, GDE, BTECH Mineral Resource Management and Mine Surveyors Certificate of Competence (Reg. No. PMS 0190 – PLATO Member).
Mr van Vuuren has over 21 years experience in the mining industry and is responsible for the overall Correctness, Standard and Compliance of this
declaration.
J van Eeden: Chief Geologist,
MSc (Geology). Mr van Eeden has over 26 years experience in the mining industry and is responsible for Geology and Exploration for Driefontein.
C Dewey: Chief Evaluator
MSc Mining Engineering, GDE, ND Mine Survey and Mine Surveyors Certificate of Competence. Mr Dewey has over 35 years experience in the mining
industry and is responsible for the Sampling and Evaluation functions for Driefontein.
KI Shaw: Chief Surveyor
Mine Surveyors Certificate of Competence and MDP. Mr Shaw has over 36 years experience in the mining industry and is responsible for Survey,Reporting and Historical Modifying Factors for Driefontein.
S Wild: Chief Mine Planner
NHD Mineral Resource Management and GDE in Mining Engineering. Mr Wild has over 13 years experience in the mining industry and is responsible
for the Mine Planning and Scheduling for Driefontein.
M Khan: Unit Manager Laboratory
BSc Chemistry. Mr Khan has over 24 years of experience in the mining industry and is responsible for the Assay Laboratory.
Key Technical Staff
|
Post |
Incumbent |
Qualifications |
Years |
Key Responsibility |
|
|
Vice President and Head of Operations |
JJ Barnard |
NHD Metalliferous Mining and Mine Managers Certificate |
24 |
Overall strategic direction, leadership and management |
|
|
Mining: Senior Manager Operations |
J Horn |
Mine Managers Certificate, Mine Overseer’s Certificate, NHD Metal Mining |
23 |
Full operational management |
|
|
Mining: Senior Manager Operations |
R Chaplin |
BSc Mining Eng (Hons) Mine Managers Certificate |
19 |
Full operational management |
|
|
Mineral Resources Manager: Mine Planning and Resource Management |
GJJ van Vuuren |
MBA, NHD, GDE and a MSCC |
20 |
Mine Planning, Mineral Resources & Mineral Reserves and compilation of CPR |
|
|
Financial Senior Manager |
C Keyter |
BCom Acc and MBA |
13 |
Financial reporting, compliance |
|
|
Metallurgy Manager |
D Taunyane |
NHD Extraction Metallurgy MAP |
20 |
Metallurgical management |
|
|
Human Resource Manager |
M Lancaster |
B Proc (Hons) and LLB |
26 |
Human resources management |
|
|
Engineering Manager |
L Neveling |
NHD (Mech Eng) GCC (Mech Eng) |
30 |
Engineering, logistics, infrastructure and management. |
|
Driefontein History
at a Glance
|