Mineral resources and reserves report

Summary of group resources and reserves

 

Assmang (jointly held)

  Measured and Indicated   Proved and Probable
Mineral Resources Mineral Reserves
Mt Fe % Mt Fe %
Iron ore
Beeshoek Mine 110,04 65,53 47,75 63,91
Dumps 7,04 55,08
Khumani
Bruce 211,11 64,36 173,05 64,31
King 470,61 64,17 315,68 64,64
Dumps 4,94 55,75
Measured and Indicated Proved and Probable
Mineral Resources Mineral Reserves
Mt Mn % Fe % Mt Mn % Fe %
Manganese
Nchwaning
Seam 1   136,76 43,7 9,1 104,1 43,7 9,1
Seam 2   180,71 42,4 15,5 3,85 44,5 15,6
Black Rock
Seam 1   43,60 40,6 18,1
Seam 2   26,81 38,6 19,8
Gloria
Seam 1   128,35 37,8 4,7 102,64 37,7 4,7
Seam 2 29,40 29,9 10,1
Measured and Indicated Proved and Probable
Mineral Resources Mineral Reserves
Mt Cr2O3% Mt Cr2O3%
Chromite
Dwarsrivier 53,14 38,10 37,31 34,04
 

Subsidiary companies

 
Mineral Resources Mineral Reserves
Measured Indicated Inferred Total Proved Probable Total
Mt Mt Mt Resource Mt Mt Reserve
Rustenburg Minerals 4,0 1,3 6,6 11,9 2,3 0,8 3,1
Zeerust Chrome 1,5 1,5 8,6 11,6 1,7 0,3 2,0
Wonderstone 4,7 0,0 107,2 111,9 4,5 4,5

Competent person’s report on Assmang’s mineral resources and mineral reserves


The report is issued as the annual update of the mineral resources and reserves to inform shareholders of the mineral assets held by Assmang.

Salient features

Khumani

Infill drilling at King and Bruce confirmed the continuation of the orebodies towards the west and north respectively.

Nchwaning

Mineral Reserves of 3,85 million tons have been declared for Manganese Seam 2 where mining has commenced.

Gloria

Measured Mineral Resources increased by 4% to 35,44 million tons due to additional geological data and remodelling of Gloria Manganese Seam 1.

General statement

Assmang’s method of reporting Mineral Resources and Mineral Reserves conforms to the South African Code for Reporting Mineral Resources and Mineral Reserves (SAMREC Code).

he convention adopted in this report is that Mineral Resources are reported inclusive of that portion of the total Mineral Resourceconverted to a Mineral Reserve. Resources and reserves are quoted as at 30 June 2013.

External consulting firms audit the resources and reserves of the Assmang operations on a three to four-year cycle basis.

Underground resources are in-situ tonnages at the postulated mining width, after deductions for geological losses.

Underground Mineral Reserves reflect milled tonnages while surface Mineral Reserves (dumps/stockpiles) are in-situ tonnages without dilution. Both are quoted at the grade fed to the plant. Open-pit Mineral Resources are quoted as in-situ tonnages and Mineral Reserves are tonnages falling within an economic pit-shell.

The evaluation method is generally Ordinary Kriging with mining block sizes ranging from 10 x 10 metres to 100 x 100 metres to 250 x 250 metres in the plan view. The blocks vary in thickness from 2,5 to 10 metres. The evaluation process is fully computerised, generally using the CAE Studio 3 software package.

The classification into Measured, Indicated and Inferred Mineral Resources is done by means of geostatistical parameters such as kriging efficiency, kriging variance, slope of regression and a combination of the number of samples used and the dynamic search volume. The spacing of boreholes as well as the geological structures are also considered in the classification.

The Mineral Resources and Mineral Reserves are reported on a total basis regardless of the attributable beneficial interest that Assmang has on the individual projects or mines. When the attributable beneficial interest on a mine or project is less than 100%, the actual percentage of the attributable interest is specified.

Maps, plans and reports supporting resources and reserves are available for inspection at Assmang’s registered office and at the relevant mines.

In order to satisfy the requirements of the Minerals and Petroleum Resources Development Act, Assmang’s operations will have to obtain new-order mining rights for all properties required to support the planned operations over the next 30 years. The Act was effective from 1 May 2004. Certain operations have already had their conversions approved while some are still in various stages of application.

Rounding of figures may result in computational discrepancies on the Mineral Resource and Reserve tabulations.

Competence

The Competent Person with overall responsibility for the compilation of the Mineral Resources and Reserves report is Shepherd Kadzviti, Pri.Sci.Nat, an African Rainbow Minerals (ARM) employee.

Shepherd Kadzviti graduated with a BSc and MSc in Geology from the University of Zimbabwe. He later completed a Graduate Diploma in Mining Engineering (GDE) at the University of Witwatersrand. He worked at RioZim’s Renco Gold Mine for 14 years in various capacities of Geologist, Technical Services Superintendent and Mine Manager. In 2005 he joined Anglo American Platinum as an Evaluation Geologist with responsibilities for geological database management and mineral resource estimation. After two years at Union Mine he was transferred to Anglo American Platinum corporate office where he was appointed Resource Geologist. He then joined African Rainbow Minerals (ARM) as Mineral Resource Specialist in 2008 where he was involved in the evaluation of the various mineral deposits. In 2012 he was appointed Group Mineral Resources Manager for ARM. He is registered with the South African Council for Natural Scientific Professions (SACNASP) as a Professional Natural Scientist in the field of practice of geological science, registration number 400164/05, and as such is considered to be a Competent Person.

All Competent Persons at the operations have sufficient relevant experience in the type of deposit and in the activity for which they have taken responsibility. Details of the Competent Persons are available from the Company Secretary on written request.

The following Competent Persons were involved in the calculation of Mineral Resources and Reserves:

PJ van der Merwe  
Pr.Sci.Nat  
(SACNASP) Iron/Manganese/Chrome
M Burger  
Pr.Sci.Nat  
(SACNASP) Iron
S van Niekerk  
Pr.Sci.Nat  
(SACNASP) Iron
B Ruzive  
Pr.Sci.Nat  
(SACNASP)  
A Pretorius*  
Pr.Sci.Nat  
(SACNASP) Chrome
   
* External consultant  

Definitions

The definitions of Mineral Resources and Reserves, quoted from the SAMREC Code (2009), are as follows:

A “Mineral Resource” is a concentration or occurrence of material of economic interest in or on the earth’s crust in such form, quality and quantity that there are reasonable and realistic prospects for eventual economic extraction. The location, quantity, grade, continuity and other geological characteristics of a Mineral Resource are known, or estimated from specific geological evidence, sampling and knowledge interpreted from an appropriately constrained and portrayed geological model. Mineral Resources are subdivided, and must be so reported, in order of increasing confidence in respect of geoscientific evidence, into Inferred, Indicated or Measured categories.

An “Inferred Mineral Resource” is that part of a Mineral Resource for which volume or tonnage, grade and mineral content can be estimated with only a low level of confidence. It is inferred from geological evidence and sampling and assumed but not verified geologically or through analysis of grade continuity. It is based on information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that may be limited in scope or of uncertain quality and reliability.

An “Indicated Mineral Resource” is that part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a reasonable level of confidence. It is based on information from exploration, sampling and testing of material gathered from locations such as outcrops, trenches, pits, workings and drill holes. The locations are too widely or inappropriately spaced to confirm geological or grade continuity but are spaced closely enough for continuity to be assumed.

A “Measured Mineral Resource” is that part of a Mineral Resource for which tonnage, densities, shape, physical characteristics, grade and mineral content can be estimated with a high level of confidence. It is based on detailed and reliable information from exploration, sampling and testing of material from locations such as outcrops, trenches, pits, workings and drill holes. The locations are spaced closely enough to confirm geological and grade continuity.

A “Mineral Reserve” is the economically mineable material derived from a Measured or Indicated Mineral Resource or both. It includes diluting and contaminating materials and allows for losses that are expected to occur when the material is mined. Appropriate assessments to a minimum of a Pre-Feasibility Study for a project and a Life-of-Mine Plan for an operation must have been completed, including consideration of, and modification by, realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors (the modifying factors). Such modifying factors must be disclosed.

A “Probable Mineral Reserve” is the economically mineable material derived from a Measured or Indicated Mineral Resource or both. It is estimated with a lower level of confidence than a Proved Mineral Reserve. It includes diluting and contaminating materials and allows for losses that are expected to occur when the material is mined. Appropriate assessments to a minimum of a Pre-Feasibility Study for a project or a Life-of-Mine Plan for an operation must have been carried out, including consideration of, and modification by, realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. Such modifying factors must be disclosed.

A “Proved Mineral Reserve” is the economically mineable material derived from a Measured Mineral Resource. It is estimated with a high level of confidence. It includes diluting and contaminating materials and allows for losses that are expected to occur when the material is mined. Appropriate assessments to a minimum of a Pre-Feasibility Study for a project or a Life-of-Mine Plan for an operation must have been carried out, including consideration of, and modification by, realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. Such modifying factors must be disclosed.

Relationship between exploration results, Mineral Resources and Mineral Reserves

mineral

Iron ore mines

Historical production at Beeshoek and Khumani mines (saleable product)

    Beeshoek   Khumani   Total
    Mt   Mt   Mt
2008/2009   2,66   6,65   9,31
2009/2010   0,52   8,77   9,29
2010/2011   0,96   8,73   9,69
2011/2012   2,10   11,60   13,80
2012/2013   2,94   13,17   16,11

Beeshoek Mine
Khumani Mine

Locality

The Iron Ore division is made up of the Beeshoek Mine located on the farms Beeshoek 448 and Olynfontein 475, and the Khumani Mine situated on the farms Bruce 544, King 561 and Mokaning 560. All properties are in the Northern Cape approximately 200 kilometres west of Kimberley. The Beeshoek open-pit operations are situated 7 kilometres west of Postmasburg and the Khumani open pits are adjacent to, and south-east of, the Sishen mine, which is operated by Kumba Iron Ore Limited. Beeshoek and Khumani are located at latitude 28°30’00”S/longitude 23°01’00”E, and latitude 27°45’00”S/longitude 23°00’00”E respectively. Khumani Mine supplies iron ore to the export markets. Exports are railed to the iron ore terminal at Saldanha Bay. Beeshoek ore is mainly supplied to local customers, with some exported via Khumani.

History

Mining of iron ore (mainly specularite) was undertaken as early as 40 000 BC on the farm Doornfontein which is due north of Beeshoek. The potential of iron ore in this region was discovered in 1909, but, due to lack of demand and limited infrastructure, this commodity was given little attention. In 1929 the railway line was extended from Koopmansfontein (near Kimberley) to service a manganese mine at Beeshoek. In 1935 the Associated Manganese Mines of South Africa Limited (Assmang) was formed, and in 1964 the Beeshoek Iron Ore Mine was established, with a basic hand sorting operation. In 1975 a full washing and screening plant was installed. The Khumani Iron Ore Mine was commissioned in 2007.

Mining authorisation

The Beeshoek mining lease (ML3/93) comprises an area of 5 686 hectares and is located on the farms Beeshoek 448 and Olynfontein 475. The converted mining right was executed on 16 March 2012 and was registered on 29 May 2013.

The Khumani new-order mining right comprises an area of 7 388 hectares and is located on the farms Bruce 544, King 56 and Mokaning 560. The mining right was executed on 25 January 2007 and was registered on 5 March 2007.

Geology

The iron ore deposits are contained within a sequence of early Proterozoic sediments of the Transvaal Supergroup deposited between 2 500 and 2 200 million years ago. In general two ore types are present, namely laminated hematite ore forming part of the Manganore Iron Formation and conglomerate ore belonging to the Doornfontein Conglomerate Member at the base of the Gamagara Formation.

The older laminated ore types occur in the upper portion of the Manganore Iron Formation as enriched high-grade hematite bodies. The boundaries of high-grade hematite orebodies crosscut primary sedimentary bedding, indicating that secondary hematitisation of the iron formation took place. In all of these, some of the stratigraphic and sedimentological features of the original iron formation are preserved. The conglomeratic ore is found in the Doornfontein Conglomerate Member of the Gamagara Formation and is lenticular and not persistently developed along strike. It consists of stacked, upward fining conglomerate-gritstone-shale sedimentary cycles. The lowest conglomerates and gritstones tend to be rich in subrounded to rounded hematite ore pebbles and granules and form the main orebodies. The amount of iron ore pebbles decreases upwards in the sequence so that upper conglomerates normally consist of poorly sorted, angular to rounded chert and banded iron formation pebbles.

The erosion of the northern Khumani deposit is less than that in the southern Beeshoek area. The result is that Khumani is characterised by larger stratiform bodies and prominent hangingwall outcrops. The down-dip portions are well preserved and developed, but in outcrop the deposits are thin and isolated. Numerous deeper extensions occur into the basins due to karst development. A prominent north-south strike of the orebodies is notable. The southern Beeshoek orebodies were exposed to more erosion and are hence more localised and smaller. Outcrops are limited to the higher topography on the eastern side of the properties. Down dip to the west, the ore is thin and deep. The strike of the orebodies is also in a northsouth direction, but less continuous.

Haematite is the predominant ore mineral, but limonite and specularite also occur. Mining operations are all open pit, based on the conventional drill- and-blast, truck-and-shovel operations. Run-of-mine ore is crushed and stored as on or off grade on blending stockpiles. Ore from the stockpiles is either sent to the wash-and-screen plants or, if off grade, to the beneficiation plants. The washing and screening plants consist primarily of tertiary crushing, washing, screening, conveying and stacking equipment. The beneficiation plants consist of tertiary crushers; scrubbers; coarse and fine jigs; lumpy and fines product stockpiles; and a rapid load-out facility. No chemicals are being used in any of the treatment plants.

Mineral Resources and Reserves

Only Measured and Indicated Resources are converted to Proved and Probable Reserves respectively. Modifying factors were applied to these resources and financially optimised. The optimised financial parameters are used to define the optimal pit. The Resources within this mining constraint are defined as Reserves. These are categorised into different product types, destined for the different plant processes and then scheduled for mining.

The methodology followed to identify targets is initiated with geological mapping, followed by geophysics (ground magnetics and gravity). Percussion drilling is used to pilot holes through overlying waste rock down to the iron orebodies. Diamond drilling is the next phase, which is usually on a 200 x 200 metre grid. Further infill drilling is carried out at spacing ranging from 100 x 100 metres to 25 x 25 metres, depending on the complexity of the geological structures. Numerous exploration programmes have been completed in the last 40 years. Core samples are logged and split by means of a diamond saw and the half-core is sampled every 0,5 metres. Before submission for assaying, the half-cores are crushed, split and pulverised. Samples with values larger than 60% are included in the definition of the orebodies.

Any lower-grade samples inside the orebody are defined as internal waste and modelled separately. Each zone is modelled per section, and then wire framed to get a three-dimensional (3D) model. Ordinary Kriging interpolation within Studio 3 is used to estimate the grade of each 25 x 25 x 10 metre block generated within the geological model. Densities in the resource model are calculated using a fourth degree polynomial fit applied to the estimated Fe grade. Densities range from 4,38 t/m3 (60% Fe) to 5,01 t/m3 (68% Fe). All blast holes are sampled on a metre basis, but composited per hole. All holes are analysed for density and blast holes in ore are sampled and analysed for Fe, potassium oxide (K2O), sodium oxide (Na2O), silica (SiO2), aluminium oxide (Al2O3), phosphorus (P), sulphur (S), CaO, MgO, Mn and barium oxide (BaO). Every fifth blast hole is geologically logged per metre, which is used to update the geological model. The chemical results of these holes are used to update the ore block model. The major analytical technique for elemental analyses is XRF spectroscopy.

Volumetric titration is used as verification method for the determination of total iron in the ore. International standards (eg SARM11) and in-house iron standards are used for calibration of the XRF spectrometer. The Khumani laboratory participates in a round robin group that includes 11 laboratories for verification of assay results.

Beeshoek Mine

Beeshoek year-on-year change
Measured and Indicated Resources for Beeshoek Mine decreased by 6% to 110,04 million tons, mainly due remodelling of the Villageorebody and mining of East and BN pits. Mineral Reserves consequently reduced from 54,00 to 47,75 million tons.

A total of 7,04 million tons of ore dumps have been declared as Probable Reserves. The dumps are beneficiated to produce a saleable product. Village Pit Feasibility Study was completed and capital application is awaited.

Beeshoek Resources and Reserves
    Measured Resources   Indicated Resources   Inferred Resources   Total
Resources
Measured
and
Indicated
  Proved Reserves   Probable Reserves   Total Reserves
Pit/area   Mt Fe %   Mt Fe %   Mt Fe %   Mt Fe %   Mt Fe %   Mt Fe %   Mt Fe %
BN   20,38 63,39       20,38 63,39   11,41 63,55     11,41 63,55
HF/HB   16,00 64,10       16,00 64,10   6,87 64,27     6,87 64,27
BF   8,45 63,51   0,23 63,54   0,001 65,24   8,68 63,51   1,02 61,59     1,02 61,59
East Pit   8,71 64,83   0,04 64,23         8,75 64,83   5,86 64,79   0,01 63,64   5,87 64,79
Village   39,90 63,10   0,64 61,40   0,180 61,40   40,54 63,07   22,50 63,86   0,08 64,56   22,58 63,86
GF   3,13 63,81   0,09 61,80     3,22 63,75      
HH Ext   0,28 62,63       0,28 62,63      
HL   2,69 64,93   0,05 65,03     2,74 64,93      
West Pit   9,45 63,19     0,050 61,88   9,45 63,19      
Detrital*       2,500 60,00        
Total
2013
  108,99 63,54   1,05 62,18   2,731 60,13   110,04 63,53   47,66 63,91   0,09 64,46   47,75 63,91
Total
2012
  114,06 63,73   3,39 63,55   2,553 60,04   117,45 63,73   53,99 64,05   0,01 63,64   54,00 64,05
Mineral Resources are inclusive of Mineral Reserves.
Totals are rounded off.
Modifying factors: Economic pit design, fines generated and customer product specifications.

* Detrital is loose and fragmented material occurring in various areas at Beeshoek

beeshoek
Beeshoek Dumps
    Proved Reserves   Probable Reserves   Total Reserves
Area   Mt Fe %   Mt Fe %   Mt Fe %
North Mine (ROM on grade)     0,06 64,00   0,06 64,00
North Mine (B Dump off grade)     0,22 55,00   0,22 55,00
South Mine (B Dump off grade)     0,01 55,00   0,01 55,00
South Mine (C Dump)     6,75 55,00   6,75 55,00
Total 2013 Dumps*     7,04 55,08   7,04 55,08
Total 2012 Dumps*     12,50 55,44   12,50 55,44
Totals are rounded off.
* Dumps are beneficiated to produce a saleable product

Khumani Mine

Khumani year-on-year change
Measured and Indicated Resources decreased by 4% to 681,72 million tons mainly due to remodelling of King and Bruce orebodies. Total Reserves decreased to 488,73 from 512,86 million tons due to remodelling of orebodies and depletion by mining. Ore dumps amounting toR4,94 million tons at 55,75% Fe have been reported as Probable Reserves.

ku_table
Click here to enlarge

khumani

Khumani Dumps
    Proved Reserves   Probable Reserves   Total Reserves
Area   Mt Fe %   Mt Fe %   Mt Fe %
Bruce (ROM on grade)     0,18 64,00   0,18 64,00
Bruce (B Dump off grade)     3,56 55,00   3,56 55,00
King (ROM on grade)     0,06 64,00   0,06 64,00
King (B Dump off grade)     0,83 55,00   0,83 55,00
King (Detrital)     0,31 60,00   0,31 60,00
Total 2013 Dumps*     4,94 55,75   4,94 55,75
Total 2012 Dumps*     1,76 56,22   1,76 56,22
Totals are rounded off.

* Dumps are beneficiated to produce a saleable product

Manganese mines

Historical production at Nchwaning and Gloria mines (saleable product)
    Nchwaning   Gloria   Total
    Mt   Mt   Mt
2008/2009   2,63   0,51   3,14
2009/2010   1,30   0,67   1,97
2010/2011   2,35   0,70   3,05
2011/2012   2,46   0,84   3,30
2012/2013   2,40   0,75   3,15

Nchwaning Mine
Gloria Mine

Locality

The manganese mines are situated in the Northern Cape province in South Africa, approximately 80 kilometres north-west of the town of Kuruman. Located at latitude 27°07’50”S and longitude 22°50’50”E, the site is accessed via the N14 route between Johannesburg and Kuruman, and the R31 road.

History

In 1940, Assmang acquired a manganese ore outcrop on a small hillock known as Black Rock. Several large properties underlain by ore were subsequently found and acquired. Today the Black Rock area is considered to be one of the largest and richest manganese deposits in the world. Manganese ore operations were extended and today include the Gloria and Nchwaning underground mines. Manganese ore is supplied locally to Assmang-owned smelters, but is mainly exported through Port Elizabeth as well as Durban and Richards Bay.

Mining authorisation

The Nchwaning mining lease (ML10/76) comprises an area of 1 986 hectares and is located on the farms Nchwaning 267, Santoy 230 and Belgravia 264. The Gloria mining lease (ML11/83) comprises an area of 1 713 hectares and is located on Portion 1 of the farm Gloria 266. The new-order mining right for Nchwaning and Gloria was executed on 13 July 2011. Registration of the right is in process.

Geology

The manganese ores of the Kalahari manganese field are contained within sediments of the Hotazel Formation of the Griqualand West Sequence, a subdivision of the Proterozoic Transvaal Supergroup. At Black Rock, Belgravia and Nchwaning, the Hotazel, Mapedi and Lucknow Formations have been duplicated by thrusting. The thrusted orebodies comprising Black Rock (Koppie), Belgravia 1 and Belgravia 2 are collectively known as Black Rock orebodies. The average thickness of the Hotazel Formation is approximately 40 metres.

The manganese orebodies exhibit a complex mineralogy and more than 200 mineral species have been identified to date. The hydrothermal upgrading has resulted in a zoning of the orebody with regard to fault positions. Distal areas exhibit more original and low-grade kutnohorite and braunite assemblages, while areas immediately adjacent to faults exhibit a very high-grade hausmannite rich ore. The intermediate areas exhibit a very complex mineralogy, which includes bixbyite, braunite and jacobsite amongst a host of other manganese bearing minerals. A similar type of zoning also exists in the vertical sense. At the top and bottom contacts it is common to have high iron (Fe) and low manganese (Mn) contents while the reverse is true towards the centre of the seam. This vertical zoning has given rise to a mining practice where only the centre 3,5 to 4,5 metre high portion of the seam is being mined. At the Gloria Mine the intensity of faulting is much less, which also explains the lower grade.

Two manganese seams are present. Seam 1 is up to 6 metres in thickness, of which up to 4,5 metres are mined, using a manganese marker zone for control. There is, therefore, minimum dilution. Limited mining of Nchwaning Seam 2 has been done, while no mining has been undertaken to date on Gloria Seam 2.

Nchwaning Mine

Nchwaning Mine year-on-year change
The Mineral Resources for Seam 1 decreased from 142,38 to 136,76 million tons mainly due to the Nchwaning 3 North West section being excluded from the Mineral Resource as Seam 1 is poorly developed due to intense thrusting in the area as well as mining depletion. Nchwaning Seam 2 Mineral Resources marginally reduced to 180,71 from 180,8 million tons due to mining which was undertaken during the year.

Mineral Reserves for Nchwaning Seam 1 decreased by 6% to 104,10 million tons mainly due to the exclusion of the Nchwaning III North West block as well as mining depletion.

Nchwaning Mineral Resources and Reserves

Mineral Resource classification at Nchwaning Mine is based on consideration of a number of parameters: kriging variance, kriging efficiency, regression slope, geological structures and quality of assay data. Each of these parameters contributes to the overall classification depending on weighting assigned to each of the parameters. Measured and Indicated Resources have been defined for Nchwaning. Geological losses are incorporated into the grade models.

The Nchwaning Mine was diamond drilled from surface at 330 metre centres and the data is captured in a Geological Database Management System (GDMS) developed by CAE Mining. The core was logged and 0,5 metre long, half-core, diamond-saw cut samples were submitted to Assmang’s laboratory at Black Rock for X-ray fluorescence (XRF) analyses. Mn and Fe values were checked by Wet Chemical analyses. Several standards were used to calibrate the XRF equipment, and results are compared with other laboratories on a regular basis.

At Nchwaning a total of 322 boreholes and 24 085 underground sample sections were considered in the grade estimation for Nchwaning Seam 1. The data was optimised over a thickness of 4,5 metres (Nchwaning III) and 3,5 metres for the rest of Nchwaning, and exported into data files for computerised statistical and geostatistical manipulation to determine the grades of Mn, Fe, silica (SiO2), calcium (CaO) and magnesium (MgO). Ordinary Kriging interpolation within Studio 3 was used to estimate the grade of each 50 x 50 x 3,5/4,5 metre block generated within the geological model. Sub-cell splitting of the 50 x 50 metre blocks was allowed to follow the geological boundaries accurately.

The relative density of the Nchwaning manganese ore was determined as 4,3 tm3.Trackless mechanised equipment is used in the board and pillar mining method. Mining in the eastern extremity of Nchwaning occurs at a depth of 200 metres while the deepest (current) excavations can be found at a depth of 519 metres below surface. Ore from Nchwaning II Mine is crushed underground before being hoisted to a surface stockpile via a vertical shaft. Similarly, ore from the Nchwaning III Mine is crushed underground before being conveyed to a surface stockpile via a declined conveyor system. Ore is withdrawn from the surface stockpile and forwarded to two stages of crushing, dry screening and wet screening to yield lumpy and fine products.

At the plant the finer fractions are stockpiled while the coarser fractions are extracted from the respective product boxes into road haulers, sampled, weighed and stored on stacks ahead of despatch. Samples from each stack are analysed for chemical content and size distribution. This ensures good quality control and enables the ore control department to blend various stacks according to customer demand.

Nchwaning Mine: Seam 1 Manganese Resources and Reserves
    Mineral Resources       Mineral Reserves
    Mt Mn % Fe %       Mt Mn % Fe %
Measured   41,10 45,6 9,5   Proved   31,35 63,30 12,79
Indicated   95,66 42,9 8,9   Probable   72,75 42,9 8,9
Total Resources (Seam 1) 2013   136,76 43,7 9,1   Total Reserves (Seam 1) 2013   104,10 43,7 9,1
Total Resources (Seam 1) 2012   142,38 43,9 9,0   Total Reserves (Seam 1) 2012   110,34 43,9 9,0
Mineral Resources are inclusive of Mineral Reserves.
Totals are rounded off.
Modifying factors: pillar losses.

Nchwaning Mine: Seam 2 Manganese Resources and Reserves
    Mineral Resources       Mineral Reserves
    Mt Mn % Fe %       Mt Mn % Fe %
Measured   53,28 42,0 16,3   Proved   1,04 44,3 15,7
Indicated   127,43 42,6 15,2   Probable   2,81 44,6 15,6
Total Resources (Seam 2) 2013   180,71 42,4 15,5   Total Reserves (Seam 2) 2013*   3,85 44,5 15,6
Total Resources (Seam 2) 2012   180,80 42,4 15,5            
Mineral Resources are inclusive of
Mineral Reserves.
Totals are rounded off.
Modifying factors: pillar losses.
* Seem 2 Mineral Reserves were confined to 150 metres around existing mining area

nchwaning

Black Rock Mineral Resources

The Black Rock orebodies occur in the Black Rock (Koppie), Belgravia 1 and Belgravia 2 areas. They are all part of a large thrust complex. Modelling of these orebodies was undertaken using 151 Nchwaning boreholes that intersected the thrust complex and 174 Black Rock infill boreholes. A 38% manganese cut-off was used in the modelling. Seam 1 and 2 were modelled at variable thicknesses.

Black Rock: Seam 1 Manganese
Mineral Resources
  Black Rock: Seam 2 Manganese
Mineral Resources
Mineral Resources   Mt Mn % Fe %   Mineral Resources   Mt Mn % Fe %
Measured    90,3 40,3 18,1   Measured   8,23 37,4 19,8
Indicated   34,57 40,7 18,1   Indicated   18,58 39,2 19,8
Total Resources (Seam 1) 2013   43,60 40,6 18,1   Total Resources (Seam 1) 2013   26,81 38,6 19,8
Total Resources (Seam 1) 2012   43,60 40,6 18,1   Total Resources (Seam 1) 2012   26,81 38,6 19,8
Totals are rounded off.   Totals are rounded off.

Gloria Mine

Gloria year-on-year change
Gloria Measured and Indicated Mineral Resources for Seam 1 increased by 1% to 128,35 million tons. Inferred Resources decreased from 48,49 to 46,99 million tons due to upgrade to Indicated Mineral Resources. Mineral Reserves increased from 93,82 to 102,64 million tons due to changes in the mining extraction factors. The Mineral Resources for Gloria Seam 2 remained the same. There are no markets for Gloria Seam 2 ore at this time.

Gloria Mineral Resources and Reserves

Procedures for drilling and assaying at Gloria Mine are the same as at Nchwaning. A total of 172 boreholes and 6 628 underground samples were considered in the evaluation of the Gloria Seam 1. The underground sampling values were used in evaluating areas close to current mining. The boreholes were optimised over an evaluation width of 3,5 metres and the relative density was determined as 3,8 t/m3. The seams were evaluated by means of statistical and geostatistical methods to determine the grades of Mn, Fe, SiO2, CaO and MgO. Ordinary Kriging interpolation within CAE Studio 3 was used to estimate the grade of each 50 x 50 x 3,5 metre block generated within the geological model. Sub-cell splitting of the 50 x 50 metre blocks was allowed to follow the geological boundaries. Mineral Resource classification techniques are the same as for Nchwaning. Gloria Mine is extracting manganese at depths that vary between 180 to 250 metres. Ore is crushed underground before being conveyed to surface stockpile via a decline shaft. Ore is withdrawn from the surface stockpile and forwarded to two stages of crushing, dry screening, and wet screening to yield lumpy and fine products. At the plant the ore is processed in a similar way as at Nchwaning.

Gloria Mine: Seam 1 Manganese Resources and Reserves
    Mineral
Resources
      Mineral Reserves
     Mt Mn % Fe %       Mt Mn % Fe %
Measured   35,44 37,7 4,9   Proved   28,34 37,7 4,9
Indicated   92,91 37,8 4,6   Probable   74,30 37,7 4,6
Total Resources (Seam 1) 2013   128,35 37,8 4,7   Total Reserves (Seam 1)
2013
  102,64  37,7 4,7
Total Resources (Seam 1) 2012   126,79 37,6 4,7   Total Reserves (Seam 1) 2012   93,82 37,6 4,7
Inferred 2013   46,99 36,8 5,0            
Mineral Resources are inclusive of Mineral Reserves.
Totals are rounded off.
Modifying factors: pillar losses and mining losses.

Gloria Mine: Seam 2 Manganese Mineral Resources
Mineral
Resources
   Mt Mn % Fe %
Measured  
Indicated   29,40 29,9 10,1
Total Resources (Seam 2) 2013   29,40 29,9 10,1
Total Resources (Seam 1) 2012   29,40 29,9 10,1
Inferred 2013   128,24    
Totals are rounded off.

gloria

Chromite mine

Dwarsrivier Mine

Dwarsrivier Mine year-on-year change
Measured Mineral Resources decreased by 9% to 18,56 million tons due to depletion related to mining. A reinterpretation of a 40 metre thick dyke on the southern portion of the mine marginally reduced Indicated and Inferred Mineral Resources by less than 1%.

Locality

Chromite operations at Dwarsrivier Mine form part of the Chrome division of Assmang Limited. The mine is situated on the farm Dwarsrivier 372KT, approximately 30 kilometres from Steelpoort and 60 kilometres from Lydenburg, in Mpumalanga province in South Africa. Located at longitude 30°05’00”E/latitude 24°59’00”S, Assmang purchased the farm from Gold Fields Limited, together with all surface and mineral rights in October 1998.

History

Neighbouring properties to the north and south of Dwarsrivier had existing chrome mining operations at the time of purchase. The feasibility study of the plant, tailings dam and designs for the open pit and underground mines then commenced. After the completion of the feasibility study, approval to proceed with the final design and construction work was given in July 1999. Chromite was obtained from the open-pit mining areas at a rate of approximately 0,9 million tons a year and these areas were mined out within five years.

Underground mining commenced in 2005 at a rate of 1,2 million tons ROM a year. Dwarsrivier Mine was specifically geared to deliver high-quality metallurgical grade chromite to the Machadodorp smelter. In addition, the plant has been designed to produce chemical grade products for export.

Mining authorisation

An old-order Mining Licence 21/99 was granted in October 1999. The new mining right was executed on 15 May 2013. Registration of the right is in process.

Geology

Dwarsrivier Mine is situated in the eastern limb of the Bushveld Complex, which comprises persistent layers of mafic and ultramafic rocks, containing the world’s largest known resources of platinum group metals, chromium and vanadium. The mafic rocks termed the Rustenburg Layered Suite, are approximately 8 kilometres thick in the eastern lobe, and are divided formally into five zones. The rocks of the Marginal Zone at the base of the succession consist mainly of pyroxenites with some dunites and harzburgites. Above the Marginal Zone, the Lower Zone comprises mainly pyroxenites, harzburgites and dunite, and is present only in the northern part of the Eastern Lobe, and only as far south as Steelpoort.

The appearance of chromitite layers marks the start of the Critical Zone, economically the most important zone. The layers are grouped into three sets termed the Lower, Middle and Upper Groups. The sixth chromitite seam in the Lower Group, LG6, is an important source of chromite ore and is the orebody being mined at Dwarsrivier Mine. In the Eastern Lobe, in the vicinity of Dwarsrivier, the strike is nearly north-south, with a dip of approximately 10 degrees towards the west. Average thickness of the LG6 seam is about 1,86 metres in the Dwarsrivier area. Pipelike dunite intrusions are evident in the area, as well as dolerite dykes that normally strike north-east south-west. No significant grade variation is evident, especially not vertically in the ore seam in the Dwarsrivier Resource.

Mineral Resources and Reserves

Mineral Resources were estimated from boreholes on 150 to 300 metre grid spacing. All possible resources down to a mineable depth of 350 metres below surface have been considered. Vertical diamond drill holes are used for geological and grade modelling. The Mineral Resources at Dwarsrivier Mine are based on a total of 284 diamond boreholes, that have been used for grade estimation and orebody modelling purposes. The drill core is NQ size and is geologically and geotechnically logged. The collar positions of the drill holes are surveyed, but no down-hole surveys are done, and the holes are assumed to have minimal deflection. The chromitite seam is bounded above and below by pyroxenites and as such, the ore horizon is clearly defined. The core is sampled from the top contact downwards at 0,5 metre intervals. The core is split and half is retained as reference material in the core sheds. The other half is crushed and split into representative samples, which are crushed and pulverised for chemical analysis. The samples are analysed using fusion/ICP-OES for chrome oxide (Cr2O3), SiO2, FeO, Al2O3, MgO and CaO. Three laboratories, all ISO 17025 accredited for this method, are used. Every tenth sample is analysed in duplicate. The density for each sample is measured using a gas pycnometer.

Mineral Resources have been estimated using ordinary Kriging, where Cr2O3, FeO, Al2O3, MnO and MgO-contents of the LG6 seam and densities were determined, using block sizes of 50 x 50 x 4 metres. During mining, a slightly diluted run of mine ore inclusive of the “false” hanging wall is fed to the beneficiation plant. In the dense media separation part of the plant, the coarse fraction is upgraded to 40% Cr2O3, with a yield of 80%. In the spiral section of the plant the finer fraction is upgraded for metallurgical grade fines and chemical grade fines to 44% Cr2O3, and 46% Cr2O3 respectively. A 67% yield is achieved in the spiral circuit.

Dwarsrivier: Chrome Resources and Reserves
    Mineral
Resources
      Mineral Reserves
     Mt Cr2O3 FeO %       Mt Cr2O3 FeO %
Measured   18,56 38,48 22,62   Proved   11,9 33,80 31,13
Indicated   34,58 37,90 22,50   Probable   26,12 34,14 21,33
Total 2013   53,14 38,10 22,54   Total Reserves 2013   37,31 34,04 21,27
Total 2012   55,03 38,11 22,54   Total Reserves 2012   39,15 34,01 21,07
Inferred 2013   48,07 38,35 22,96            
Mineral Resources are inclusive of Mineral Reserves.
Totals are rounded off.
Modifying factors: pillar losses and mining losses.

Historical production at Dwarsrivier (ROM)
Financial year    Mt
2008/2009   1,03
2009/2010   0,78
2010/2011   1,25
2011/2012   1,50
2012/2013   1,60

dwarsrivier