Mineral Testing

Bureau Veritas - AmdelA-Z Minerals Service Directory

SERVICE PAGE

C COMMINUTION TESTING....................................................................................................

COAL AND COKE EVALUATION ..........................................................................................

3-4

5

D DAVIS TUBE TESTING...................................................................................................................... 5

E EFFLUENT ANALYSIS TO LOCAL SPECIFICATIONS TRADE WASTE.................................. 5

F FLOTATION........................................................................................................................................ 6

G GRAVITY CONCENTRATION..................................................................................................

GOLD AND SILVER METALLURVGY......................................................................................

7

7-9

H HYDROMETALLURGY........................................................................................................... 10

L LEACHING............................................................................................................................ 11-12

M MINERALOGY - MINERAL SAND AND ALLUVIAL ORE.......................................................

MINERAL SEPRARTION (CODE SEP)..................................................................................

MINERALOGY - SPECIALIST SERVICES..............................................................................

MAGNETIC SEPARATION.....................................................................................................

MECHANICAL TESTING......................................................................................................

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13-15

15

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N NUTRIENT ANALYSIS.......................................................................................................... 15

P PETROGRAPHY AND MINERAGRAPHY (CODE PET)..........................................................PROCESS MINERALOGY - GENERAL..................................................................................

PROCESS MINERALOGY - GOLD AND SILVER (CODE GOLD).............................................

PYROMETALLURGY..............................................................................................................

PILOT PLANT.......................................................................................................................

PCB’s IN OILS / CAPACITORS.............................................................................................

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16-17

18

18

19

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R REMEDIATION SERVICES - RAPID ANALYSES FOR METALS, ORGANICS AND INORGANICS........................................................................................................................

REFRACTORIES ANALYSIS..................................................................................................20

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S SIZING, SAMPLE PREPARATION AND DENSITY DETERMINATIONS(CODE SIZE).............

SILVER AND GOLD METALLURGY.......................................................................................

SIZING AND SPECIFIC GRAVITY..........................................................................................

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20-22

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T TRACE METALS...................................................................................................................

TRADE WASTE / EFFLUENT ANALYSIS TO LOCAL SPECIFICATIONS................................

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X X-RAY DIFFRACTION IDENTIFICATION (CODE XRD).......................................................... 24

TABLE OF CONTENTS

3 Minerals Service Guide - Bureau Veritas Australia

C

Communition Testing

AMDEL - A CENTRE OF EXCELLENCE FOR COMMINUTION TESTING

Standard comminution tests provide a reliable means to obtain preliminary design data for crushing and grinding circuits when there are no comparative plant or pilot plant data available. Most of the tests are based on the work of F C Bond and Allis-Chalmers.

Bond Ball and Rod Mill Work Indices

The work index is a measure of the resistance of an ore to grinding. It is used to calculate mill power and the size of grinding media required.

The ball and rod mill work indices are determined by cyclic grinding tests in standard mills with standard grinding charges. Tests are continued until the net amount of ore ground per revolution is constant. The recirculating loads used are 250% for the ball mill and 100% for the rod mill. The work index is calculated from the feed and product sizings and from the quantity of net product obtained per revolution of the mill.

Bond Abrasion Index

This test is used to determine the abrasiveness of a material in relation to metal wear during comminution. Correlations are available in graphical form between the abrasion index and metal wear rates on crushers, mill liners and grinding medium for both wet and dry grinding.

The index is determined by tumbling sized ore in a standard drum and measuring the wear on a hardened steel plate.

Impact Crushing Work Index

This test is used to determine the crushing work index of an ore for use in calculating power requirements for primary crushing. A number of pieces of ore are broken using pendulum hammers that simultaneously impact on opposing faces of the rock piece. The work index is calculated from the energy required to fracture the rock, the thickness of the rock and its specific gravity.

Unconfined Compressive Strength

The compressive strength, or resistance to crushing, of rocks is determined by loading a prepared cylinder of rock to failure under slow compression. The prepared cylinder is obtained by drilling a 50 mm core sample from a specimen of component rock. The test is carried out according to ASTM D 2938-95 “Standard Test Method for Unconfined Compressive Strength of Intact Rock Core Specimens”. This standard recommends the testing of a minimum of 10 samples. However Amdel is pleased to also offer testing of 1 to 9 samples via a modified ASTM D2938-95 method.

JK Drop Weight Test

Amdel is a licensed laboratory for undertaking JK Drop Weight testing to determine breakage parameters.

Minerals Service Guide - Bureau Veritas Australia 4

SMC Testing

Amdel is also licensed to conduct SMC Testing on core or rock samples to provide comparable data to the full JK Drop Weight test when available sample weights are limited.

Autogenous Media Competency Test

This is a preliminary test used to assess the suitability of an ore to grinding in an autogenous mill. The ore sample is tumbled in a mill, the product is sized, and the size analysis is compared with corresponding size analyses of ores that are known to be suitable for autogenous or semi-autogenous grinding. This comparison gives an assessment of whether the test ore is likely to be amenable to autogenous or semi-autogenous grinding. It can also be used as the first stage of the Advanced Media Competency Test.

Advanced Media Competency Test

This test combines the information derived from most of the previous tests to obtain prefeasibility design data for autogenous or semi-autogenous grinding.

Samples are chosen initially for unconfined compressive strength testing. The remaining material is tumbled either to perform the Autogenous Media Competency Test or to remove any planes of weakness and break up the ore to provide a range of sizes. The following tests are then carried out:

• Impact crushing work index for several size ranges• Abrasion index• Rod mill work index• Ball mill work index• Unconfined compressive strength

Amdel can arrange for an evaluation of the test data to be carried out. Computerised modelling programs and historical data base can be used to provide mill size and motor power requirements and circuit configuration details. Price extras apply.

Pilot plant testing can be undertaken by Amdel to confirm detailed design, engineering and performance data requirements.

Grind Establishment Tools

Primary Grind Establishment is used to determine grinding times per laboratory ring mill to achieve a known size distribution. Laser particle sizing is conducted to verify sizing results.

Secondary Grind Establishment (Regrind) is used where additional grinding is required in order to successfully liberate minerals to achieve satisfactory flotation performance. Again laser sizing is conducted to verify sizing results.

Fine Grinding

A laboratory Metprotech stirred ball mill located at Amdel’s Kalgoorlie Laboratory is used for preliminary fine grinding studies and for preparation of material for subsequent testing. Fine grinding can also be undertaken at pilot scale.

High Pressure Grinding Rolls

HPGR testwork is available on request.

Coal and Coke Evalutation

• Ash analysis

• Total Major, Minor and Trace Elements

• Physical Characterization

D

Davis Tube Testing

Magnetic Separation

Davis Tube testing is used to separate ferromagnetic and non-magnetic fractions in small samples of approximately 20 g at a time. This equipment is ideally suited to establishing the recoveries likely from a magnetic separation process. This can assist orebody assessment for hematite, magnetite, pyrrhotite etc.

E

Effluent Analysis to Local Specifications / Trade Waste

Amdel Limited offers services direct to industry as part of the Tradewaste Monitoring Programme, in accordance with organizations such as Sydney Water.

Services not only include the analysis of samples, but also the provision of pre-preserved sampling containers, or using our tradewaste sampling equipment and trained staff.

A comprehensive range of tests is available including:

• Inorganics

• physical tests

• metals

• organics

• microbiological parameters

Minerals Service Guide - Bureau Veritas Australia 66 Minerals Service Guide - Bureau Veritas Australia

F

Flotation

Flotation of Sulphides, Industrial Minerals and Precious Metals

All aspects of flotation of sulphide and non-sulphide minerals are tested in Amdel’s mineral processing laboratories. Facilities for flotation testing range from bench to pilot-plant scale, and from the simplest to the most complex sequential separations. In addition to unparalleled expertise in sulphide flotation, Amdel’s metallurgists have extensive experience in the flotation of industrial minerals (e.g. phosphate, fluorite, vermiculite, barite etc.) and in the flotation of gold, silver and platinum group metals (PGMS). Flotation is the most common method of concentrating gold, silver and PGMS into a low-weight concentrate for more intensive processing and can be used for removal of interfering base metals ahead of CIP/CIL processing.

Batch Flotation TestsPerformance is evaluated in a series of batch tests to examine the effects of variables such as grind size, reagents, conditioning and flotation times, pulp densities etc. Staged rougher, scavenger and cleaner operations give time – metallurgical response information.

Differential flotation of sulphide minerals can be studied. Re-grind stages, including ultrafine grinding, are used where appropriate. Small quantities of concentrates can be produced for marketing purposes and tailings can be examined for settling characteristics.

Locked Cycle Flotation Tests

Confirmatory locked cycle tests, using batch test flowsheets as the basis, can be undertaken to obtain information on circulating loads and their effect on flotation performance. These tests provide preliminary data towards engineering design, as well as early indications of flotation performance under continuous operation. Sufficient quantities of concentrate can be generated to allow further process testing or for marketing purposes. Tailings storage characteristics and recycled water quality can also be examined.

Controlled Potential Sulphidisation (CPS)

Sulphidisation is used in the flotation of oxidised base metal or partially oxidised sulphide ores. Addition of too much reagent results in wastage of reagent and increased costs. Addition of too little reagent reduces the efficiency of flotation recovery.

The applicability of CPS to an oxidised ore is evaluated at bench scale and the conditions for the best flowsheet determined. Amdel has the capability to extend the testwork to pilot scale.

Mineralogy

Mineralogical investigation is a vital component in a complete assessment of the flotation process. Amdel’s mineralogist provides assessment of ore samples and test products with respect to liberation/ locking characteristics, the identification of valuable and gangue minerals and diagnosis of process problems.

Jameson Flotation Cell Testing

Amdel has a pilot-scale Jameson Flotation Cell test rig supplied by Xstrata Technology for testwork at Amdel or in the field. Under the agreement between Amdel and Xstrata for the use of the Jameson Cell technology, Amdel requires client’s permission to release test data to Xstrata for use in development and scale up design.


G

Gravity Concentration

Heavy Liquid Separation

Heavy liquid separation can be used to assess the potential of gravity concentration techniques. Separations are carried out over a range of specific gravities (typically in the range of 2.6 to 4.2) and the resulting fractions weighed and assayed. Weight and element distributions are calculated and the data used to indicate optimum density cut points or product weight splits to achieve the desired results in terms of grade and/or recovery.

Heavy liquid separation is applicable to fine particles (down to 10 to 20 mm) and coarse particles (up to 13 mm).

Heavy Medium Separation -Erickson Cone

The Erickson Cone is used for separation of coarse particles (-50+6 mm). It is a semi-continuous unit in which a batch of ore is separated in a continuous circulating stream of heavy medium. Small batches of a few kilograms can be treated, but it is desirable to have a 50 kg sample available for processing over a range of specific gravities.

Fine Particle Concentration

A range of equipment is available for gravity concentration of ‘fine’ particles (e.g.; less than 1 to 2 mm), as summarised below:

• laboratory Wilfley Tables

• spirals, different pitch angles, with and without wash water

• Knelson concentrators

• cycloning (centrifugal)

Quotations will be supplied for gravity concentration testwork on request.

Gold And Silver Metallurgy

Amdel carries out testing of free milling and refractory gold/silver ores to allow flowsheet design or problem solving related to plant operations.

Process Mineralogy of Gold and Silver

Determination of the nature and location of gold and silver in ores and tailings is discussed under Mineralogical Services (pp 21)



Gravity concentration performance is evaluated using a variety of techniques including:

• heavy liquid separation

• table and spiral concentration

• centrifugal concentration

• amalgamation

Such tests are frequently carried out to produce tailings for further agitation cyanide leach testing, ensuring that leach kinetics are not affected by the presence of coarse, liberated gold. Test results will, therefore, more accurately reflect CIP/CIL performance in a plant which incorporates a gravity circuit ahead of leaching.

Agitation Leaching

Agitation cyanide leaching tests under controlled laboratory conditions provide metal extractions and reagent consumptions against leaching time. These tests can be carried out with carbon present to demonstrate CIL performance.

Standard tests involve grinding the sample to the required size distribution, followed by cyanide leaching in mechanically agitated beakers. Dissolved gold and silver and reagent levels are determined from solution samples taken at intervals during the leach.

Variables tested for their effect on gold and silver extraction include:

• grind size

• cyanide concentration

• reagent additions (e.g., lead nitrate)

• oxygen injection

Site water should be used if this is likely to affect the chemistry of the process.

Recovery of Gold and Silver from Solution

CIP design data and Merrill-Crowe performance are obtained from multi-batch carbon contact and zinc precipitation tests respectively.

Column and Bottle-Roll Leaching

Bottle-roll cyanide leaching of crushed samples is used to provide information on the effect of crush size on gold extraction.

Following preliminary selection of crush sizes, column leach tests are undertaken to provide indications of heap leach gold extraction and reagent consumption. Heap leach performance with and without agglomeration can also be evaluated at this stage. Gold extraction rate and reagent consumption curves are determined for each test.


Column dimensions are selected on the basis of sample weight and crush size. Leach solution is circulated through the column, via a carbon adsorption stage, at an irrigation rate comparable to the full-scale application.

Flotation

The most common method of concentrating gold, silver and platinum group metals (PGMS) into a low weight concentrate for more-intensive processing is flotation of free gold, silver and PGMS and accompanying sulphide and oxide minerals. Removal of interfering base metals ahead of CIP/CIL can be examined.

Amdel is highly qualified to carry out flotation tests at laboratory and pilot scale, with facilities designed to cater for tests ranging from simple to the most complex sequential processes. Conventional and column flotation cells are available at pilot scale.

Roasting

Flotation concentrates can be roasted to achieve oxidation of sulphide minerals and exposure of gold and silver for cyanide leaching. This is carried out at laboratory scale in electric muffle furnaces.

Pressure Oxidation

In situations where roasting is seen as environmentally inappropriate, pressure oxidation should be considered. Pyrite and arsenopyrite will oxidise under oxygen pressure at elevated temperatures, rendering associated gold and silver available for dissolution by cyanide solution.

Bacterial Leaching

Bacterial attack of sulphide minerals provides an alternative method of exposing enclosed gold and silver for subsequent dissolution by cyanide.

Bacterial leaching studies are undertaken by Amdel in conjunction with reputable laboratories in Australia.


H Hydrometallurgy

In addition to gold and silver leaching, Amdel can undertake a range of hydrometallurgical tests, including agitation leaching, heap and percolation leaching, pressure leaching, solvent extraction tests and recovery from solution.

Agitation Leaching

• mechanically agitated vessels, either open or vented to atmosphere in a range of sizes

• bottle rolls

Heap and Percolation Leaching

• bottle rolls for preliminary characterisation tests

• columns for either drip or flooded percolation leaching, range of sizes

Solvent Extraction

Batch shake-out tests to develop extraction and stripping isotherms at a range of extractant concentrations and organic : aqueous ratios; loading capacity; loading kinetics; phase disengagement.

Recovery From Solution

• ion exchange

• carbon adsorption

• precipitation

Acid Leaching

Acid leaching of concentrates and tailings can be tailored to suit specific ore types. Autotitration is available as well as measurement of key parameters such as acid consumption and extraction rates.

Settling and Rheology

Customised programs can be performed to measure parameters for conventional and paste thickening, Haake Rheometer measurements, Brookfield viscosities and yield stresses and Marsh Funnel measurements.

Quotations will be supplied for hydrometallurgical investigations on request.


L

Leaching

In addition to gold and silver leaching, Amdel can undertake a range of hydrometallurgical tests, including agitation leaching, heap and percolation leaching, pressure leaching, solvent extraction tests and recovery from solution.

Agitation Leaching

• mechanically agitated vessels, either open or vented to atmosphere in a range of sizes

• bottle rolls

Heap and Percolation Leaching

• bottle rolls for preliminary characterisation tests

• columns for either drip or flooded percolation leaching, range of sizes

Solvent Extraction

Batch shake-out tests to develop extraction and stripping isotherms at a range of extractant concentrations and organic : aqueous ratios; loading capacity; loading kinetics; phase disengagement.

Recovery From Solution

• ion exchange

• carbon adsorption

• precipitation

Acid Leaching

Acid leaching of concentrates and tailings can be tailored to suit specific ore types. Autotitration is available as well as measurement of key parameters such as acid consumption and extraction rates.

Settling and Rheology

Customised programs can be performed to measure parameters for conventional and paste thickening, Haake Rheometer measurements, Brookfield viscosities and yield stresses and Marsh Funnel measurements.

Quotations will be supplied for hydrometallurgical investigations on request.

Leachate Analysis TCLP / Zero Headspace

TCLP determinations are performed by Amdel Limited to Australian Standards to assess the long-term leaching capacity of potentially toxic components of soils, sediments and waste.


Testing is conducted on contaminated site assessments and with waste classification producing results directly comparable against EPA tables for the Assessment and Classification of Liquid and non-Liquid Waste.

Amdel Limited holds NATA accreditation for these tests including TCLP by Zero Headspace.

M Petrography and Mineragrophy (Code PET)

Petrography and mineragraphy are carried out by our highly experienced petrologist/mineralogist using microscopes with photomicrographic facilities.

Petrography involves the use of transmitted light microscopy on a thin section sample to identify minerals. Typical minerals identifiable by this technique include silicates and carbonates.

Mineragraphy involves the use of reflected light microscopy on a polished sample to identify minerals. Typical minerals identifiable by this technique include sulphides and iron oxides.

Where the nature of the minerals are unknown or where both types of minerals are likely to be present then both petrography and mineragraphy are used. This is sometimes referred to as Petrology.

Brief descriptions of minerals do not include estimates of mineral percentages whereas routine descriptions do. As a rough guide, a brief description will occupy _-1 page, whereas a routine description will occupy 1-1_ pages of typescript. In addition, a brief petrographic summary is offered in which the main minerals and textural features are listed in tabular form.

Colour photomicrographs can be provided if required.

Amdel’s petrologist/mineralogist is familiar with rocks and ores from a wide range of geological environments.


M

Mineralogy - Mineral Sand and Alluvial Ore

Amdel has been involved in mineral sand assessment for over 30 years and staff have worked on most of the deposits in Australia, including those in the Murray Basin, as well as overseas deposits (e.g., India, Bangladesh, Indonesia).

Special techniques have been developed to quantify the valuable heavy minerals to various degrees of accuracy.

Pure concentrates of individual minerals can be prepared and characterised chemically and physically to assess whether they meet commercial specifications.

Mineral Separation (Code SEP)

Small-scale (<30 kg) mineral separation is a specialty of Amdel.

Heavy liquid separation can be done at specific gravities up to 4.2 and particle sizes down to 10 mm. Special methods have been developed for effective separation at particle sizes below 38 mm.

Magnetohydrostatic separation enables separation to be done at specific gravities of up to 19.

Low and high-intensity magnetic separation, flotation and superpanning are other methods used.

Mineralogy - Specialist Services

Specialist mineralogical services related to mineral exploration but not included in the previous codes are outlined below. In each case we would be pleased to discuss possible applications of the techniques and to supply quotations for investigations.

Diamond Indicator Assessment

Amdel staff have considerable experience in the concentration and identification of diamond indicator minerals (e.g., pyrope garnet, picroilmenite, chrome diopside, chromite, etc.) in exploration samples.

Concentration is carried out using gravity methods (e.g., tabling), heavy liquid separation (at specific gravities up to 4.2), magnetic separation and more-specialised techniques.

Concentrates are then assessed microscopically and suspected diamond indicator grains and diamonds/ microdiamonds are hand-picked and identified optically or by X-ray diffraction or energy-dispersive analysis using a scanning electron microscope or electron-probe microanalyser.


Electron-Probe Microanalysis

The electron-probe microanalyser detects and analyses qualitatively or quantitatively elements in polished sections or polished thin sections. It can analyse for most of the elements in the Periodic Table except the lightest ones, and has a resolution of about 3 µm (0.003 mm).

Thus any mineral that can be observed under a petrological microscope can be characterised chemically. Uses include:

• Identification of unknown minerals (e.g., diamond indicator minerals).

• Location of particular elements in rocks, ores and minerals (e.g., Ag, Au, Cu, Sn, U, W).

• Qualitative or quantitative point analyses of minerals, metals, etc.

Wavelength-dispersive analysis is particularly applicable where low detection limits (~100-200 ppm) are required.

Energy-dispersive analysis is commonly used where rapid multi-element analyses of mineral grains are required; the detection limit is normally ~0.1% but peak overlaps may occasionally cause problems in determining specific elements.

In addition to point analyses, line scans or area scans can be obtained to illustrate compositional variations and element distributions.

Diamond Drill Bit Quality

A related service is the assessment of diamond drill bit quality. The quality of surface-set diamond drill bits can be assessed in terms of the weight, sizing and quality of diamonds present, the hardness of the matrix and the general size and configuration specifications of the bit. The quality of the diamonds is assessed by comparison with US Army Corps of Engineers specifications. A certificate is issued if required. (Note that the assessment entails destruction of the bit although the diamonds are recovered and can be returned to the client).

Radioactive Mineral Location and Identification

A comprehensive service is provided in the identification of the source of radioactivity in radioactive materials (e.g., rocks, ore, oil-well drillcores, sediments).

Typically autoradiography is used to detect the distribution of radioactivity in a rock or polished section. The radioactive areas are then identified using X-ray diffraction if large discrete radioactive mineral grains are present, or electron-probe microanalysis if the radioactivity is dispersed or in very small (<50 µm) grains.

Pulverising and heavy liquid separation may be required to concentrate radioactive mineral grains for X-ray diffraction or electron-probe microanalysis where the grains are sparse or where low levels of U or Th (e.g., <200 ppm) are present in the sample.


Scanning Electron Microscopy

In recent years scanning electron microscopy has developed considerably and, in combination with energy-dispersive analysis (EDA), back-scattered electron (BSE) detection and computerised processing of the data, enables the following information to be obtained on samples:

Morphology: The extreme depth of focus enables sharp images to be obtained of very irregular surfaces. Magnification can range from ¥5 up to ¥40,000.

Chemistry/Mineralogy: The energy-dispersive part of the system enables features on a scale of down to one micron to be analysed qualitatively (and in some cases quantitatively) for a wide range of elements. The chemistry can then often be used to infer the mineralogy (e.g., the presence of Ag and Cl in a mineral indicates chlorargyrite). If polished sections or polished thin sections are used, quantitative analyses can be obtained.

Back-scattered electron contrast: Use of a sensitive BSE detector (e.g., Robinson detector) which operates at TV scanning rates allows atomic number contrasts to be clearly displayed, with rapid scanning of large fields. Thus, for example, native gold in pyrite can be easily and rapidly detected.

Image analysis: Digitised data derived from the EDA and BSE systems can be computer-processed to give information on mineral proportions, grain size distributions, and associations.

Magnetic Separation

Davis Tube Testing

Davis Tube testing is used to separate ferromagnetic and non-magnetic fractions in small samples of approximately 20 g at a time. This equipment is ideally suited to establishing the recoveries likely from a magnetic separation process. This can assist orebody assessment for hematite, magnetite, pyrrhotite etc.

Mechanical Testing

• Tensile and fatigue testing to 2000kN

• Hardness Tests

• Bend and Impact Tests

• Consultancy

N

Nutrient Analysis

Amdel Limited performs a comprehensive suite of trace and ultra-trace analyses to meet the needs of the Environmental community. Many of these analyses are performed on long-term monitoring projects.


P

Petrography And Mineragraphy (Code PET)

Petrography and mineragraphy are carried out by our highly experienced petrologist/mineralogist using microscopes with photomicrographic facilities.

Petrography involves the use of transmitted light microscopy on a thin section sample to identify minerals. Typical minerals identifiable by this technique include silicates and carbonates.

Mineragraphy involves the use of reflected light microscopy on a polished sample to identify minerals. Typical minerals identifiable by this technique include sulphides and iron oxides.

Where the nature of the minerals are unknown or where both types of minerals are likely to be present then both petrography and mineragraphy are used. This is sometimes referred to as Petrology.

Brief descriptions of minerals do not include estimates of mineral percentages whereas routine descriptions do. As a rough guide, a brief description will occupy _-1 page, whereas a routine description will occupy 1-1_ pages of typescript. In addition, a brief petrographic summary is offered in which the main minerals and textural features are listed in tabular form.

Colour photomicrographs can be provided if required.

Amdel’s petrologist/mineralogist is familiar with rocks and ores from a wide range of geological environments.

Process Mineralogy - General

Determination of the nature and location of precious metals in ores and mill products is often of great importance to the process metallurgist. Amdel has extensive experience in this area and has developed and applied a range of techniques to identify the precious metal carriers and quantify the distribution of the metals among these carriers.

Amdel provides a complete service in process mineralogy, from initial examination of drill core and bulk test samples to evaluation of the efficiencies of individual unit processes and the overall efficiency of the final plant. In this work, close liaison is maintained with Amdel’s experienced metallurgists and consultants. Amdel has established an international reputation in the field of process mineralogy and has developed special techniques, particularly in the evaluation of gold ores and tailings.

Using a combination of microscopy, mineral separation, chemical analysis, X-ray diffraction and electron-probe analysis, and drawing on specialist facilities such as the CSIRO QEM*SEM and HIAF systems, it is possible to provide quantitative data on mineralogical composition, liberation characteristics, element distributions among minerals, differential grinding, etc., and to evaluate the data in relation to beneficiation. Such information can be invaluable to the metallurgist and can prevent much abortive and time-wasting beneficiation testwork.

Rapid turnaround can be provided where the mineralogical information is required for laboratory-scale or plant-scale testing.


The following is a summary of the main types of investigation undertaken and the information obtainable.

HEAD OR FEED SAMPLES

• Mineralogical composition• Optimum grind size• Maximum concentrate grade obtainable• Differential grinding or sliming• Liberation characteristics• Size/assay analysis• Problems likely to arise during beneficiation• Mineralogical locations of various elements

CONCENTRATE SAMPLES

• Mineralogical composition• Locations of credit and penalty elements• Size/assay analysis• Variation of mineralogy with particle size• Suggestions for improving grade• Liberation characteristics and necessity for regrinding• Presence of slimes or easily floatable gangue minerals• Maximum grade obtainable

TAILING AND MIDDLING SAMPLES

• Mineralogical composition• Variation of mineralogy with particle size• Cause of low recovery• Size/assay analysis• Liberation characteristics• Suggestions for improving recovery

DRILL-CORE SAMPLES

As for feed samples above. Can provide valuable information on orebody variation, particularly with different lithologies.

PYROMETALLURGICAL SAMPLES

• Identities and proportions of phases• Textural relations and grain sizes• Compositions of phases• Locations of elements

Quotations will be supplied for process mineralogy investigations on request.


Process Mineralogy - Gold And Silver (Code GOLD)

The main aim of these investigations is to provide the process metallurgist with fundamental information on the mineralogical locations of the precious metals and interpret this in metallurgical terms. In gold ores and tailings, for example, information can be provided on the following:

• The nature of the gold-bearing minerals present (e.g., native gold, gold-bearing sulphides, tellurides, gold-bearing carbon).

• The liberation/locking characteristics of the gold-bearing minerals, including the extent of locking in silicate/carbonate gangue and as inclusions in sulphides at various particle sizes.

• The extent of submicroscopic gold in sulphides (e.g., in solid solution).

• The mineralogy of the gangue.

• The distribution of gold among various mineralogical sites at different particle sizes and overall.

• The possibility of increasing gold recovery by modifications to the metallurgical process.

In addition to the detailed assessment of gold in ores and tailings, Amdel offers a rapid, inexpensive service for characterising gold in plant tailing samples.

Pyrometallurgy

Pyrometallurgical testwork is carried out in units ranging from laboratory muffle furnaces and a batch rotating reactor to a fluid bed reactor and rotary kiln, both of which operate on a continuous basis. Initial tests use a minimum of sample, after which processes can be investigated in continuous operation under conditions representative of full-scale practice. Samples can be generated for subsequent leaching or other product evaluation testwork.

Batch Reactor

Laboratory muffle furnaces of various sizes are also available for treating batch samples.

Differential Thermal Analysis

Combined Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) is a very useful adjunct to pyrometallurgical investigations. It can be used for:

• identifying and estimating the amounts of minerals or chemical compounds in a mixture

• studying thermal stability, reactivity and combustibility of solids

• determining reaction temperatures and heats of reaction

This information can assist in the development of processes for drying, calcination, combustion and pyrolysis.

Quotations will be supplied for pyrometallurgical testwork on request.


Pilot Plant

Amdel owns a range of Mineral Processing Pilot Plant equipment. This equipment can be configured to simulate many flow sheet configurations.Types of plant available include:

• crushing and grinding (rod and ball mills)

• autogenous / semi-autogenous grinding

• gravity concentration

• flotation; conventional and column including Jameson Cell

• drying

• hydrometallurgy

Amdel’s involvement in Pilot Plant work can be from simple rental of equipment involved and consultation on flowsheet configurations to full design, mobilisation and operation of a Pilot Plant on-site at the client or at an off-site facility in Adelaide. Amdel has designed, built and managed over 100 pilot plants in its history.

Using Amdel for this work makes it possible to extend laboratory investigations into the pilot scale while maintaining continuity of personnel and familiarisation with process development to date. Recent Pilot Plants include:

• Iluka – mineral sands separation

• SAMAG – magnesium extraction

• Metzo Minerals – SAG mill and scrubbing of nickel laterite

• KCGM – on-site leach Pilot Plant

• North Parkes Mines – regrinding/flotation Plot Plant for copper

Quotations will be supplied for pilot plant investigations.

PCB’s in Oils / Capacitors

Amdel Limited has long been a provider of analytical services for PCBs in capacitor insulator oils. These tests are performed to assist industry in the removal of PCBs from workplaces in conjunction with OH&S requirements.

Amdel Limited uses GC/ECD in the determination of seven arochlors in oil, capacitors, water and soils. These tests fall under the scope of Amdel Limited’s NATA accreditation.


R

Remediation Services - Rapid Analyses for Metals, Organics and Inorganics

Amdel Limited is a major provider of rapid remediation services to the Environmental Industry across Australia. We recognise the importance in remediation projects of not only producing high quality data, but producing this in an extremely short timeframe.

Amdel Limited prides itself on our ability to dedicate staff and resources, communicate well and manage such projects to the benefit of our clients.

Refractories Analysis

Analysis of all refractories, sands and refractory raw materials

Like to know more? Simply contact us now.

S

Sizing, Sample Preparation and Density Determinations(Code SIZE)

Various preparation services are available including:

Wet sieving, sieve analysis, cyclosizer analysis, sub-sieve sizing and desliming.

Silver and Gold Metallurgy

Amdel carries out testing of free milling and refractory gold/silver ores to allow flowsheet design or problem solving related to plant operations.

Process Mineralogy of Gold and Silver

Determination of the nature and location of gold and silver in ores and tailings is discussed under Mineralogical Services (pp 21)


Gravity concentration performance is evaluated using a variety of techniques including:

• heavy liquid separation

• table and spiral concentration

• centrifugal concentration

• amalgamation


Such tests are frequently carried out to produce tailings for further agitation cyanide leach testing, ensuring that leach kinetics are not affected by the presence of coarse, liberated gold. Test results will, therefore, more accurately reflect CIP/CIL performance in a plant which incorporates a gravity circuit ahead of leaching.

Agitation Leaching

Agitation cyanide leaching tests under controlled laboratory conditions provide metal extractions and reagent consumptions against leaching time. These tests can be carried out with carbon present to demonstrate CIL performance.

Standard tests involve grinding the sample to the required size distribution, followed by cyanide leaching in mechanically agitated beakers. Dissolved gold and silver and reagent levels are determined from solution samples taken at intervals during the leach.

Variables tested for their effect on gold and silver extraction include:

• grind size

• cyanide concentration

• reagent additions (e.g., lead nitrate)

• oxygen injection

Site water should be used if this is likely to affect the chemistry of the process.

Recovery of Gold and Silver from Solution

CIP design data and Merrill-Crowe performance are obtained from multi-batch carbon contact and zinc precipitation tests respectively.

Column and Bottle-Roll Leaching

Bottle-roll cyanide leaching of crushed samples is used to provide information on the effect of crush size on gold extraction.

Following preliminary selection of crush sizes, column leach tests are undertaken to provide indications of heap leach gold extraction and reagent consumption. Heap leach performance with and without agglomeration can also be evaluated at this stage. Gold extraction rate and reagent consumption curves are determined for each test.

Column dimensions are selected on the basis of sample weight and crush size. Leach solution is circulated through the column, via a carbon adsorption stage, at an irrigation rate comparable to the full-scale application.

Flotation

The most common method of concentrating gold, silver and platinum group metals (PGMS) into a low weight concentrate for more-intensive processing is flotation of free gold, silver and PGMS and accompanying sulphide and oxide minerals. Removal of interfering base metals ahead of CIP/CIL can be examined.


Amdel is highly qualified to carry out flotation tests at laboratory and pilot scale, with facilities designed to cater for tests ranging from simple to the most complex sequential processes. Conventional and column flotation cells are available at pilot scale.

Roasting

Flotation concentrates can be roasted to achieve oxidation of sulphide minerals and exposure of gold and silver for cyanide leaching. This is carried out at laboratory scale in electric muffle furnaces.

Pressure Oxidation

In situations where roasting is seen as environmentally inappropriate, pressure oxidation should be considered. Pyrite and arsenopyrite will oxidise under oxygen pressure at elevated temperatures, rendering associated gold and silver available for dissolution by cyanide solution.

Bacterial Leaching

Bacterial attack of sulphide minerals provides an alternative method of exposing enclosed gold and silver for subsequent dissolution by cyanide.

Bacterial leaching studies are undertaken by Amdel in conjunction with reputable laboratories in Australia.

Sizing and Specific Gravity

Settling Tests

Cylinder settling tests (0.5 or 2 litre) are undertaken to screen different flocculants and examine the effect of flocculant dose rates. The settling curves are used to derive preliminary thickener area requirements.

Filtration Tests

Top feed or inverted leaf vacuum filtration tests are used to determine preliminary vacuum filtration rates and filter area requirements.

3.Transportable Moisture Limit

Procedure is as per “Code of Practice for Solid Bulk Cargoes” published by the International Maritime Organisation - London (1989).

The test is carried out to determine the moisture content of a sample (e.g., flotation concentrate) at which a flow state might be induced during transportation.


T Trace Metals

Trace level metals by ICP-MS and ICP-AES are an important part of the services we offer to our industry clients – reporting many elements to levels below 0.1ppb (parts per billion).

Heavy metals are a key concern in the environment, and Amdel Limited performs trace level analyses for dissolved and total recoverable metals on groundwater and leachate water samples.

Trade Waste / Effluent Analysis to Local Specifications

Amdel Limited offers services direct to industry as part of the Tradewaste Monitoring Programme, in accordance with organizations such as Sydney Water.

Services not only include the analysis of samples, but also the provision of pre-preserved sampling containers, or using our tradewaste sampling equipment and trained staff.

A comprehensive range of tests is available including:

• Inorganics

• physical tests

• metals

• organics

• microbiological parameters

Like to know more? Simply contact us now.

clay-poor samples requiring clay mineral identification, a sample weight of 25-50 g is desirable (minimum ~12 g).


X X-Ray Diffraction Identification (Code XRD)

X-ray diffraction (XRD) is used to identify minerals and other crystalline materials on the basis of their crystal structures. It is particularly applicable where the grain size of the minerals is too small for microscopic identification (e.g., soils, clays, volcanic rocks and altered rocks).

Geological applications include identification of mineral assemblages (e.g., alteration minerals), and clay mineral identification.

Industrial applications include identification of chemical products, boiler scales, corrosion products, asbestos, etc.

Amdel’s XRD system includes computer control of the diffractometer, digital data collection and computerised search-match facilities that can scan the whole XRD database of over 60,000 phases (including chemicals and organics).

Sample requirements: The minimum is 0.005 g but for most services 0.1 to 1 g is preferred and for

Bureau Veritas Australia Head Office - 3/435 Williamstown Rd Port Melbourne 3207, Vic, AustraliaTel: +61 (0)3 9922 0700 - Fax: +61 (0)3 9922 0710

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Mineral Testing

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