Alex Stewart International provides metal assaying, lab analysis and lab testing services for ferrous and non-ferrous metals, minor and precious metals including gold and silver bullion, platinum group metals, auto catalysts, jewellery, ores and concentrates, ferro alloys, recycled scrap metal, electronic scrap, metallurgically complex materials and plastics.

Through Alex Stewarts International's global inspection network, we can also provide you with weighing, sampling and inspection services. Our professional and technically knowledgeable team provide a dedicated, high quality service to meet the specific requirements of the metal industry, mining companies, traders, metal producers and refiners, governments, banks and financial institutions and the general public.

Metal Analysis – Non Ferrous and Ferrous Ores and Concentrates
Alex Stewart International provides a complete service of global inspection, weighing and sampling supported by its UKAS Accredited ISO 17025 laboratories in Liverpool England for copper, cobalt, managenese, silver and nickel; additional metal tests for ores and concentrates include zinc, lead, tin and iron all of which are carried out at our laboratories in Liverpool, England. Analysis is performed by classical wet chemistry techniques, combined with state-of-the-art high-tech instrumentation including Atomic Absorption, ICP, Carbon Sulphur and XRF.

Supervsion of loading and discharge, inspection, weighing, sampling and analysis is provided for:

Copper Iron
Zinc Tin
Lead Minor Metals

Ferro Alloys & Minor Metals - Inspection and Analysis

Our strategically located inspection operations cover all major loading and discharging ports and refineries for ferro alloys and minor metals such as cobalt, nickel and manganese. Inspection and analysis locations include all leading South American countries of mining importantance such as Argentina, Bolivia, Brazil, Chile, Ecuador, Peru; African - Rwanda and Zambia; Asia - India, Kazakhstan, UAE; Pacific Rim - Australia, Malaysia, Indenesia, Thailand; also Black Sea and all principal European ports, refineries and warehouses. Services include full inspection, draft survey, transportable moisture limits, shore scale or belt weighing surveillance, stockpile control and sampling.

Inspection, weighing, sampling and analysis for Minor Metals and Ferro Alloys includes:

Antimony Cobalt
Bismuth Indium
Cadmium Magnesium
Chromium Manganese
Tungsten Selenium
Vanadium Silicon
Molybdenum Nickel
Rhenium Titanium

Geochemical Analysis for Global Mining Exploration Projects
Alex Stewart International provides mining, geochemical, environmental, metallurgical and analytical services to the mining and mineral exploration industry in Africa, Europe, South America and Asia.

Alex Stewart International is able to design, install and staff laboratories at for major exploration projects at mining sites almost anywhere in the world.

Laboratories are accredited to ISO 9001, 14001 and 17025 standards and participate in inter-laboratory tests and international round robins. Alex Stewart Argentina TV Interview at Argentina Mining 2016, Jujuy

Geochemical Analysis

Preparation Fire Assay
Dissolution Fusion
Trace level analysis Drill core analysis
Calcinations Environmental analysis
Solid and liquid brines Mineral processing
Metallurgical testing Sample storage and custody

Classical Geochemistry Methods

Atomic absorption spectrophotometry -AA Multi element emission spectrophotometry by Argon Plasma – ICP Mercury determination by cold vapor Gravimetric determinations

Precious Metals Analysis
Alex Stewart International are internationally recognised as a leading provider of analytical services to the precious metals industry. At our UK Head Office laboratories, we have the capability to assay all types of precious metal bearing materials and provide testing for precious metals content and impurities, moisture determination and loss on ignition (LOI).

Our assaying methods are both time-tested and in-house developed with validation by the use of certified reference materials. External validation is also regularly performed, whereby samples are analysed for round robin exercises and technical committees.

Reflecting growing demand for our precious metals analytical services and our continued drive to provide our clients with the best possible service, we have continued to expand and upgrade our precious metals laboratories. During 2020-2021, upgrade work included the installation of state of the art multi-pour fire assay furnaces and the modernisation of our ICP-OES laboratory. This increased our assaying capabilities significantly and such investment will help to ensure continued swift assay turn-around times and the high quality accurate analysis which is expected within the industry.

Please watch our new Precious Metals Laboratory Services Video here.

In addition to our main head-office UK laboratory, we also have analysis facilities located across other strategic global locations, including well-established gold and silver analytical laboratories in Lima, Peru and Mendoza, Argentina.

Analysis for precious metals is by classical and modern instrumental techniques and materials include:

Bullion/Dore Bullion Auto Catalysts and Petrochemical Catalysts
Jewellery Scrap PGMs, PGM Gauzes and Catchment Gauzes
Electronic and Computer Scrap Industrial, Chemical and Pharmaceutical Catalysts
Precious Metal Concentrates Sweeps, Slimes, Sludges and Residues

Gold and Silver Testing - Accurate Fast Analysis
Our Liverpool Assay Office will weigh, test and analyse any gold or precious metal containing jewellery including earrings, bracelets, necklaces, rings, filings, chains, watches, pendants, coins, sovereigns and krugerands. Tests are determined by rapid XRF which is able to provide detailed analysis by measuring the intensity of the generated gold X-rays by wavelength dispersion analysis. This technique is essentially non-destructive and minimal sample preparation permits very fast turnaround times.

When testing is complete, a full report indicates the percentages of gold content as well as other alloying metals such as copper, silver, zinc, etc. This method is remarkably accurate and can certify the value of your gold or silver before selling on. Having tested for gold, we will then send you an official certificate of its content and correct gold or silver market value at current precious metal market prices.

Scrap & Recycled Metals Analysis - ISRI Standards
Alex Stewart International can provide quantity and quality certification for ferrous, non-ferrous, electronic or plastic scrap material conforms to all contractual terms, conditions and also including all international regulations such as ISRI and GOST.

Digital photographic evidence will be provided for all Pre-shipment Inspection and Proof on Arrival for scrap metal inspections, inspection during loading and sealing of containers. Radioactivity testing and checking for the presence of hazardous or dangerous materials will also be rigorous to protect you from any unnecessary financial or environmental claims. Materials inspected include:

Steel scrap: Radioactive certification, quantity determinations by draft and barge survey, quality assessment to contractual or international (ISRI) guidelines, off grade and dust/dirt assessments, density assessments. Steel products: Pre-shipment quality inspections, tally, loading and discharge supervision, mill test certificate approval, physical and chemical tests. Pig iron: Loading and discharge supervision, weight determination, broken ingot assessment, sampling and chemical analysis.

RoHS and WEEE Screening Tests
Rapid XRF screen testing of electronic components and PCB's is performed in accordance to the Restriction of Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE) Directives. This means that to comply with RoHS and WEEE you must be sure that your products are checked. Our screening tests will verify the percentage of harmful elements in line with the RoHS directive.

Whether your organization is the manufacturer of products, a supplier to the end manufacturer or recycles electronic scrap by testing electronic components, household appliances, telecommunications equipment, toys and other consumer goods you will receive our certificate which confirms whether or not your product contains lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls. If evidence is found then further in depth analyses can be applied. We are available to discuss and help you comply with RoHS and WEEE Directives.

XRF Detection Limit Analysis:

Cadmium 100ppm Chromium, Lead, Mercury, Bromine 1000ppm

All analysis can be combined with representative sampling, weighing and inspection services carried out by Alex Stewart International's network of offices in Africa, Americas, Asia, Australia and Europe.

Our Locations 

A Global Network

ASI Inspections, Loads and Discharge Operations

ASI Laboratory, Sample Preparation and Customer Services

ASi Government Business Head Quarters

Translate »