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. For base metals inspections and analysis services, please contact Mr. Stephen Russell: T: +44 151 525 2132

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:


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

PreparationFire Assay
Trace level analysisDrill core analysis
CalcinationsEnvironmental analysis
Solid and liquid brinesMineral processing
Metallurgical testingSample storage and custody

Classical Geochemistry Methods

Atomic absorption spectrophotometry -AAMulti element emission spectrophotometry by Argon Plasma – ICPMercury determination by cold vaporGravimetric 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.

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 can 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. For more information about all of our precious metals inspection and analysis services, please contact: Mr. Rob Smith: +44 7934 857877;


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. For more information about scrap inspection, please contact Mr. Levent Delibas: T +90 212 8711325

Scrap 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.

Refined and Crude Oil, Gas and Chemicals
Quantity and quality inspection and certification for ship to ship services of Oil, Gas and Chemicals including crude oil, all refined petroleum productsliquified gases, chemicals for both inspection and supervision of loading and discharge. All analytical tests, are carried out in accordance with all international standards. Operating mainly in West and Central AfricaStewart Intersea’s inspectors are equipped with GSM handheld internet devices that are suitable for offshore work and enable them to relay information quickly and efficiently to our team in the UK; for more information about these services, please contact Mr. Ben Hughes  T +44 151 305 2300


  • ASI Inspections, Loads and Discharge Operations
  • ASI Laboratory, Sample Preparation and Customer Services
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