Services
Assaying
Services
Assaying

Government controlled and certified laboratory

Valcambi operates a state-of-the-art testing laboratory. Our testing methods have been accredited since 1995 according to ISO/IEC 17025 standards.

All sampling and testing activities are performed by independent certified precious metals assayers in compliance with the Swiss Precious Metals Control Law, and supervised by the Central Office for Precious Metals Control.

A highly qualified professional team carries out a range of analyses to ensure that Valcambi consistently meets both production and environmental standards of excellence.

Our laboratory employs a comprehensive range of testing techniques, for example traditional fire assay, potentiometric methods, WD-XRF, SPARK-OES, and ICP-OES spectrometry.

Testing methods are applied on a case-by-case basis and may include various testing techniques applied singly or in combination, as appropriate.

Our laboratory also has the ability to perform detailed microstructural analysis (failure, surface defects, inclusions) using EDX combined with a SEM.

Valcambi maintains close and effective communication with our clients and their representatives and co-operate closely with the Swiss public authorities.

Audited trust: with over 50 years of experience behind us we deliver the highest professional standards of precious metals testing and comprehensive assaying services complemented by accurate and timely sampling procedures.

Alessia Sironi - Head of Laboratory

Sampling and Analysis

Each shipment of Non-Good Delivery (NGD) precious metals is first weighed and melted to ensure homogeneity.

Sampling is then undertaken – the method chosen depends on the quantity and kind of material received.

Phase 1 Verifying homogenisation of the melt

The laboratory cleans and drills the samples, and places the drillings from each sample into separate envelopes. The laboratory then analyses the individual samples to verify the homogeneity of the melt.

If homogeneity is verified and there is an agreement for exchange of assays between the client and Valcambi, three equal final samples of usually 5 g each are prepared, together with the drillings of the sample taken from the melt just before pouring. If our laboratory cannot prove homogeneity, then the lot is re-melted.

Phase 2 Distribution of the samples

The samples are sealed by the client’s representative, labelled with the melt number, and distributed as follows:

  • One sealed sample is kept by Valcambi but is at the client’s disposal or it is delivered to the client’s representative, if present.
    Valcambi mails the sample to the client or to their requested laboratory upon written instructions.
  • One sealed sample is kept at Valcambi’s laboratory to perform the analysis.
  • One sealed sample remains with Valcambi for contingent umpire assay.

Phase 3 Sampling the recovery bar

The laboratory samples the recovery bar.
The samples are put into separate envelopes, labelled with the melt number, and the drilling side.
The samples are analysed by Valcambi to verify the homogeneity of the recovery bar.

Phase 4 Preparation/sealing of the final samples of the recovery bar

If homogeneity of the recovery bar has been proved, then three sealed envelopes are prepared.
Each usually contains 5 g of drilled material after having mixed equal parts of the drillings taken from the recovery bar.
The samples obtained from the recovery bar are sequentially stored with the other samples.

Phase 5 Assays

The assays are carried out by the fire assay method.
Results of these assays are exchanged simultaneously between the client and Valcambi by mail on an agreed upon date, and followed up by fax or e-mail the following day.

If the difference between the exchanged results do not exceed the splitting limits, then the arithmetic mean of Valcambi and the client ‘s results are taken as final.

Phase 6 Splitting limits

Subject to exchange of assays including splitting limits contractually agreed upon, for gold, silver, platinum and palladium.

Gold assay results shall be expressed to four (4) significant figures for 995,0 and higher fineness and to five (5) significant figures for gold below 995,0 fineness.

Silver assay results shall be expressed to four (4) significant figures for fineness above and below 999,0.

Platinum and palladium assay results shall be expressed to four (4) significant figures for 999,5 and
higher fineness and three (3) significant figures with fineness below 999,5

Phase 7 Umpire

  1. If the difference between the assays exceeds the splitting limits, both the client and Valcambi have the right to ask for assays to be remade or to request an umpire analysis.
  2. If requested, the second assay or the umpire analysis must be initiated within four business days after the request is made.
  3. The umpire assayer must not be the client’s or Valcambi’s representative.
  4. The umpire assayer must be one of the firms previously agreed upon on a rotational basis and they must use the fire assay method.
    From time to time, and upon mutual agreement by the client and Valcambi, any other organisation may be designated as umpire assayer.

    • ALS Inspection UK Limited
      Caddick Road
      Knowsley Business Park
      Prescot L34 9HP
      United Kingdom
    • AS International Corporation Ltd
      20 Sefton Business Park
      Aintree, Liverpool
      Merseyside, L30 1RD
    • Bureau  Veritas Commodities LTD
      2 Perry Road
      Withan
      Essex CM8 3TU
      United Kingdom
    • Federal Office for Customs and Border Security FOCBS
      Office fédéral de la douane et de la sécurité des frontières OFDF

      Industriestrasse 37
      2555 Brügg
      Switzerland
  5. Umpire results
    • If the difference between Valcambi’s and the client’s assay results is within the agreed splitting limits, then the average of these assay results is taken as the agreed settlement assay.
    • If the subsequent exchange exceeds the splitting limits, the umpire sample must be submitted within four business days to one of the assayers in (d) above, who act as umpire assayers on a shipment-by-shipment rotational basis.
    • If the client or Valcambi submit the umpire sample to an umpire assayer, and the umpire’s assay results are between the client and Valcambi’s re-assay results, then the umpire’s results are final and binding on both parties for settlement.
    • If the umpire’s assay results are outside the client and Valcambi’s re-assay results, then the assay results of the party closest to the umpire re-assay results are final and binding on both parties for settlement.
  6. The cost of the umpire’s assay is borne by the party whose re-assay results are furthest from that of the umpire.
    If the umpire’s assay is the arithmetic mean between the re-assay results of the two parties, the costs of the umpire’s assay is born equally by the client and Valcambi.