Homogenization & Sampling process

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The homogenization procedure

Phase 1 - Homogenization of the lots
The material shall be melted in lots as prepared during the weighing process. Before melting any Client's material, Valcambi shall clean the crucible to remove any residual contamination from previous melts.

Phase 2 - Representative sample
Valcambi shall sample each melted lot by taking two or more representative samples of approximately 100/200 grams in the form of buttons, sample bars or any other suitable shape. Depending on the kind of material and on the lot size Valcambi will take the samples from the molten metal prior to and/or in course of pouring in ingots or anodes, by using the appropriate sampling devices. The samples must be representative of the melt and will be used to verify its homogeneity as well as to perform the analysis on the precious metals contents.

Phase 3 - Recovery bar
Once all lots have been melted the cleaning procedure shall begin. This process includes the furnaces, the tools, the crucibles, the moulds as well as the furnaces surrounding area. The recovered material is melted with the addition of flux and poured in the form of a bar suitable for sampling.

Phase 4 - Determination of the weights after melting
The melted lots and the recovery bar shall be weighed to establish the “weight after melting” and the melting weight loss. Upon the Client's request the slag produced during the melting shall be weighed, sealed and kept at the disposal of the Client or its Representative for a period of six months from the date of delivery unless otherwise agreed.

Phase 5 - Settlement weight
The settlement weight per lot shall be the weight after melting less the weight of the Client’s sample. The umpire sample shall be deducted from the weight only if the Client wishes to enter into the umpire process.

Phase 6 - Reporting
Upon completion of the weighing, melting and sampling operations described in this section, a report summarising the following information shall be issued:

  • Date of the material's arrival at Valcambi's premises
  • Client's reference numbers
  • Valcambi's reference numbers
  • Established net weight per lot
  • Weight after melting
  • Weight of the recovery bar
  • Weight of Client's samples
  • Weight of Umpire sample
  • Weight of the slag
  • Closing remarks of the Representative in regards to the work performed
  • Contingent remarks of Valcambi pertaining to the material received and the conduct of the operations

The report shall be signed by an officer of Valcambi and by the Client's Representative if so designated to attend. A copy of the report is handed over to the Representative or transmitted to the Client. A second copy is kept for Valcambi's files.