Preparation and Expedition of the Samples

In a big strategic prospection, it is useless to send thousands of samples of 400 grams each to a laboratory; it is a good idea therefore to take into account the preparation of the samples that consist essentially in:

• Drying
• Disintegration
• Sifting

The drying can be done in the sun or with a fire, without cooking the minerals; disintegration, this does not mean grinding though, can be done in a wooden or ceramic pan being careful to not break the bigger sized minerals; the sifting can be done in a mesh of 0.125 mm (100 mesh). After the sifting the sample will then be quartered until two small cups have been filled and one of these will be sent to the laboratory and the other one will remain as the witness. The expedition will need to be carried out like for the alluvial samples. Attention: mainly in the case of the grinding of rocks, each geochemical grinding will need to avoid any sort of contamination due to the pans and sieves. Therefore it is preferable to use agate sieves and stainless steel sieves or the one that have nylon net. 

Data treatment
The treatment of the data is usually done by the geochemist on the computer in the case of strategic prospection or by hand in the tactical prospection where the number of samples is a lot less. Once the real value of a determined element in an area has been established, in other words the values that should be considered anomalous, a legend will normally be established with variations in tone inside of the same color, showing lighter tones in the case of lower values (For instance, white, light brown, brown, dark brown, hot orange, etc.) the choice of the anomalous areas will be a decision of both the prospector and the geochemist who will analyze the data that is at disposal, as the ones that have been given by the prospector due to his knowledge of the land, as well as by the considerations of the moving of the elements, characteristic associations, etc. given by the geochemist.