You are hereExamination and Study of Heavy Minerals in a Concentrate
Examination and Study of Heavy Minerals in a Concentrate
In prospecting “concentrate” is known as to the minerals that remain in the pan, after the evacuation of the white minerals that form on the edge of the washed material. During the operations the washing needs to be paid close attention to as it should not wash the concentrates too much in order to not risk losing some of the minerals, amongst which gold is very fine. During the prospecting process of gold it is recommended to use the following terminology, as far as it is related to the results of the washing:
- Color: when the gold particles are so fine that they are no longer visible than with the binocular of by the set of their color, when there is a good amount (they let out a golden color to the concentrate).
- Point: of the bigger sized particles, but always with dimensions that can only be determined with a magnifying glass. Another thing that can be used is the binocular.
- Spill: of the particles that show a surface with discrete dimensions but with a thickness that cannot be determined with a magnifying glass.
- Grain: particles of gold with very well defined dimensions. These are denominated as “small” when they do not go through the 1 mm and “thick” when the dimensions are of 1 to 2 mm.
- Pebble: this is a fragment in which the dimensions are over 2mm.
There are some people that affirm that gold can pass in a solution of water in the presence of humic acids and precipitate forming pebbles in this way (even in great dimensions), at many kilometres away from the source and that, when going upstream, it can disappear without having reached the mother rock.
Numbering and packing of the samples
In some cases, especially if the sending to the laboratory needs to be done by air, the samples can be dried on the field and this can be done by using the heat of the sun or with fire. As far as the numbering is concerned, you will be able to use a sequential numbering of the type PE/19 0025 in which for example: PE means Peru, 19 means the are defined as 19 before the prospection began, 0025 is the sequential number of 4 figures. This type of numbering does not localize the sample, but it does provide geographical coordinates. If rigid containers are used it is better to build boxes in which an exact number of tools enter, in the contrary case, fill the empty spaces with paper or straw. In the following we will talk about how to determine the tenor of gold and how to calculate the amount of an alluvial placer.
