You are hereSampling Through Wells
Sampling Through Wells
Before beginning the excavation of a well it is good to make sure of the presence of a layer of gravel and its strength possibly placing some probes in the on the land. The prospecting can be done for isolated wells or in the case of big placers by parallel lines of 200 – 1.000 meters and that are perpendicular to the valley with different wells starting from 10 to 30 meters.
Excavation of Wells
The wells will need to have a rectangular section of 0.80 x 0.50 meters for depths of up to 0.60 meters approximately. For wells with a comprised depth between 0.60 and 3 meters it is advisable to have a comprised area of 1.50 to 1.80 x 0.70 to 0.80 meters. For the wells of 3 meters or more, it is good to make circular sections of 0.70 meters (less risk of collapsing) or rectangular ones of 3.60 x 0.80 meters with one or two grades. In the case of the presence of big boulders, the initial part (0.80 x 0.50) will need to be increased to 1.20 x 1 meter. The sterile part (floor and superficial sand), will need to be piled up on one side, at a certain distance of the edge of the well and the gravel on the other side. Based on the characteristics of the terrains and the depth, the wells will possibly need to be strengthened with stakes to avoid collapses and accidents. The wells will in any case come fenced up and in cases where these are inhabited areas, they will be covered once they have been sampled. Even if the given data of a well are more complete, in the case that the alluvial deposits are in the actual bed of the river or have been covered by unstable sand again, light weight probing machines will need to used. There are some types of light weight machines that can be put together and down to a unitary weight of 30 kilograms that allow them to be transported even into inaccessible areas.
