b. Flotation: These tests have the objective of prove if a preconcentration before cyanidation is possible. Usually, during the tests is necessary modifying some parameters until get the maximum recovery. Always, we have to have presents that the direct commercialization of a concentrate with high content of pyrite and gold has several difficulties, mainly during the sample systems for assaying. Even though, is an alternative when there is not much capital and only can be build a plant step by step.

First, a flotation plant that can generate incomes from the trading of concentrates, and later, a cyanidation plant like final process.

c. Gravimetry: Its objective is preconcentrate and has a product with better grade. There are several equipments for gravimetric tests and the more common are jigs for capturing free gold, centrifugal concentrator like Falcon and Knelson have the same aim; also there are spirals and tables. Each equipment has a range of operation according to the particle size. The gravimetric process is a complement of other processes. They are useful in order to improve recoveries, but alone, most the time offer poor recoveries.