In solutions of high gold content it is advisable to run a check with every batch, using a quantity that will compare with the expected value of the routine sample and following the same procedure as that of the sample assay. Check solution for this purpose is made up by dissolving exactly 100 mg of proof gold in aqua regia and making up to 1000 mL with water.

With the development of the atomic absorption technique for rapid processing of gold content of low value solutions, some methods have fallen in disuse in the extraction plants on modern gold operations. Nevertheless, it is a regular means of assaying precipitated solution on site and can be performed rapidly by the plant operator.

Hydraulic traps are employed for performing the prior separation of coarse gold particles such as grains and nuggets in order to obviate the need for their subsequent milling, amalgamation or leaching. Hydraulic traps are also widely employed for recovering amalgam and mercury downstream of amalgamating stages (e.g. stamp mills or amalgamating plates). Hydraulic traps differ according to design and function. In this way, some hydraulic traps are designed for counterflow of water.

There are some gold ores appropriate to heap leaching and other group present some problems. These ores are fractured volcanics and schists; gossans; porous rocks with sulphides; disseminated gold in limestone; and silver ores. Fractures volcanics and schists located near high gold grade veins present coarse gold, which is detected easily.

The design and operation of small gold concentrators with gravity equipment is a great deal more subtle and complex than normally considered. It is well known that small scale gold operations are characterized based on small reserves with variable gold grades. In this way, quality and flexibility and flexibility are factors that have impact on the operation and they are as important as the processing capacity of the plant.

The profile of gold mining operations is very similar in many locations around the world. First, alluvial deposits are mined, later small, high grade, coarse grained and hard rocks. Also tailings from old operations are reworked when the gold process rises strongly or when a new process or technology is available. The successful opening of a small hardrock deposit is often a trade-off between capital exposure and gold production.

A possible recipe is composed of one hundred parts, by weight, of copper of the purest quality; 14 of zinc or tin; 6 of magnesia; 3/6 salt ammoniac, limestone and cream of tartar. The copper is first melted, then the magnesia, salt ammoniac, limestone and cream of tartar in powder are added separately and gradually. The whole mass is kept stirred for a half hour, the zinc being dropped in piece by piece, the stirring being kept up till they melt.

The operation of Reichert Cones concentrators at gold plants with crushing and comminution circuits has some operative problems that yield low gold recoveries. The explanation is not simple, but some plant metallurgists consider that thin steel flakes from broken grinding balls, nails from underground, bits of wire and other materials find their way through the slotted scalping screen ahead of the cone and enter the cone feed.