It is well known that a simple method to detect and recognize gold in crushed quartz or any rock is by washing it in gold pan, but gold if often present in the matrix grains or particles extremely fine that it cannot be detected by the eye and sometime is quite distinguish by admixture with other metals and mineral. In this cases it is important to know how to recognize the presence of gold by other methods such those using especial chemical reagents. Basically, in commencing gold mining operations the first point to determine is, of course, whether gold exists in any appreciable proportion, and if this affirmative, the next step is to know the quantity of gold contained. The first process is called testing for gold or the qualitative examination of the potential gold ore. The second procedure is the quantitative examination or assaying process. When a gold prospector is in field, he must use any quick method the select the prospecting areas and some experienced gold prospector are used to employ iron sulphate, tin chloride and oxalic acid to evaluate the sample and give a first opinion of the material.
The procedures are very useful when the prospector is familiarized with the chemistry process. Obviously these procedures are important in places where the exhaustion of the easily worked placer digging occurred. In this case, the miner turns his attention to quartz. He soon finds out that the appliances then in existence in other parts for the treatment of gold bearing rock does not correspond to the typical and easy conditions of the placer. Basically, improvement after improvement of those appliances or devices has a limit and the necessity for new tools is urgent. For example, quartz mining operations were merely in an experimental stage until the introduction of gravimetric equipment with improved design.
Many places are categorized as free milling gold ores due the geological characteristics. Nevertheless, the final decision is not easy because only a very small percentage of the gold in the ore is free, but other part not. Many failures in gold mining were the results of the inability of the prospector to detect the gold. These experiences helped to develop new methods and quartz mining has been assuming the character of a scientific industry. In this way, ores that were considered as waste material due to an inappropriate concept or idea are carefully prospected and presence of gold is positive just considering simple and qualitative methods. Obviously, prospector’s experience is important and more even when it is possible to establish a balance between qualitative and personal perceptions.