A disseminated deposit is a type of mineral deposit in which the valuable minerals are dispersed or scattered throughout the host rock, rather than being concentrated in veins or other localized areas. Disseminated deposits are formed when mineral-rich fluids flow through porous rocks and deposit minerals in the spaces between the grains or along the grain boundaries. This process typically results in a relatively low concentration of valuable minerals within a large volume of rock.
Disseminated deposits are commonly found in association with certain types of ore deposits, such as porphyry copper deposits and epithermal gold deposits. In porphyry copper deposits, the copper minerals (usually chalcopyrite) are disseminated throughout a large volume of rock, typically in association with quartz, feldspar, and other minerals. Similarly, in epithermal gold deposits, the gold is often disseminated throughout the rock, although it may also be found in veins or other localized structures.
Mining of disseminated deposits often requires large-scale open-pit mining techniques, as the low concentration of valuable minerals necessitates the processing of a large volume of rock to extract the minerals economically. The extracted ore is typically crushed and ground before being subjected to various mineral processing techniques, such as flotation or heap leaching, to separate the valuable minerals from the host rock.
Although disseminated deposits can be more challenging to mine and process than high-grade, localized deposits, their large size can make them economically attractive and an important source of valuable minerals.