The prospecting process takes a long time, and deposits are hard to find.
FREMONT, CA: Prospecting leads to the discovery of new deposits. Geologists find large quantities of minerals such as apatite (used in fertilizers) and important metals such as copper, gold, and nickel. The process of prospecting takes a long time, and deposits are hard to find.
It is possible to extract minerals of commercial value at a reasonable cost from ore, a naturally occurring material. A deposit may contain several ores and metals, which must be concentrated in quantities 100-10,000 times greater than in the surrounding bedrock. Different geological processes create ores deep within the earth's crust. The purpose of prospecting is to locate the ore whose properties can be detected. Geophysical measurements reveal the presence of many ore minerals that are heavy, magnetic, or electrically conductive. The ore often results in high metal content in groundwater and surrounding ground.
The inland ice lifted small sections of ores during the most recent ice age and transported them along its routes. To find the ore, geologists must find these routes and interpret them.
Prospecting to mining: the long process
During prospecting, all existing data on the bedrock and its chemical and physical properties are analyzed to determine whether certain types of mineralization and ore are suited to the area. A company looking for gold looks for rock types that concentrate on different metals, so if it's looking for gold, it looks for rock types favorable to gold deposits. The company searches for other types of rocks if it is interested in industrial minerals like calcite or dolomite.
Geological mapping and sampling are usually the first steps in prospecting projects to create an understanding of the rock types and their compositions.
Geologists hammer small pieces of stone from rock surfaces in the area as part of the investigation. Measuring instruments are carried by ground personnel on foot, or low-flying aircraft make geophysical measurements from the air. Based on geophysical measurements, mapping and sampling must be directed to the most suitable areas.
All the collected data are analyzed after the first mapping and sampling phase, which usually takes several years. It is abandoned if no interesting finds are made. If there is evidence that something interesting may be hidden underground, field investigations are initiated. Investigations are usually focused on areas with high potential for discovering ore based on the information collected. Heavier and more expensive methods, such as diamond drilling, are used to gain information from deeper in the ground. Based on drilling results, prospecting activities are either stopped or steered more precisely to an area with the best indications.
In a typical prospecting project, only about one in 1,000 yields sufficient evidence for the presence of ore. Even if the area has geological indications of ore, the entire process of field mapping to mine planning usually takes several decades. Ore is rarely found in prospecting projects.
The exploration process
In most cases, mining projects don't lead to mines because exploration takes a long time. Many reasons, such as a small or low-grade find, low prices, or difficulty obtaining a permit, may apply. In general, it takes 20-30 years to find a mineral resource and obtain all the permits if everything goes according to plan.