The first part of the process is to reduce the size of the pieces of mined material. It might be crushed into pebble-sized pieces or ground into a fine powder. The mineral or metal resource is then extracted by one of the following processes, or by a combination of them:. After extraction, the metal or mineral product in solid, slurry or dissolved form may require further processing to increase its purity.
The waste material is sent to long-term storage. Coarse waste is moved to a residue pad and tailings fine waste is pumped to the tailings storage facility. For more about the criticality of tailings management, refer here insert link to tailings page. The state solid, liquid or dissolved or the metal or mineral determines how it is purified. Some products, like iron ore, only need to be sized and shaped. To produce London Metal Exchange LME grade copper cathodes the copper must first be changed from a dissolved to a sold state by solvent extraction or activated carbon adsorption.
This is then followed by electrowinning and electrorefining. Metals in a liquid slurry form are filtered and dried before being smelted or roasted.
Smelting is a high-temperature process that extracts the molten metal from the slag unwanted molten waste. Roasting is also a high-temperature process.
It produces metal oxide particles. Experts talk about the concept of peak gold - when we have mined the most we ever can in any one year. Some believe we may have already reached that point. This is the first annual decline in production since Even when peak gold happens, experts say the years immediately after it are not likely to see a dramatic decrease in production. Instead, we could see a gradual depletion of output over a few decades.
Mining companies estimate the volume of gold that remains in the ground in two ways:. Reserves - gold that is economic to mine at the current gold price.
Resources - gold that will potentially become economic to mine after further investigation, or at a higher price level. The volume of gold reserves can be calculated more accurately than resources, although this is still not an easy task.
The below-ground stock of gold reserves is currently estimated to be around 50, tonnes, according to the US Geological Survey. To put that in perspective, around , tonnes of gold has been mined in total, although estimates do vary. But this is a moving target. New technologies may make it possible to extract some known reserves that aren't currently economical to access. The most recent innovations include big data, AI, and smart data mining, which can potentially optimise processes and bring down costs.
Robotics are already being used at some sites, and are expected to increasingly become standard technologies in mine exploration. Biggest sources. The largest single source of gold in history has been the Witwatersrand Basin of South Africa.
The energy-intensive nature of mining is evident by the recovery ratio of the various materials being mined.
Thus, to recover 1 ton of metal, 22 tons of material will need to be mined. Minerals are essential to nearly every aspect of our lives and our economy. Key markets include utilities, the primary metals industry, non-metallic minerals industry glass, cement, lime , and the construction industry. Mining operations are often the leading employers in the communities where they operate. More than , people work directly in the U. Advanced Manufacturing Mining Industry Profile. Energy The mining industry consumed an estimated trillion British thermal units Btu in Markets Minerals are essential to nearly every aspect of our lives and our economy.
0コメント