Open pit Mining
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Underground mining
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Environmental Concerns
One environmental concern for open pit mining is that it is used to mine strategic minerals, which are usually found in small quantities. Thus, more land must be mined to uncover the small areas in which there are minerals. Moreover, in this process, rock that may have been covered for millions of years is now in the open, and may exert radioactive and dangerous chemicals into the environment. Concerns of underground mining are that it may result in land subsidence and the collapse of mines. Underground mining creates less environmental concerns and is less hazardous than open pit mining (Massachusetts Institute of Technology, n.d.).
Milling and Smelting
Milling is the process where ore is to a concentrate through crushing, separating, filtering and drying whilst smelting is the process where the concentrate is melted with flux, which mixes with the waste rock and floats above the metal due to the higher density and is easily removed from the metal (which will be cooled and used in industries). Milling occurs in a processing plant, or mill, close to the mine whilst smelting occurs in a smelter (Clark, et.al., 2006).
The waste products, or tailings, are dumped in tailing ponds surrounded by dikes lined with clay, so that they do not seep into neighboring rivers and lakes. Once the water has evaporated and the chemicals are solids fertilizer is added so that vegetation can grow. This must be done carefully because the chemicals are very poisonous and can be extremely dangerous if not handled properly (Clark, et.al., 2006).
The waste products, or tailings, are dumped in tailing ponds surrounded by dikes lined with clay, so that they do not seep into neighboring rivers and lakes. Once the water has evaporated and the chemicals are solids fertilizer is added so that vegetation can grow. This must be done carefully because the chemicals are very poisonous and can be extremely dangerous if not handled properly (Clark, et.al., 2006).