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Types of Pollution Generated by Gold Mining

Gold mining or prospecting has been performed in areas of the world for hundreds of years. While early excavation methods included the use of crude tools or picks and shovels, more productive techniques have evolved over the last one hundred years. Unfortunately, many modern gold mining practices have led to elevated air, soil and water pollution levels as a result.

  1. Air Pollution

    • Air pollution is created from several processes associated with gold mining. Open air mining, sometimes called open pit mining, involves digging in vertical levels to prevent danger from falling rocks. Haul roads are placed near the mines to collect waste and ore. Mining close to the ground surface and driving to and from the mine site generates large amounts of dust, which pollutes the air. The process of refining the ore also causes pollution, particularly when the ore goes through a smelting process which heats the ore to melt the metal and release it from the surrounding material. The smelters release large amounts of lead as well as nitrogen and sulfur, which are returned to the earth in the form of acid rain.

    Water Pollution

    • Once ore is gathered from mines, it can be extracted by using different methods. One such method, called leaching, is a low-cost method of removing ore from waste. During the process, workers pile low-grade gold ore into an outdoor heap and put a cyanide solution on it. The cyanide then dissolves the gold, which it runs down a slope into reservoirs before it is collected. In some countries, environmental laws require that the slopes and collection vats are impenetrable so that poisons cannot be released into the ground. However, the lack of protections in other countries mean that the poisons are often leaked into the soil. These materials then make their way into local water supplies, lakes, rivers and streams. Drainage of this type raises acid levels in lakes which are harmful to both animals and people. Additionally, some mines intentionally dispose of toxic wastes into oceans, lakes and rivers, while others place wastes or tailings in dammed reservoirs that can occasionally burst and flood areas, releasing mercury and other heavy metals into the water supply. Pollution from mines can cause drinking water contamination and high levels of mercury or heavy metals in fish.

    Soil Pollution

    • Because a small amount of gold is extracted from large areas of land, large piles of toxic tailings and waste are the result of gold mines. These piles can cause heavy metals and other toxins to penetrate the soil, preventing plant life or creating high levels of toxins in plants. Animals who eat these plants can then be subject to disease or other health problems. Heavy metals and toxins can remain in soils for decades after mining, which leaves the areas unsuitable for use by humans and animals for some time.

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