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The Role of Geomembrane in Gold Mining

Earthshields’ geomembranes are chosen for lining the tailing ponds in Tanzania, between 2020-and 2021. The buyer was a growing enterprise focusing on gold mining from Indian families.

Speaking of gold mining, we need to know more knowledge about this industry. The most abundant gold deposit to date is the Witwatersrand Basin in South Africa. About 30% of the gold mined in the world over the years comes from there. Others include the deepest gold mine in the world, Mponeng in South Africa, Bodington in Australia, and Nevada in the United States. China is currently the world’s largest gold mining country, and Canada, Russia, and Peru are also important gold producers.

Barrick Gold’s Nevada Gold Mine is the world’s largest gold mining company with an annual output of 3.5 million ounces.

The exploration of gold resources is becoming more and more difficult, and the discovered deposits are becoming less and less, so most of the gold on the market now comes from gold mines that have been mined for decades.

Large-scale underground mining is a capital-intensive industry with a high degree of mechanization and high technology content.

Geomembrane gold mine
Geomembrane Gold Mining

At present, 60% of the world’s mining activities are carried out on the surface. Easy to mine, mature gold mines are almost exhausted.

Gold mines in China are generally small in scale and expensive to mine, and some untapped gold resources are located in unstable regions, such as West Africa. Before gold can be extracted, extensive exploration and development work is required to determine possible the size of the deposit and how the ore can be mined and processed, and. Once a deposit is discovered, it usually takes 10 to 20 years to produce raw materials that can be refined into gold ingots.

Gold exploration is challenging and complex. Exploration is time- and financial-intensive, and requires expertise in many disciplines, including geography, geology, chemistry, and engineering. The odds of finding a mine with a development value are very low – less than 0.1% of exploration sites can become production mines. Only 10% of the world’s gold deposits contain significant levels of gold, supporting further development.

Once mining companies have constructed basic data on local geology and potential ore-hosting deposits, they can model gold ore bodies in detail and conduct feasibility assessments. Gold mine development is the next stage in the gold mining process. Gold mine development requires the planning and construction of gold mines and associated infrastructure. Mining companies must get appropriate permits and licenses before starting construction. Although obtaining a license depends on the location of the mine, it usually takes several years.

Mining construction may not be limited to the mine itself. Besides potential processing capacity, extraction companies often need to build local infrastructure and amenities to support logistical and operational needs, as well as employee and community benefits. Such developments provide long-term support for local communities and are one of the primary initial ways that gold supports broader socioeconomic development.

Smooth Geomembrane HDPE Liner for Gold Mine Project in Tanzania
Geomembrane Gold Mine Project in Tanzania

Gold mining operations: 10 to 30 years

The gold mining operational phase represents the productive life of a gold mine, during which ore is refined and processed into gold. Gold processing involves turning stones and ores into a very pure metal alloy (called a gold alloy), 60-90% gold.

During the life of a gold mine, many factors, such as gold price or input costs, will affect which areas of the ore body are profitable to mine. Mining lower-grade ore will become profitable during periods of rising prices, as higher prices offset the increased costs of refining and processing more ore. Refining and processing higher-grade ore can only be profitable when prices are lower or costs are rising. Mining plans are re-evaluated as market conditions change, new technology information emerges, and process and technology improvements are taken into account.

More and more technological advancements are making the gold mining process smarter, cleaner, and more efficient. These technologies are now considered during the mining design phase, and electrification, digitization, and automation are common factors reshaping gold mining operations and processes.

After a gold mine may stop operating because the ore body is depleted or the remaining deposits are unprofitable (uneconomical) to mine, the focus will be on decommissioning, dismantling, and restoring the land to its original state.

Closing a gold mine is a complex job. Mining companies will also be required to watch the mines long after they mines are closed.

Gold mining companies still have mine management responsibilities long after gold mines are closed and demolished, often five to 10 years or more. During this time, the land on which it is located will be reclaimed—purified, and replanted, and the mining company will work to ensure the successful reclamation of the gold lands and the restoration of long-term environmental stability.

Why HDPE liners are suitable for gold mining?

HDPE series, the high-density polyethylene liners.

HDPE geomembrane, with the features of anti-seepage,  waterproof, high tear resistance, and high tensile strength, is becoming more and more popular used in a wide range of engineering projects. The service life can last for 50-70 years if underground, for aquaculture and agriculture usage, there are lots of fish and shrimp ponds, farm water ponds, and artificial reservoirs using the pond liner exposed to the sun, that will last about 20-30 years.

From the different thicknesses to meet the various needs of the project, the PE liners can do from 0.3 mm to 3.0 mm.

The features of the PE liners are as follows:

1. Good physical and mechanic performance.non-toxicity, long service life.

2. For service temperature range:-700℃-+110℃.

3. Corrosion resistance, aging resistance

4. Excellent environmental stress cracking resistance property

5. High tensile strength and elongation.

6. Low cost and easy installation for the seepage control project.

Several facts about mercury.

Mercury is an occurring element found in air, water, and soil.

Exposure to mercury, even in small amounts, can cause serious health problems and threaten the development of fetuses and young children.

Mercury may have toxic side effects on the nervous, digestive, and immune systems, as well as on the lungs, kidneys, skin, and eyes.

WHO considers mercury to be one of the ten largest chemicals or groups of chemicals of major public health concern.

People are exposed to methylmercury, an organic compound when eating fish and shellfish.

There is a big difference between methylmercury and ethylmercury. Ethylmercury is used as a preservative in some vaccines and poses no health hazard.

Miners have been mining gold for hundreds of years, which requires large amounts of mercury. After mercury and its compounds enter the soil environment, under the physical and chemical effects of adsorption, exchange, dissolution, precipitation, redox, biochemistry, and other physical and chemical actions, some of them exist in the soil for a long time in different ways, and some of them are absorbed by plants and enter the food chain. Circulation, part of which is released into the air in gaseous form, and part of which is scoured into the water circulation system by precipitation or runoff.  The form of mercury can be divided into three forms: metal mercury, bound mercury, and inorganic bound mercury. The content of metal mercury is very small, but it can be absorbed by plant roots or leaves. Besides, the soluble organic matter (DOM), humus, iron oxides, and clay minerals contained in the soil all have a certain adsorption effect on Hg2+[18], which can form bound mercury. Cl- has a strong affinity for Hg2+ and can form soluble inorganic compounds (HgCl2), which can be absorbed by plants for biological migration, enter the food chain, and cause harm to the human body.

People get mercury poisoning by drinking water contaminated with mercury and its compounds or by eating contaminated aquatic animals and plants.

Gold Mine Tailing Treatment
Gold Mine Tailing Treatment

The water circulation system includes the upper water body and the lower sediment, and the interaction between the water body and the sediment affects the mercury content of the water body. Mercury and its compounds will accumulate in the sludge at the bottom of the water body, be converted into methylmercury under the action of microorganisms, and enter the fish through the food chain, resulting in mercury poisoning after human consumption.

The skyrocketing price of gold in recent years has led to a boom in small-scale gold mining, in which mercury is used to separate gold from ore-bearing rocks. The world’s largest mercury pollution comes from emissions and releases from gold mining and coal-fired power stations. Small-scale gold mining workers and their families are exposed to mercury contamination in several ways, including inhalation during smelting. These small-scale mining results in mercury being released into rivers, polluting fish, the food chain, and people downstream.

So upon the mercury pollution, we are facing now, it is important to use the liners in the mining plant. The PE liners play an important role to prevent heavy metal seepage into the ground, then can stop the second-pollution to the human body and natural environment.

As the leading geomembrane manufacturer, supplier, and wholesaler, Our Geomembrane quality satisfies the ASTM GRI-GM13 standard. Besides, we have obtained CE, ISO9001, ISO14001, and ISO45001 certificates. Our customer projects include aquaculture (fish ponds, shrimp ponds), water conservancy (canals, dam), environmental protection (landfill sites, sewage treatment), mining (heap leaching ponds, tailings), agriculture (water reservoirs), and many other projects, customer satisfaction is 100%.

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