كيفية استخراج الذهب في المناجم؟
من المنتجون الكبار للذهب وكيف يستخرج من باطن الأرض وكم عمر مناجمه؟
واعتمادا على عوامل مثل سعر الذهب وحجم الرواسب، تستغرق عمليات التنقيب عن الذهب عادة ما بين 10 إلى 30 عاما، وبعد توقف عمليات التنقيب، عادة ما يتم ...
Oct 2, 2020
"إنترستنغ إنجينيرينغ"
في مقال نشره موقع <anchor>"إنترستنغ إنجينيرينغ"</anchor> (interesting engineering) الأميركي، قال الكاتب كريستوفر ماكفادين إن التنقيب عن الذهب ممارسة قديمة وواسعة الانتشار في جميع أنحاء العالم، وقد أصبحت في العصر الحالي نشاطا تجاريا عالميا يمارَس في كل القارات، باستثناء القارة القطبية الجنوبية ولأسباب مختلفة.
How and at What Cost Gold is Mined
# How and at What Cost Gold is Mined

#### Where does most of the world’ gold come from? Let’s find out.

Published: Sep 22, 2020 10:39 AM EST

4 years ago

0

- Share

How and at What Cost Gold is Mined

Gold has been a prized material since immemorial times. But do you know where it comes from?

Here we take a look at the major sources of gold today and take a peek at just how the gold is extracted. We will also consider the potential environmental impacts of the practice, too.

## Where can you mine gold?

Gold mining has become much more geographically diverse than even a few decades ago. Previously most of the global supply of gold came from South Africa.

gold mining around the worldGold mine in Dahlonega, Georgia. _Source: Neal Wellons/Flickr_

China, for example, was the world’s largest global gold producer in 2016. It produced about 14% of the total global supply for that year. Even so, no one dominates the total gold supply. Asia as a whole, for example, produces something like 23% of total global production today.

Central and South America produce around 17%, North America 16%, 19% come from Africa, and another 14% from the Commonwealth of Independent States (CIS) region. In 2019, according to gold.org, the top 10 gold producing countries were:

Rank****Country****Tonnes****% of global supply1China383.211.71%2Russian Federation329.510.07%3Australia325.19.93%4United States200.26.12%5Canada182.95.59%6Peru143.34.38%7Ghana142.44.35%8South Africa118.23.61%9Mexico111.43.40%10Brazil106.93.27%

However, most known gold deposits and mines tend to be privately owned. It is usually illegal to attempt to extract gold yourself without prior permission from the owner.

That being said, there are some places where you can happily prospect for gold. You can still legally pan for gold (for a fee) in the following locations in the United States:

- Reed Gold Mine, North Carolina
- Big Thunder Gold Mine, South Dakota
- Jamestown, California
- Dahlonega, Georgia
- Crow Creek, Arkansas
- Alabama Gold Camp, Alaska

## How long does a gold mine last?

Gold mining is not just about physically extracting the gold ore from the ground. It often takes considerable planning and work before the mining operations can commence.

Before you actually get your hands on some refined gold, years, even decades of investment may be necessary. For example, significant exploration and development have to take place to determine, as accurately as possible, the size of the deposit as well as how to extract and process the ore efficiently, safely, and responsibly.

This stage typically takes between 10 and 20 years(exploration and mine development).

gold mining equipmentAbandoned mining equipment, Crisson Gold Mine, Dahlonega, Georgia. Source: Neal Wellons/Flickr

Once the size and extent of the gold deposits have been ascertained, the production phase of gold mining can begin. This is the business end of the operation, when the gold ore is actually extracted and processed.

Processing of the ore usually involves turning the rock and ore into a metallic alloy of substantial purity. Commonly known as doré, this alloy is typically 60-90% pure gold.

The lifespan of a gold mine is directly affected by both external and internal factors, like the price of gold and operational costs for the mining operation. These factors will impact any plans for mining parts of the deposit, as they become more or less economically profitable.

For example, if gold prices are relatively high, it may become economically viable to extract low-grade ore, as the increased cost of extracting and refining this ore would then be profitable. When gold prices drop significantly, higher-grade ores will likely be prioritized.

gold mine new zealandHistoric Waihi Gold Mine, Waikato, New Zealand. Source: Sue/Flickr

Depending on factors like gold price and deposit size, gold mining operations typically last somewhere between 10 to 30 years.

After mining operations have ceased, the mine is usually decommissioned. This takes anywhere between 1 and 5 years. Following this, mining companies will typically rehabilitate the land where the mine was previously located. Depending on the location, companies are usually required to manage the land for a period of between 5 to 10 years after the mine’s closure. Using these figures, the average total lifespan of a gold mine is between 25 and 65 years.

However, it should be noted that most gold mines are never completely exhausted. This often leads to some mines reopening when the price of gold justifies such an endeavor. One example, of many, includes the Sakdrisi gold mine in Georgia. Also known as Sakdrisi-Kachagiani, the site of the mine is also a protected archaeological site.

The site is one of the oldest known gold mines in the world, with scientists estimating that gold mining operations first began here sometime in the 3rd to 4th millennia BC. Mining operations have recently recommenced, much to the despair of local cultural and environmental conservationists.

## What are the largest gold mines in the world?

So, of all the thousands of gold mines around the world, which ones are the largest? Some of the most notable and biggest gold mines currently in operation are:

- Muruntau gold mine, Uzbekistan
- South Deep gold mine, South Africa
- Grasberg gold mine, Indonesia
- Olimpiada gold mine, Russia
- Lihir gold mine, Papua New Guinea
- Norte Abierto gold mine, Chile
- Carlin Trend gold mine, USA
- Boddington gold mine, Western Australia
- Mponeng gold mine, South Africa
- Pueblo Viejo gold mine, Dominican Republic
- Cortez gold mine, USA

## What are the negative environmental impacts of mining gold?

Like most mining operations around the world, gold mining can have a number of serious impacts on the local ecosystem and the health of miners who work there. The operation often contaminates water supplies, ravages landscapes, and can contribute to the destruction of vital local ecosystems.

Mining operations can also release various hazardous substances into the environment, like cyanide and mercury that pollute both land and water for many decades or longer if not treated properly. Practices like open pit mining and cyanide heap leaching can generate somewhere in the region of 20 tons of toxic waste for every 0.333-ounce (9.44 gr) of gold produced.

This kind of waste, often appearing as a gray liquid sludge, is literally laden with cyanide and other heavy metals. Many poorly regulated mines will simply dump this waste directly into natural bodies of water like rivers, lakes, and oceans.

One prime example is the Lihir gold mine in Papua New Guinea. This mine has been recorded as dumping over 5 million tons of toxic waste directly into the Pacific Ocean every single year. This waste destroys local corals and other oceanic life.

Around the world, it is estimated that around 180 million tons of such waste products are dumped into rivers, lakes, and oceans every single year.

To mitigate the worst of these kinds of issues, most mines will build dams to temporarily store toxic waste. But these dams are not 100% effective, and oftentimes waste will seep into surrounding soil and groundwater.

This can lead to catastrophic spills from time to time. Of the thousands of mine dams around the world, 1 to 2 major spills are recorded each year.

Catastrophes like this are usually observed in countries like Romania, China, Ghana, Russia, Peru, South Africa, and Canada. For example, in 2014, a dam collapsed at the Mount Polley gold and copper mine in British Columbia.

6.6 billion gallons (25 million cubic meters) of cyanide-rich waste poured into nearby rivers and lakes. This spill devastated the ecosystem, killing fish and damaging local tourism. Gold mining has other environmental impacts that can also seriously damage the environment. For example, acid mine drainage can be a very serious issue.

Poor-mining practices can lead to freshly exposed rock surfaces reacting with the air to form strong acids, like sulfuric acid. This acid mixes with water draining from the mine and kills any organisms it comes into contact with. This acidic water can also leach out other toxic heavy metals like cadmium, arsenic, lead, and iron, further compounding the damage to local ecosystems. The problem can persist for a very long time too.

gold mining russiaRussian gold mine near the Chukchi Sea. Source: Stuart Rankin/Flickr

Another major impact on the environment from gold mining operations is mercury pollution. This liquid metal is often used in artisanal and small-scale gold mines to extract gold from rock and sediment.

However, mercury is very toxic that can seriously damage miners’ health and the local plant and wildlife. It is estimated that for every gram of gold extracted, two grams of mercury are released into the environment.

#### RECOMMENDED ARTICLES

Mercury, when it reaches the environment through rivers, lakes, and oceans, can travel a great distance. Mercury exposure can cause significant damage to many major organs of the body and chronic exposure is often fatal.

So, next time you consider buying some gold for your significant other, or as an investment, you might want to do a little digging (pun intended) into its origins. By being more aware of the gold sources with the highest possible environmental standards, you will be doing your part to help the environment.

0COMMENT

NEWSLETTER

##### The Blueprint Daily

MasterCard

Stay up-to-date on engineering, tech, space, and science news with The Blueprint.

Mail Me

MasterCard

#### ABOUT THE EDITOR

Christopher McFadden Christopher graduated from Cardiff University in 2004 with a Masters Degree in Geology. Since then, he has worked exclusively within the Built Environment, Occupational Health and Safety and Environmental Consultancy industries. He is a qualified and accredited Energy Consultant, Green Deal Assessor and Practitioner member of IEMA. Chris&rsquo;s main interests range from Science and Engineering, Military and Ancient History to Politics and Philosophy.

#### POPULAR ARTICLES

1

a day ago

0

2

a day ago

0

3

a day ago

0

4

a day ago

0

#### RELATED ARTICLES

New X-ray discovery could lead to the holy grail of long-lasting EV batteries

Mountaintop falling into sea caused mega-tsunami, shook Earth for 9 days

T-Mobile sends 1st-ever emergency alert via SpaceX Starlink to 500,000 sq miles

Huawei&#8217;s bold drive: Steering China&#8217;s EV revolution, eyeing Bosch&#8217;s throne

##### JOBS

###### Follow Us On

© Copyright 2024

Interesting Engineering, Inc.

All Rights Reserved

### Events

### News

### Topics

### For Engineers

© Copyright 2024

Interesting Engineering, Inc.

All Rights Reserved