Category Archives: Mining

How Tunnel Boring Machines Work

NYC subway tunnel with tracks crossing
NYC Subway Tunnel. Note the concrete slabs, called rings on the sides and ceiling of the tunnel Photo by wirestock – freepik.com

Did you ever wonder how a tunnel is created?  Well, you’ve come to the right place.

Human ingenuity has taken us from the industrial revolution to space exploration, but it has also taken us underground, from the giant Bagger 293 bucket wheel excavator for mining to machines that crush through the dirt to make tunnels deep below the surface.

A Little Tunnel History

In the earlier days, boring through the underground required many hours of tedious labor. It was not just the dig that was time-consuming but buttressing the area around the tunnel so that it stayed safe was also tedious.

Men would create concrete rings and secure them along the top of the tunnel and alongside the walls.  This would ensure that the tunnel didn’t weaken and collapse.

Greathead-tunnelling-shield
Assembling concrete rings were previously done with manual labor

The process of securing the tunnel by hand was the normal way of doing things back in the day, but now, all that hard, unhealthy labor is a thing of the past. Why? Enter the tunnel boring machine (TBM).

The Tunnel Boring Machine

Tunnel Boring Machine

Power Saw
Photo by Greyson Joralemon on Unsplash

If there was ever a device that one would call a machine, the TBM would be just that. Large, noisy but effective, it is used to cut through soil and rock much like a power saw is used on wood. As the saw’s steel blade spins, it cuts right through the wood, which is similar to the job of the boring machine, only larger. Much larger!

How Does the TBM Work?

The machine consists of three major parts (actually, a lot more, but we’ll keep it simple so that we don’t bore (pun intended) you with all the intricate details). 

The Three Parts are: 

  • Cutter-head (front)
  • Tunnel shield (middle)
  • Trailing gear (rear)

Of course, each of these sections is made up of smaller parts and together they comprise the boring machine.

The Cutting Head

Preparation for TBM cutting head to be lowered into a tunnel
Preparation for TBM cutting head to be lowered into a tunnel. Photo by david carballar on Unsplash

We spoke about the saw, but what does this saw have that cuts the wood so precisely? It is a circular piece of steel with cutting blades.

For the TBM, they are called disc cutters and are integrated onto the edges of a round piece of steel. For the TBM, the cutting head is located at the very front of the machine. 

As the boring machine’s cutter-head rotates, it breaks through the rock and/or soil at a rate of 2.7 revolutions per minute and at a pace of about 50 feet per day. 

The machine looks like a giant worm, expanding about 272 feet in length. It is this long because after the soil is extracted, it is sent down long conveyor belts where it is extracted to the surface and carted away.  See these videos below, which provide expert explanations about how the Tunnel Boring Machine operates. 

The Tunnel Shield 

A tunneling shield is a cylindrical protective structure that is located just behind the cutting head and is used to shelter the workers from the dangers of falling dirt and debris and/or actual collapse of the tunnel.

The shield is used as a temporary support structure until the tunnel is secured with concrete (see Tunnel Rings below).  The first shield was designed by Marc Isambard Brunel and was rectangular in design with iron scaffolding and consisting of three levels. Then it was later modified into a cylindrical form, which is what is used today.

What are Tunnel Rings?

Tunnel Ring
Tunnel rings. From HerrenknechtAG video above.

The tunneling shield is designed to be used only until the tunnel is safely secured with a more permanent process; as such, prefabricated concrete rings are secured along the roof and sides of the tunnel to stabilize it and turn it into a permanent structure. The process begins when the cutting head stops spinning, synchronized to do so each time a new set of rings are needed to be installed. 

A robot called an erector lifts each ring and sets it in place along the tunnel lining, resulting in a solid cylindrical wall of concrete at the top and along the sidewalls, subsequently maintaining the structural integrity of the tunnel.  

The rings are assembled as segments from above-ground factories. They are transported from the factory to the tunnel location, moved down into the tunnel and onto the boring machine where the erector lifts them and secures them inside the tunnel.

Precast molded lining sections were first patented in 1874 by James Henry Greathead, a mechanical and civil engineer famous for his work on the London Underground. Greathead also improved the tunnel shield from its rectangle form into its current form of cylindrical steel.

This process of cutting through the dirt then stopping so that the rings can be installed alternates every 5–7 feet. The cutting heads spin, evacuating the earth in front of it, then stops and the erector builds the supporting rings and then the cutting head begins to spin again, moving forward at its slow but efficient pace.

Trailing Gear

How Does the Evacuated Dirt and Rock Get Taken Out from Underground?

Tunnel Boring Machine
Tunnel Boring Machine trailer section. Screenshot from video HerrenknechtAG

Enter the trailing mechanisms. They include a conveyor belt that removes the soil that was excavated from the cutter head. As the cutter pulls dirt out, it places it onto a belt conveyor which consists of a machine belt, cross belt and a tunnel belt. The tunnel belt is dynamic, in that it expands as the machine digs forward. The tunnel belt can expand up to 18 miles back to the extraction point where the soil is lifted to the ground.

The first two belts, the machine and cross belt are located at the very front of the TBM and the tunnel belt is the conveyor that moves the debris through the TBM to the area where it is taken out of the tunnel. 

Summary

The engineering that goes into the assembly of a tunnel boring machine is quite sophisticated, but fascinating as well. 

In this article, we simplified the process so that it can be easily understandable and we hope you were able to gain a good understanding of how tunnels are created, so the next time you drive through a tunnel or ride through the subway, you can be grateful for the ingenuity and hard work of the people who built it. 

 

Loneliness, Darkness and Miners, Oh My!

Mponeng Gold Mine
Mponeng Gold Mine, South Africa (GNU Free Documentation License)

If you think quarantining in your house for a month or two is bad, just wait till you hear how miners live each day, especially in the very deep ones such as the Mponeng gold mine near Johannesburg South Africa, which is the world’s deepest mine.

Is it Worth it?

The Mponeng mine only needs to extract a minimum of 0.35 ounces from a ton of rock to be profitable, but that is certainly attainable because they pull out over 6,000 tons of rock per day.

How Deep is the Mponeng Mine?

Well, in order to grasp just how deep this mine is, as well as how to manage working there, and in the cases of illegal miners – living there, let’s take an imaginary ride to the bottom of the mine; however, let us remember that this might be imaginary for us, but definitely real for them!

Jumping on the next elevator (called a cage) to descend from the surface,  we take the long ride 1.6 miles down where you will reach a connection to a second elevator that will take you down further.

Don’t expect the place to look like a hotel lobby when you get there. Instead, you will be greeted with a huge array of tunnels with a diameter of about five or six feet in all directions and stretches for hundreds of miles. Yes, ‘hundreds’! 236 miles to be exact. That is more extensive than the New York City subway system. So if you don’t mind trudging through this dare, dreary area to get your gold, go for it, but you might want to still reconsider because there is an additional factor – temperatures in these caves can reach as high as 140º F. 

Why are the Temperatures So High?

You descended almost three miles down through the earth’s crust and the closer to the earth’s core you go, the higher the temperatures will be. Not to worry though because there are sophisticated cooling systems that will keep your body from going into dehydration and may be sudden death. 

What are These Cooling Systems? 

6,000 tons of ice per day is pumped down to cool the tunnels, along with giant fans that blow the air over the ice which subsequently reduces the temperature to a nice 85º, but you will need to bring one of those tanning lamps (not recommended) because that’s the only way you will be able to get a suntan if you have the time to do so.

Within these small rock-layered tunnels, these are the temperatures that these miners are faced with; however, there are other miners who face even worse conditions. These people are hired by international criminal organizations to dig out gold from these same mines. Called ghost miners, they sneak into the mines (actually the bribed guards look the other way) and live down there for months on end.

Don’t expect them to get caught as they will blend into the miles of tunnels where it is almost impossible to locate them, but if they do get caught, they have the firepower to push the ‘mining police’ back with their AK-47s and bottle grenades.

Ghost miners might not know each other, but they have their allegiances and help out each other when they can with food and supplies, which undoubtedly helps to keep them from going insane.

Bacteria in the Mponeng Gold Mine

So you thought that all living organisms need the sun to nourish them. Wrong. Deep in the Mponeng mine, scientists found Candidatus Desulforudis audaxviator, otherwise known to the general public as bacteria. These tiny creatures have never seen the sun. They live independently from all other organisms and can be considered a single-species ecosystem.

How Does This Bacteria Live in This Harsh Environment?

Water does find its way from above through cracks in the rocks and they acquire nourishment from the breakdown of organic matter. D. audaxviator, which is the common denominator for this family of microbes has been living down there for millions of years.

How Would One Get a Job as a Mponeng miner?

Hold on! We suggest not to quit your day job so fast, but if you insist and don’t mind the dark, dreary, hot conditions to get your hands on a few ounces of gold (if you are successful), here are the job offerings

 

 

Tanzanian Miner Finds Tanzanite Gem Worth Millions

Coat of Arms of Tanzania
(Photo: Wikimedia
Public Domain)

Looks like Saniniu Laizer, an independent miner in Tanzania has the luck of the Tanzanians, after finding, for a third time, a discovery of two violet-blue tanzanite gemstones, which are some of the world’s rarest gems.

These stones are said to be the largest ever found in the country and this discovery made 52-year-old Saniniu a self-made millionaire. He sold 33 pounds of stones to the Tanzania government for a whopping 7.74 billion Tanzanian shillings ($3.4 million U.S. dollars).

Laizer is not employed by any organization or company. Like others, he mines on his own by hand, but if this gemstone find was not enough, he went back to make another discovery, grabbing a 14-pound gemstone valued at $2 million.

Surface Mining
Surface Mining (CC)

Mining makes up more than 50% of Tanzania’s exports with gold the primary mineral. Saniniu’s mining is considered legal, although there are Illegal mining techniques as well as corruption in this country and it is a big problem for the government. 

In 2019, Tanzania set up trading centers to allow miners to sell their gems to the government. Many reportedly mine by hand, like Saniniu without any affiliation to any mining companies. This also encourages other small scale miners to work.

So What is Laizer Going to Do with His Fortune?

Farmers_in_Igunga,_Tanzania
Farmers in Igunga,_Tanzania (Wikipedia)

“There will be a big party tomorrow” he said. “I want to build a shopping mall. Laizer also mentioned that he will slaughter one of his 2,000 cows for his party, according to the BBC.

Tanzania is a poor country located in East Africa and despite its mining production of gold, it still remains one of the most impoverished countries in the world. About 36 percent of the population lives below the poverty line and although they have a structured educational system, the attendance rate is poor.

There is a lack of trained teachers, a lack of student motivation from students to attend, most probably due to the lack of esteem due to the low poverty level; subsequently, there is a large drop out rate. Poor nutrition is also a big problem. No doubt this also adds to the overall impoverishment of the country.

Saniniu Laizern is a bright spot in these areas of low morale, so it’s not surprising to hear that he wants to build a school and healthcare facility in his community. “I want to build this school near my home. There are many poor people around here who can’t afford to take their children to school.”

Additionally, he said: “I am not educated but I like things [sic] run in a professional way.” And he said that he would like his children to manage his business. This should not be a major problem for Saniniu, since it has been reported that he has four wives and over 30 children.

Opal Demand is Soaring as Australian Mines Struggle to Keep up with Demand

Opal Mines in AustraliaEven in the opal-rich fields of South Australia, one needs luck, months and even years of patience to come across this rare gem. Potential miners spend hours in the sun waiting for a fortune that can be made on the sale of opal. The market for larger pieces of opal can go north of $1 million because of high demand from jewelers and fashion brands.

South Australia is the producer of over 80% of the opals currently circulating in the market. But even then, finding opal stones is extremely rare. The town associated with opal mining is Copper Bend where many of these gems are found in the surrounding areas. Currently, the population of the town stands at 3,500. However, at the height of the mining, thousands of miners lived in the town where summer temperatures can go up to 116° F (47° C). There are still massive profits to be made, thanks to the high demand from fashion brands and countries like China and India.

A Rise in Demand

The depletion of opal mines is making it harder for South Australian miners to keep up with high demand from Chinese and Indian buyers who keep on placing large orders for export.

The locals have been frustrated as the price of the precious gem has gone through the roof and Chinese and Indian buyers are flooding the market for requests. There is not enough opal to export as no new mines are being discovered.

The local mining population has started its own exploration but only managed to find satellite mines so far. These small mines are only capable of producing opals worth $2 to $3 million whereas the locals estimate they need about $200 to $300 million worth to fulfill demand and bring back the old mining towns to their former glory.

A Darling of the Fashion World

Opals are making their way back to the fashion limelight as they are being used by both old timers and upcoming designers to distinguish their work from the competition.

Though opals were first discovered in the 1800s in Australia, it was not until the 1990s that their market price started gaining more momentum, helped mostly by a surge in European demand at the time.

Opal carries with a sense of individuality and creativity, two characteristics that are highly sought after in the fashion world. Compared to colored diamonds, rubies, and blue sapphires that have sky-high prices and are out of reach for many people, opals come as an equally dazzling alternative. Furthermore, all the opals in Australia are mined ethically. As ethical sourcing is becoming a huge concern for the next generation of jewelry buyers, Australian opals are being considered more desirable.

What Needs to be Done

Most miners from South Australia believe that the surface of opal mining has not even been scratched yet. There needs to be a more robust government policy to ramp-up investment in opal mining and exploration which miners feel a lack of government support.

However, the government has its own reasons for not giving enough support to middle and small-scale miners. A report identifies the following reasons for not providing more to support to the opal mining industry.

    • Tax evasion on a large scale by small miners which forces the government to ignore their needs as they believe taxpayer money could be spent better.
    • The lack of unity amongst the mining community on how the industry should be supported is also an issue, preventing the miners from lobbying collectively.
    • Australia is rich in minerals and stones such as gold, iron, and ore. It receives royalties from these industries, unlike opal mining which requires no royalty payments to the government.
  • The government believes that the potential of opal is not worth the time and money as other resources like nickel and gold yield better returns.

A lack of unity by the miners and a lack of interest by the Australian government are creating a situation where the supply of opal might dwindle from Australia. Of course, this is good news for sellers, hoarders, and other countries that have opal mines as the loss of a major supplier would drive up prices. But the problem for small-scale Australian miners and opal cutter would just exacerbate as they are being neglected.

Immediate steps are necessary to be undertaken by the government if the opal mining industry in Australia is to be saved from doom. Investment and explorations of new mines and new mining equipment are needed as well as subsidies.

From the part of the miners, a more united front for stronger lobbying efforts are required if they want the government to focus on a dying industry.

Mining History of Diamonds

Sunrise open-pit Australia
Sunrise open-pit Australia

Diamonds have always possessed a treasured place in the human conscious. The history of diamonds stretches back to the pre-BC era. It has been mentioned in ancient Sanskrit and Greek literature and reference can be found in even earlier scripts. To this day, diamonds continue to set the human fancy on fire.  

For the most part of the history, diamonds remained a rare stone and the mining process has always been tedious. It begins some 100 miles underground where heat and pressure crystallize carbon into rough diamonds (diamonds that haven’t gone through the polished cut, faceted process, also called natural diamonds). These diamonds reside in kimberlite rocks via kimberlite pipes – vertical structures that contain the kimberlite rocks. Volcanic eruptions, which has occurred millions of years ago brought up these rocks much closer to the earth’s service. 

Bucket Wheel-Excavator open pit-mining

To extract these rocks from the kimberlite pipes, a process called open pit-mining is used, which is a surface mining technique that removes material from an open pit or borrow, with respect to tunneling into the earth, such as longwall mining. Aside from diamond excavation, open-pit mines are also popular for removal of construction material and these mines are commonly known as quarries.

Heavy machinery and hydraulic shovels are required for kimberlite extraction from these open pits and the process of facet checking, cutting, smoothing and polishing begins.

When Did it All Start?

In the early years, wealthy people who can afford everything expensive couldn’t get their hands on diamonds because the stone was so short in supply. However, things changed after 1300 AD when it began to be used as an ornamental stone in medieval Europe.

The real transition, AKA ‘the diamond rush’ occurred in the 19th century, when diamond mines were discovered in different parts of Africa. The gemstone once so rare became available for elites as they were still considered precious and very expensive.

So here we will discuss how the mining of diamonds in different parts of the world has taken its shape from previous millennium to contemporary times.  

India: The earliest diamond producer

India was considered to be the place where mining and trading of diamonds started in the 4th century BC. At that time there was no mass scale mining and usually, diamonds were retrieved from rivers, streams and other sedimentary rock formations.  

The demand of those Indian diamonds increased in 13 AD when they were introduced in markets of medieval Europe by trade caravans of the time, who were mesmerizing Western Europe with exotic Indian commodities.

Brazil succeeds India

Due to the increased utilization of diamonds by the elites of Europe during the rise of the colonial era, the Indian supply of diamonds began to deplete during the early 16th century. By the same time, Brazil appeared as the major supplier of diamonds along with its already rich resources of gold.  

18th century: Africa takes the reins

The dynamics of diamond mining and trade witnessed dynamic changes in the 18th century, when mines were discovered in Africa, including mines in Kimberley and South Africa, the annual production of diamonds increased exponentially in the following years. In the 1870s, the annual yield of diamonds was well under a million carats, but in 50 years, this production reached the mark of 50 million carats. Almost 90% of those mined rough diamonds were coming out of the mines in Africa.

World Mining Map
World Mining Map. Pink box represents diamond mines.

Through the first half of 20th century, South Africa and The Republic of Congo (then Zaire) were responsible for more than 90% supply of diamonds in the world. In the latter half of the century, the Soviet Union also became a big player in the diamond market. The year 1982 became a fortunate year for Botswana, as they became the third largest contributors to the world’s diamond supply, with newly discovered mines. Additionally, mines in Australia and Northern Canada were discovered; thus, making this once fairly unknown mineral a world commodity.  

The Ugly side of diamond mining and trade

Sierra Leone Miners
Sierra Leone Miners

The symbol of love, luxury and passion can also transform into the manifestation of blood and gore due to the shortcomings of human greed.

In recent decades, the presence of diamond mines in underdeveloped countries in Africa, such as The Republic of Congo, Sierra Leone, Angola, and Liberia have become the reason for civil wars and unrest. Warlords and guerrilla leaders used rough diamonds to finance their rebel movements and to feed their militias, and miners often work in terrible conditions. The diamonds that serve this purpose are called ‘blood diamonds’ or ‘conflict diamonds’. 

Angola was a primary source of the illegal diamond trade and was responsible for 20% of the total world production in the 1980s. In order to get a handle on the illegal diamond trade, the UN-appointed Canadian ambassador Robert Fowler to investigate it and in 2000, he produced the Fowler Report, which mentioned the countries involved.

Present status of diamond mining

Apart from some pockets of trouble in those countries mentioned, the supply of the diamond is stable and in safe hands. According to the forecasted figures of 2017, around 142 million carats of diamonds worth $15.6 billion will be mined worldwide. This production volume would be 11% more than the previous year. It is interesting to note that even with these huge volumes of diamond mining as compared to the 19th or 20th century, only 10 mines in the whole world are producing around 60% of global supply of these precious stones.

The largest mine is located in Botswana with the name of Jwaneng, which independently produces 15% value of the world’s diamonds.

No matter how technology-savvy we become, with each passing generation, it may be in our human DNA that we still get spell bounded by the beauty and delicacy of this gem. It seems as if we are far from getting over this obsession. Moreover, this slogan might be true after all that ‘A diamond is forever’.

Aquamarine – The Jewel of the Sea

AquamarineAquamarine is given its name because of the blueness of this gem that depicts the blueness of the ocean. In Latin, it means the water of the sea, and the name was actually given by the Romans in 2000 BC. Since the ancient times, aquamarine has been regarded as a precious gemstone.

In Greek mythology, sailors believed that the stone would protect them from the destruction of Poseidon, the God of sea in Greek mythology, and Neptune according to Roman mythology. It was possessed by the sailors with the hope of a safe journey through the seas. Since it represents water, it is the birthstone representing the month of March, also known as the month of Pisces. Because of its blue color, it is believed that it possess the tendency to calm a person with its tranquil effects and bring forth wisdom.

Composition

Aquamarine belongs to the Beryl family, which includes heliodor, emerald, morganite and goshenite. Beryl is aluminum beryllium silicate, which has the hardness level of 7.5. The blue color of aquamarine is due to the presence of traces of iron in it, each with different amount that then cause different shades of blue, sometimes with a hint of green. Unlike emerald, it has little to no inclusions. It has a hexagonal crystalline structure.

Properties and formation

Aquamarine is an almost transparent gem because of no inclusions in it. Since it is very clear, the color plays an important role in determining its worth. Lapidaries try to accentuate the colors of aquamarine by focusing on its cuts. They go for deeper cuts to bring the colors out. You will never find an aquamarine too dark. The color ranges between light blue to intense blue, with inclusions of some greenish shades. However, light shades of aquamarine are most common, making the intense shades of blue more precious and demanded. Aquamarine is usually associated with the family of quartz, biotite, topaz and garnet because of its density and hardness and because it occurs in the form of pegmatite.

Where it is found

In modern times, Brazil is the top supplier of aquamarines as they are abundantly found there. More recently, South Africa has also become a leading supplier of aquamarine. Pakistan, Mozambique, Nigeria, and Madagascar have large reserves of aquamarine.

Mystical attributes of aquamarine

Aquamarine is believed to help in stimulating better mental health due to its calming effects. It is used to bring tranquility, a sense of peace and unity. People use it to aid themselves in spiritual meditations. It was thought to be an antidote or poison. Sailors wore this for protection, and in the battleground, it was worn by soldiers to instill a sense of glory and victory in them. It represents the throat chakra, which is why people believe it to help in unblocking the communication blocks and stimulating spiritual connection. The blueness of aquamarine depicts the openness of the sea. It represents the absolute truth and helps a person in letting go of things and patterns, which does not benefit them any longer.

 

Miners Hopeful After US Lifts Sanctions

Myanmar Map The country of Myanmar produces more than 80 percent of the world’s rubies. North of the city Mandalay is a valley named Mogok that is known as the “land of rubies.” Mogok is where the Sunrise Ruby was found. The gem sold for $30.3 million last year and is one of the so-called “pigeon-blood” stones, known to be one of the most expensive colored gems in the world. Pigeon’s-blood red is considered the most precious hue of all according to the American Gemological Laboratories color rating system.

Every day, thousands of natives in Myanmar barely make a living mining for gems, hoping to one day find the ruby that could change their lives. Production in the Mogok region has skyrocketed since the mid-1990s, when the former junta rulers allowed private companies into the region with their heavy machinery and new mining methods.

In 2003, the United States implemented sanctions that would stop the import of gems from Myanmar. This effort was imposed in an effort to starve the military government of its funds. Miners usually earn about $200 dollars or less a month working in the mines. For decades, the junta military and ex-army chiefs oversaw the mining industry. Even though the Mogok valley is filled with mines, the locals see very little of the profits. Mogok is not only a source of rubies, but also sapphires, spinel, peridot, zircon, topaz, and others. It is also a source of the rare painite gemstones.

In October 2016, the US lifted sanctions that prevented imports of rubies as a result of Myanmar’s shift towards democracy under its new government. Sellers of stones in the region hope that the end of these sanctions will see a surge in American tourists and new business. In the past, high-quality gems such as red rubies and blue sapphires were sent to black markets in Thailand. The gem market in Myanmar is optimistic that with ruby prices going up and US companies entering the market, US dealers will be returning to do business. Chief executive Douglas Hucker from the American Gem Trade Association says that they will only work with “licensed dealers and seek to determine that the gemstones they are buying are sources responsibly.”

To prevent further exploitation of Myanmar’s gemstones, the government implemented a moratorium last July on new mining licenses. Companies will have to meet stricter environmental regulations to get mining permits. US buyers will also have to follow stricter international rules to make sure mines enforce good working conditions. These new efforts will help ensure that profits don’t fuel Myanmar’s conflicts with rebels.

Asteroid Mining : A New Gold Rush

The idea of mining asteroids has been around for over one hundred years. In the late 1800s, this idea first came about, and today it is not just an idea, but a reality. There are currently four different private asteroid mining companies that are actively pursuing this new endeavor, such as Planetary Resources and Deep Space Industries.

All the different types of minerals and metals needed to make electronics such as platinum and gold is quite scarce on Earth. Space, however, is rich in these metals. Platinum is a fantastic conductor, yet it is rare on Earth but very plentiful in space. A typical 100-foot asteroid could contain as much as 50$ billion worth of platinum. Asteroid 433 Eros contains about $3 trillion dollars worth of gold. This amount of gold could devalue the entire market, but one thing is for sure, it will definitely have an economic impact.

Twenty years ago, Shell discovered the first North Sea oil deposit located underneath 5,000 feet of water and 10,000 feet of rock. Shell took a very costly risk to extract the oil using robotics, in a very hostile and distant area. This same technique can be applied to mining asteroids. The technology for mining already exists. There have already been three missions, two from NASA and one from Japan, that used probes to reach asteroids and collect dust from their surface. This is the first step to mining asteroids. Besides the scientific value, these explorations are on the brink of launching an entirely new industry.

There are nearly 10,000 asteroids near Earth that have mineral mining potential. With the need for electronics such as smartphones, computers, and other technologies increasing, the global demand for minerals such as copper, gold and platinum is also increasing. The lure of asteroid mining is powerful. Congress has already passed a bill, the Asteroid Act, that will allow those that mine asteroids to claim their resources as private property.

Mining: A Brief Overview

mining-imageThe term ‘mining’ means extraction. The process of mining entails the extraction of valuable resources from the earth by using various methods and techniques.

Discovery of Mining Techniques – A Revolutionary Development

The discovery of the methods and techniques to extract the treasures that lie beneath the surface of the earth and the development of various machines to carry out the processes was a revolutionary development in the history of mankind.

It not only makes our daily lives a lot easier by allowing us to utilize the vast reserves of oil, coal and gas for daily purposes, but it also led to the invention of various instruments, gadgets and items of everyday use which are made with the help of various metals, like copper, iron, aluminum etc. In addition to these, we were also able get our hands on some of the most precious metals and stones just because of the development of various mining techniques and methods. Had geologists not invented these techniques, we would not have been able to use gold, silver, diamond, emerald and other precious stones to make beautiful ornaments to adorn ourselves with.

Countries prospered and civilizations developed as they started extracting the natural wealth lying beneath the surface of the earth and used it to further their economic activities and industrial growth.

bucket_wheel_excavator-for-mining
Bucket Wheel Excavator for Surface Mining

Types of Mining

The process of mining can be broadly divided into 2 categories:

  1. Surface Mining
  2. Underground Mining

These types are further divided into various sub-categories.

Surface Mining

Surface mining is a broad category that is comprised of various methods used by geologists to extract the mineral deposits, metals and ores lying near the surface of the earth. Different kinds of surface mining are:

  • Open pit or Opencast mining
  • Strip mining
  • Quarrying

The most common element extracted through surface mining is ‘coal’.

Underground Mining

Underground mining includes techniques and methods used to extract metals, ores and minerals that lie deep within the earth and cannot be taken out with surface mining techniques. In these types of mining techniques, an entrance point is made from the earth’s surface, which is in the form of a mine shaft, an adit or a tunnel. Major types of underground mining are:

  • Longwall mining
  • Room and pillar mining
  • Shaft mining
  • Block caving
  • Cut and fill stoping
  • Borehole mining

Negative Effects of Mining

In addition to the numerous benefits provided to human beings due to the extraction of valuable natural resources, the processes used to carry out mining produces have some negative effects as well, particularly on the environment. Some of the major negative impacts are as follows:

  • Mining causes the emission of various gases, dust and trace elements that lead to the contamination of air and surface water.
  • The quality of the soil and its fertility is compromised because of mining. Also, it makes the soil toxic.
  • It causes deforestation, destruction of landscapes and wildlife habitats.
  • The water table gets lowered due to mining which in turn affects the flow of groundwater.

Understanding the Extraction and Processing of Minerals

A large part of the earth’s crust contains minerals. However, in some places, minerals are present in negligible quantities. Therefore, mining minerals in such places is not viable. Luckily, there are methods to determine which places have economically viable mineral deposits. Categorized as geological processes, these methods are used for finding as well as extracting economically viable mineral deposits.

The deposits come in various shapes and sizes. The two most commonly used methods for extracting/mining minerals are surface mining and underground mining. Let’s take a brief look at both these methods.

Surface Mining

Trucks working in a mine
2002-08 No.26 truck and loader operations in the Omya Limestone quarry south of Bathurst.

Used to mine the metals and minerals present near the earth’s surface, surface mining is a much more economically viable option than underground mining. The three basic types of surface mining are quarry mining, strip mining, and open pit mining. Used to obtain all minerals except coal, open pit mining involves making cuts into the ground and working the area at that depth around the mine’s circumference. Also known as hard rock mining, open pit mining is generally used to mine metal ores such as aluminum, iron, gold, and copper.

Primarily used for extracting coal, strip mining involves the removal of rock and soil above a seam or layer. The removal of the exposed mineral is what follows next. The process is repeated until the exhaustion of the ore. Finally, quarry mining is used to extract the minerals used in granite, clay, sand, and gravel. In order to create the best fracturing, quarry mining starts off by blasting into to rock. Using crushing machines, rocks are reduced further.

Furthermore, they are separated based on size. However, blasting isn’t involved in the mining of ornamental stone. Instead, it involves a method known as broaching. In broaching, rather than using explosives, wedges are put into holes. The process involves hammering the wedges into the holes until the stones come off.

Underground Mining

Underground Mining Loulo Mali
Underground Mining in Loulo Mali

Used to mine valuable minerals and ores, underground mining is more dangerous than surface mining and involves harrowing into the ground to extract the minerals and ores. This method of mining minerals is very different from surface mining. Contrary to popular belief, underground mining is used to mine a lot more than coal. For example, underground mining is the best way to access gold deposits. When mineral deposits are buried so deep that extracting them with surface mining is simply not possible, companies use underground mining.

There you have it—the ways of extracting and processing minerals. Using the aforementioned information, companies can choose the mining method that suits them best.