Overground Mining vs Underground Mining: Everything You Need to Know

 Humans began mining for specific minerals around 40,000 to 20,000 years ago in southern Africa. But it was only 10,000 to 7,000 years ago when mining became a significant industry. There are different kinds of mining and they each get specific minerals and specific help from engineering companies that specialize in heavy industry.

Coal Mining
Image Credits: Unsplash

Of the different kinds of mining, there are two that you need to be fully aware of if you want to fully understand the industry: overground mining and underground mining.

This article will help you under the basic features and differences between overground mining and underground mining.

What is mining?

Mining is a primary global industry that helps in the production and creation of products like cell phones, laptops, construction materials, and jewelry. It is the process of extracting materials from the earth. The most mined substances are as follows: copper, feldspar, lithium, silver, gold, iron ore, lead, and nickel. 

It will be impossible to enjoy all the perks of the modern world without the substances that the mining industry provides. Mining substances help all sectors of society. 

The world’s biggest mining companies are Rio Tinto, BHP, and Anglo-American. The following are the leading mining countries in the world: China, Australia, the United States, Indonesia, Russia, Brazil, Chile, South Africa, Canada, Peru, India, and Kazakhstan.

What is Underground Mining?

Underground mining is the kind of mining that deals with the extraction of substances below the surface. Hard minerals below that surface are usually extracted through this kind of mining. Such hard materials usually contain metals with ore that has gold, silver, copper, iron, zinc, lead, tin, and nickel. 

Schematic Cross-Section of a Typical Underground Mine

As substances mined are deeply located below the surface, this kind of mining is highly dangerous. Despite the danger, this is the most common kind of mining.

Underground mining involves two main stages:

• Removal of unwanted material
• Extraction of the target material.

There are different categories of underground mining that vary depending on the processes used, shaft types, and extraction techniques. 

For successful underground mining, it is essential for an orebody or coal seam examination to take place. This very process determines the exact location of target substances. 

What is Overground Mining?

Overground or surface mining is the oldest form of extracting resources from the earth. It has been used since ancient times. The only difference between surface mining during ancient times and surface mining in the modern day would have to be the types of equipment utilized. 

Overground Mining

Surface mining is done because some minerals simply exist on the earth’s surface or just below its ground. This is why surface mining is still mostly done these days.

Surface mining is also referred to as open-pit mining. There are primarily four advantages to this type of mining and they are as follows: higher productivity, safer, more complete recovery of substances, and more affordable. 

What are the main differences between overground mining and underground mining?

Underground mining and overground mining mainly differs when it comes to the following:

1. Need for Deep Shafts

Underground mining deals with materials that are deep below the surface. This is why deep shafts are always necessary. Deep shafts allow for the easy vertical pushing of materials from top to bottom.

The process of using a deep shaft is also referred to as shaft sinking. Deep shafts are used to allow for easy mining in instances where there is initially no access to space at the bottom.

Mineshaft Construction

 
Overground mining will not require the use of deep shafts. It will usually just require the removal of the overburden. In mining, materials located immediately above the ore body or coal seams like rocks, plant life, and soil are referred to as overburdened. An overburden can also be composed of any material found in different ecosystems.

2. Work Intensity

Underground mining is more intensive. Because for underground mining, the techniques and processes need to be particularly deployed to access substances from below the surface. Working for access and working around such underground access takes a lot of work that is very separate from substance extraction.

Workers in Underground Mining
Image Credits: Business Insider

Work is not as intensive when it comes to overground mining. There are no particular techniques and processes needed to reach for substances deep below the surface because targeted ones are by the surface of the earth. This is why it can also be said that overground mining is safer than underground mining. However, open-pit mining is only partially safe. Pits can also collapse when unstable rock faces are mined.

3. Environmental Assessment

When it comes to the need for extensive environmental assessment, much will be required if one is involved in open-pit mining or overground mining. This is the case because this kind of mining requires a massive amount of space that can damage fragile ecosystems and even contaminate groundwater. This is why extensive environmental assessment is more needed if mining is done on the surface.

Pollution from Copper Mine
Image Credits: Inhabitat

Environmental assessment is also extensively done for underground mining as it can easily cause land subsidence, soil erosion, biodiversity decrease, and air pollution. Similar to open-pit mining, it can also cause the destruction of water resources. However, more time and effort are dedicated to the environmental assessment of open-pit mining projects where more surface space is affected.

References:

A Brief History of Mining: https://www.earthsystems.com/history-mining/#:~:
We Need To Talk About Mining: Death, Dangers & Prevention: https://www.howden.com/en-us/articles/mining/we-need-to-talk-about-mining

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