Environmental Management (0680) | Extraction of rocks and minerals from the Earth

Welcome to Section 1: Extraction of Rocks and Minerals!

Hello future Environmental Manager! This chapter is all about how we get the vital resources (rocks and minerals) we need from the ground, and more importantly, how we manage the massive impact this process has on our planet.

We often take for granted the metals in our phones or the concrete in our buildings, but they all start deep underground. Understanding extraction methods, deciding whether or not to mine, and ensuring we do it responsibly is at the heart of Environmental Management. Don't worry if some terms look new – we will break them down step-by-step!

---

1. Methods of Extraction of Rocks and Minerals (Syllabus 1.2)

The way we dig up rocks and minerals depends mostly on how deep the resource is buried. We mainly use two types of mining: Surface Mining and Subsurface Mining.

A. Surface Mining (Shallow Resources)

Surface mining involves removing the layers of soil and rock (called overburden) lying above the resource. This is used when the deposits are close to the Earth's surface.

Types of Surface Mining:

• Opencast / Open-pit / Open-cut Mining: This creates a large, deep hole, getting wider as it gets deeper. It looks like a massive inverted cone or crater.
  Analogy: Imagine scooping out a huge bowl of ice cream.
• Strip Mining: Used when the resource (like coal) occurs in horizontal layers close to the surface, over a large area. Miners remove a strip of overburden, extract the resource, and then use the removed overburden to fill the previous trench.
  Key Takeaway: Surface mining is generally safer and cheaper than subsurface mining, but causes much greater surface damage.

B. Subsurface Mining (Deep Resources)

Subsurface mining (also called Deep Mining or Shaft Mining) is necessary when the deposits are too far underground to be reached economically by surface methods.

How Subsurface Mining Works:

• Vertical shafts (tunnels) are drilled down into the Earth to reach the deep mineral veins.
• Horizontal tunnels are then dug outwards from the shafts to extract the mineral.
• The extracted material is brought back up to the surface using lifts or conveyor belts.

Did You Know? Deep mines can extend thousands of metres underground! This makes them incredibly complex and dangerous due to risks like rockfalls, flooding, and poisonous gases.

---

2. Factors Affecting the Decision to Extract (Syllabus 1.2)

Deciding whether to open a mine is a huge investment decision. It’s not just about finding minerals; it’s about whether it makes economic, environmental, and social sense.

A. Geological Factors (Is it worth it?)

• Exploration: Before digging, companies spend millions on exploration (drilling, surveying) to confirm the size and quality (grade) of the deposit. If the resource is low grade or too small, it won't be profitable.
• Geology: The type of rock and its structure affects the stability of the mine. Difficult geology (e.g., prone to flooding or collapse) increases costs and risks.

B. Economic Factors (Can we afford it?)

• Supply and Demand: This is the biggest factor. If the market price for the mineral is high (high demand, low supply), the mine is more likely to open. If the price drops, the mine might close.
  Analogy: You won't bother digging for copper if the price of copper is less than the cost of your shovel and labour!
• Accessibility: How easy is it to get equipment in and take the finished product out? Remote areas require huge investment in infrastructure (roads, rail links, ports, power supply), which significantly increases initial costs.

C. Environmental and Social Factors (Is it responsible?)

• Environmental Impact Assessment (EIA): Governments require a detailed study of how the mine will affect the environment (air, water, land, wildlife) and the community. If the predicted damage is too severe, permission may be denied.
• Legislation and Policy: The laws of the country regarding pollution control, worker safety, and land restoration heavily influence the cost and feasibility of the project.

---

3. Impacts of Rock and Mineral Extraction (Syllabus 1.3)

Mining, while necessary, radically changes the environment and society around it. We must look at both the negative effects and the positive benefits.

A. Environmental Impacts (The Damage)

• Loss of Habitat: Surface mining requires removing everything on top of the resource, leading to massive deforestation and loss of biodiversity. Habitats are permanently destroyed.
• Land Pollution (Visual): Mines create huge scarred landscapes, dumps of waste rock (spoil heaps), and large pits, which are often described as visual pollution.
• Water Pollution: This is extremely serious.
  • Rainwater mixes with waste rock, creating toxic acidic runoff (acid mine drainage).
  • Sediment and heavy metals (like lead and arsenic) wash into nearby rivers and groundwater, making water unsafe for humans and wildlife.
• Air and Noise Pollution: Heavy machinery, blasting, and transportation of materials generate huge amounts of noise. Dust created during digging and processing is a form of air pollution that can harm respiratory health.
• Waste Management: Mining produces vast amounts of waste material (tailings) that must be managed safely to prevent chemical leaks or dam failures.

B. Economic and Social Impacts (The Trade-offs)

Mining brings both powerful opportunities and significant social costs.

Positive Impacts (Economic/Social):

• Employment Opportunities: Mines create jobs for local people (miners, engineers, support staff), providing stable income.
• Improvements in Local/National Economy: The mine generates taxes and revenue for the government, funding essential services.
• Improvements in Facilities and Infrastructure: To support the mine, new roads, electricity grids, housing, and hospitals are often built, benefiting the local community.

Negative Impacts (Social):

• Community Displacement: If a mine is located beneath a town or village, the community may be forced to relocate.
• Health Issues: Air and water pollution can cause long-term health problems for nearby residents.
• "Boom and Bust": When the mine opens (the "boom"), money and jobs flood in. If the resource runs out or the market price falls, the mine closes (the "bust"), leaving high unemployment and abandoned infrastructure.

---

4. Managing and Restoring Damaged Landscapes (Syllabus 1.4)

Environmental management requires that mining companies not just extract resources, but also plan for the eventual closure and restoration of the site. This process is called Land Restoration or Reclamation.

A. Safe Disposal of Mining Waste

• Tailings Ponds: Toxic slurry (tailings) left after mineral processing is pumped into specially designed, secured ponds. These must be monitored constantly to ensure dams do not fail and pollute the surrounding area.
• Waste Rock Disposal: Waste rock should be stored carefully and sometimes treated to neutralise potential acid drainage before being used for infilling or restoration.

B. Land Restoration Strategies (Bringing the land back to life)

The goal is to return the landscape to a useful, safe, and stable state, often similar to the pre-mining conditions.

1. Contouring and Soil Improvement: The spoil heaps and waste rock are reshaped (contoured) to look more like natural hills. Topsoil (which must be carefully stored during the initial digging) is then spread back over the surface.
2. Bioremediation: This is a clever process using living things! It involves using plants or microbes (bacteria) to remove pollutants, especially heavy metals, from the soil or water.
3. Tree Planting and Revegetation: Planting local, native species of trees, grasses, and shrubs helps stabilise the soil, prevents erosion, and restores habitats.
4. Making Lakes and Nature Reserves: Deep open-pits can be allowed to fill with water (if safe) to create new lakes, which can then become centres for recreation or nature reserves.
5. Using as Landfill Sites: Sometimes, excavated pits are used for controlled disposal of solid municipal (city) waste, after which they are capped and covered.

Common Mistake Alert! Restoration doesn't mean making the land look exactly like it did before, but rather making it environmentally stable and useful again (e.g., for forestry, farming, or recreation).

---

5. Sustainable Use of Rocks and Minerals (Syllabus 1.5)

Rocks and minerals are non-renewable resources; once they are gone, they cannot be replaced within a human timescale. Therefore, sustainable management is vital.

A. Defining Sustainability

• Sustainable Resource: A resource that is used in a way that allows it to continue being available for future generations, or one that is naturally renewed (although minerals are typically non-renewable, we manage their use sustainably).
• Sustainable Development: Meeting the needs of the present generation without compromising the ability of future generations to meet their own needs.
  In mining, this means ensuring today’s wealth doesn’t come at the expense of irreversible environmental destruction for the future.

B. Strategies for Sustainable Use

1. Increased Efficiency of Extraction (Getting more out of the ground)

• Better Technology: Using advanced techniques to process ores, ensuring that we extract the maximum amount of mineral from the raw rock (reducing waste).
• Processing Lower-Grade Ores: As high-grade ores run out, new technologies allow us to profitably extract resources from rock that previously would have been considered waste.

2. Increased Efficiency of Use (Using less)

• Minimising Waste: Designing products to use less material overall (e.g., lighter car parts).
• Product Life Extension: Manufacturing goods that last longer, reducing the need for continuous raw material consumption.

3. Recycling Rocks and Minerals (The most important strategy!)

• The Need to Recycle: Recycling reduces the need for new extraction, saving energy, reducing pollution, and conserving finite reserves. For example, recycling aluminium uses about 95% less energy than producing new aluminium from bauxite ore.
• Metals: Easily recycled (e.g., steel, copper, gold).
• Rocks: Aggregates (crushed stone used in construction) can be recycled from old building rubble and road materials.

4. Legislation and Policy

• Governments use legislation to enforce sustainable practices, such as requiring all mining companies to implement detailed restoration plans, setting limits on water usage, and imposing strict pollution controls.