Open-Pit Mining and Mineral Extraction

Open-Pit Mining

• Open-pit mining is also known as open-cast or open-cut mining.
• It is employed when a valuable deposit lies near the surface, often beneath a thick layer of valueless material called overburden.
• The overburden is removed and stored for later use in mine restoration.
• Mines are dug in sections called benches, with walls angled to reduce the risk of rock falls.
• The safe angle depends on the deposit and overburden type.
• Roads facilitate mineral deposit and overburden removal.
• Quarries extract building materials like sand, gravel, and stone using similar methods.

Economic Impacts of Mineral Extraction

• Mineral extraction provides employment and government tax revenue.
• Modern mining employs few people directly due to the use of machines; however, refining and processing can create additional jobs.
• Exporting minerals to other countries for manufacturing creates jobs in those countries.
• Mineral extraction benefits local and national economies by creating jobs, supplying transportation, and manufacturing equipment.
• Refining minerals into products generates income for buying goods and services, as well as investing in infrastructure.
• Mining operations require improvements to transport, healthcare, and education.
• Mining companies may fund some improvements as part of their mining license.
• Taxes from mining companies and workers can fund infrastructure projects benefiting the population.

Managing the Impact of Rock and Mineral Extraction

• Mining operation management includes plans for safe waste disposal and land restoration.
• Historically, mining waste was piled near extraction points, leading to water pollution and collapses.
• Today, safe mine waste storage and disposal are crucial for mining license applications.
• Applications must include plans to prevent collapse and water pollution, with monitoring systems.

Land Restoration and Bioremediation

• After mining, land should be restored.
• Mine waste can be reshaped and covered with soil and fertilizer to allow plant and animal colonization
• Planting trees creates habitats, especially for managing coal mining waste.
• If tree roots cannot grow, contaminated waste can be treated in situ (bioremediation) or removed to a treatment plant (ex situ treatment).
• Bioremediation involves using living organisms to remove toxic chemicals from a site.
• Microorganisms, like soil bacteria, break down toxic substances into less harmful ones, gaining energy or nutrients in the process.
• Microorganisms can remove pollutants faster when their environment is rich in oxygen and nitrogen.
• Some plants naturally bioaccumulate toxic metals and can be utilized by increasing fertilizers; plants absorb the toxins and the toxic part of the plant is removed leaving the soil less toxic.

Encouraging Sustainable Use of Minerals and Rocks

• Designing products to use less material (e.g., titanium) can reduce mineral consumption.
• Governments encourage sustainable mineral use by requiring manufacturers to recycle and reuse materials.
• The Waste Electrical and Electronic Equipment (WEEE) Directive in the European Union (passed in 2002) requires manufacturers to take responsibility for recycling electronic waste.

This resource explores open-pit mining techniques, including overburden removal, bench construction, and quarrying. It also examines the economic impacts of mineral extraction, such as job creation and government revenue, while noting the shift towards mechanized processes.