Mining

An element is a substance which cannot be broken down further into something simpler. Elements which are malleable or workable are called metals. There are 92 known elements (makes up the chemical table of elements we learned about in high school chemistry). Elements bonded together which make up solid crystals are minerals. Rocks are made up of many different minerals. Precious metals are those which do not rust: gold, silver, and platinum.

Metals and stones both come out of the ground. In order for something to be successfully mined, first we have to want the metal or the stone, second there has to be a market for it-someone who will purchase it and pay more for it than it costs to get it out of the ground-that is the demand part of supply and demand. Once the above is decided, then a way to get 'it' out of the ground must be found. Usually it is by drilling and using explosives. Once it is extracted from the ground, then it has to be separated from the non-desired rock which housed it for thousands if not millions of years. Often chemicals are used in this process.

Types of Mining

Processing

The metal then needs to be separated from the surrounding rock. It is crushed and pulverized or ground into smaller particles. The metal is then 'leached' out of the ground-up rock by using chemicals and water. Cyanide is used with Gold and Silver, Sulfuric Acid is used with Copper. Cyanide and Arsenic bind with the desired metal, and it is then separated from the water. The waste rock varies from location to location, but usually contains acidic minerals which also contain lead or cadmium. When rain water falls on these rocks, runoff becomes very acidic, often killing surrounding plants.

Smelting further processes the metal by removing impurities. Gases are produced which are harmful to the environment. Solid waste from smelters is slag which usually has increased concentrations of metals such as lead and arsenic; slag is often piled 100' high and covers 10-100's of acres. Often there is no vegetation surrounding these areas.

The gold bar is 999.9 gold, 1000 grams, and the approximate size is 4½" x 2" x ½".

Treatment of the acidic water is done by adding lime to neutralize the acidity, but this causes dissolved metals to precipitate from the water, which then must go through another treatment facility, and slag is created which must be stored safely.

Mining Issues

Mining is one of the most polluting industries. However, we would not be able to live the lives we do today without many metals which are obtained only through mining. We must mine in a sustainable way where a balance is obtained between the environment, miners, and the businesses which must make a profit to continue mining. Many mining companies continue to explore methods which are safer for both miners and the environment.

When it rains on the now exposed waste rock, the rainwater interacts with the sulfide in the rocks, it becomes 20-300 times more acidic than acid rain, which then enters surface and ground water sources. Smelter operations can leave soil lifeless within 2 miles, and damage forests, lakes, and wetlands within 18 miles. The U.S. law forbids mine waste from being dumped into the ocean. This is usually not the case in other countries.

Artisanal and Small-scale Mining (ASM) accounts for 13 million people employed in mining-large industrial mining companies employ only 2.75 million. ASM are individuals, families, and collectives. ASM has a higher rate of accidents, and illness (silicosis can result after only 7 months of exposure to silica dust), a shorter life span of usually only 35-40 years (rather than 64 for the rest of population-in Bolivia). Too often the 'boost to the local economy' disappears once the land is fully mined, or the 'Company Store' takes over, and locals are subject to the desire of the company which sets the prices for goods sold. EarthWorks

The GAO estimated that in 2007 there were 560,000 abandoned mines in the US. Twenty-five percent are physical safety hazards. They can contain deadly gases. Often air is without any oxygen, called 'Blackdamp' and is a deadly killer. Since 1999 there have been more than 200 deaths in these abandoned mines.

The American Geological Institute (AGI) lists the following environmental concerns and solutions for mining (American Geological Institute click on Slide Show, then Environmental Geosciences, then Slide Show, then choose Metal Mining and the Environment pdf file.):

Heavy metals, such as lead, cadmium, cyanide, and arsenic, left behind in mining in ground water causes:

Framework for Responsible Mining: Common Principles:

This is a paper by the Center for Science in Public Participation (CSP2), based on science, which outlines issues that should be considered in order to develop sustainable policies for hard-rock mining Center for Science in Public Participation (click on Reports, click on Framework for Responsible Mining):