1. 5.5 mining, metallurgy, and the environment
By Sydney, Charlotte, Jack, Megan, Ashton, Julia  

2. Mining: Chemical processing
Smelting is the old fashion way of chemical processing, heat the air to 1000°C. The metals sink to the bottom of the smelter and then separated. Wastes are then skimmed off and discarded. 
 Disadvantages:
• Waste materials are skimmed off and discarded
• Acid rain can be produced
• Needs a lot of fuel to reach and stay at 1000° C

3. Mining: Chemical Processing
Flash smelting is the new more modern technology, with more benefits. 
 Advantages
• Faster – uses almost pure oxygen
• Better for environment – less pollution, reduced fuel
• Sell the sulfuric acid to offset costs
• Thermal energy is released: little additional fuel is then needed
• Better quality metals are produced 

4. Further Processing
To create a more pure substance (above 90% pure), one will use electrolysis. (see the diagram for an example)
The purified metals can then be used to make electrical circuiting, anything less than 99% pure is not conductive enough.
Sheets of the impure metals are slowly broken into ions by way of an electrical current flowing through them, and into the solution.
The pure metal ions transfer to the separate sheet of metal, while the impurities  sink to the bottom.

5. The impact of mining on the environment
uMining can have devastating impacts on local wildlife, can kill vegetation, and make the surrounding regions barren. uIn north America today mining companies must fund detailed environmental assessments before they get permission to open a mind: plans for closure, rehabilitation of the site etc. uThese stricter government regulations have greatly reduced the environmental impact of mining uBut not all countries have these same strict regulations, and risk of contamination of air and water still remain.

6. Water pollution 
Freshly exposed rock after mining is prone to erosion, which can result in water quality problems called acid mine drainage 
Acid drainage is the outflow of unusually acidic water from a mine or tailings dump site caused by the reaction of sulfide minerals reacting with oxygen and water 
The hydrogen ions produced in the reaction make the water acidic
Iron (iii) ions and the precipitate they form give the water a rust colour 
Acid drainage is dangerous because the acidic ground water can easily dissolve toxic metals and harm aquatic life 
The only way to deal with the acidic pollution is to neutralize with calcium carbonate to raise the pH of the water to more normal levels

7. Air Pollution
Mining operations can be a source of air pollution, mainly dust from surface mining
Digging, blasting, and crushing produce rock dust
Wind spreads this dust world wide
Sulfur dioxide emissions are the most important air pollutant
A large portion of acid precipitation in Canada is from sulfur dioxide   emission in the U.S.A.
Technology and strict emission standards are decreasing the sulfur dioxide emissions
The standards are still continuing the decline of emissions
This is not the case in all countries who are still producing these gases

8. What is Mining? 
Mining is the excavation and extraction of minerals from the earth.
Minerals take definite form as crystallite structures and have a definite chemical composition. ie) bornite Cu5FeS4
Occasionally you can find a mineral which takes the form of a pure element. 
Ie) gold, silver, and sometimes copper
A rock that contains a valued resource that is profitable is known as an ore.
     - Highly desired metals like gold, silver, are precious. Less valuable metals  like copper, nickel, and zinc are sometimes called base metals.

9. E.g.) Underground mining
Miners have two options to excavate ores/minerals. Surface mining and underground mining.
Surface mining involves opening a large pit to expose the mineral deposits. Often used to extract ores closer to the earth's surface.
     - Returning the site to its previous state can be a challenge environmentally
Underground mining involves drilling a shaft deep into the earth to reach its core.
    
E.g.) Surface mining  
E.g.) Underground mining

10. What is Metallurgy?
Metallurgy is the extraction of the metals form the ores. A massive amount of rock must be extracted in order to have a good amount of the desired metal.
See Figure 4 in textbook on page 213. It summarizes the key steps of processing a metal (such as copper) from its ore/mineral to a finished product.
The physical processing of the ore/mineral involves a machine grinding the massive pieces of rock into tiny pieces.
The tiny pieces are then mixed with water and broken down into ions. The resulting anion is negatively charged at one end and non-polar at the other.The negatively charged end is hydrophilic and the non-polar end is hydrophobic. 
See Figure 5 on page 214 for a good summary on this process.  

11. Definitions
Mining- a naturally occurring solid that has a definite crystal structure and chemical composition
Ore- rock containing a relatively high proportion of a desirable mineral  
Smelting- the chemical process that extracts a metal from its ore using heat and chemicals
Flash smelting- new technology for separating a metal from its ore by heating ore in the atmosphere of almost pure oxygen
Electrolysis- electrical current passed through a substance to effect a chemical change. The substance will either lose or gain electrons.
Acid mine drainage- the outflow of unusually acidic water from a mine or tailings dump site