Use of Mercury for Artisanal and Small-Scale Gold Mining

This specific issue became evident to me when I surfing twitter. Artisanal and small-scale gold mining (ASGM) is the extraction of minerals by miners working in small and medium sized operations, using rudimentary techniques.  Simple practices with minimum economic investment are employed be these miners. It is the largest intentional-release source of mercury in the world.

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How can mercury be used for gold-mining? Mercury is used to separate and collect the gold from the rocks. Mercury binds with gold to form an amalgam which facilitates it to separate from rock, sand or other material. The amalgam is then heated to vaporize the mercury leaving the gold behind.

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Mercury is a powerful neurotoxin that is harmful to people, especially to developing fetuses, and young children. Once emitted, it can travel great distances through the atmosphere, causing global contamination of ecosystems, fish, birds, mammals, and the human food chain.Local exposures in mining communities that use mercury can be acute.

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What to do now?

  1. The most important measure a mining community can take to reduce its mercury use is to concentrate the gold-containing portion of the ore before adding mercury. This can be done by crushing and grinding the ore and then using carpeted or magnetic sluice boxes or gravity concentration techniques such as panning or centrifuges. In this way, more gold will be captured, less mercury will be required and residual mercury can be more completely captured.
  2. Protective measures include the use of retorts when burning amalgam and the use of gloves by those handling mercury or amalgam.
  3. Most promising technology to replace the use of mercury is cyanidation, but this method may not be affordable or technically available to all artisanal miners. Also, cyanidation methods must be used with care and carefully introduced due to its significant risks to human health and the environment.

For further info check reference texts http://www.unep.org/hazardoussubstances/Portals/9/Mercury/AwarenessPack/English/UNEP_Mod3_UK_Web.pdf

http://www.unep.org/hazardoussubstances/Portals/9/Mercury/Documents/ASGM/Techdoc/UNEP%20Tech%20Doc%20APRIL%202012_120608b_web.pdf

Ever Used This Device?

I hope you did use it at some point of your lives. This pulse oximeter measures the oxygen level in blood and also records heart rate. It’s so amazing and thought provoking that such a small device can do such wonders. Let’s see how it does so!

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So, the basic principle of pulse oximetry is based on the red and infrared light absorption characteristics of oxygenated and deoxygenated hemoglobin. Oxygenated hemoglobin absorbs more infrared light and allows more red light to pass through. Deoxygenated hemoglobin absorbs more red light and allows more infrared light to pass through. Pulse oximeter uses a light emitter with red and infrared LEDs that shines through a reasonably translucent site with good blood flow.

figure-1-dr-petty-brochure An emitter and photo detector are involved in the transmission and receiving of these LEDs. After the transmitted red (R) and infrared (IR) lights pass through the measuring site and are received at the photodetector, the R/IR ratio is calculated. For example,

  1. a R/IR ratio of 0.5 equates to approximately 100% SpO2,
  2. a ratio of 1.0 to approximately 82% SpO2,
  3.  and a ratio of 2.0 equates to 0% SpO2.

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References and further reading

http://www.oximetry.org/pulseox/principles.htm

http://www.nonin.com/How-Does-a-Pulse-Oximeter-Work

How pulse oximeters work explained simply.

 

Sadness Beyond Reasons

Does it ever happen to you that you suddenly feel sad and lonely even if you are sitting in the middle of a crowd? You become distant from others? Your mind wanders and all you want to do is to look at something far away? Your voice suddenly lacks any emotions? You speak in a low tone, a lonely tone?

There are some days when I feel like it. Maybe that is why I love this picture so much. Maybe that is why I love autumn and lonely benches. Maybe that is why I want wind to breeze through me. Maybe that it why I love looking at the rain droplets running down my glass window.

But then I think. I look around me. Observe my life. Look at all the beautiful things God has blessed me with. Look at family, my uncles, my aunts, my friends. Look at those who love me, care about me, and can sacrifice everything for me. And suddenly realize that I have no legitimate reason to be unhappy. I shouldn’t be unhappy. I should be thankful to Allah for giving me whatever is best for me.

Test: How Well Do You Know Your Environment?

Hi. I am thinking about starting a daily quiz on environment. I hope you enjoy it and that it helps us know more about our environment! Please answer my question by typing in the correct option in the comments section. The winner’s name will be shared in the next quiz along with the correct option.

Which element causes the minamata disease?

a) Arsenic

b) Mercury

c) Cadmium

d) Uranium

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Which Superpower Would You Like To Have?

Recently, I have been watching a T.V show known as “The Flash”. Got me thinking which superpower would I want to have if given the chance!

Now, mind-reading has always been a passion of mine. I sometimes want to penetrate into other people’s mind to see what they think on a perspective. Do others have the same concerns as I do? Is everyone as optimistic as I am? How someone has understood what I meant to say? So, yeah I would love to have mind reading and controlling capabilities like Charles Xavier . 

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Also, I would want Flash’s speed so that I can travel without the help of an airplane or bus. It will also help me get to work early. And yeah I would love to read all the books in a library :-P. 

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Slowing or freezing time. Yeah maybe for the fun of it.

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Enough about what I want. Let me know in the comments section about which superpower would you want to have?

What causes lightning???

A couple of days ago our car was moving through clouds (yeah, it was very cool!). My family was very worried about the dark cloud. They wondered if lightning can occur in the cloud. This got me thinking how lightning forms. I think this post answers my question.

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Lightning begins as static charges in a rain cloud. Winds inside the cloud are very turbulent. Water droplets in the bottom part of the cloud are caught in the updrafts and lifted to great heights where they freeze. Meanwhile, downdrafts in the cloud push ice and hail down from the top of the cloud. When the ice going down meets the water coming up, electrons are stripped off.

The result of this activity is a cloud with a negatively charged bottom and a positively charged top. These electrical fields become incredibly strong, with the atmosphere acting as an insulator between them in the cloud.When the strength of the charge overpowers the insulating properties of the atmosphere, lightning happens.

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As the storm moves over the ground, the strong negative charge in the cloud attracts the positive charges in the ground. These positive charges move up into the tallest objects like trees, telephone poles, and houses. As the negative charge gets close to the ground, a positive charge, called a streamer, reaches up to meet the negative charge. The channels connect and we observe the lightning stroke.

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This infographis provides some interesting info about lightning.

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