A century ago a lucky gold miner might find a nugget as big as an apple and virtually all mined gold was from veins that could seen easily, if you knew where to look. That gold is gone. Now mines squeeze precious flecks from deposits that look to the naked eye to be just plain old rock. Test your knowledge of modern gold mining.
1. Which chemical is used to separate gold from rock?
- Hydrogen peroxide.
- Diet Cherry Vanilla Dr. Pepper.
When cyanide is spayed over pulverized rock, it absorbs gold molecules.
2. How much rock must be unearthed to produce an ounce of gold?
- Hundreds of pounds.
- Tons and tons.
- None, it is picked out of river beds.
In some mines as many as 50 tons of rock must be dug up and pulverized to produce an ounce of gold.
3. What is most mined gold used for?
- Bling bling.
- Dental filings.
- Industrial applications, such as gold-plating electrical contacts.
Bling. 80 to 90 percent of mined gold is used for jewelry.
4. On a potential mining site on the border of Chile and Argentina part of a large deposit of gold lies under three glaciers on the Chile side. What did the mining company propose to do about the chilly Chile gold?
- Pull the ore through holes drilled into the glacier.
- Move the ice to another nearby glacier to expose the deposit.
- Leave the ore in the ground.
The company planned to move the glaciers. Later, after elections in Chile, the new administration required the company to leave the glaciers alone.
5. How much do gold prices vary?
- Average prices are relatively steady from year to year.
- A chart of annual gold prices over the last 30 years looks like a rollercoaster.
- Gold prices have increased each year.
Gold rides a rollercoaster. Prices per Troy ounce in the last 30 years have dipped near $100 in 1976 (just a year earlier they were almost twice that) and spiked to almost $850 in 1980. Currently an ounce of gold is about $600, twice the price of just five years ago.
6. Which weighs more?
- An ounce of gold
- An ounce of potatoes
- An ounce of feathers
Gold is measured in Troy ounces, which weigh 10 percent more than the ounces used for potatoes and feathers.
7. Mercury can used to separate gold from rock. As a result of gold mining hundreds of thousands of pounds of mercury have been introduced to the environment in parts of California, where it continues to kill water dwelling animals and make some kinds of fish unsafe to eat. When did California gold mines stop using mercury?
- About 30 years ago.
- About 100 years ago.
- California mines still use mercury.
Mercury hasn’t been used in California mining for more than 100 years. It is still used by small mines and individual wildcat miners in remote locations such as the Amazon jungle.
8. What is a common side effect when rock is unearthed in gold mines?
- Water that is acidic enough to burn through metal tools.
- Toxic gases that some miners sniff to get high.
- Toxic dust that can drift thousands of miles from the mine site.
Gold is often found in rock that contains sulfides, which when exposed to oxygen, water, and specialized bacteria produce highly acid water.
9. The Summitville gold mine closed in 1990 but continues to contaminate Colorado waterways. What is the estimated cost that taxpayers will pay to clean it up?
- Hundreds of thousands of dollars.
- More than 100 million dollars.
- None, the mining company is responsible for cleaning the site.
The mining company declared bankruptcy and as a result taxpayers will pay about 120 million dollars to clean up the site.
10. What other pollutants are often associated with gold mining?
- Frankincense and myrrh.
- Greenhouse gases such as carbon dioxide, methane, nitrous oxide, and ozone.
- Heavy metals.
Cyanide, in addition to bonding with gold, can release heavy metals -- such as arsenic, lead, cadmium, mercury, manganese, and chromium -- as it is passed through ore. Acid runoff from mines, called acid mine drainage, can also shake heavy metals loose from minerals it passes over.
11. In some remote locations, such as Papua New Guinea, mine waste has contaminated local rivers and coastal fishing areas. What is the source of the contamination?
- Mines disposing of mine waste into rivers.
- Trucks overturning and spilling cyanide into rivers.
- Dams full of mine waste leaking cyanide and heavy metals into rivers.
Some third-world sites are too rainy and too seismically unstable for the dams that are usually used to contain mine waste. Instead mining companies pour tons of mine waste directly into rivers and oceans.
12. Sometimes dams that hold tailings, the slurry of moist ground ore from which gold has been extracted, fail. Six years ago a tailings dam in Romania ruptured, spilling about 100,000 cubic meters of liquid, which was laced with cyanide and heavy metals, into a local water shed. What was the result?
- Many fish and other creatures were killed in nearby lakes and ponds.
- Most fish and other creatures were killed for hundreds of miles of the Danube River system.
- Any animal that contacted the water, as far away as a thousand miles, died.
Virtually all aquatic life in 250 miles of the Danube River system was killed.