Subject-specific learning materials

• Resource 1 - What is Gold?
• Resource 2 - Panning for Gold
• Resource 3 - Mount Morgan - processes used to get the gold
• Resource 4 - The Mine Game (for 2 to 4 players)
• Resource 5 - Acid River

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Resource 1: What is Gold?

Gold has been valued by mankind for thousands of years. In Australia from the 1850s onwards gold has had a major impact on the fortune of the country.

Gold is a soft metal that is easily hammered into thin layers or drawn into long wires. This means it is easily drawn into long wires and can be hammered into very thin sheets. Gold, unlike many metals, does not tarnish or corrode. It will last forever.

Throughout history gold has been the sign of wealth. King Tutankhamun of Egypt was buried in a solid gold casket with many priceless gold statues.

See Tutankhamun Boy King or National Geographic for photographs of these golden artifacts and the story of “the boy king”.

Gold is still very important in many modern situations. We are used to its role in money and decorative uses like jewelry but gold also has very important uses in electronics, medicine, avionics and industry.

How much is it worth?

Find out how much gold was mined at Mount Morgan. Find out the day to day price of gold at World Gold Council site. The figures are quoted in US dollars per ounce. How much is this in Australian dollars per ounce. Get today’s exchange rate at XE.com. Select US dollars into Aus dollars. Type the gold price in and calculate the amount.

How much is an ounce? Go to Online Conversion to find out.

How much money was all the gold mined at Mount Morgan worth today?

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Resource 2: Panning for Gold

A placer deposit is a concentration of a gold that has collected in sediments of a stream bed. The weight of gold means that it does settle and accumulate in one place. This can be found by panning. The gold pan is a shallow plate with sloping sides and flat bottom. It is used to wash gold-bearing sediment. It is a slow process and takes a lot of practice to effectively wash away the sediment leaving behind the heavier gold, easily recognisable by its sun-yellow colour.

Nowadays the gold in the streams is often due to slag or tailings dumped from a large- scale commercial gold mining operation and been washed downstream until it has collected.

Also visit: Prospecting for Gold in the United States

How to pan for gold

• Step 1 - Select your site.
  Select your site. The water needs to be slow moving so the gold has time to sink to the bottom. It is also best if the water is caught in a curve of a bank so the gold collects.

• Step 2 - Submerge your pan
  Put a few handfuls of sediment from the bottom of the stream into your pan. Submerge the pan under water and slowly move the pan in circular motions. This will allow lighter material to escape from the pan.

• Step 3 - Panning
  Now most of the lighter material has left the pan lift the pan from the water. Tip the pan slightly and move the water around so it slowly swirls out of the pan. Add more water and repeat.

• Step 4 - Retrieving your gold
  Use a spray or your finger to gently move the sand in the pan to see if you have any gold.

• Step 5 - Try again
  It is easy to pan but not so easy to find gold. Keep trying you will get better with practice and then who knows...

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Resource 3: Mount Morgan - processes used to get the gold

Gold was discovered on Ironstone Mountain by William Mackinlay around 1870. When he went prospecting in the area in his spare time he discovered the ironstone outcrop was gold bearing. He never developed this site and it was not until 1882 that Tom and Ned Morgan visited the area and pegged out a claim.

The full story can be found on the Mount Morgan Experience website or at The Discovery of Mount Morgan.

Processes used:

1. Amalgamation method.
2. Chlorination method.
3. Concentration method, this included grinding, vibration, flotation and eventually sintering.
4. Froth flotation method.
5. Cyanidation
6. Flash smelter

STEP 1 - find a definition for the processes that uses simple phrases to explain.

In nearly 100 years, Mount Morgan yielded a total of 225000 kg of gold, 50000 kg of silver and 360000 tonnes of copper.

From A Brief Account of the Treatment of Mount Morgan Ore.

Research each of these processes in more detail. View the photographs and equipment in the Mount Morgan Museum.

Additional information -

1. Amalgamation:

This method is now forbidden in most countries of the world due to the dangers of using mercury and the waste left in rivers downstream from the plant. The rocky ores are crushed in mills and then mercury amalgamation was used to extract gold (60 %) from the ores. The gold reacts with the mercury and sticks to it and becomes a compound leaving the rock behind. The mercury and the gold can then be separated by heating. See: Treating  Gold  Ores  by  Amalgamation

2. Chlorination

This method consists of blowing chlorine gas over the gold and it dissolves. This solution can be collected and the gold recovered when it precipitates on charcoal.

See: Glossary of gold mining terms

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Resource 4: The Mine Game (for 2 to 4 players)

• Download PDF: Mine Game Cards (126k)

Rules:

The cards are divided into four steps:

• STEP 1 The site to mine
• STEP 2 The material collected
• STEP 3 The equipment used
• STEP 4 The separation process used
• STEP 5 The metal collected

Each player is dealt 5 cards. The rest of the cards are placed in a draw pile, face down, in the centre of the table. The top card is turned over and is placed face up to start the discard pile.

Each player, in turn, takes either the top card from the pile or the top visible card on the discard pile. They select the card they wish to discard and place it on the discard pile.

The aim of the game is to get a card at each step that will join together into a single process in order to successfully mine that material.

Winning combinations are:

The miner cards can be used as anything and replace any step except step 5.

If the game has not been completed once all cards from the pile have been selected, the discard pile should be shuffled and placed as the draw pile again.

The following cards should be printed onto GOLD card and cut out. Laminating would make them last longer.

Also: A wordsearch and a crossword are contained in the Science8-10 resources.

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Resource 5: Acid River

What is an Acid?

All substances can be classed as acid, base or neutral. An acid can be mixed with a base to produce a neutral substance, one that is neither acidic nor basic. Water is normally neutral but if other things are added to it then it can become an acid solution or a basic solution. The degree of acidity is shown on the pH scale.

How do we tell if something is acidic?

Making an indicator solution

We need an indicator, something that changes if an acid touches it. We can make a simple indicator out of certain foods. To make a Purple Cabbage Indicator first coarsely shred a head of purple cabbage. Then place it in a saucepan and fill until its 1/2 full of water. Boil the cabbage for about ten minutes. Strain the liquid into some bottles and refrigerate until ready to use. If very brave, eat the cabbage!

Testing for acidity

To test your substance put a small amount in a small jar and add a teaspoonful of the purple cabbage water. Try it first with Vinegar, Water and Ammonia (from a kitchen cleaner). If it turns red it is an acid, if it stays the same it is neutral and if it goes blue it is a base.

Now test a range of substances, but include lemon juice, soluble aspirin, orange juice, milk, milk of magnesia (or other upset stomach liquid) and put your results in a table.

What kind of substances were acids?

It is also possible to get prepared indicator papers. These are easier to use when testing rivers because you simply dip the paper in the river. We could have made something similar by soaking coffee filter papers in our purple cabbage liquid and letting the paper dry before cutting it into strips.

Acid Mine Drainage, or AMD, is the process where the sulphide containing rocks that have been discarded as tailings or waste from gold or copper mines reacts with oxygen and water to produce sulphuric acid. Mount Morgan due to the size of the mine workings has produced considerable amounts of slag waste and tailings.

The acid flow from the mine waste has considerable effect on the Dee River and the aquatic species that live there.

The pH scale simply assigns a number to the amount of colour change we see on our indicator papers.

• A pH of 7.0 is neutral and means no colour change
• A pH less than 7.0 is acidic
• A pH greater than 7.0 is considered alkaline or basic

The river water is usually considered to be acidic when the pH of the water is less than 5.0. The quality of the water in the 18km downriver of the mine has at times been recorded to have dropped to pH levels around 2.5.

Water Quality Testing

To determine the exact impact of the mine on the local environment we need to look at the effect on the local waterways; in this case, the Dee River. Stream Watch provides a useful guide to testing the quality of the water. Samples need to be collected while visiting Mount Morgan.

We are going to concentrate on pH readings when at Mount Morgan.

Measure the pH of the water at the specified water sites.

When collecting water try to do away from the bank, get someone to hold you, and do not disturb the sediment. Label the bottle with date, position collected and time.