Welcome to the Moranbah Earth Cache at the Big Red Bucket.
At the listed coordinates you will be standing at the Moranbah Big Red Bucket which signifies the entrance to the mining town of Moranbah.
The Bucket in front of you was known as Bucket 19 and was used at the Peak Downs Mine. It is a drag line Bucket that is used to drag earth at the mine .
Bucket 19 spent 21 years moving over 1.3 million cubic metres of earth before it was retired and voluntarily restored by the mine maintenance crew before being placed here as an entrance marker to Moranbah.
In front of the Bucket you will find pieces of coal that they dig out of the ground here for use in making metals.
The Bowen Basin in Central Queensland where Moranbah sits is known for having the best coal in Australia and 83% of Queensland's coal production comes from the area.
Coal is classified as a sedimentary rock. It is a common non-renewable fuel used mainly in the production of electricity. It is a fossil fuel because it forms from dead plant matter. The quality of coal depends on how it formed; as the organic matter is subjected to greater heat and pressure, the carbon content increases.
Properties
Coal is a combustible rock mainly composed of carbon along with variable quantities of other elements, mostly hydrogen, sulphur, oxygen and nitrogen. Coal occurs as layers, called coal beds or coal seams, that are found between other sedimentary rocks. Coal is slightly denser than water but less dense than most of the rocks of the Earth¿s crust. The density varies depending on how porous (full of holes) the coal is. Sometimes the pores contain a gas called methane.
Coal properties vary depending on how much carbon is in the coal (coal rank). Black coal is so called because of its colour; it varies from having a bright, shiny lustre to being very dull, and from being relatively hard to soft. The term 'black coal' is used in Australia to refer to anthracite, as well as bituminous and sub-bituminous coals. Brown coal is also called lignite; it contains less carbon and so has less chemical potential energy than black coal and has more moisture in it.
| Type of coal / material |
Other names |
Properties
|
Approximate carbon content (dry ash-free basis)
|
|
Peat
|
|
An organic sediment. It is considered to be a precursor of coal. |
Less than 60% |
| Brown coal |
Lignite |
Usually yellow to dark brown in colour and can have a woody appearance or recognisable plant structures in it. |
60 to 70% |
| Black coal |
Sub-bituminous coal |
Black lignite |
Dark brown to black in colour. It does not have a woody appearance and often has alternating bands of dull and bright material. |
70 to 76% |
| Bituminous coal |
Soft coal, steam coal or rock coal. |
A dense, usually black, but sometimes dark brown rock, often with well-defined bands of bright and dull material. The dull bands can contain sedimentary mineral grains. |
76 to 86% |
| Anthracite |
Hard coal |
A harder, glossy black coal. It is the highest rank of coal meaning the carbon content is highest. |
Over 86% |
Brown and black coal are mostly used as a source of fuel for power stations. Burning the coal produces heat which is used to make steam, so the the coal is sometimes called thermal or steam coal. The steam spins turbines to generate electricity. In Australia in 2017 coal was used to produce about 60% of the nation's electricity requirements. Using brown coal for power generation is problematic because of the high water content. It crumbles easily on exposure to the air which reduces its value as a fuel and requires specialised storage. It has also been known to spontaneously combust. Since the 1970s the amount of natural gas used to generate electricity has increased and there has been a gradual decline in the use of coal for power. The amount of greenhouse gases generated by burning gas for energy is far less than the volume produced by burning coal.
Certain types of bituminous coal are used to make an essential raw material for making steel — coke. This type of coal is also called metallurgical (steel making) coal and it is processed to produce coke. Coke is a hard porous substance composed of about 90% carbon, it is vital for making steel which is used in millions of items such as cars, trucks, fire engines, refrigerators and bridges.
Coal and peat is still used for residential and commercial heating in some parts of the world (e.g. Ireland and Finland). In its dehydrated form, peat is a highly effective absorbent for fuel and oil spills on land and water. It is also used as a conditioner for soil to make it more able to retain and slowly release water.
Formation
Coal is formed in sedimentary basins. Sedimentary basins are regions where the Earth has subsided or sunk down. Water and sediments then flow into the basin and they fill with layers of sediments. Australia's black coal resources range from Permian to Jurassic in age (299 to 145 million years old), although most are Permian in age. During this time, the climate was warm in Australia, and Eastern Australia, including the Sydney Basin was covered by large, meandering rivers, marshes, bogs and swamps. The sediments deposited in these environments eventually formed rocks such as shale, sandstone and coal. Brown coal in Australia formed more recently than the black coals. These are mostly of Paleogene age (66 to 23 million years old).
Coal is a sedimentary rock formed when abundant plant material is covered by sediments and the material accumulates faster than it can decay. The weight of the overlying sediments compacts the organic layers, increasing the temperature and pressure, which leads to physical and chemical changes to the plant material. Water, carbon dioxide and methane are produced and escape, so the material becomes progressively enriched in carbon. With increasing time, and higher heat and pressure, the plant material first forms into peat, then is converted into brown coal, then sub-bituminous coal, bituminous coal, and lastly anthracite.
When you are at the location look at the coal in front of you and answer these questions:
1. What colour is the coal? Is it shiny or dull?
2. The coal here is used for metallurgical purposes, using the above information, try to determine what type of coal you are looking at.
4. Also using the above information, determine how long ago you think the coal was formed.
5. Submit a picture of yourself with the big red Bucket with your log (you can cover your face if you wish).
All information regarding coal above was sourced from Geosciences Australia (https://www.ga.gov.au/education/classroom-resources/minerals-energy/australian-energy-facts/coal#heading-3)
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