Getting to GZ
Coalmine Road, which you use to access this area and the official viewing area for the Anglesea open-cut coalmine were both closed off a while ago due to fears of a collapse after mining operations undercut the cliff along that side of the pit. The road has recently been fully closed, even to pedestrian access. Unfortunately the fenced off area includes a big chunk of the former viewing area and its information signs, which at the time of this listing, were still there.
However, a decent view can be obtained a couple of hundred metres back down the road, so GZ has been moved there. While the views are not as good as they were from the official area and the information signs are now inaccessible, you can certainly see what's going on and watch the operations of the mine if there's anything going on.
About Coal
Formation of coal has occurred in most prehistoric ages, with the exception of the Permian-Triassic Extinction event of approx 252.28 Million years ago. Coal is the remains of dense prehistoric forests which have become covered in sediment due to flooding and rising sea levels. As the weight of these sediments increased the vegetation became compressed and deprived of oxygen by this heavy mud and often acidic water. In this anaerobic environment and subjected to high pressures, forest remains do not decay as they would on the surface, but form peat, which is a precursor to coal. As the sediment buries the peat more deeply, both pressure and temperature increase and the it undergoes a process called carbonisation, forming coal. Some sources use the term 'coalification' to distinguish this gradual process from the more rapid ones used in charcoal making for example. If a coal deposit is to be mined, then these sediments become what is known as overburden and if the mine is an open-cut like this one, they must be removed for the coal to be extracted.
There are different grades, or 'ranks' of coal, based on their content of volatile materials. Over time, the continued pressure and temperature cause the coal to become denser and harder, changing from the softest true coal, which is brown coal (Lignite) to the hardest (Graphite), which is difficult to ignite and is seldom used as fuel. The hardest coal commonly used as fuel is Anthracite, which is mainly used for heating homes and commercial spaces. While the 'lower ranked' coals are sedimentary rocks, the 'higher ranked' ones have often been subjected to sufficiently high temperature to undergo metamorphosis.
About this mine
The brown coal in the Anglesea deposit is approximately 40 Million years old and these days, is exclusively used in the power station you can see from the GZ area. This station provides 41% of the power used by the Point Henry smelter in Geelong.
Mining operations at the Anglesea open-cut began in 1959 and for the first 10 years, the coal was sold to businesses and homes throughout the region. The power plant came online in 1969 and was recently closed and is currently being decommissioned.
To the left of GZ, you can see the active working part of the mine and in front and to the right, the older parts can be seen. To the left, on the far side of the pit, the demarcation line between the overburden and the coal deposit is clearly visible and you can see where this material has been removed in preparation for extraction of the coal. Once extracted, the coal was transported to the power plant, at the rate of 1.1 Million tons per year and was fed into the burners as pulverised coal at the rate of 144 tons per hour. There is an estimated 80 Million tonnes of coal un-mined in the lease area.
While very high in Sulphur at ~3%, the Anglesea brown coal is a very high-energy fuel, compared with other deposits, with an energy content of 15 megajoules per kilogram. At Anglesea, 1 tonne of coal will produce 1.3 megawatt hours of power, while the deposits in the Latrobe Valley take almost twice that amount for the same output.
In addition to the high SO2 emissions due to the high Sulphur content of the coal, it is estimated that the power station produced 1.21 Million tons of CO2 per year and the owners, Alcoa, had plans to extend the mine footprint by approximately 50%. This has created some controversy in the surrounding community. If you look across the mine to the workface, you will see the type of country which would have been mined and form your own judgements about the merits of continuing these operations.
Update for 2016
The mine and power station have now closed down. The power station is in the process of being decommissioned and dismantled. As of November 2016, there is still no fixed plan for how the mine area will be rehabilitated or what will happen with the land. However, Alcoa have given a commitment to do what they can in line with the community's wishes, so over time, the questions for this earthcache may change, but for now, the original questions are still valid.
Update for 2018
The power station has recently been demolished. It took 2 attempts, a couple of months apart to finally demolish the whole structure. The chimney stack has been left and will remain standing as part of a historical display to be erected on the site. As yet, no final plan has been agreed to for the site. At this stage, the original questions remain valid.
To Claim This Cache
Please email me the answers to the following questions
Note: I will delete any logs where I don't receive the answers to the questions within a week of the log, unless you let me know there will be a delay because you're on the road with no Internet or similar reason. If you would like a reply, please ensure you send your email address along with the message.
Q1:Coalmines frequently use either an overland conveyor system, or trucks to transport the coal from the working face to nearby power stations. How do you think was this done at Anglesea ?
Q2:Looking to the left, you can see the distinction between the overburden and the coal itself. Please describe what you see and how you can tell which is which.
Q3:The process of mining involved removing the overburden from the coal deposit. What do you think they did with this material ? Where is it put and what ultimately happens to it ?
Q4:Was there any activity in the mine the day you were there ? If so, what was happening ?
Note that while it's not possible to require a photo, it would be greatly appreciated if you could include a photo with your log of you at GZ, or just the view on the day you were there.