At this EarthCache you will need to visit the location given, make some observations, answers some questions and if you are willing, add a photo to your log. Please don’t add photos that will spoil the questions.
Please either message or email the answers to me and feel free to log your find at the same time.
Walverden reservoir
An early map of the area published in 1848, shows a corn mill with a pond at what was still the small village of Bradley (today Nelson) Also a little further north, a sluice appears to feed a mill race to a small pond, across the canal at Hodge Bank. By the time Nelson developed into a mill town water-power had given way to the steam power, however these still required a good supply of water. Walverden Mill (built before 1850), Victoria Mill (1857) and Vale Street Shed (1867) where constructed at sites next to the river in the decades that followed.
The parliamentary act authorising the creation of a reservoir was passed in 1866, construction was delayed as all the bids exceeded the budget of £3196. It was completed by 1869, under the direct management of the water board with a capacity of 250,000 imp gal (1.1 million l). The reservoir still supplies water for the town of Nelson and is now owned and managed by United Utilities.
In order to find the information you need to answer the questions below you will need to read the information below and look at the facing of the dam wall on which you are standing.
Earth cache information.
Stone which contains certain minerals will display the colour associated with that mineral.
Here are some minerals and the colour they would display in the stone that houses them.
Iron
Though we expect iron to be a metal colour, greyish, when it is found in its natural state it will be a rust colour. This is because as soon as the iron (Fe) is exposed to air it oxidises, and become Fe2O3 which is iron oxide, or rust. Consequently when you find iron deposits at surface level, it will be brown. This oxidisation is very fast and can happen as quickly as 24hours. If iron is here you will see some of the faces of the split stone to be rust coloured in large sheets.
Copper
Copper is a lovely red colour when it is smelted and made into jewels or pots. We’re used to seeing it this way but this is not what it looks like when it is dug out of the ground. Copper ore tends to be quite green in colour and this is because the pure copper (Cu) oxidises when it comes into contact with Oxygen to produce Cu2O (there are other derivatives of Copper oxides but they are rare). The process of copper oxidisation is quite slow and from the ore being exposed to air it can take several years to show a clear blue green colour. If there is copper here you will see clear green stripes in the rock strata and chunks of rock which are blue green, even chunks which look like molten bits of metal.
Aluminium
Aluminium ore is called Bauxite and Aluminium (Al) is the most abundant metal on Earth. Despite this, it is expensive, largely because of the amount of electricity used up in the extraction process. Aluminium ore is called bauxite. The bauxite is purified to yield a white powder, aluminium oxide, from which aluminium can be extracted. I would advise that you search for images of Bauxite ore to see if it matches the rock formation you can see before you, however, a quick description is a lumpy rock with what look like marbles embedded in it, there marbles will be pale yellow or white in colour depending how long they have been exposed.
So what metal element is here?
- Please look at the facing stone that has been used to protect the dam wall, describe the construction and colours of the stones used
- Please tell me the metal element that is found in the stones you have described and explain your reasoning
- An easy one, please tell me the height of the wall and what is on top.
Thanks for attempting this cache and if you have the time have a walk round the water, it’s a lovely 1 mile walk. (not a requirement of this cache)
Happy caching
treboR