Xtracting from the Earth Cache EarthCache
Xtracting from the Earth Cache
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You have 3 options to get here:
1. HIke up the Donkey Trail from Hedley
2. Hike up the Power Lines from Hedley to the road and then down the road
3. With either a Quad or very very short wheel based 4x4 you can drive if you have the experience - if not then hike it!
This is an old abandoned mine site, the mine tunnel has collapsed now – but in the olden days they “Extracted” from here – obviously it wasn’t worth pursuing as it is long since collapsed and no further developments were made.
Today we are going to talk about "Acid Mine Drainage" - or what happens to the earth when we drill holes in it, walk away and the water comes out where it originally wasn't intended to.
Acid mine drainage (AMD), or acid rock drainage (ARD), refers to the outflow of acidic water from (usually abandoned) metal mines or coal mines. However, other areas where the earth has been disturbed (e.g. construction sites, subdivisions, transportation corridors, etc.) may also contribute acid rock drainage to the environment. In many localities the liquid that drains from coal stocks, coal handling facilities, coal washeries, and even coal waste tips can be highly acidic, and in such cases it is treated as acid rock drainage. Acid rock drainage occurs naturally within some environments as part of the rock weathering process but is exacerbated by large-scale earth disturbances characteristic of mining and other large construction activities, usually within rocks containing an abundance of sulfide minerals.
Sub-surface mining often progresses below the water table, so water must be constantly pumped out of the mine in order to prevent flooding. When a mine is abandoned, the pumping ceases, and water floods the mine. This introduction of water is the initial step in most acid rock drainage situations. Tailings piles or ponds may also be a source of acid rock drainage.
After being exposed to air and water, oxidation of metal sulfides (often pyrite, which is iron-sulfide) within the surrounding rock and overburden generates acidity. Colonies of bacteria and archaea greatly accelerate the decomposition of metal ions, although the reactions also occur in an abiotic environment. These microbes, called extremophiles for their ability to survive in harsh conditions, occur naturally in the rock, but limited water and oxygen supplies usually keep their numbers low. Special extremophiles known as acidophiles especially favor the low pH levels of abandoned mines. In particular, Acidithiobacillus ferrooxidans is a key contributor to pyrite oxidation.
Metal mines may generate highly acidic discharges where the ore is a sulfide mineral or is associated with pyrite. In these cases the predominant metal ion may not be iron but rather zinc, copper, or nickel. The most commonly mined ore of copper, chalcopyrite, is itself a copper-iron-sulfide and occurs with a range of other sulfides. Thus, copper mines are often major culprits of acid mine drainage.
If possible please post a picture of your gps at the location
In order to claim this cache:
1. E-mail: - How many rooms are in the nearby cabin that you pass to get here
2. What Color is the Oxidation?
3. Why do you think the rock's that are left here are still getting oxidized – even though not in the mine and are on the ground outside?
4. What does the cache site smell like?
5. What kind of mine do you think it was?
6. Observe the rocks on the slope above - what do you notice?
7. Place one of the rocks in the nearby stream - what happens when it interacts with the water?
8. What colors do you notice in the rocks and what minerals do you think the colors represent that are in the rocks?
Additional Hints
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