Form a Hypothesis

Now we should have an understanding of the Chemistry involved in Acid Mine Drainage. If you are still a bit shakey, then remember these key points:

1. Acid enters streams from abonded mine sites.
2. The acid creates a number of effects which destroy river ecology.
3. Yellow Boy is characteristic of acidified rivers.
4. Lime (CaCO₃) can be used to remediate rivers.

Keeping these in mind, especially the first point, let's look at the map to the right. There are five points marked. The first point is upstream of the coke ovens, and the water here seems clear. Point 2 is near the coke ovens, and is suspected to be acidic because of the years of burning coal in the area. Point 3 is downstream from the coke ovens. If the water near the coke ovens is acidic, then when it joins the river, it will add acid to the river. But the river has a lot of good water in it already, and so it will dilute any acidic water that joins it some (but not completely). Point four is on a stream running out of an abandoned coal mine; it is highly suspect of acidity. Finally, point five is downstream from both the coke ovens and where the coal mine stream empties into the river; what can you suspect about it's acidity?

Take out a piece of paper and make a diagram like the on the left on it. Now, think about how much acidity you might expect at each of the sites on the map. You can't know specific values, like 10mg/L, yet, but you can make a prediction about how much acid there is at each site relative to the other sites. Assign each site a number from 1 to 5, with 1 being almost no acid, and 5 being very acidic, and put that number in your Acidity column. Write a few sentences explaining why you assigned each site the number you did.

Now, let's go back to what you learned about the Carbonate Curve. Remember how Acidity (as represented by H⁺) and Alkalinity were inversely proportional? Going on what you suspect to be true about acidity at each site, assign each site another number from 1 to 5 that represents Alkalinity. Make 1 represent sites where you expect almost no alkalinity and make 5 represent sites with a lot of alkalinity. Again, write a few sentences explaining your choices.

When you've built your hypothesis diagram, continue to Test your Hypothesis.