Acid Mine Drainage

Submitted by Steve DeMers on Tue, 2017-07-11 00:00

Surface area is sometimes a difficult process to understand.   Today we measured the surface area of some sponges and we then made cuts to them and measured the increase.  It was difficult for some as it was pretty early in the morning.  We weren't quite sure where this activity was going.  Idaho City is a sprawled out community in the Boise National Forest.  It has a long history of gold and silver mining since its incorporation in 1862.  It is very evident of this as you drive up highway 21 from Boise.  It is 36 miles of twisting highway to Idaho City.  As you near the city you will notice piles of rock, a lot of them.  These are mining tailings that have been dredged up from the bottom of Mores Creek by a massive dredging machine.  The same process has occurred along Elk Creek which flows through town as well as the Idaho Center for Outdoor Education (ICOE).  The Basin School District runs the ICOE and we camped there for the evening.  Our instructor, Brian Lawless, informed us that we were tenting in an area that had been hydraulicly mined. Placer mining was also very common in the area as well as hard rock mining.  Placer mining is when you remove sediment from the stream bed and run it through a sluice box.  Hard rock mining is when you dig holes into the hillside and remove the material, crush it, and then sluice it.  All three process expose massive amounts of surface area of rock that were not naturally exposed.  Many people, when they think of mining, think that acid is used in the process of mining but in this situation the acid is a byproduct.  By exposing more surface area water can come in contact with you also expose more sulfides, which are commonly found in metal bearing mines.  Ecologically speaking this can cause a pH change to both the surface and ground water making it sometimes unusable.  It is very expensive to clean up when mining companies pull out of an area.  Do you think new mines should be permitted in our watershed?  




First of all, I am starting to regret signing up as a digital learner, because you guys seem to be learning and doing a lot of interesting stuff! What a great question you pose and it would be a great one to throw out to my environmental science students. I could find a few different articles with different perspectives both about the positive and negatives to mining in our state. After the students have read and marked the text I would ask them to pick a side and then use the text to defend their stance. This could be in the form of philosophical  chairs. I think it would be a great culminating event to my mining unit. 

I also wanted to upload an activity I do at the start of my mining unit, but my word doc was not supported. I found something similar online. I have students mine for chocolate chips out of chocolate chip cookie. It's a pretty simple activity but it drives home the point that you make about the effects of mining. 

In terms of your question, here are my two cents. I think mining in our state is necessary because it is a source of revenue and provides jobs. My husband is a water resource engineer and has worked on mining projects , so I know my family relies on this work. But I think we do need to be smart about our growth in the mining industry. Mines come with the risk of environmental disasters and we all know the huge ripple effect that can have on everyone downstream of the mine. I take comfort in knowing there are many regulations that come with establishing a mine. Before the mine is even established, permits have to be secured that regulate the scale of mining operations that can occur in an area and companies are required to have the restoration plan established before they even begin. 



This is a complex and very political subject.  After reading your post and the question you posed, I looked into recent debate about this in our area.  What I found was The CuMo Mine Project which would allow a Canadian company to create 10 miles of roads and 137 drill pads.  


Several groups, including the Idaho Conservation League and Idaho Rivers United, had sued, concerned about potential damage to the watershed that provides 20 percent of Boise's drinking water.  A judge's ruling was based on the fact that the Forest Service had not provided an in-dept environmental assessment before issuing a permit to CuMo.  I attached the two articles that I found related to this.

Carly Grant's picture


Thank you for posting the articles. I had not actually read these, only followed what there was in the news. I agree with the ruling on this case, for now.  First of all, it is a Canadian company that may not really have a vested interest in the local water and the problems that they could cause for the water shed. It is not worth the risk. I am somewhat walking a fine line with my views because I have family that are miners. My father was a phosphate miner back in the day and I have extended family working at the Cortez mine in Nevada. I have also have had a vested interest in a mineral exploration company out of Twin falls. I witnessed first hand what mining can do to an area and how long it can take for land to recover from exploration, especially if it is not done meticulously. 

In the first article they mentioned the mining of Molybdenum, which is a trace mineral that is essential to most all organisms. The trace mineral provides a number of health benefits such as fighting anemia, asthma, and some cancer. The U.S. has about 5.4 million tons of mineable Molybdenite identified and part of that was from a mine located at Thompson Creek in  Challis, Idaho. Moly mines (Molybdenite mines) created about a 1.8 billion dollars worth of revenue in 2014 and so it is understandable as to why people are interested in mining this mineral ( What most people do not understand is that gold, silver, and copper are also found with this mineral and that the profits could be much larger. The jobs and revenue that the mine could create for Idaho is huge and so it is understood as to why a company would want to fight for their claim. For me, the potential damage to a water shed will never outweigh a profit. Water is just way too important. 

I posted an earlier news article concerning the topic. This was the only one that I had heard of before you posted the most recent ones. 

Pam Gibba's picture

I think the right answer to your question for me is it depends on the specifics of what is being mined, what environmental precautions are being taken, and who will profit. I think both of the previous comments by Maddie and Kelly show just how controversial a topic like mining in a watershed can be. I also feel like I can see both sides to the debate without agreeing 100 percent with either side. I understand that mining produces jobs, resources, and profits. I also understand that mining can wreak havoc on the environment and the quality of water resources.

Your question actually reminded me of a film called "Promised Land" from 2012.  This movie highlights the process called fracking. At the time when I saw the film, I thought that there was a lot of thought put into showing how both sides of the debate are affected. More importantly, the film seemed to heavily focus on the question of who profits in these situations. I would never say that I intend to be controversial myself...  But I think that looking at the underlying reasons for creating a new mine would have to be thoroughly explored.  Like I said earlier, it depends.

On a lighter note, the math teacher in me loves the idea of exploring an ever changing expansion of surface area.  How fun would that be to calculate!!!

I am torn with my answer to this question.....

Bethany Updike's picture

This is obviously a heated debate, and one that I heard a lot about growing up in Lowman and attending high school in Garden Valley. The CuMo Project in Idaho City has been in the works since 2004 when the company acquired the claim and the conversation about the potential benefits and costs has been roaring since. The small communities surrounding Idaho City, like Lowman and Garden Valley, stand to benefit economically and socially from the development and opening of the mine. Friends and family in Garden Valley often talk about how the mine will bring new residents to the town becuase of limited housing in Idaho City; they predict families would opt to live farther away from the mine and commute into work. According to the CuMo Project website, the mine would "create 1,000 well-paying direct jobs plus thousands of ancillary and supporting jobs for the community of Boise County." This would be a big economic boom for the county as a whole, and this is what I hear most locals talking about when the topic of the mine comes up.

I worry that the long-term environmental costs are ignored too often at the promise of an influx of jobs and money. As you mentioned in your post, the exposure of acids and sulfides can impact the watershed and make the water unusable. Others have already noted that 20% of Boise's water comes from this watershed, and the possibility of that water being unusable would mean shortages in clean water for the valley. CuMo's website suggests they are doing a full environmental impact study, but the two blocks by federal judges make it seem like the Forest Service and CuMo are rushing through the process and not adequately assessing potential impact on wildlife, flora, and groundwater. There's a lot at stake, and I would rather Boise County didn't take the risks associated with mines.

I am a mathematics teacher, and I am always looking for real world explanations for topics of study in mathematics. One component of Geometry is the study of surface area, and I think the "sponge activity" provides a relatively simple measurement activity that can link the concept of surface area to a real world application - in this case mining waste or tailings. It always helps to be able to see a use for the mathematics we study.

Cheryl and I are long time residents of North Idaho, and we have seen the results of poor, or no, regulation of the mining industry. Virtually the entire town of Kellogg, Idaho was an EPA Superfund site and the watershed involved would empty into Lake Coeur d'Alene. Lake Cd'A is a beautiful body of water and is heavily used for recreation, but it is still advised not to eat any fish taken from the lake due to heavy metal poisoning from the mines upstream on the Coeur d'Alene River, and it has been over 20 years since the cleanup. The first time I ever set foot in Idaho - perhaps about 1972 - I remember crossing into North Idaho from Montana on the freeway across Lookout Pass and dropping down into the valley where Kellogg sits. The hills before entering the valley were lush and thickly forested, but approaching Kellogg they were totally denuded, nothing growing! That was the result of the smelter and the mining operations in the Silver Valley.

At any rate that wasn't this part of the state, but it gives one plenty to ponder about the desirability of new mining operations.

Troy Gleave's picture

I'm a native of North Dakota and have watched from a far the Bakken Oil explosion. The price the people of the state had to pay to allow all the oil frakking to happen was horrilble. I may be reaching on the comparision a bit, but if there is more mining allowed and they find anything that is valuable... the explosion and problems that come with it are way to high of a cost to me. No matter the safe guards they claim to have, no matter the watch they claim to have, no matter the precaustions they claim to have, there will be issues with the environment that the people who live here will have to deal with. The mine tailings, the pH changes, the pollutants in the water. It all adds up and takes a huge toll. This area is thriving and I always want to welcome in more jobs, but I am totally against opening our doors up to people who only care about the profit margin. I also lived in Kellogg for a couple of years and saw the incredible damage those mines did to the area and the amount of money it took to make it look like it wasn't a disaster area was way too much... GO MINE SOMEPLACE ELSE....