Science Moab

In 2015, the Animas and San Juan rivers suffered from the infamous Gold King Mine disaster, where almost 3 million gallons of toxic waste spilled into the waterways from an abandoned mine. The acidic waste temporarily turned the waterways orange and led to a years-long reclamation effort.

Author and journalist Jonathan Thompson’s book, “River of Lost Souls: the Science, Politics, and Greed Behind the Gold King Mine Disaster,” explores the history of mining in the San Juan Mountains and its positive and negative effects on communities and ecosystems. Here, Science Moab talks with Thompson about how the Gold King mine spill is only a small part of a larger picture of the extractive industry in the Four Corners.

Fire years to the day after the spill, the State of Utah and the Environmental Protection Agency reached a legal settlement worth at least $220 million in environmental cleanup and monitoring benefits for the area affected by the Gold King mine disaster.

Science Moab: Could you explain what happened with the 2015 Gold King Mine spill and how it related to other mining spills that are entering the rivers in this region?

Thompson: The Gold King mine was last really mined in 1924. Since then, it has just sat there. Three bulkheads, or big plugs, were put into the mine, which was draining 1600 to 2000 gallons per minute of water. Once it was plugged, water started backing up behind it. Within months, the Gold King mine was starting to put out nasty water with a pH of about 2.5: fairly acidic and definitely loaded with quite a bit of metals. Over the years as the EPA was watching it and in the summer of 2015, the EPA decided to take another look at the Gold King mine to figure out what to do next. For some reason, they started digging into the mine with an excavator. It broke through the debris pile into all the water that was backed up inside the mine. Turns out it was 3 million gallons of sediment that had been dissolved and came blasting out into the creek and ultimately into the Animas River and all the way down to Lake Powell.

Science Moab: Could you go a little more into the effects that this has on these different river systems?

Thompson: So the first thing to think about is the acidity. Most aquatic life can’t live in a pH below five and so a lot of these streams that run through Silverton are at 3.5. The acidity alone makes it uninhabitable but the other issue is the fact that there is a huge amount of iron in the water. The iron that does not dissolve occurs as very fine suspended material that gets caught in gills of fish, or it cuts off the light to the plants. It also creates something called ferric hydroxide, or “yellow boy,” which is essentially an orange cement that coats the bottom of a stream. This creates an impossible habitat for aquatic life and bugs.

Science Moab: What are some of the cleanup efforts that are going on?

Thompson: Really, for a big acid mine drainage problem, the only real solution is to treat the water forever. When the water comes out of the mine, it is put into ponds with a bunch of calcium carbonate which raises the pH and so all the metals drop out of solution and mix with the calcium carbonate. For smaller drainages, the water flows like a waterfall over a bunch of limestone, and that lowers the acidity and helps some of the heavy minerals fall out of solution naturally.

Science Moab: Is their likelihood that something like this is going to happen again?

Thompson: There will be blowouts like this again. It’s not that uncommon, because these old mines collapse and you get this buildup of water behind the collapse. The issue is being addressed, but it’s a very slow process and there’s not a very clean solution in most cases.

To learn more and listen to the rest of the interview, visit This interview has been edited for length and clarity.

Science Moab chats with Jonathan Thompson about the Gold King disaster