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Antelope gather at an ISL mine site

​"We live in an unscientific age in which almost all the buffeting of communications and television - words, books, and so on - are unscientific.  As a result, there is a considerable amount of intellectual tyranny in the name of science." ~R. Feynman, 1968 


At left:  Antelope gather at an active ISL mine site in Wyoming. 

Uranium Mining and Recovery Operations Information

​The purpose of this website is to provide scientific information regarding uranium mining.

The goal is to identify misinformation and provide accurate, scientific information.

We do NOT advocate for or against mining.

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 Documents and Publications


 Other Information


 An environmental assessment at an ISL uranium mine in Wyoming - This document gives an overview of the environmental impact of ISL mining.  the restoration of the groundwater after mining is presented on pages 23 and 24.  Page 25 presents information on the one "excursion" that occurred during the previous years, the results of that excursion and corrective action.  The impacts to local wells is also on page 25

 Scientific evidence exists that challenges the statements made in paragraphs 3, 4, and 7 of the

Larimer County Medical Society resolution

 See the Peer Reviewed Studies list here

The Colorado Mining Association letter accurately represents the cited literature.

 The rights of surface owners is not an area where we have expertise, but some interesting information regarding these rights is available from the State of Colorado​


 Miscellaneous Reports


​This project was initiated in August 2007 and the information here is expected to increase as it is screened and gathered.

This page was created as an ongoing compilation of scientific research.

Since it is unusual for people to have training in radiation safety and a proposed uranium In-Situ leach project is located approximately five miles from concentrated population areas, this webpage is an ongoing compilation of the scientific research that has been done and is being done regarding uranium mining.  It is difficult to separate the rhetoric from the scientific information.

The Health Physics faculty, who have formal training in radiation safety and are well aware of the radiation risks associated with uranium mining, hope the information on this page will assist thoughtful people in this process.

This page is provided as a service of Colorado State University and is produced by the Health Physics faculty and the Colorado State University Student Branch of the Health Physics Society.


What is ISL or ISR mining?

A non-technical description:

Millions of years ago uranium was dissolved (solubilized) in water.  As this water moved underground the oxygen within the water was consumed, probably by bacteria and other organic matter, causing the uranium to settle out (precipitate).

In-Situ Leach mining (ISL), or In-Situ Recovery mining (ISR) reverses the process that caused the uranium to settle out.  this is done by pumping water mixed with oxygen and carbon dioxide through the uranium deposits via wells.  In order to reverse the process that caused the uranium to settle out, the water that is pumped into the deposit has oxygen added.

However, if only oxygen is added to the water, the same processes that used up the oxygen in the past will use this new oxygen again and the uranium will not move very far before it re-settles out.

Adding Carbon Dioxide (CO2) suspends uranium in water 

Adding CO2 to the water, in addition to the oxygen, keeps the uranium from coming out of the water.  If you have ever had a soft drink, then you are familiar with carbon dioxide in water - that's what makes the bubbles in your drink!

When the water and uranium mixture is pumped to the surface, the uranium is "filtered" out, via an ion exchanger, and the oxygen and carbon dioxide replenished so that the cycle can repeat.  The "filter" (ion exchanger) is taken away for processing once it is filled with uranium.

The removal of oxygen from the water millions of years ago also caused other metals to settle out.  These metals include arsenic and selenium.  Naturally, these metals will also get into the circulating water.  The mining process does not generate these metals. They circulate with the water as they remove uranium.

Miners are very careful when performing this process, since their profits rely on keeping the uranium in the water that they remove.  If there are any leaks, they would immediately begin losing money, and with uranium worth almost $100 a pound, you can imagine the controls they have!  Since they must control the uranium in order to make a profit, the environment is also incidentally protected.

Leaks are a major loss of profit and also an environmental concern.  Multiple tests are performed on wells to make sure there are no leaks.  Additionally, miners test nearby wells frequently, with instruments that are so sensitive they can detect the gravity from the moon, just like the ocean's high and low tides!

After the uranium is removed, the goal is to return the ground to low oxygen conditions.  This will cause the metals, including selenium and arsenic, to settle out again, and return the ground to original conditions.

In the past this was done using various methods, but today the solution that is injected is one of the favorite food groups - Sugar!  The sugar is pumped into the ground to feed the bacteria that live there.  The bacteria feed on the metals (selenium, arsenic, and any leftover uranium) and cause them to settle out again.  it is thought that these are the same type of bacteria that used up all the oxygen millions of years ago, and are using it up again.

Next, alcohol is pumped in to assist the bacteria in removing the last of the oxygen from the ground.  Off the record, many in the mining industry say "First we feed the bacteria and then get them drunk!"  This method seems to work much better than those used in the past, and is popular because it is very cheap and effective.

Who checks the water for cleanliness?

So who checks the water to make sure the miners cleaned it up?  The state regulators verify that the water has been restored so that it can be used for the same things as it could be prior to the mining.  the regulators must be satisfied, or the mining company will forfeit a bond, usually worth millions of dollars.  The value of the bond is set by the regulators prior to the beginning of mining operations.  Since the regulators work for the state, there is no downside to them rejecting anything that does not meet standards.

ISL process not complex

Overall, the ISL process appears difficult to understand, and uses language like "lixiviant" for the water mixed with oxygen and carbon dioxide.   The reality is that it's not too complex.  The people operating ISL mines are usually cautious and careful in the job they do and have welcomed genuinely concerned visitors to operating sites.  They have been willing to show the precautions they take, and are concerned about their workers and the environment.  At on mine with a staff of 100 employees, 15 of those employees are in the environmental and safety department.

Mining using ISL does change things, but the resulting radiation doses to the public are so low that they are difficult to measure.  The underground water is locally altered but can still be used as if the mining had not occurred.  The long-term surface impact appears to be minimal.

Uranium Toxicity

A good source for scientific information on uranium toxicity is the ATSDR (Agency for Toxic Substances and Disease Registry), a part of the U.S. Department of Health and Human Services, under the Center for Disease Control.

Their complete profile for uranium is linked below.  The "Public Health Statement" portion of the document is an excellent overview of uranium.  A key statement made in the document is on page 9.  "No human cancer of any type has ever been seen as a result of exposure to natural or depleted uranium."

ATSDR Report on Uranium Toxicity - 1999

 Human Uranium Studies

During the late 1800's and early 1900's, uranium was used to treat the symptoms of diabetes.  As a result, several papers were published on the effects of uranium that was ingested (eaten) by humans.  Two of those studies are linked below.  We apologize for the poor quality reproduction of some pages.  there are many additional later uranium studies that we will post as we obtain permission.