Chemistry in Mining

During Earth Science WeekTM, we went to a lecture by Dr. Innocent Pumure from UCM called “Sonochemical Extraction of Arsenic and Selenium from Pulverized Rocks Associated with Mountaintop Removal Valley Fill (MTR/VF) Method of Coal Mining”.

You may be wondering, what is Mountaintop Removal Valley Fill Mining? First, the excavation company blows up (or strips) the top part of the mountain to remove vegetation and expose the coal seams. The coal seams are then mined through the open cast/strip method, and the extra rock and soil is dumped in nearby valleys called valley fills. It is cheaper and easier to do than regular mining, where they dig a vertical shaft down and do everything through the tunnel, but it blasts the mountain apart and looks ugly. Since 30% of electricity in the USA comes from coal, valley fill mining is still pretty popular.

In 2002, the EPA found too much selenium downstream of a certain mine in West Virginia (we’re not going to say which one). It was over 5 ng/mL, which was the limit back then.[*] 7 years later, there was still an active mine there and the water still had too much selenium. Even worse, the surrounding sediment had 10.7 mg/kg selenium. This could cause problems for the environment later. Due to bioaccumulation, you could say once it’s in there, it’s really in there.

So now we get to the topic of Dr. Pumure’s talk, in which he and his colleagues discovered a way to quickly find out how much selenium and arsenic were in the ground around this mine in West Virginia. When you do a chemical analysis, you usually have to break down the samples in order to measure what is in them. One method to do this would be to take some core samples and do an acid extraction, but that takes a long time and uses a lot of reagents. Sonochemical extraction uses ultrasound energy to accelerate the leaching process that would naturally happen as rocks become weathered. Since it is ultrasound, it does not directly touch the sample, is minimally invasive, and does not need any reagents except water.

Next, he explained the methodology, which means a description of exactly how they did it in the lab: the size of the extraction cells, how much water and power were used (200W/cm3), how long the samples were sonicated, and all the other pertinent information for chemists. Pumure actually spent quite a lot of time finding out the optimal sonicating time to get the best extraction. It turned out the best times for his sample sizes were 20 minutes for Se and 25 minutes for As. That’s really fast![**] Then, he did a comparison to a chemical sequential extraction to make sure that the sonochemical extraction method was getting everything. To summarize, yes it was. Finally, he did a principal component analysis of core samples from different places all over the mountain using this same technique. They found some really interesting trends and correlations, for example, it appears that there is more arsenic in illite clay than other types of clay.

This research has many useful applications. If you were running a mine, you could take samples more frequently to see if your mine is polluting the surrounding environment, and then you could do something about it before the EPA finds out. The method could probably be used for other analytes, too. For other research needs, you could now quickly analyze large batches of mineral samples to get lots of data that would otherwise be too expensive or time consuming to obtain.

[*]The EPA has since lowered the limit and now it is 3.1 ng/mL.
[**]For comparison, some of my colleagues do chemical extractions that take 2 days.

Earth Science Week 2017

earth science week logo

This week (October 8-14, 2017) is Earth Science Week and the theme is “Earth and Human Activity.”

According to

“This year’s event, the 20th annual Earth Science Week celebration, promotes awareness of what geoscience tells us about human interaction with the planet’s natural systems and processes.

“Earth Science Week 2017 learning resources and activities are engaging young people and others in exploring the relationship between human activity and the geosphere (earth), hydrosphere (water), atmosphere (air), and biosphere (life). This year’s theme promotes public understanding and stewardship the planet, especially in terms of the ways people affect and are affected by these Earth systems.”

Be on the lookout for fun activities in schools and in the community to promote awareness of earth science this week, and National Fossil Day this Wednesday.

1917 Geologic Maps

kansas city missouri geologic mapShow-Me Rockhounds member Dan Snow has provided these geologic maps of Kansas City from 1917 which contain topographical, geological, and cross-sectional data. The maps show where to find several different types of rocks common to this area. They are also a great way to see how Jackson County has changed in the last 100 years. The maps are in PDF format and are very high resolution, so please zoom in!

Cross Sections (21 MB)
Jackson County (55 MB)
Kansas City (53 MB)

What Does a Research Geologist Do?

Research Geologist Career Spotlight title
An article originally by Andy Orin found on Lifehacker here:

It’s appealing to think that a geologist spends most of their time scouring remote landscapes with a rock hammer and a magnifying glass, but in reality they spend more time in a laboratory than a Land Rover. The work of a research geologist is eclectic, analytical, and scientific.

To learn a little about the field, we spoke with Circe Verba, Ph.D., a young researcher at the National Energy Technology Laboratory, and who has previously worked with NASA and SETI. Circe is also involved with science outreach and education with high school students, and has even designed a LEGO set depicting what it’s like to be a geologist. Now let’s take a look through the microscope:

Tell us a little about yourself and your experience.

I am a research geologist at the National Energy Technology Laboratory’s (NETL) Office of Research & Development (ORD). I specialize in bridging geochemistry and civil engineering—specifically projects that involve carbon sequestration and wellbore integrity (relevant to mitigating climate change) and understanding the interaction of oil-gas shale in unconventional systems. My expertise is electron microscopy and image analysis.

What drove you to choose your career path?

I had many inspirations as a child; it started with my earth science class with discovering the planets. I had a thirst for knowledge to understand processes at a macroscopic scale down to a micro-scale. Geology is a multidisciplinary science that spans several fields, such as engineering and research, which enabled me to pursue several interests.

How did you go about getting your job? What kind of education and experience did you need?

I wanted to pursue a career that would expand my perception of the universe by conducting research. I participated in high school science clubs which provided a scholarship opportunity to attend college at Oregon State University. Research (nowadays) requires a Ph.D., which took me long nine years. During my undergraduate, I explored astronomy, oceanography, and geology. I studied microbial boreholes in freshwater pillow basalt for planetary applications. Then I started a geology master’s program at Northern Arizona University, studying Martian aeolian [wind erosion] and volcanic features as part of a NASA HiRISE fellowship. Once that program ended, I switched gears and participated in an Oak Ridge Institute for Science and Education (ORISE) post-graduate fellowship in 2009. At NETL I was encouraged to further my education which led to the completion of my Ph.D in 2013, and a permanent job studying engineered systems on Earth.

Verba in the lab with a SEM (Scanning Electron Microscope).

Verba in the lab with a SEM (Scanning Electron Microscope).

What kinds of things do you do beyond what most people see? What do you actually spend the majority of your time doing?

My time depends on what stage the project is at—at the moment I have four projects in different stages. I can spend time in the laboratory conducting experiments, analyzing and characterizing samples under an electron or light microscope, or working on the computer drafting manuscripts for publications. I also spend a lot of time interfacing with other team members and key partners from universities. It is also vital for scientists to communicate with one another on their work at scientific conferences.

What misconceptions do people often have about your job?

One misconception is not about my job, but more about the field. A common joke is that geology is rock for jocks, however, geology can be quite complex. In addition, as a geologist you get a lot of random rocks brought to you hoping for special identification when it’s usually a common rock like an agate (quartz-polymorph).

A close up view of a sample inside a SEM (Scanning Electron Microscope).

A close up view of a sample inside a SEM (Scanning Electron Microscope).

What are your average work hours?

A normal, professional work week—40 hours/week. More if there are deadlines or traveling.

What personal tips and shortcuts have made your job easier?

Spreadsheets are essential for project management to keep track of project tasks or budgets, as well as from a technical stand point to understand chemical analyses and to calculate, graph, and import data.

Another tip is sharing data; part of being a scientist is to not replicate work that has been done or is being conducted. It is then helpful to publish the research or put data onto a database for distribution. We use the Energy Data eXchange (EDX) at NETL.

What do you do differently from your coworkers or peers in the same profession? What do they do instead?

As I said above, I spend more time in the experimental and petrographic laboratory and interpreting the results. I spend less time in the field than my peers, for example, collecting samples, mapping regions, or being on an oil rig. In addition, several of my peers primary focus use applied geophysical modeling or geographic information system (GIS) to capture, store, manage, analyze spatial data. Furthermore, many geologists are in academia, which includes research and teaching.

What’s the worst part of the job and how do you deal with it?

Personally, the worst part of the job is the amount of technical writing required. You undergo a lot of revisions for technical reports and peer reviewed journal articles. I’m a descriptive writer, so I’ve had to learn to reign it in and learn from mistakes.

What’s the most enjoyable part of the job?

The most enjoyable part of the job is when I’m using the microscopes. You get to see details down to a micrometer scale, something the naked eye can’t see. It’s an unseen world that I get to be a part of. It can also be like a micro-treasure hunt to find changes in mineral phases or microorganisms.

What kind of money can one expect to make at your job?

Salary can range depending on your education level and where you are employed. The bottom 10% make $46k whereas the median salary for geologist in all sectors is $84k.

How do you move up in your field?

A geologist can advance their career by getting additional certifications (e.g. registered geologist) or pursue higher education. Specifically where I work, advancement of job positions [would be] into project management, such as technical team coordinator, team lead, or division director.

What advice would you give to those aspiring to join your profession?

The best advice I can give to an aspiring geologist is to never stop learning. Take as many science courses so can to figure out what field interests you, such as geology, engineering, physics, or mathematics. In addition, geography, computer science, environmental science, GIS, and drawing/art courses are also very helpful. Geology is a wide field with many hot topics to explore, including environmental or climate change, energy, geological hazards or mitigation, and mining. Examples of [jobs] in the field are engineering geologist, geochemist, geophysicist, hydrologist, mudlogger, wellsite geologist, environmental consultant, exploration geologist in academia, the oil, gas, petroleum sector, engineering or construction firms, government, museums, and private industry.

The Lego set that Verba designed. There is a figure using a SEM in the lab and another collecting samples of purple crystals in the field.

Vote for her LEGO set here:

I created the Research Geology LEGO set [because] I am also an active participant in Science, Technology, Engineering, and Mathematic (STEM) education by being involved in high school career fairs and science activities. I feel that it is important to find fun ways to encourage children, of both genders, to use critical thinking skills. As an adult, I still play with LEGO, a cobblestone of my childhood. So I created a LEGO set called Research Geology, which highlights my career as a research geologist both in the field and in the laboratory. While I included both genders in my set, I wanted to highlight that women can be scientists too. I strongly believe that we can impact young minds and pave the way for future scientists. We can change the world, one geek at a time.