During the week of July 16th, I was doing much of the same in the RJ Lee concrete world. There were a couple of major projects that had to get done and which project had priority keep getting switched around. No matter what project it was, the same types of work needed to be completed on them. Cutting the different sample pieces and creating lapped and/or polished sections. Something new that I did begin doing during this week was prepping samples for air void analysis. To prepare these samples, one first must make a lapped section. Then you complete black out the polished side with a marker, and roll on a white powder material that then fills into any air void that may be present within the sample. These samples are then taken to machine that counts the amount of white space there is on a sample. Giving us the proportion of air to concrete, which is an important ratio when concrete is mixed. The tedious part about this prep is coloring all the cracks that are not voids with a maker under a microscope. Which is fun at first but after awhile beware you will start seeing spots.
So, thing went on as normal, and these different preps became very routine and everyday practice. It was interesting to feel like I have settled into a place at RJ Lee in such a short time when remembering how many different things go on there on a daily basis. Just as I was getting into a certain routine, a new and very different project came along. This project would get me out of concrete for the time being. This project was for the PLM department of RJ Lee, PLM standing for Polarized Light Microscopy. In this department, samples are prepped and analysis for different petrographic type studies; many having to deal with finding asbestos minerals in different materials. I was super excited to start work on this project because I would get to use a microscope to identify minerals; even if I am just looking for one main mineral which is chrysotile.
The image above is a of chrysotile fiber just like the ones I was picking out over the last week.
Chrysotile is a part of the serpentine mineral group; which are known as TO sheet silicates. TO sheet silicates are known to have a 1:1 layer ratio; meaning that there elemental crystallography repeat in a TO:TO:TO pattern alternating the elements that make up the mineral. What makes chrysotile special is that it’s TO dimensions allow for the mineral to form in layers that curve so that roll into hollow, slender fibers. These fibers are flexible compared to the amphibole asbestos forms making it more popular to use in building material because it could be spun or woven. Chrysotile made up 95% of the asbestos used in America until it was made to phase out starting in 1983 and banned in December 2003. Although it is banned now, there is still plenty of materials that still contain chrysotile and the other asbestos forms. Due to the fact that asbestos is still found in material today, it possible for RJ Lee to complete a lot of projects that have to do with testing whether or not a product contains asbestos.
Bringing us back to the new project I am getting to work on. In order to prep the samples to be looked at under the microscope they had to be treated with deionized water and dilute hydrochloric acid to get rid of the gypsum and calcite. This took three days due to the high number of samples. After all the samples went through the process and were dried they could be sieve into coarse and fine grained material. Then I take each of those and look at it under a stereo microscope and being to pick out any of the white chrysotile fibers I see. This process was started at the beginning of this week and will take me into next week most likely. After I get finished sorting the material, another geologist at RJ begins to do a point count with a petrographic microscope on the sample to find the fibers that could not be picked out by me.
This project, which I got finished picking through today (Aug. 6th) was a little bit more challenging to me than the other projects I have worked on thus far at RJ Lee. I can 100% say that I really working on this project. I was able to develop new skills while still getting to use the geology skills I have learned about at Juniata. It was also nice to be able to work with other geologist and hear their opinions about not only this project but working at RJ in general. At JC this past year, I learned how much I like working with a microscope and identifying minerals in thin section in order to identify how a certain rock body was formed. This project I have be working on over the past week was so exciting for me because I learned that people (geologists) in a industry setting are using the same basic skills that I spent so much time and effort learning this past year. It was just kind of reassuring to me that those skills I have so much fun doing could be very useful to me in my future.
These skills are ones I learned in my mineralogy, petrography, petrology classes, and also my research at Juniata. These classes also taught me how to make and have the thin sections skills that have helped me in concrete world at RJ too. So I just wanted to put a quick note in here how thankful I am to the Juniata College geology staff for setting me up so well to succeed this summer. I am still amazed, as my internship comes to a close at the end of this week, how prepared I was intellectually for all the projects I have completed this summer. I know there is still a ton I have yet to learn in my field but as of right now I feel that I am pretty prepared to enter the work force come graduation.
