Life Cycle Assessment of Boron Industry from Mining to Refined Products

Round 1

Reviewer 1 Report

This study conducted a cradle-to-gate LCA regarding the boron mining process based on Turkey. There are few questions and suggestions regarding the LCA procedure and especially the data quality:

• Authors stated that there are other LCA studies regarding the boron mining process. Is this study's result similar with the previous studies, especially An and Xue (2014), and Wu et al (2017)? It will be great there's some discussions about the differences.
• Uncertainty needs to be discussed.
• What Pedigree scores are missing for the inventories. How do you justify the data quality?
• Sensitivity analysis is required if there are uncertain factors in this LCA.
• It would be great if the authors show the environmental impacts of each life cycle phase and discuss them, instead of showing the environmental contributions of individual process.

Author Response

Reply to reviewers

concerning the manuscript

Life cycle assessment of boron industry from mining to refined products

by Tuğçe Türkbay, Bertrand Laratte, Ayşenur Çolak, Semra Çoruh, Birol Elevli

We are grateful for the comments and questions of the reviewer and have modified the manuscript accordingly. In the following, we reply to the points raised. The corresponding changes were marked up using the track changes in the paper, such that any changes can be easily viewed by the editors and reviewers.

Reviewer 1

Comments:

1. This study conducted a cradle-to-gate LCA regarding the boron mining process based on Turkey. There are few questions and suggestions regarding the LCA procedure and especially the data quality:

Reply: Thank you for your comments.

2. Authors stated that there are other LCA studies regarding the boron mining process. Is this study's result similar with the previous studies, especially An and Xue (2014), and Wu et al (2017)? It will be great there's some discussions about the differences.

Reply: Thank you. We would like to compare our results.

• An and Xue (2014) used LCA method of borax and boric acid derivation from ludwigit and szaibelyite in China. However, the main borate minerals are tincal and colemanite in our study and the reference place for the mining is Turkey. So, we could not compare our results with the study of An and Xue.

• Wu et al. (2021) used LCA method of boric acid production by solvent extraction technique from salt-lake brine. Since the derivation method of boric acid is different from our study, we could not compare our results with the study of Wu et al.

3. Uncertainty needs to be discussed.

Reply: Thank you for the comment. The uncertainty analysis was added in section “4. Discussion”.

4. What Pedigree scores are missing for the inventories. How do you justify the data quality?

Reply: Thank you. The Pedigree Matrix is put in the Supplementary materials.

5. Sensitivity analysis is required if there are uncertain factors in this LCA.

Reply: As we used the directly real data from the literature of the process, we did not conduct any sensitivity analysis. However, the uncertainty analysis has been conducted in order to highlight the data quality of our modelization. The processes have been modelized based on real data used in Turkey and it is difficult to identify some alternative of the processes

6. It would be great if the authors show the environmental impacts of each life cycle phase and discuss them, instead of showing the environmental contributions of individual process.

Reply: Thank you for the comment. Since we used the modelization in SimaPro as system rather than the unit, we do not have the detail of each life cycle phase or one has to remodel all the modelization.

Reviewer 2 Report

The article present a Life cycle assessment of some boron industry products. As ecology is a subject of public interest, such research is very important for both scholarship and industry. Despite being very interesting and accurate in terms of the actual LCI and LCA, the discussion and results still need some work.

 

You write a lot about LCA analysis of other minerals. Maybe it would be interesting to do some comparison between boron and other minerals? Not necessary in this article, but You can use it in future and treat this article as a starting point to another research (as possibilities are really wide). Also I miss some kind of main thought or some general idea behind the article, especially in discussion and conclusions. It looks like some set of unrelated thoughts with no thesis, so I think that you can work on it a little bit more.

 

Also I have some minor comments to the article:

• Line 38: “day by day” is not a really scientific term. It is not a mistake per se, but I find it a little bit disturbing in this context in the article.
• Line 45: Is the year of the publication in brackets really necessary here?
• Lines 45-56: The article you refer to is more than 20 years old. Isn’t it a little bit too old to relate to it precisely?
• Lines 86-87: I do not really know what do you mean by “boron mining in Turkey is considered a case study”.
• Lines 87-89: I am not sure that the information about the companies operating mines are really valuable, especially for non-Turkish.
• Line 97: This map is barely readable. Please make it bigger or just change it to a list, because it is basically a list printed on a world's map. The better option is to present a map with actual deposits' locations, at least a map of Turkey. Please consider adding the actual map of Turkish deposits.
• Lines 99-100 and 105: Please be more specific. I guess that borate deposits, mines and other facilities are presented in the table. Please specify which is which, because now it is does not bring much to the subject.
• Table 1: Please be more specific what do you mean with “Deposit”. Is it the amount of the ore?
• Line 108: Are you sure about the “run-of-borate ore”? Not a run-of-mine borate ore or just borate ore? I think it is enough and it will be pretty understandable.
• Line 118: Again, the “run-of mine” certainly misses something.
• Lines 118-119: Do you mean “overburden”?
• Lines 119-120: I find it a little bit confusing. Is the mining method a drill and blast with LHD transport or is it mechanical mining method using excavators only?
• Lines 117-127: I am not sure if such long description is necessary, as it is a typical open-pit mining process using drill and blast method and LHDs.
• Line 140: This figure might be a little bit larger, as some blocks captions are hard to read.
• Line 153: This figure might be a little bit larger as well.
• Lines 157-159: I miss the accurate goal determination. You write a lot about the scope and the goal looks a little bit neglected.
• Lines 190-191: Is referred data really the most up-to-date?! It is more than 30 years from now!
• Lines 196-205: Did you analyse all of the impact categories or do you just listing them? Do you think that all of them are relevant in this research? I think that this section might be expanded, especially that the data I am asking is also missing in discussion and conclusions.
• Lines 221-222: That's a lot of "impact categories" in one sentence. Moreover, why are they major?
• Lines 226, 235, 237, 239, 241: As it is the essence of your work, the figures should be larger. They are barely readable now. Also why are they scaled from -20% to 120%? If you change it to 0-100(110) it should be easier to read it. Also placing a caption below the chart will make it more clear, as now the diagram is too small and you lose a lot of potential room for the caption.
• Lines 243-287: I am not sure if it is necessary to make single subsections for each of the impact categories. They are really short now. Maybe it would be better to place it all in one section and then just put them in single paragraphs (with bold names maybe?)? Also how about missing impact categories? Why are they omitted here? It is enough to just write why.
• Lines 244-253: If you are listing data maybe it would be more intuitive for a read to actually list it or place it in a table?
• Lines 289-299: Does it really belong to the discussion? Isn't it more like an introduction or eventually an introduction to the results?
• Lines 300-308: Again, you write about the literature. Isn't the literature review a part of the introduction? You do not really discuss results here.
• Line 311: Is the word “totally” really necessary here?
• References 1-7, 19-23, 26-31 and 39: Are those thesis or something? If yes, I think that it would be better to replace them with some articles or book chapters etc. Especially since there are a lot of them in the references.
• Also there is a room for improvement of English and some minor design and layout changes.

Author Response

 

Reply to reviewers

concerning the manuscript

Life cycle assessment of boron industry from mining to refined products

by Tuğçe Türkbay, Bertrand Laratte, Ayşenur Çolak, Semra Çoruh, Birol Elevli

We are grateful for the comments and questions of the reviewer and have modified the manuscript accordingly. In the following, we reply to the points raised. The corresponding changes were marked up using the track changes in the paper, such that any changes can be easily viewed by the editors and reviewers.

Reviewer 2

Comments:

1. The article present a Life cycle assessment of some boron industry products. As ecology is a subject of public interest, such research is very important for both scholarship and industry. Despite being very interesting and accurate in terms of the actual LCI and LCA, the discussion and results still need some work.

Reply: Thank you for your support and comments.

2. You write a lot about LCA analysis of other minerals. Maybe it would be interesting to do some comparison between boron and other minerals? Not necessary in this article, but You can use it in future and treat this article as a starting point to another research (as possibilities are really wide). Also I miss some kind of main thought or some general idea behind the article, especially in discussion and conclusions. It looks like some set of unrelated thoughts with no thesis, so I think that you can work on it a little bit more.

Reply: Thank you so much for the suggestion. It is actually an interesting idea to do a comparative study among the mining processes of different minerals. We will consider it for our following study. Thank you. Besides, we tried to extend the discussion section.

3. Line 38: “day by day” is not a really scientific term. It is not a mistake per se, but I find it a little bit disturbing in this context in the article.

Reply: Thank you. We changed “day by day” with “over time”.

4. Line 45: Is the year of the publication in brackets really necessary here?

Reply: There is a few investigation related to LCA of boron mining. Azapagic’s study is the closest study to ours. Azapagic's study was done 23 years ago and we think that it might be useful to highlight there is no so similar study for a long time after her study.

5. Lines 45-56: The article you refer to is more than 20 years old. Isn’t it a little bit too old to relate to it precisely?

Reply: Thank you. We deleted the excluded parameters in their system boundaries.

6. Lines 86-87: I do not really know what do you mean by “boron mining in Turkey is considered a case study”.

Reply: Thank you for the comment. We changed the sentence: “The majority of borate minerals in the world are located in Turkey. Therefore, the focus has been given to the mining, processing and refining of the borate minerals (tincal and colemanite) in Turkey in this study.”

7. Lines 87-89: I am not sure that the information about the companies operating mines are really valuable, especially for non-Turkish.

Reply: We think that it might be useful to keep this information for better understanding of Table 1 and the supplementary materials.

8. Line 97: This map is barely readable. Please make it bigger or just change it to a list, because it is basically a list printed on a world's map. The better option is to present a map with actual deposits' locations, at least a map of Turkey. Please consider adding the actual map of Turkish deposits.

Reply: Thank you for the comment. We deleted the world’s map and changed it with the actual map of Turkish deposits.

9. Lines 99-100 and 105: Please be more specific. I guess that borate deposits, mines and other facilities are presented in the table. Please specify which is which, because now it is does not bring much to the subject.

Reply: Thank you for the comment. We deleted lines 100-103 to avoid duplication:

10. Table 1: Please be more specific what do you mean with “Deposit”. Is it the amount of the ore?

Reply: We changed “deposit” with “ore reserve”.

11. Line 108: Are you sure about the “run-of-borate ore”? Not a run-of-mine borate ore or just borate ore? I think it is enough and it will be pretty understandable.

Reply: We changed “run-of-borate ore” with “borate ore”.

12. Line 118: Again, the “run-of mine” certainly misses something.

Reply: Thank you. We changed “run-of mine” with “run-of-mine borate”.

13. Lines 118-119: Do you mean “overburden”?

Reply: Yes, we added overburden to make it clear.

14. Lines 119-120: I find it a little bit confusing. Is the mining method a drill and blast with LHD transport or is it mechanical mining method using excavators only?

Reply: Yes, this sentence is confusing. It is for mechanical mining methods, but we decided to shorten the steps of open-pit mining process. Therefore, we deleted this sentence.

15. Lines 117-127: I am not sure if such long description is necessary, as it is a typical open-pit mining process using drill and blast method and LHDs.

Reply: We shortened this part.

16. Line 140: This figure might be a little bit larger, as some blocks captions are hard to read.

Reply: We enlarged the figure a little bit, increased the text size and bolded the text.

17. Line 153: This figure might be a little bit larger as well.

Reply: We enlarged the figure a little bit, increased the text size and bolded the text.

18. Lines 157-159: I miss the accurate goal determination. You write a lot about the scope and the goal looks a little bit neglected.

Reply: Thank you for the comment. We extended the section “2.1. Goal and scope definition of the study”.

19. Lines 190-191: Is referred data really the most up-to-date?! It is more than 30 years from now!

Reply: The data of Eti Maden Boron Company is not available to the public. These literature resources we obtained were the most up-to-date resources that we could access the company's information. We think that within the scope of company confidentiality, the company does not share its data with the public. In addition, the classical open pit mining method is used in boron mining in Turkey. The mining methods used have not changed much. We also have updated old value data inventory, e.g. we used EURO 6 trucks, electricity production mix.

20. Lines 196-205: Did you analyse all of the impact categories or do you just listing them? Do you think that all of them are relevant in this research? I think that this section might be expanded, especially that the data I am asking is also missing in discussion and conclusions.

Reply: We performed the LCA with ILCD characterization methods as recommended by European Commission. This method was used for the LCA of many mining such as aluminium, copper, silver, steel, uranium, and zinc. We extended section “2.3. Life cycle impact assessment (LCIA)”.

21. Lines 221-222: That's a lot of "impact categories" in one sentence. Moreover, why are they major?

Reply: Thank you for the comment. Here, we interpreted the results which are coming from the single score. However, since the single score results are not comparable, we decided to remove these results.

22. Lines 226, 235, 237, 239, 241: As it is the essence of your work, the figures should be larger. They are barely readable now. Also why are they scaled from -20% to 120%? If you change it to 0-100(110) it should be easier to read it. Also placing a caption below the chart will make it more clear, as now the diagram is too small and you lose a lot of potential room for the caption.

Reply: Thank you for your comments. We updated the figures.

23. Lines 243-287: I am not sure if it is necessary to make single subsections for each of the impact categories. They are really short now. Maybe it would be better to place it all in one section and then just put them in single paragraphs (with bold names maybe?)? Also how about missing impact categories? Why are they omitted here? It is enough to just write why.

Reply: Thank you. We deleted the headings for each section. Here, we tried to put the most relevant impact categories related to the boron mining.

24. Lines 244-253: If you are listing data maybe it would be more intuitive for a read to actually list it or place it in a table?

Reply: We put this table in the document of supplementary materials.

25. Lines 289-299: Does it really belong to the discussion? Isn't it more like an introduction or eventually an introduction to the results?

Reply: Thank you for the comment. We put lines 289-299 in the section “4. Results”.

26. Lines 300-308: Again, you write about the literature. Isn't the literature review a part of the introduction? You do not really discuss results here.

Reply: Thank you for the comment. We wanted to show to the readers our study is complementary of LCA of boron mining. Since we compare our study and Azapagic’s study between lines 309-327, we think that it is better to highlight the similarities and differences between the two studies.

27. Line 311: Is the word “totally” really necessary here?

Reply: Thank you. We deleted it.

28. References 1-7, 19-23, 26-31 and 39: Are those thesis or something? If yes, I think that it would be better to replace them with some articles or book chapters etc. Especially since there are a lot of them in the references.

Reply: Thank you for the comment. Yes, they are theses. However, there is not that much information about the boron mining process in Turkey in the articles or book chapters. We did a comprehensive study using the theses. We tried to add the report of the boron mining company in Turkey.

• Reference 1 was changed with the report of the boron mining company in Turkey.

• References 1-7 are used to create Table A1 in Appendix.

• Reference 20 was changed with the report of the boron mining company in Turkey.

• References 19-23 are used to create Table 1. In addition to this references, the report of the boron mining company in Turkey is added.

29. Also there is a room for improvement of English and some minor design and layout changes.

Reply: We went through the entire manuscript to eliminate grammatical mistakes. We enlarged some figures thanks to your comments.

Round 2

Reviewer 1 Report

Thanks for the response and revision!

Reviewer 2 Report

All is good, thanks for amendments.