Selection and Optimization Mechanism of the Lower Return Roadway Layout in the near Residual Coal Pillar Area

Round 1

Reviewer 1 Report

The deformation and damage characteristics of the lower return road-way in the residual coal pillar zone of the proximity coal seam group are very important. Detailed modelling work carried out by the authors. There is nothing wrong with the overall content, and it can be acceptable with a few minor changes.

1.      The abstract could be more condensed, it is a bit wordy in parts at the present time.

2.      There should be a space between the unit and the number.

3.      Line 178, there is no 0 in the title.

4.      The analysis in Figure. 10b is not clear enough, and also why there is a low point at around 2 m

Author Response

The deformation and damage characteristics of the lower return road-way in the residual coal pillar zone of the proximity coal seam group are very important. Detailed modelling work carried out by the authors. There is nothing wrong with the overall content, and it can be acceptable with a few minor changes.

 (1)The abstract could be more condensed, it is a bit wordy in parts at the present time.

Response: Thanks for this valuable comment. Accordingly, we have revised and adjusted the abstract as a whole.

(2) There should be a space between the unit and the number.

Response: Thanks for this valuable comment. According to your comments, we have modified the introduction section of the revised manuscript. we added a space between the unit and the number.

(3) Line 178, there is no 0 in the title.

Response: Thank you for your comments. Due to a clerical error, the number "0" was added here by mistake, I have corrected it, I am very sorry for this problem here.

(4) The analysis in Figure. 10b is not clear enough, and also why there is a low point at around 2 m

Response: Thank you for your comments. According to your comments, we have analyzed Figure. 10b in detail and made additional explanations in the revised draft, in addition, we believe that it is due to the influence of the residual coal pillar that leads to the lowest point at the 2m position.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper attempts to analyze a practical mining-related pavement performance issue and is generally an interesting topic. However, the article did not provide sufficient background information to help readers appreciate and understand the subject of the article. The authors should consider the following suggestions:

1. The title of the article is unduly long and confusing. Consider trimming it. For instance, deformation and damage are superfluous. Note that deformation is a type of pavement damage.

2. The abstract did not articulate the significance of the research problem, and no recommendations were provided.

3. The discussion section essentially contained a presentation of results, and there was virtually no discussion on their practical significance. 

4. The basis for selecting the dimensions of the pavement system (500m x 500m x 156m), the imposed load (8.7MPa) and the simulation tool utilized for the analysis were not adequately discussed. Please provide some discussion to help readers make sense of the analysis results.

5. In Table 1, kindly correct the units of Tensile Strength.

6. Please provide recommendations.

Thank you.

Author Response

The paper attempts to analyze a practical mining-related pavement performance issue and is generally an interesting topic. However, the article did not provide sufficient background information to help readers appreciate and understand the subject of the article. The authors should consider the following suggestions:

 (1) The title of the article is unduly long and confusing. Consider trimming it. For instance, deformation and damage are superfluous. Note that deformation is a type of pavement damage.

Response: Thanks for this valuable comment. Accordingly, we have changed the title of the article to " Selection and Optimization Mechanism of the Lower Return Roadway Layout in the Near Residual Coal Pillar Area ". Thanks a lot!

(2) The abstract did not articulate the significance of the research problem, and no recommendations were provided.

Response: Thanks for this valuable comment. Accordingly, we have revised and adjusted the abstract as a whole.

(3) The discussion section essentially contained a presentation of results, and there was virtually no discussion on their practical significance.

Response: Thanks for this valuable comment. According to your comments, we have modified the discussion section of the revised manuscript.

(4) The basis for selecting the dimensions of the pavement system (500m x 500m x 156m), the imposed load (8.7MPa) and the simulation tool utilized for the analysis were not adequately discussed. Please provide some discussion to help readers make sense of the analysis results.

Response: Thank you for your comments. According to your comments, we have explained the model dimensions and the stresses applied to the upper surface of the model in the revised version.

 We have used FLAC3D numerical simulation software for modeling and calculations.

The main reason for applying FLAC3D numerical simulation software is that FLAC3D is a fast Lagrangian 3D numerical analysis software based on an explicit finite difference method, which can divide the calculation area into several hexahedral cells with the help of a Lagrangian algorithm, and the cell mesh can be deformed with the material deformation. This software is suitable for simulating the nonlinear mechanical behavior of damage or plastic flow of geological materials when they reach the strength limit or yield limit, especially in the elastic-plastic analysis and large deformation analysis of materials, so we use this software for analysis and calculation.

 (5) In Table 1, kindly correct the units of Tensile Strength.

Response: Thank you for your comments. Due to a clerical error, the unit was written incorrectly, I have corrected it here, I am very sorry for this problem here.

 (6) Please provide recommendations.

Response: On behalf of my co-authors, we thank you very much for giving us an opportunity to revise our manuscript, we really appreciate your positive feedback and the precious comments to enhance the quality of our manuscript entitled “ Analysis of deformation and damage characteristics of the lower return roadway in the residual coal pillar area of the proximity coal seam group and optimization of roadway layout” (ID: processes-2035271).( We have now changed the title of the article to " Selection and Optimization Mechanism of the Lower Return Roadway Layout in the Near Residual Coal Pillar Area ")

We have studied the reviewers’ comments carefully and have made revisions which are marked in red in the paper.

We have tried our best to revise our manuscript according to the comments. Attached please find the revised version, which we would like to submit for your kind consideration.

Author Response File: Author Response.docx

Reviewer 3 Report

Reviewer Comments

Paper title: Analysis of deformation and damage characteristics of the lower return roadway in the residual coal pillar area of the proximity coal seam group and optimization of roadway layout

A manuscript has a practical application and also provides important theoretical for the next studies. The paper can be accepted for publication after providing the corrections mentioned below.

Point 1. The abstract section sounds unclear. It consists of two very long sentences. The abstract should follow the MDPI style of structured abstracts:

- Background (place the question addressed in a broad context and highlight the purpose of the study);

- Methods (describe briefly the main methods);

- Results (summarize the article's main findings);

- Conclusion (indicate the main conclusions or interpretations).

Point 2. Keywords need to be modified. Please use words not combinations of words or phrases.

Point 3. In the Introduction section, an enhanced literature review is required. For this study, the authors have used only 32 literature sources. It seems insufficient for such type of research. What about foreign research?

Point 4. It will be great if the authors show some description in context – Why it is important to conduct this study? Can the expected result be used or implemented within other geological conditions? If yes, then how? What limitations?

Point 5. The aim and the tasks must be highlighted at the end of the Introduction section.

Point 6. Line52. Where Figure 1.5 can be found?

Point 7. Line178. “Research0….” 0 – ?

Point 8. What software was used for modelling? Why selected software was chosen?

Point 9. You should substantiate the boundary conditions.

Point 10. What is the thickness of each lithology rocks?

Point 11. Results are presented very good but discussion is insufficient. Please extend the Discussion section. Here you can compare you results with a previously received and add description of further research.

Point 12. The novelty of the paper must be highlighted in the conclusions section.

Point 13. The references are presented not in MDPI style. You need to reformat existing references with a proper guide.

Point 14. Please consider the suggested research in your paper when enhancing the literature review (experience of authors from Poland, Ukraine and Kazakhstan). I believe they are worth considering in your paper.

Małkowski, P., Niedbalski, Z., Majcherczyk, T., & Bednarek, Ł. (2020). Underground monitoring as the best way of roadways support design validation in a long time period. Mining of Mineral Deposits, 14(3), 1-14. https://doi.org/10.33271/mining14.03.001

Khalymendyk, I., & Baryshnikov, A. (2018). The mechanism of roadway deformation in conditions of laminated rocks. Journal of Sustainable Mining, 17(2), 41-47. https://doi.org/10.1016/j.jsm.2018.03.004

Begalinov, A., Almenov, T., Zhanakova, R., & Bektur, B. (2020). Analysis of the stress deformed state of rocks around the haulage roadway of the Beskempir field (Kazakhstan). Mining of Mineral Deposits, 14(3), 28-36. https://doi.org/10.33271/mining14.03.028

Point 15. In general, the presented article leaves a positive impression and, after eliminating these comments and taking into account the recommendations made, it can be recommended for publication in the journal "Processes".

Author Response

Response to Reviewer 3

A manuscript has a practical application and also provides important theoretical for the next studies. The paper can be accepted for publication after providing the corrections mentioned below.

(1) The abstract section sounds unclear. It consists of two very long sentences. The abstract should follow the MDPI style of structured abstracts:

- Background (place the question addressed in a broad context and highlight the purpose of the study) ;

- Methods (describe briefly the main methods) ;

- Results (summarize the article's main findings) ;

- Conclusion (indicate the main conclusions or interpretations).

Response: Thanks for this valuable comment. Accordingly, we have revised and adjusted the abstract as a whole.

(2) Keywords need to be modified. Please use words not combinations of words or phrases.

Response: Thanks for this valuable comment. Accordingly, we have modified and adjusted the keywords.

(3) In the Introduction section, an enhanced literature review is required. For this study, the authors have used only 32 literature sources. It seems insufficient for such type of research. What about foreign research?

Response: Thank you for your comments. According to your comments, we have supplemented the introduction section of the article by adding some literature citations, your suggestions played a crucial essential role in further improving the article.

(4) It will be great if the authors show some description in context – Why it is important to conduct this study? Can the expected result be used or implemented within other geological conditions? If yes, then how? What limitations?

Response: Thanks for this comment. This paper is based on the premise that a short period of large deformation occurred in the roadway during the excavation of the 30503 working face in Tashan coal mine, and this study analyzes the optimization of the layout of the lower return roadway in the residual coal column area.

The control of the deformation damage of the lower back mining roadway in the residual coal column area has always been a difficult task, because of its complex stress environment, if the roadway is not reasonably arranged, it will lead to roadway support difficulties, large deformation and even cause the occurrence of roof accidents, in order to improve the support effect, the preliminary roadway layout optimization is particularly important.

I believe that the expected results of this paper can be applied under other geological conditions, as long as the stress field in the area where the roadway is located is non-uniform, the ideas presented in this paper can be useful, but in terms of application restrictions, I have considered the degree of deformation and stress distribution of the roadway in the two cases of filling and not filling the roadway near the void area in my previous study, and the results are not satisfactory.

Once again, thank you for your suggestions, and while replying to you, I have been thinking about them, and your suggestions have provided me with new ideas and directions for my subsequent research.

(5) The aim and the tasks must be highlighted at the end of the Introduction section.

Response: Thank you for your comments. According to your comments, we carefully improved the introduction section. In the revised manuscript, clarified the aim and the tasks of the study.

(6) Line52. Where Figure 1.5 can be found?

Response: Thank you for your suggestion, the article initially drew several images in the introduction section, which were removed in the subsequent revision process, but we forgot to change the description in this sentence. We have made the change here and are very sorry for this problem, which we will take to heart in our subsequent research, and again, we thank you for your conscientious attitude.

(7) Line178. “Research0….” 0 – ?

Response: Thank you for your comments. Due to a clerical error, the number "0" was added here by mistake, I have corrected it, I am very sorry for this problem here.

(8) What software was used for modelling? Why selected software was chosen?

Response: We have used FLAC3D numerical simulation software for modeling and calculations.

The main reason for applying FLAC3D numerical simulation software is that FLAC3D is a fast Lagrangian 3D numerical analysis software based on an explicit finite difference method, which can divide the calculation area into several hexahedral cells with the help of a Lagrangian algorithm, and the cell mesh can be deformed with the material deformation. This software is suitable for simulating the nonlinear mechanical behavior of damage or plastic flow of geological materials when they reach the strength limit or yield limit, especially in the elastic-plastic analysis and large deformation analysis of materials, so we use this software for analysis and calculation.

(9) You should substantiate the boundary conditions.

Response: Thanks for this comment. According to your comments, we have explained the model dimensions and the stresses applied to the upper surface of the model in the revised manuscript.

 (10) What is the thickness of each lithology rocks?

Response: Thanks again for your comments. According to your comments, we have added the thickness of each rock layer in the model in the revised version.

 (11) Results are presented very good but discussion is insufficient. Please extend the Discussion section. Here you can compare you results with a previously received and add description of further research.

Response: Thanks for this valuable comment. According to your comments, we have modified the discussion section of the revised manuscript.

 (12) The novelty of the paper must be highlighted in the conclusions section.

Response: Thanks for this valuable comment. Accordingly, we have revised the conclusion section of this paper.

 (13) The references are presented not in MDPI style. You need to reformat existing references with a proper guide.

Response: Thank you for your comments. According to your comments, we have modified the citation format according to MDPI style

 (14) Please consider the suggested research in your paper when enhancing the literature review (experience of authors from Poland, Ukraine and Kazakhstan). I believe they are worth considering in your paper.

Małkowski, P., Niedbalski, Z., Majcherczyk, T., & Bednarek, Ł. (2020). Underground monitoring as the best way of roadways support design validation in a long time period. Mining of Mineral Deposits, 14(3), 1-14. https://doi.org/10.33271/mining14.03.001

Khalymendyk, I., & Baryshnikov, A. (2018). The mechanism of roadway deformation in conditions of laminated rocks. Journal of Sustainable Mining, 17(2), 41-47. https://doi.org/10.1016/j.jsm.2018.03.004

Begalinov, A., Almenov, T., Zhanakova, R., & Bektur, B. (2020). Analysis of the stress deformed state of rocks around the haulage roadway of the Beskempir field (Kazakhstan). Mining of Mineral Deposits, 14(3), 28-36. https://doi.org/10.33271/mining14.03.028

Response: Thank you for your comments. According to your comments, in the introduction section, we have cited all of your suggested citations and researched these citations, which have played a very crucial essential role in the progress of the article.

 (15) In general, the presented article leaves a positive impression and, after eliminating these comments and taking into account the recommendations made, it can be recommended for publication in the journal "Processes".

Response: On behalf of my co-authors, we thank you very much for giving us an opportunity to revise our manuscript, we really appreciate your positive feedback and the precious comments to enhance the quality of our manuscript entitled“Analysis of deformation and damage characteristics of the lower return roadway in the residual coal pillar area of the proximity coal seam group and optimization of roadway layout” (ID: processes-2035271).

We have studied the reviewers’ comments carefully and have made revisions which are marked in red in the paper.

We have tried our best to revise our manuscript according to the comments. Attached please find the revised version, which we would like to submit for your kind consideration.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Dear authors,

I am more than satisfied with the corrections provided by you.

This study is an important contribution to sustainable and safe mining.

Congratulations to the authors.