Study of the Internal Rebreaking Characteristics of Crushed Gangue in Mine Goaf during Compression

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The subject of the paper is undoubtedly interesting. The authors take for granted many aspects that should be described more carefully. I suggest a more rigorous description of materials and methods.

 

1)

The Introduction is confusing.

The authors reported studies related to different type of  tests and materials. The link between them is not clear. The authors also reported studies carried out with the Particle Flow Code or other discrete software (lines  71-73 and 77-78) together with results of lab tests. Are the results of numerical simulations relevant in the context of the paper, which focuses on lab experiments?

Details such as “using an SANS testing machine and steel cylinder” or “steel chamber and 64 a SANS material testing machine” seem to be unnecessary. On the other hand, the results of previous studies should be reported in a more clear and effective way.

Lines 102-119: Do the sentences refer to the study reported in the paper or  refer to literature review.

In the end, the novelty of the paper cannot be appreciated by reading the Introduction.

The Introduction should be reconceived in a more rigorous way, by clearly reporting the results of previous studies, by following a scheme (for instance: type of material, type of test, etc).

 

2)

I had problems in understanding what you tested and the type of tests. My following comments can have no connection with your experiments

Section 2.3. This Section is named “Test Device and Scheme”. However, the first sentences “Manual crushing was conducted in the laboratory, and the gangue crushed according to the particle size… etc” do not belong to a test device nor to test scheme. These sentences describe the procedure used for sample preparation. By the way, the sentence “…to obtain two single mixed particle size loose gangue samples, and then these were combined at equal volume to obtain combined lithology gangue samples” is not clear. The term “two single mixed” is misleading. Do you mean you obtained two samples that after were tested? Furthermore, what do you mean with “were combined…”. I suggest to add a figure with a sketch describing the type of samples you prepared by highlighting the final combination of grain size and type of crushed rock.

Lines 158-160. It is not described the type of test. The term compression test includes a variety of tests: hydrostatic, uniaxial, triaxial, oedometer test. The sentence “was placed into a cylinder” seems to indicate oedometer tests: the samples  are radially constrained by  a steel (?) cylinder to avoid radial strains and the load is applied axially, resulting just in axial strains. Do you confirm?

Furthermore, in the oedometer test the radial stresses are not zero and increases with the axial stress. Did you measure the induced radial strains?

Figure 5. The last stage is named “consolidation stage”. However in the text is compaction stage. Consolidation and compaction are not always interchangeable in Soil Mechanics.

Figure 2. In the caption are reported a), b), c)… However, the pictures have not the correspondent a), b) c)…

Figure 4 reports the strain rate during  compression tests. It is not clear which is the grain size of the three tests carried out on the three types of crushed rock.

 

3)

Lines 287-289 and Figure 7. “The compaction, crushing, and rescreening processes of crushed gangue samples in the goaf..”. Why in the goaf? You analyzed samples prepared in lab. Do the pictures in Figure 7 refer to “naturally” crushed gangues?

Section “3.2.1. AE monitoring results of crushed gangue compaction deformation”. The name of this Section is not understandable. Do you mean “ AE monitoring results of the deformation of the crushed gangue”? the word compaction can be removed, because you tested only compaction.

Lines 307-308 refer to in situ measurement. I intended that you measured in lab. You should connect the similarity between in situ and lab AE measurements with a sentence.

In the field of AE measurement, can you clearly establish a connection between the results in situ and in lab? I think that the measurements are not related in a simple way.

 

 

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Mine Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer :

1.(1) The authors reported studies related to different type of  tests and materials. The link between them is not clear. The authors also reported studies carried out with the Particle Flow Code or other discrete software (lines  71-73 and 77-78) together with results of lab tests. Are the results of numerical simulations relevant in the context of the paper, which focuses on lab experiments?

Modifications: Thanks for the good suggestion. One technique for researching crushed rocks is PFC numerical simulation, which is unrelated to the subject matter of this work. I have made modifications here. Please check and thank you again.

(2) Details such as “using an SANS testing machine and steel cylinder” or “steel chamber and 64 a SANS material testing machine” seem to be unnecessary. On the other hand, the results of previous studies should be reported in a more clear and effective way.

Modifications: Thanks for the good suggestion. I have made modifications here. Please check and thank you again.

(3) Lines 102-119: Do the sentences refer to the study reported in the paper or  refer to literature review.

Modifications: Thanks for the good suggestion. These sentences refer to literature review.

2. (1) Section 2.3. This Section is named. However, the first sentences “Manual crushing was conducted in the laboratory, and the gangue crushed according to the particle size… etc” do not belong to a test device nor to test scheme. These sentences describe the procedure used for sample preparation.

Modifications: Thanks for the good suggestion. I have “Test Device and Scheme” to “Test system”. Please check and thank you again.

(2)I suggest to add a figure with a sketch describing the type of samples you prepared by highlighting the final combination of grain size and type of crushed rock.

Modifications: Thanks for the good suggestion. I have added a schematic diagram here. Please check and thank you again.

(3)Lines 158-160. It is not described the type of test. The term compression test includes a variety of tests: hydrostatic, uniaxial, triaxial, oedometer test. The sentence “was placed into a cylinder” seems to indicate oedometer tests: the samples  are radially constrained by  a steel cylinder to avoid radial strains and the load is applied axially, resulting just in axial strains. Do you confirm? Furthermore, in the oedometer test the radial stresses are not zero and increases with the axial stress. Did you measure the induced radial strains?

Modifications: Thanks for the good suggestion. This paper is a uniaxial compression test of crushed rock samples placed in a self-made steel drum. The self-made steel drum is radially constrained to avoid radial strain, and only axial load is applied to the rock sample, resulting in only axial strain.

(4)Figure 5. The last stage is named “consolidation stage”. However in the text is compaction stage. Consolidation and compaction are not always interchangeable in Soil Mechanics.

Modifications: The fragmented rock sample undergoes rotation, rubbing, and fracturing throughout the uniaxial compression process; following two rounds of quick compaction and slow compaction, it enters the stable compaction stage.

(5)Figure 2. In the caption are reported a), b), c)… However, the pictures have not the correspondent a), b) c)…

Modifications: Thanks for the good suggestion. I have made modifications here. Please check and thank you again.

(6)Figure 4 reports the strain rate during  compression tests. It is not clear which is the grain size of the three tests carried out on the three types of crushed rock.

Modifications: The tests for these three crushed rock types are all mixed particle sizes.

3. (1) Lines 287-289 and Figure 7. “The compaction, crushing, and rescreening processes of crushed gangue samples in the goaf..”. Why in the goaf? You analyzed samples prepared in lab. Do the pictures in Figure 7 refer to “naturally” crushed gangues?

Modifications: Thanks for the good suggestion. It is supposed to be from the goaf as the rock sample I used for the experiment was taken from there. I shattered the cracked rock sample shown in Figure 7 during the experiment, but my explanation was not sufficiently explicit. I've completed the changes. Once again, thank you, and please check.

(2)Section “3.2.1. AE monitoring results of crushed gangue compaction deformation”. The name of this Section is not understandable. Do you mean “ AE monitoring results of the deformation of the crushed gangue”? the word compaction can be removed, because you tested only compaction.

Modifications: Thanks for the good suggestion. I have changed the Section of 3.2.1 to “Evolution of AE parameters during the axial compression”

(3)Lines 307-308 refer to in situ measurement. I intended that you measured in lab. You should connect the similarity between in situ and lab AE measurements with a sentence.

In the field of AE measurement, can you clearly establish a connection between the results in situ and in lab? I think that the measurements are not related in a simple way.

Modifications: Thanks for the good suggestion. It is in fact a challenging point to connect laboratory testing and on-site testing. I haven't made a straight connection as of yet, and that will be the subject of my next research. This is covered in the discussion content as well.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Reviewer 2 Report

Comments and Suggestions for Authors

General Comments:

Clarify the opening sentence to explicitly mention that the research focuses on the compaction and bearing behavior of broken gangues in the goaf, specifically how it affects the movement and failure of overlying strata. Consider restructuring the paragraph to present information in a more organized manner. Start with an introductory sentence summarizing the objective, followed by a structured presentation of the methodology, findings, and conclusions. Define technical terms such as "AE" (acoustic emission) upon first use to enhance reader understanding, especially if the audience may not be familiar with these terms.

Ensure consistency in the use of terminology. For example, use either "compaction" or "compression" consistently throughout the text. Provide specific quantitative findings, such as numerical values for stress, strain, and porosity. This enhances the precision and scientific rigor of the research description.

Clearly articulate the criteria for dividing the compression and AE processes into stages. What defines the transition from one stage to another? Make this explicit for the reader. Ensure a logical flow of ideas. For instance, when discussing the impact of axial pressure on the broken rock samples, establish a clear connection between stress, porosity, and particle behavior.

Consider referencing any figures or diagrams that accompany the study to support visual understanding. If available, mention specific figures that illustrate key findings. Conclude the paragraph with a concise summary of the significance of the research results. How do these findings contribute to understanding the overlying strata and safety management in the goaf? Emphasize the scientific rigor of the research by mentioning the scale of the study, statistical methods employed, or any other relevant details that validate the reliability of the findings.

 

Specific comments:

1.       The novelty part of this research is non-existent or needs to be highlighted.

2.       Add key specific results to attract audience.

3.       The abstract should contain a clear state the research problem studied

4.        The introduction part must present the problem and its scope in a way that the audience should be able to understand the research problem.

5.       The text in some figures and diagrams is not visible

6.       Reduce the number of figures to less than 8

7.       How much confinement is applied to the samples?

8.       In Figure 6 there are waves in the curves obtained. Explain why we see waves near the start of the curve

9.       Explain the parameters used in the mathematical models.

10.   In Figure 13-16, relate the stress-strain with AE.

11.   Relate the results with existing literature

 

12.   Add recommendations and future work

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Authors carried out an interesting study on compression of broken rock, analyzing the results using Fractal dimension and AE. A few issues should be addressed before the manuscript is suitable for publication:

Lines 158-160: please remove these lines, since they were part of the instructions to authors.

Reference #2 is misidentified as #3.

Line 38: Whiten model.

Figure 2: unclear if all fractions prepared were used in the compression tests. Please clarify.

Figure 5: I believe authors meant it is the experimental setup including the AE sensors, not the sensor itself. Also, inform in the captions that measures are given in mm.

In discussing Figure 7 authors may find it useful to consider the analysis of other publications that deal with confined bed breakage. A good example is the recent publication on the subject: 10.3390/min10080666

Lines 228-229: subscripts not properly represented in the variables.

Figure 8: the caption does not represent the content of the figure, which simply shows the difference between intact and broken rock.

Equation (3) requires a proper reference. Indeed, derivations leading to Equations (6) and (7) are not novel and proper references should be included.

Lines 300-301: please inform the stresses that resulted in the size distributions given in Figure 10. Indeed, size distributions of the samples prior to stressing should also be included in each graph, for comparison.

The approach used in measuring the size distribution of the material should be informed in the methodology section.

Line 322: “fitting coefficient”? Please define it properly.

Table 2: please consider removing mass of samples, in grams, in favor of % values, to facilitate comparison. In that case, also maintain a constant number of decimal places.

Line 335: typo in “easiest”.

Authors should discuss their results more in light of the literature: for instance the relationship between AE signal and the stress-strain curve has been analyzed in earlier studies.

Comments on the Quality of English Language

Generally good, with a few typos. 

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The article "Study of the Internal Rebreaking Characteristics of Crushed gangue in Goaf During Compression" is a work written according to the template with all the necessary steps. I also noticed that in this study, a number of 53 bibliographic titles in the field were studied. Personally I'm not impressed, it's like a lab work.

I know the problem mentioned by the authors, it is interesting but also with many risks due to mining excavations. From the accumulated experience, I state that a work must be attractive to bring citations and increase the rating of the magazine as well as the authors.

 

In those regarding the conclusions, they report the results obtained and also indicate future research (I appreciate this a lot because it indicates that the authors have an interest in the field). I would like a complete change of this article, possibly a comparison with another method to take over the allure of a scientific article. Thank you for your understanding and I hope you don't mind the opinions expressed!

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Mine Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer :

The article "Study of the Internal Rebreaking Characteristics of Crushed gangue in Goaf During Compression" is a work written according to the template with all the necessary steps. I also noticed that in this study, a number of 53 bibliographic titles in the field were studied. Personally I'm not impressed, it's like a lab work.

I know the problem mentioned by the authors, it is interesting but also with many risks due to mining excavations. From the accumulated experience, I state that a work must be attractive to bring citations and increase the rating of the magazine as well as the authors.

In those regarding the conclusions, they report the results obtained and also indicate future research (I appreciate this a lot because it indicates that the authors have an interest in the field). I would like a complete change of this article, possibly a comparison with another method to take over the allure of a scientific article. Thank you for your understanding and I hope you don't mind the opinions expressed!

Modifications: Thanks for the good suggestion. I have made some modifications in this manuscript. Please review and provide criticism and correction for any shortcomings.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Reviewer 5 Report

Comments and Suggestions for Authors

It is a pleasure to greet the authors of the article entitled: Study of the Internal Rebreaking Characteristics of Crushed gangue in Goaf During Compression. I have read and reviewed the article proposed for the Journal Applied Sciences.

I consider that the article has a state of major revisions, and to be published it must raise and respond to the following observations. Below, I communicate my impressions and recommendations to further increase the quality of the document submitted for peer review:

1.- I suggest adding the word mine to the title, as explained below: Study of the Internal Rebreaking Characteristics of Crushed Gangue in Mine Goaf During Compression

2.- The abstract of the manuscript must clearly indicate that the article is applicable to mining activity. Write where appropriate the word mining or mine.

3.- It is necessary in the introduction of the article to provide a context of the importance of controlling the conditions of goafs in underground mines, pointing out applications and also considering experiences from different countries in the world, not just China. Consider for example the following articles:

•         Qi, C.; Fourie, A. Cemented paste backfill for mineral tailings management: Review and future perspectives. Miner. Eng. 2019, 144, 106025.

•         Cacciuttolo, C.; Marinovic, A. Experiences of Underground Mine Backfilling Using Mine Tailings Developed in the Andean Region of Peru: A Green Mining Solution to Reduce Socio-Environmental Impacts. Sustainability 2023, 15, 12912.

4.- Eliminate the red color from the text presented in the article, all text must be black.

5.- Check line 41 where the period should be a comma, and also the word gob in line 42, perhaps it should say goaf.

6.- On line 61 it says SANS. What does it mean? Describe the acronym in the text.

7.- The article uses many abbreviations. Therefore, it is necessary to generate a subchapter called a list of abbreviations with a table, a subchapter that must be located after the subchapter called conflicts of interest and before the references chapter. Consider the following example:

Abbreviations

ICTs	Information and Communication Technologies
CAPEX	Capital Costs
OPEX	Operational Costs
masl	Meters above sea level

 

8.- On line 162 it should say Fig.3.

9.- Improve the quality of the text indicated in figure 5.

10.- The discussion chapter should be improved. Currently as it is presented it is very brief. The authors must discuss the results obtained in this research, also point out the limitations of the study, as well as make a comparison of the results obtained with the reviewed literature, in order to validate said results.

11.- A review of the English in the article by a native english person is suggested.

Regards,

Comments on the Quality of English Language

A review of the English in the article by a native english person is suggested.

 

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer :

1. I suggest adding the word mine to the title, as explained below: Study of the Internal Rebreaking Characteristics of Crushed Gangue in Mine Goaf During Compression.

Modifications: Thanks for the good suggestion.. I have made the modifications. Please check and thank you again.

2. The abstract of the manuscript must clearly indicate that the article is applicable to mining activity. Write where appropriate the word mining or mine.

Modifications: Thanks for the good suggestion.. I have made the modifications. Please check and thank you again.

3. It is necessary in the introduction of the article to provide a context of the importance of controlling the conditions of goafs in underground mines, pointing out applications and also considering experiences from different countries in the world, not just China. Consider for example the following articles:

Qi, C.; Fourie, A. Cemented paste backfill for mineral tailings management: Review and future perspectives. Miner. Eng. 2019, 144, 106025.

Cacciuttolo, C.; Marinovic, A. Experiences of Underground Mine Backfilling Using Mine Tailings Developed in the Andean Region of Peru: A Green Mining Solution to Reduce Socio-Environmental Impacts. Sustainability 2023, 15, 12912.

Modifications: Thanks for the good suggestion. I have made the modifications Please check and thank you again.

4. Eliminate the red color from the text presented in the article, all text must be black.

 Modifications: Thanks for the good suggestion. Except for the modifications I made, everything has been changed to black font. Please check and thank you again.

5. Check line 41 where the period should be a comma, and also the word gob in line 42, perhaps it should say goaf.

Modifications: Thanks for the good suggestion. I have made modifications to this area. Please check and thank you again.

6. On line 61 it says SANS. What does it mean? Describe the acronym in the text.

 Modifications: Thanks for the good suggestion. SANS refers to a brand name for a testing machine.

7. The article uses many abbreviations. Therefore, it is necessary to generate a subchapter called a list of abbreviations with a table, a subchapter that must be located after the subchapter called conflicts of interest and before the references chapter.

Modifications: Thanks for the good suggestion. SANS refers to a brand name for a testing machine.

8.On line 162 it should say Fig.3.

Modifications: Thanks for the good suggestion. I have made modifications here. Please check and thank you again.

9. Improve the quality of the text indicated in figure 5.

Modifications:Thanks for the good suggestion. I have made modifications here. Please check and thank you again.

10. The discussion chapter should be improved. Currently as it is presented it is very brief. The authors must discuss the results obtained in this research, also point out the limitations of the study, as well as make a comparison of the results obtained with the reviewed literature, in order to validate said results.

Modifications: Thanks for the good suggestion. I have made modifications here. Please check and thank you again.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

after the revisions the paper is more clear. There are some typos. For instance you should change "confining compression" with "confined compression".

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Mine Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer :

After the revisions the paper is more clear. There are some typos. For instance you should change "confining compression" with "confined compression"

Modifications: Thanks for the good suggestion. I have made modifications here. Please check and thank you again.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have yet to address my earlier comments, suggesting a potential lack of intent to enhance their work. This situation is regrettable, as the opportunity for improvement remains unexplored.

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer:

Modifications: I apologize for not being able to make the required adjustments in a few places the last time. Based on your comments, we have made more revisions, particularly to the introduction. We hope you can give it a second read and offer valuable comments. Many thanks.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Author Response File: Author Response.doc

Reviewer 3 Report

Comments and Suggestions for Authors

Authors improved their manuscript, but a few issues remain:

Modify captions of Figure 1 to: “Schematic diagram of "three vertical zones" of overlying gangue in longwall caving mining.”

Lines 112-113: Modify to “Take out the compacted sample and then screen and weight it again.”

Figure 6: figure caption is not clear, since it is not evident what “different lithology” is!

Table 2: please include unit in size ranges; unclear either what 15-25 stands for!

Line 255: please change to “The fitted result is:”

Lines 261-263: these lines are unintelligible. Please rewrite!

Lines 269-270: please change to “AE parameter evolution properties are quite consistent with the three stages of stress–strain curve.”

Lines 362 and 364: please replace “lithologic” by “lithology”.

Comments on the Quality of English Language

Authors should seek professional review of the entire manuscript, in particular the edits from this round of review. 

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer :

1. Modify captions of Figure 1 to: “Schematic diagram of "three vertical zones" of overlying gangue in longwall caving mining..
2. Lines 112-113: Modify to “Take out the compacted sample and then screen and weight it again.”.
3. Figure 6: figure caption is not clear, since it is not evident what “different lithology” is!
4. Table 2: please include unit in size ranges; unclear either what 15-25 stands for!
5. Line 255: please change to “The fitted result is:”
6. Lines 261-263: these lines are unintelligible. Please rewrite!
7. Lines 269-270: please change to “AE parameter evolution properties are quite consistent with the three stages of stress–strain curve.”
8. Lines 362 and 364: please replace “lithologic” by “lithology”

 Modifications: Thanks for the good suggestion. I have made modifications to the above content Please check and thank you again.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Dear authors, please understand that the article does not have an attractive form for a scientific article. Although you have changed a number of things, it is not enough for me. Will you write me one more time:

- the article resembles the description of a work by some laboratory workers who analyzed "Mine Goaf" but it is not enough to compare these results with

- from a comparison/analogy/parallel made with another material/element, many conclusions could result that will be good/or not, etc.

- or you just want to tell us what a great thing "I goof" is

Author Response

Dear Editors and Reviewers:

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Mine Goaf During Compression.”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as providing important guidance for our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red on the paper. The main corrections in the paper and the responses to the reviewer’s comments are as follows:

Responses to Reviewer:

Dear authors, please understand that the article does not have an attractive form for a scientific article. Although you have changed a number of things, it is not enough for me. Will you write me one more time?

the article resembles the description of a work by some laboratory workers who analyzed "Mine Goaf" but it is not enough to compare these results with

from a comparison/analogy/parallel made with another material/element, many conclusions could result that will be good/or not, etc.

Modifications: Thanks for the good suggestion. Based on your suggestion, I have revised some parts of the manuscript again. The overall structure was based on lateral compression tests on crushed composite gangue samples of different gangue types. Comparative analysis and research were conducted on sandstone, sandy mudstone, and sandstone sandy mudstone combination based on strength, fractal dimension, and acoustic emission characteristics, and relevant conclusions were drawn. Thank you again for your insightful feedback.

A special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Author Response File: Author Response.pdf

Reviewer 5 Report

Comments and Suggestions for Authors

The author has made changes and recommends acceptance of the article.

Comments on the Quality of English Language

Moderate editing of English language required.

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer :

Moderate editing of English language required

Modifications: Thanks for the good suggestion.. I have made the modifications. Please check and thank you again.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

In the revised version, I've observed some alterations, but clarity is lacking regarding the authors' responses to the reviewer's comments. I urge the authors to enhance their replies by providing explicit guidance on the modifications made, including page numbers and line numbers. Despite the authors' assertion of changes, I am still unable to pinpoint the specific revisions in the updated manuscript.

Author Response

Dear Editors and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Study of the Internal Rebreaking Characteristics of Broken Rock in Mine Goaf During Compression”. Those comments or suggestions are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments or suggestions carefully and have made corrections that we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as following:

Responses to Reviewer :

In the revised version, I've observed some alterations, but clarity is lacking regarding the authors' responses to the reviewer's comments. I urge the authors to enhance their replies by providing explicit guidance on the modifications made, including page numbers and line numbers. Despite the authors' assertion of changes, I am still unable to pinpoint the specific revisions in the updated manuscript.

Modifications: I have made some modifications on the basis of the first two revisions. Please review and provide criticism and correction for any shortcomings.

Special thanks to you for your good comments.

We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we marked them in red in the revised paper. We appreciate the Editors/Reviewers’ work earnestly, and hope that the corrections will meet with approval.

Once again, thank you very much for your comments and suggestions.

Yours sincerely,

WEN peng and Yang weiqiang

Author Response File: Author Response.pdf