A multifactor coupling prediction model for the failure depth of floor rocks in fully mechanized caving mining: a numerical and in situ study

To study the mining-induced failure depth of floor rocks in a fully mechanized mining caving field affected by different coal seam pitches, mining face lengths, burial depths and aquifer water pressures, multifactor-coupled orthogonal numerical tests on the failure depth of floor rocks were conducted. The numerical results show that the failure depth of floor rocks increases with increasing mining face length, coal seam pitch and burial depth. According to the relationship between failure depth and these impact factors, a multifactor-coupled prediction model for the failure depth of floor rocks was established. In addition, the in situ measurement of the failure depth of floor rocks in the Yitang Coal Mine in Huoxi coal field in Shanxi Province, China, was performed, and the in situ failure depths of floor rocks in the 100 502 (80 m) and 100 502 (180 m) mining faces were approximately 12.50–14.65 m and 17.50–19.20 m, in good agreement with the results of the multifactor prediction model. Furthermore, the sensitivity of each impact factor in the prediction model of the floor failure depth was further analysed by F-test and range analysis, and the impact order of studied factors on the floor failure depth is coal seam pitch > mining face length > burial depth > aquifer water pressure.


Comments to the Author(s)
The manuscript titled "A Multi-factor Coupling Prediction Model for the Failure Depth of Floor Rocks in Fully-mechanized Caving Mining: A Numerical and In-situ Study" presents an interesting work on the failure depth prediction of floor rocks in mining through the methods of numerical tests and field monitoring. The prediction model that established in this paper works well in describing the failure depth of floor rocks in mining under different geological conditions. I would like to recommend this manuscript to be accepted for publication if the following small issues could be settled. 1) In the numerical tests, how did you apply the aquifer water pressure to the coal seam and why? 2) In Table 3, the failure depths of floor rocks in each numerical test are presented, but the data lack of proper units, which makes me confusing.
3) In this field monitoring, how did you tell the floor rocks fail or not? 4) In section 5.1, how was the strain measured? The detailed measurement principle should be clearly stated. 5) In the model validation, both the F-test and range test are used and what is the validation difference between the two tests? 6) The English editing should be improved. 7) The figures should be provided with high-resolution.

21-Jun-2019
Dear Dr Jiang, The editors assigned to your paper ("A Multi-factor Coupling Prediction Model for the Failure Depth of Floor Rocks in Fully-mechanized Caving Mining: A Numerical and In-situ Study") have now received comments from reviewers. We would like you to revise your paper in accordance with the referee and Associate Editor suggestions which can be found below (not including confidential reports to the Editor). Please note this decision does not guarantee eventual acceptance.
Please submit a copy of your revised paper before 14-Jul-2019. Please note that the revision deadline will expire at 00.00am on this date. If we do not hear from you within this time then it will be assumed that the paper has been withdrawn. In exceptional circumstances, extensions may be possible if agreed with the Editorial Office in advance. We do not allow multiple rounds of revision so we urge you to make every effort to fully address all of the comments at this stage. If deemed necessary by the Editors, your manuscript will be sent back to one or more of the original reviewers for assessment. If the original reviewers are not available, we may invite new reviewers.
Please pay attention to the various issues raised by the reviewers. Although their comments are relatively brief, they do raise matters of substance that need to be addressed before we can consider publication. I share the reviewers and Associate Editor concerns about the use of English and suggest that you enlist a native English speaker or professional assistance to get you manuscript into good shape. Remember: if a paper is not well-written, it will not be well-read.
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If you wish to submit your supporting data or code to Dryad (http://datadryad.org/), or modify your current submission to dryad, please use the following link: http://datadryad.org/submit?journalID=RSOS&manu=RSOS-190528 • Competing interests Please declare any financial or non-financial competing interests, or state that you have no competing interests.
• Authors' contributions All submissions, other than those with a single author, must include an Authors' Contributions section which individually lists the specific contribution of each author. The list of Authors should meet all of the following criteria; 1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) drafting the article or revising it critically for important intellectual content; and 3) final approval of the version to be published.
All contributors who do not meet all of these criteria should be included in the acknowledgements.
We suggest the following format: AB carried out the molecular lab work, participated in data analysis, carried out sequence alignments, participated in the design of the study and drafted the manuscript; CD carried out the statistical analyses; EF collected field data; GH conceived of the study, designed the study, coordinated the study and helped draft the manuscript. All authors gave final approval for publication.
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Once again, thank you for submitting your manuscript to Royal Society Open Science and I look forward to receiving your revision. If you have any questions at all, please do not hesitate to get in touch. Dear Authors, Now, we have received two revision reports back from your submitted manuscript. They seem to agree that the quality of the manuscript is good. However, at this point the manuscript still need some major revisions.
Reviewers highlighted 1) several technical aspects that need serious clarifications. And a common recommendation is a 2) strong revision of the English language. I agree with their view, and recommend that the manuscript will be sent back to you pending of major revisions. In particular, I will pay attention to the revision of the English language in any resubmission. I hope you could hire a professional or a native English speaker to improve your manuscript.
Thanks for your patience and also considering RSOS journal for your submission. I hope to see the resubmitted manuscript soon.

Best regards, Pablo
Comments to Author: Reviewers' Comments to Author: Reviewer: 1 Comments to the Author(s) The failure depth of the floor strata is of great significance for ensuring the safe mining over an aquifer. In this paper, a multi-factor coupling orthogonal numerical tests on failure depth of floor strata were performed, the factors impact was analyzed and a mathematics multi-factor prediction model was established. Furthermore, the prediction model was validated by the insitu monitoring results. The results can provide important guidance to coal mining under water pressure and offer a theoretical reference for failure depth control of floor rocks under similar geophysical conditions. Thence, the paper is interesting, and the work of this manuscript is practical and logical. There are some problems to be further improved as follows: 1. The English of the manuscript must be improved seriously. We suggest you to get assistance from colleagues who are well-versed in English. 2. There are too few overseas relevant research review in the Introduction part. 3. The words should be in unified font form in the Table 2. 4. In Fig. 2, the damage zone in the floor is not clear. 5. Does the impact factor influence order on failure depth applicable in the other similar conditions? 6. The paper should be revised following the format specification of the journal.

Reviewer: 2
Comments to the Author(s) The manuscript titled "A Multi-factor Coupling Prediction Model for the Failure Depth of Floor Rocks in Fully-mechanized Caving Mining: A Numerical and In-situ Study" presents an interesting work on the failure depth prediction of floor rocks in mining through the methods of numerical tests and field monitoring. The prediction model that established in this paper works well in describing the failure depth of floor rocks in mining under different geological conditions. I would like to recommend this manuscript to be accepted for publication if the following small issues could be settled. 1) In the numerical tests, how did you apply the aquifer water pressure to the coal seam and why? 2) In Table 3, the failure depths of floor rocks in each numerical test are presented, but the data lack of proper units, which makes me confusing. 3) In this field monitoring, how did you tell the floor rocks fail or not? 4) In section 5.1, how was the strain measured? The detailed measurement principle should be clearly stated. 5) In the model validation, both the F-test and range test are used and what is the validation difference between the two tests? 6) The English editing should be improved. 7) The figures should be provided with high-resolution.

Comments from Editorial Office to Authors:
For more information about language editing services endorsed by the Royal Society, please follow the link below: https://royalsociety.org/journals/authors/language-polishing/ On behalf of the Editors, I am pleased to inform you that your Manuscript RSOS-190528.R1 entitled "A Multifactor Coupling Prediction Model for the Failure Depth of Floor Rocks in Fully mechanized Caving Mining: A Numerical and In Situ Study" has been accepted for publication in Royal Society Open Science subject to minor revision in accordance with the editor's suggestions. The Associate Editor is happy for your paper to be published pending one very small correction, as noted below.
The Editors have recommended publication, but also suggest some minor revisions to your manuscript. Therefore, I invite you to respond to the comments and revise your manuscript.
• Ethics statement If your study uses humans or animals please include details of the ethical approval received, including the name of the committee that granted approval. For human studies please also detail whether informed consent was obtained. For field studies on animals please include details of all permissions, licences and/or approvals granted to carry out the fieldwork.
• Data accessibility It is a condition of publication that all supporting data are made available either as supplementary information or preferably in a suitable permanent repository. The data accessibility section should state where the article's supporting data can be accessed. This section should also include details, where possible of where to access other relevant research materials such as statistical tools, protocols, software etc can be accessed. If the data has been deposited in an external repository this section should list the database, accession number and link to the DOI for all data from the article that has been made publicly available. Data sets that have been deposited in an external repository and have a DOI should also be appropriately cited in the manuscript and included in the reference list.
If you wish to submit your supporting data or code to Dryad (http://datadryad.org/), or modify your current submission to dryad, please use the following link: http://datadryad.org/submit?journalID=RSOS&manu=RSOS-190528.R1 • Competing interests Please declare any financial or non-financial competing interests, or state that you have no competing interests.
• Authors' contributions All submissions, other than those with a single author, must include an Authors' Contributions section which individually lists the specific contribution of each author. The list of Authors should meet all of the following criteria; 1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) drafting the article or revising it critically for important intellectual content; and 3) final approval of the version to be published.
All contributors who do not meet all of these criteria should be included in the acknowledgements.
We suggest the following format: AB carried out the molecular lab work, participated in data analysis, carried out sequence alignments, participated in the design of the study and drafted the manuscript; CD carried out the statistical analyses; EF collected field data; GH conceived of the study, designed the study, coordinated the study and helped draft the manuscript. All authors gave final approval for publication.
• Acknowledgements Please acknowledge anyone who contributed to the study but did not meet the authorship criteria.
• Funding statement Please list the source of funding for each author.
Please note that we cannot publish your manuscript without these end statements included. We have included a screenshot example of the end statements for reference. If you feel that a given heading is not relevant to your paper, please nevertheless include the heading and explicitly state that it is not relevant to your work.
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On behalf of the Editors of Royal Society Open Science, we look forward to your continued contributions to the Journal. In-situ Study" (ID: RSOS-190528). All your comments are valuable and helpful for improving our paper. We have considered your recommendations and the reviewer's comments carefully and have made detailed revisions to our previous manuscript. In our revised submission, the revised parts are highlighted in red for your convenience. The responses to the Associate Editor's recommendation and the reviewer's comments are listed below.

Responses to Associate Editor:
1) Reviewers highlighted 1) several technical aspects that need serious clarifications. And a common recommendation is a 2) strong revision of the English language. I agree with their view, and recommend that the manuscript will be sent back to you pending of major revisions. In particular, I will pay attention to the revision of the English language in any resubmission. I hope you could hire a professional or a native English speaker to improve your manuscript.
Authors' response: Thanks for your comments. According to your suggestion, we have made detailed modifications to our previous manuscript. In our revised version, we rewrote the introduction section to highlight the innovation in our paper, a multifactor coupling prediction model for the failure depth of floor rocks in fully mechanized caving mining. Importantly, we also improved the language editing by the Springer Nature Author Service. Here is the language editing certification.

Responses to reviewer #1:
Reviewer's comments: The failure depth of the floor strata is of great significance for ensuring the safe mining over an aquifer. In this paper, a multi-factor coupling orthogonal numerical tests on failure depth of floor strata were performed, the factors impact was analyzed and a mathematics multi-factor prediction model was established. Furthermore, the prediction model was validated by the in-situ monitoring results. The results can provide important guidance to coal mining under water pressure and offer a theoretical reference for failure depth control of floor rocks under similar geophysical conditions. Thence, the paper is interesting, and the work of this manuscript is practical and logical.
1) The English of the manuscript must be improved seriously. We suggest you to get assistance from colleagues who are well-versed in English.
Authors' response: Thanks for your comments. We are sorry for our improper writing. The language editing in our manuscript have been improved by Springer Nature Author Service. Here is the language editing certification.
2) There are too few overseas relevant research reviews in the Introduction part.
Authors' response: Thanks for your comments. We cite many high-quality papers published in international journals reporting the failure of floor rocks in China because they are of great significant guidance for the failure of floor rocks control. According to your recommendation, we rewrote the introduction section and supplemented several overseas researches to enrich the literature review in our revised version. The detailed revision is listed below.
"Currently, many studies on the failure of floor rocks have been reported since a critical energy-release point was introduced to analyze the bearing capacity and stability principles of the floor rocks in long-term conditions by Santos  [11]. Generally, among the above studies, many impact factors, such as in-situ stress, burial depth and isotropic rocks, were taken into accounts [12][13][14][15], while few studies that include aquifer water have been reported. The failure depth of the floor rocks affected by the mining process is mainly composed of two parts: the direct failure zone formed by the mining stress field and the floor rising zone affected by the aquifer water. The sum of the two is the final failure depth of the floor rocks [16]. However, the effect of aquifer water on the direct failure zone is always ignored. The high-pressure of the aquifer water will cause structural changes in the floor rocks and can eventually lead to the changes in failure depth of floor rocks [17]. Therefore, the influence of the aquifer water on the failure depth of the floor rocks cannot be ignored.
The in-situ measurement of the stress or strain of floor rocks under active mining is the most direct and effective method for determining the deformation and failure of floor rocks [18][19][20]. However, limited by the specific and nonrepeatable geophysical conditions in in-situ monitoring, only certain impact factors could be considered in field measurements. The failure of floor rocks is always the result of several impact factors, and numerical testing is an effective method to take multi-factor coupling into consideration. It is of great significance to study the failure depth of floor rocks affected by multiple impact factors and give the impact order of the factors.
Please see section 2 Introduction. The revisions are marked red.
3) The words should be in unified font form in the Table 2.