Reasonable Working-Face Size Based on Full Mining of Overburden Failure

Round 1

Reviewer 1 Report

1)       Please ask the author team to consider whether the title of the article is appropriate, and please optimize it further.

2)       Explain why there is a difference between the morphological results of physical and numerical simulations?

3)       Further summary optimization of the summary section is recommended.

4)       Further adjustments and optimization of the conclusion section are recommended.

Author Response

Comment 1: Please ask the author team to consider whether the title of the article is appropriate, and please optimize it further.

Reply:After team discussion, the topic is optimized to “Reasonable working face size based on full mining of overburden failure”

 

Comment 2: Explain why there is a difference between the morphological results of physical and numerical simulations?

Reply: In the process of physical simulation, it is greatly disturbed by the outside world. The influence of laboratory conditions, temperature, humidity and human operation of experimental materials will lead to a reasonable difference between the physical simulation results and the numerical simulation results to a certain extent, but the overall regularity is very consistent, which can ensure the reliability of the results.

 

Comment 3: Further summary optimization of the summary section is recommended.

Reply: The summary section has been re-optimized and summarized, as detailed in the summary section of the manuscript.

 

Comment 4: Further adjustments and optimization of the conclusion section are recommended.

Reply: The conclusion part has been re-optimized and summarized, and the details are shown in the conclusion part of the manuscript.

Reviewer 2 Report

This manuscript based on the actual geological conditions of a coal mine, fully considering the quantitative influence of working face length, physical similarity simulation experiment and 3DEC discrete element software were used to study the influence of different working face sizes on the height development of water flowing fractured zone under this geological condition, according to the simulation results, the boundary size of the working face under the fully mining of overburden failure is determined, provide a reference for the selection of reasonable working face size of mine, the mine production efficiency will be improved for further. My detailed comments are as follows:

1. Please noted that your manuscript needs careful editing by someone with expertise in technical English editing paying particular attention to English grammar, spelling, and sentence structure so that the goals and results of the study are clear to the reader.

2.  Lines 179-182 ‘When the length of the working face increases from 150m to 300m,’ It can be seen from Figure 2 that the increase of the length of the working face is a discontinuous process. It is not appropriate to use 150-300m here. Different values should be listed separately.

3. Lines 155-182 .The maximum length of the model is 300cm. Why the length of the working face 150 m....300m are used in  in the paper?.How to convert the length in the model  to actual length of the working face?

4. Lines 225-227 :‘when the length of working face is greater than or equal to 300m’,lines 229:‘When the length of the working face is 300 m'.

5. In  Engineering outline  section: the  average buried depth of 2 # coal seam is  586 m. but  in Physical Similarity Experiment section ,the model height is 130cm，Geometric similarity ratio is 200；in the 3DEC numerical simulation in section ,the moding height is 135m. Why are the Geometric parameters of numerical simulation and similar simulation inconsistent with the buried depth of 2 # coal seam？

6. In the similar simulation（Fig.1）, the depth of the coal seam is 130cm, while in the numerical simulation(fig.5), the depth of the coal seam is 100m.

Author Response

Comment 1: Please noted that your manuscript needs careful editing by someone with expertise in technical English editing paying particular attention to English grammar, spelling, and sentence structure so that the goals and results of the study are clear to the reader.

Reply: The English grammar, spelling and sentence structure of the manuscript have been perfected and revised by professionals. See the manuscript.

 

Comment 2: Lines 179-182 ‘When the length of the working face increases from 150m to 300m,’ It can be seen from Figure 2 that the increase of the length of the working face is a discontinuous process. It is not appropriate to use 150-300m here. Different values should be listed separately.

Reply: " When the working face length increases from 150 m to 300 m, " has been changed to " when the working face length is 150, 200, 250, 300 m, " see lines 155-158 of the manuscript ;

 

Comment 3: Lines 155-182 .The maximum length of the model is 300cm. Why the length of the working face 150 m....300m are used in  in the paper?.How to convert the length in the model  to actual length of the working face?

Reply: The length of the model is converted according to the geometric similarity ratio ( 1 : 200 ), that is, the length of the 300cm model is converted into the actual working face length of 60,000cm ( 600m ), and the boundary coal pillars of 50cm are left on both sides of the model, which is converted into the actual working face length of 200m, that is, the distance that the model can be mined is 300-50-50 = 200cm, which is converted into the actual working face length of 400m.In the experimental process, six working face lengths with obvious overburden caving phenomenon are selected, namely 150m, 200m, 250m, 300m, 350m and 400m.

 

Comment 4: Lines 225-227 :‘when the length of working face is greater than or equal to 300m’,lines 229:‘When the length of the working face is 300 m'.

Reply: The two have been uniformly expressed as ' when the length of the working face is 300m ' ;

 

Comment 5: In Engineering outline  section: the  average buried depth of 2 # coal seam is  586 m. but  in Physical Similarity Experiment section ,the model height is 130cm，Geometric similarity ratio is 200；in the 3DEC numerical simulation in section ,the moding height is 135m. Why are the Geometric parameters of numerical simulation and similar simulation inconsistent with the buried depth of 2 # coal seam？

Reply: The geometric parameters of the similar simulation and numerical simulation are consistent with the buried depth of No.2 coal. In the similar simulation, for the safety of the experiment, the height of the model is limited to 130 cm, which is converted into the actual height of 260 m. The unsimulated strata above are converted into weight and laid on the upper surface of the model by iron brick. In the numerical simulation, the simulated height is 135 m, and the unsimulated rock layer above also applies the corresponding load on the upper boundary of the model. There is no corresponding relationship between the simulated height of the two, but the condition of coal seam buried depth of 586 m can be accurately simulated in the simulation process.

 

Comment 6: In the similar simulation（Fig.1）, the depth of the coal seam is 130cm, while in the numerical simulation(fig.5), the depth of the coal seam is 100m.

Reply: The buried depth of the two is the same, but the positions in the respective models are different. The strata that are not simulated in the respective models are converted into corresponding weights applied to the upper boundary of the model.

Reviewer 3 Report

The paper need major revision. Please consider with reviewer comment at the manuscript attached.

Some additional variable need to be considered into the research scope. 

Comments for author File: Comments.pdf

Author Response

Comment 1:

The abstract need to re-draf with

1. Simplified the background
2. Objective must clear
3. Material and method
4. Result and Discussion
5. Conclusion

The abstract less than 300 words

Reply: The summary has been reorganized according to the expert opinions. See the summary section of the manuscript for details.

 

Comment 2:

①Please improve quality of writing on this manuscript. Difficult to understood form some sentence;

②Format please improved;

③Repeated....please good sentence;

④Please improve sentence. english need to be improved;

⑤English.

Reply: The English grammar, sentence structure and spelling of the whole article have been revised. Please refer to the article for details.

 

Comment 3:

①Objective of the research must be clear.

②Please improve objective of the research

Reply: The research objectives of the manuscript have been further clarified in the summary and introduction. Please refer to the summary or introduction for details.

 

Comment 4:

①The rock mass and orientation of rockmass wasn' considered at the research?

②Rockmass has been not exterminated yet?

③Rockmass orientation has been not considered also at this research?

Reply: The orientation of rock mass and rock mass has an important influence on the stability of rock mass. However, in this study, the rock strata and rock joints are evenly divided in physical simulation and numerical simulation, and the model has boundary conditions. Therefore, the main research is on the macroscopic aspect of the collapse shape and collapse height of the overlying rock, and the orientation of rock mass and rock mass is not taken into account.

 

Comment 5: Detail rockmass is similar for all drilling lane?

Reply: The locations of the four drillings are in the coal walls on both sides of the same roadway, and the geological conditions are very close to the location, so it can be considered that the rock masses of each drilling are similar.

 

Comment 6:

①Conclusion must refer to objective.

②The Conclusion need to simplified.

③Quantitative conclusion is recommended refer from result and discussion section.

Reply: The conclusions have been re-summarized and summarized according to the opinions, which are detailed in the conclusion part of the manuscript.

 

Comment 7: Some additional variable need to be considered into the research scope.

Reply: In the macro aspect, in order to control the variables, only the influence of the length of the working face is considered. In the micro aspect, the design of the model is uniform and the material is consistent, so the direction of the rock mass is not taken into account, and the influence degree in this study is small.

Reviewer 4 Report

The manuscript presented an investigation on the boundary size of fully mining working face based on overburden failure. However, the manuscript is not well organized, and is very hard to understand its meaning. More important, the manuscript lacks forward looking and innovation, the readers in this field may guess the results without referring this manuscript. Therefore, I think the manuscript should be rejected for the present form.

Some more comments are listed as followings:

1. The introduction is not balanced, the research progress in this filed is not well described.

2. Majority of the referred papers are published in Chinese, which may not  suitable for publication in international peer-reviewed academic journals.

3. The language should be extensively edited by an English native speaker.  

Author Response

Comment 1: The introduction is not balanced, the research progress in this filed is not well described.

Reply: The introduction has been re-combed and improved, and the progress made in this research field has been re-summarized and described, as detailed in the introduction of the manuscript ;

 

Comment 2: Majority of the referred papers are published in Chinese, which may not  suitable for publication in international peer-reviewed academic journals.

Reply: Due to the leading position of China 's coal technology in the world, the literature retrieval mainly refers to the domestic literature in related fields. This part has been readjusted, and the retrieval and review of international literature in this field have been strengthened on the original basis. See the introduction and reference section of the manuscript ;

 

Comment 3: The language should be extensively edited by an English native speaker.

Reply: The manuscript has been perfected and revised by professionals on English grammar and sentence structure. See the manuscript for details.

Round 2

Reviewer 2 Report

The authors have substantially revised the paper andaddressed the comments.

Reviewer 3 Report

The revision of manuscripts has been meet with reviewer comment and the paper able to accepted. 

Reviewer 4 Report

The contents of the manuscript has been revised as per the recommended comments/suggestions. The authors have satisfactorily responded to all the comments.