Management of Thermal Hazards in Deep Mines in China: Applications and Prospects of Mine Cooling Technology

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The review of the manuscript entitled "Management of thermal hazards in deep mines in China: application and prospect of mine cooling technology"The authors have reviewed extensively almost one hundred papers in the area of the mines cooling, which demonstrates the comprehensive knowledge in the area of study. The authors identify
correctly the deficiencies in this area.

Reviewer’s Comments:

1. There are some unnecessary space numbers in the article. Please check the full text and delete the extra space. Text punctuation please use Chinese punctuation, please check the full text for modification.
2. Section 2.1 of the second chapter of the article classifies the main mine heat sources. In this section, the classification and description of mine heat sources in this section are relatively vague. If not the professionals in this field may not understand, it is suggested to relayout, so that readers can more clearly understand the classification of mine heat sources.
3. Picture 2 talks about the impact of mine heat damage on four aspects. What is the significance of the author's classification? The classification of effects on humans and effects on the environment is not clear. Later, you discuss the impact on the environment, but provide facts related to people's health. So what is the purpose of the above classification? Recommended to modify the picture or content
4. The expression of "our mine cooling technology" mentioned in the first paragraph of chapter 3 of the article is incorrect.
5. The sentence 'Non mechanical cooling mainly adopts ventilation and heat dissipation, heat source control, and natural cold source to cool down' mentioned in section 3.2 of Chapter 3 is incorrect.
6. The definition of "artificial mechanical refrigeration" is not appropriate.
7. 3.22 In the description of roadway thermal insulation materials, the author did not give too many of his own comments, which I think is inappropriate.
8. The text should be noted that your English grammar, spelling and sentence structure.
In general, the paper extensively discusses the application and advantages and disadvantages of mine cooling technology. The authors of the manuscript reviewed the literature on heat processes in deep mines and methods to minimize their negative effects. This is a relevant topic that is not fully developed at the moment.I suggest accepting the article directly after making appropriate modifications.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Document Revision Note

Dear editors and reviewers：

Thank you very much for the valuable opinions of your editors and reviewers. According to the suggestions of reviewing the manuscript, we have revised the original manuscript. For the convenience of review, the revised part is specially expressed in blue font in the article, and the specific content of the revision is as follows:

Review expert opinion 1：

The review of the manuscript entitled "Management of thermal hazards in deep mines in China: application and prospect of mine cooling technology"The authors have reviewed extensively almost one hundred papers in the area of the mines cooling, which demonstrates the comprehensive knowledge in the area of study. The authors identify correctly the deficiencies in this area.

Reviewer’s Comments:

1. There are some unnecessary space numbers in the article. Please check the full text and delete the extra space. Text punctuation please use Chinese punctuation, please check the full text for modification.

According to your suggestion, we deleted the redundant Spaces and corrected the parts with incorrect punctuation marks, and the corresponding modifications have been reflected in the article.

2. Section 2.1 of the second chapter of the article classifies the main mine heat sources. In this section, the classification and description of mine heat sources in this section are relatively vague. If not the professionals in this field may not understand, it is suggested to relayout, so that readers can more clearly understand the classification of mine heat sources.

Thank you very much for your valuable suggestions. We have revised all parts of Section 2.1 of the article, and corrected the non-standard content expression and typesetting problems.Each cause of the heat damage problem is bolded to facilitate readers to better understand the article.

(1)Underground geothermal water release heat

(2)Heat release and air flow heat transfer of surrounding rock in roadway

(3)Heat release from mechanical equipment

(4)Oxidation heat dissipation of coal (coal gangue)

(5)Other factors

3. Picture 2 talks about the impact of mine heat damage on four aspects. What is the significance of the author's classification? The classification of effects on humans and effects on the environment is not clear. Later, you discuss the impact on the environment, but provide facts related to people's health. So what is the purpose of the above classification? Recommended to modify the picture or content.

According to your suggestion, we find that Figure 2 is indeed not appropriate in this position, and we delete this unreasonable figure. A table of mechanical cooling technology used in Chinese mines is added, which can increase the persuasion of the article.

4. The expression of "our mine cooling technology" mentioned in the first paragraph of chapter 3 of the article is incorrect.

Many thanks to the reviewer for pointing out my mistake, which has been modified in the original text:The purpose of mine cooling technology is to create a safe and comfortable underground working environment by addressing high temperatures in deep mines.

5. The sentence 'Non mechanical cooling mainly adopts ventilation and heat dissipation, heat source control, and natural cold source to cool down' mentioned in section 3.2 of Chapter 3 is incorrect.

According to your suggestion, we have changed the name of non-mechanical cooling technology to other mine cooling technology, so that readers can better understand the content of the article. We also deleted the incorrect description and replaced it with ‘Other mine cooling technologies do not require refrigeration equipment, refrigerants, so this method does not require a large amount of energy to provide a cold source for the mine’.

6. The definition of "artificial mechanical refrigeration" is not appropriate.

According to your suggestion, we have corrected the wrong definition in Conclusion 3, and the details of the correction have been reflected in the article.

7. 22 In the description of roadway thermal insulation materials, the author did not give too many of his own comments, which I think is inappropriate.

In response to your suggestion, we have included our views on the development of insulation materials at the end of the text description in section 3.22. The views are as follows' The above studies mainly focus on the research and development of roadway thermal insulation materials and the study of thermal insulation effect, but there is a lack of research on the influence of roadway thermal insulation layer and raw rock temperature on the cooling characteristics of air flow in roadway and the heat regulating ring, and there is no further exploration of the change characteristics of surrounding rock temperature field.In view of this, the study of thermal insulation material in mine roadway should consider the influence of time factor on the temperature field of surrounding rock, so as to provide theoretical basis for the actual design of thermal insulation layer in mine '.

8. The text should be noted that your English grammar, spelling and sentence structure.

Thank you for your suggestion, we have reviewed the article globally. We have polished and modified the sentence structure, English grammar and the expression of professional terms of the article, and the details of the modification have been reflected in the article.

In general, the paper extensively discusses the application and advantages and disadvantages of mine cooling technology. The authors of the manuscript reviewed the literature on heat processes in deep mines and methods to minimize their negative effects. This is a relevant topic that is not fully developed at the moment.I suggest accepting the article directly after making appropriate modifications.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper titled "Management of thermal hazards in deep mines in China: application and prospect of mine cooling technology" provides an overview of the current status, technical applications, and future outlook of thermal hazard management in deep mines in China, offering insights into mine cooling technologies. However, the paper is out of scope of the journal-Water. Moreover, there are some deficiencies that impact the overall quality of the paper:

(1)   The organization of the paper should be refined. For instance, section 4.1 is mainly about the problems. But the sections 4.2, 4.3 and 4.4 are about the cooling methods and geothermal utilization.

(2)   The classification of mine cooling technologies (mechanical & non-mechanical) seems odd to me.

(3)   In section 3.2, the specific technical measures are not clear.

(4)   The paper lacks sufficient data support and experimental validation. For instance, when discussing the advantages and disadvantages of various cooling technologies, the author primarily relies on theoretical analyses and empirical summaries without specific data to back up claims. Additionally, no experimental verification or field test results are mentioned to support conclusions, making them less persuasive.

(5)   Figure 1 shows the coal mine accident fatalities and energy consumption trends in China from 2016 to 2023. However, the paper does not directly cite or analyze these data. What is the coal mine accident fatalities caused by the thermal hazards?

(6)   Figure 3 is unclear with small English letters. Could you explain the flowchart of the mine thermal environment optimization process in words? Additionally, is there a direct correlation between Figure 3 and the preceding content? Is it appropriately placed here?

(7)   When describing different cooling technologies, the paper provides detailed information but is rather brief on specific technical details. It is recommended to strengthen the elaboration of technical details and conduct in-depth analyses with specific case studies.

(8)   When describing intelligent mine ventilation, there is no explanation of mine ventilation's basic principles and workflows.

(9)   The concluding section proposes future development directions for mine cooling technologies. However, it lacks specific examples or case studies to support these viewpoints. Other issues: Most figures are blurry with unclear text. Figures 4, 5, 6, 8, and 9 could benefit from detailed flowchart explanations to facilitate reader understanding. Lastly, there are inconsistencies in reference formatting. Some references, such as author names, publication years, and journal titles, fail to adhere to a uniform style. Standardizing the reference format would improve the paper's overall presentation.

Comments on the Quality of English Language

Fine

Author Response

Review expert opinion 2：

This paper titled "Management of thermal hazards in deep mines in China: application and prospect of mine cooling technology" provides an overview of the current status, technical applications, and future outlook of thermal hazard management in deep mines in China, offering insights into mine cooling technologies. However, the paper is out of scope of the journal-Water. Moreover, there are some deficiencies that impact the overall quality of the paper:

Dear reviewers, we hope that an explanation can be given for this article, and we hope that this review can be published in a Special Issue in Water: Risk Management Technologies for Deep Excavations in Water-Rich Areas, 2nd Edition.Because underground hot water is also the main cause of thermal damage problems in mines, mines choose mechanical cooling methods according to their different conditions. For example, water-cooled cooling is suitable for mines with rich water sources, and mine water inrush can be used as cooling water sources in water-rich areas, while air-cooled cooling is suitable for mines with good ventilation conditions. Therefore, we believe that this article is suitable for journals.

1. The organization of the paper should be refined. For instance, section 4.1 is mainly about the problems. But the sections 4.2, 4.3 and 4.4 are about the cooling methods and geothermal utilization.

Thanks for your valuable suggestions, according to your suggestions, we have revised the organizational content of Chapter 4, and the problems existing in the application of mine cooling technology in Section 4.1 has become a separate chapter.Because it can make our articles more organized.

2. The classification of mine cooling technologies (mechanical & non-mechanical) seems odd to me.

We realize that this classification of mine cooling technology may cause confusion for readers in this field, and we have considered changing the non-mechanical cooling technology to other mine cooling technology based on your suggestion. Mechanical cooling technology achieves the effect of cooling by installing mechanical refrigeration equipment in the mine, while other mine cooling technologies do not require refrigeration equipment and refrigerants, so this method does not require a lot of energy to provide a cold source for the mine.

3. In section 3.2, the specific technical measures are not clear.

Thanks for your suggestion, we have revised the title of section 3.2, changing the non-mechanical cooling technology to other mine cooling technology. In Summary 3.2, we only gave a detailed description of the thermal insulation materials and workers' cooling suits laid in the mine roadway, because these two aspects have not been fully developed at present and have hardly been applied in the mine. But there's no question that these two directions are hot topics right now. At present, it has not been verified whether the thermal insulation material can ensure the temperature control in the mine roadway for a long time. Some workers' cooling suits will release some heat to the environment during the work of the project, and whether the wearing of cooling suits has any effect in the roadway needs to be further studied.

4. The paper lacks sufficient data support and experimental validation. For instance, when discussing the advantages and disadvantages of various cooling technologies, the author primarily relies on theoretical analyses and empirical summaries without specific data to back up claims. Additionally, no experimental verification or field test results are mentioned to support conclusions, making them less persuasive.

Thank you for your valuable suggestions. Our article is an overview of the development of mine cooling technology in China. We consider that the data part of the article may lack some persuasion, so we add a table in the article. The main content of the table is the use and effect of mechanical cooling technology in some mines in China. The content added to the article is as follows:

From the perspective of mine application in China, mechanical refrigeration is the main method to prevent high-temperature mines. The application and implementation effect of mechanical cooling technology in some mines in China are shown in Tab.1. The mine chooses mechanical cooling methods according to its own different conditions, such as water-cooled cooling is suitable for mines with abundant water sources, and air-cooled cooling is more suitable for mines with good ventilation conditions. The widely used mechanical refrigeration technology in high-temperature mines includes water cooling, ice-making systems, and air compression refrigeration[53].

Tab.1. Application of some Chinese mining machinery refrigeration technology

5. Figure 1 shows the coal mine accident fatalities and energy consumption trends in China from 2016 to 2023. However, the paper does not directly cite or analyze these data. What is the coal mine accident fatalities caused by the thermal hazards?

Fig.1.  China's coal mine accident fatalities and energy consumption trends, 2016-2023

According to your suggestion, we have added a description of picture 1 in the article: “ As shown in Figure 1, the rate of safety accidents in China's coal mines decreased significantly from 2016 to 2021, and showed an increasing trend after 2021, indicating that with the development of mining work to the deep in recent years, the safety problems of some deep coal mines have not been solved. In 2023, China's total annual energy consumption will reach 5.72 billion tons of standard coal, and coal consumption will account for 55.3% of total energy consumption. It can be seen that China's economy development still needs coal as the main guarantee for sustainable energy power. Mine cooling technology is the core technology to solve the problem of mine thermal damage. Its technological development level is of great significance to the strategic application of deep resource mining in China in the future. "to ensure that picture 1 makes sense in the article.

6. Figure 3 is unclear with small English letters. Could you explain the flowchart of the mine thermal environment optimization process in words? Additionally, is there a direct correlation between Figure 3 and the preceding content? Is it appropriately placed here?

Fig.8.  Traditional thinking diagram to solve the problem of mine thermal damage

Thanks again for your advice. According to your suggestion, we find that Figure 3 is not suitable for Chapter 3. Now we put Figure 3 in Chapter 4. The theme of this picture is the general idea of dealing with mine thermal damage in China, and we have added a detailed description to this picture: The traditional way to solve the problem of mine heat damage is shown in Figure 3. Firstly, the conventional analysis of mine ventilation heat exchange and cooling, underground heat source and geological survey are carried out. On this basis, the prediction of mine thermal environment and optimization of ventilation network for cooling are carried out. Then, the underground thermal environment is evaluated. When the underground thermal environment does not meet the requirements of thermal comfort standard, the appropriate cooling method is selected according to the mine's own situation, and the cooling effect and cooling cost are analyzed. Finally, the mine ventilation network is optimized after taking cooling measures, and the underground thermal environment is evaluated again. When the underground thermal environment meets the thermal comfort standard, the mine thermal energy utilization is studied.

7. When describing different cooling technologies, the paper provides detailed information but is rather brief on specific technical details. It is recommended to strengthen the elaboration of technical details and conduct in-depth analyses with specific case studies.

Thank you very much for your suggestion. Our article is a review. In this part of mine cooling technology, the main focus is to introduce the mechanical cooling technology, the thermal insulation materials laid in the mine roadway in other cooling technologies, and the research on personal cooling suits. We will add data on the actual application effect of mechanical cooling technology in mines in China to better support the conclusions of the paper.

8. When describing intelligent mine ventilation, there is no explanation of mine ventilation's basic principles and workflows.

Thank you for your suggestion. In Section 5.1, we described the working principle and working process of the intelligent cooling system in detail, but did not describe the basic principle of mine ventilation. Therefore, we added a brief description of the basic principle of mine ventilation in the article: Traditional mine ventilation uses ventilation facilities to form air flow, bring fresh air into the mine, and expel high-temperature air, harmful gases and dust from the well. On this basis, intelligent mine ventilation system can improve the efficiency of ventilation and cooling and reduce energy consumption.

9. The concluding section proposes future development directions for mine cooling technologies. However, it lacks specific examples or case studies to support these viewpoints. Other issues: Most figures are blurry with unclear text. Figures 4, 5, 6, 8, and 9 could benefit from detailed flowchart explanations to facilitate reader understanding. Lastly, there are inconsistencies in reference formatting. Some references, such as author names, publication years, and journal titles, fail to adhere to a uniform style. Standardizing the reference format would improve the paper's overall presentation.

Thanks for your valuable advice, we have modified the picture of the article according to your suggestion, now the handwriting of the picture in the article is clearer, and the content of the article statement is also clearer. Finally, we have modified the reference part of the article, and the modification part is reflected in the reference part of the article. It is hoped that the quality of articles can be improved to meet the requirements of journals.

Fig.2. Ice cooling system for mines

Fig.3. Air compression cooling system

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Detailed comments for the authors can be found inside the attached PDF file.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Minor improvements to English language are needed.

Author Response

Review expert opinion 3：

1. Place：General

Thank you very much for your valuable suggestions on our article. We will revise the article one by one according to your suggestions, and the specific revision measures have been reflected in the article. Thank you again for your contributions to our article, and the changes are highlighted in blue for your convenience.

2. Place：Introduction（Page4）

According to your suggestions, I have made the following modifications in the paper:

Liu Heqing et al. (2018) deeply discussed the changes of climatic parameters in the micro-space inside the clothing when people wear air-cooled clothing, and how the skin temperature of the human body is affected by factors such as ambient temperature, labor intensity and ventilation [ 70 ].

Jiang et al. (2018)summarized three research methods used to explore the influence of air layer under clothing on the heat transfer performance of clothing system and their advantages and disadvantages, and analyzed the influence of thickness, volume, position, direction, non-uniform shape and motion state on the heat transfer performance of clothing one by one. By analyzing and summarizing the relevant research at home and abroad[ 71 ].

Li Wanyue et al.(2023)discussed the influence of different states of underwear space on clothing contact comfort, pressure comfort and thermal-wet comfort, and focused on the relationship between underwear space and clothing thermal-wet comfort. The results show that the ambient temperature has the most significant effect on the temperature and humidity of the airflow in the clothing micro-space and the temperature of the human skin[ 72 ].

Wen Hu et al.(2017) proposed a new design, which stitched semiconductor materials skillfully on the basic clothing in parallel[ 77 ].

Taking Dahongshan Copper Mine as the research object, Zhang Xi et al.(2022) discussed the cooling effect of spraying thermal insulation materials on surrounding rock of high temperature roadway, and verified that spraying thermal insulation materials had good cooling effect. Xue Hanling et al.used silicone rubber hollow glass beads as the thermal insulation material, and used the thermal insulation material for the simulation test bench[ 86 ].

Wang Feifan et al.(2017) used Fluent numerical software to simulate the thermal insulation effect of sprayed fly ash concrete. The study found that fly ash thermal insulation concrete has a good thermal insulation effect, and the temperature in the roadway is significantly reduced [ 87 ] .

3. Place：Introduction（Page1）

Thank you for your suggestions. We have revised the article according to your suggestions. Please refer to the revised manuscript for details.

4. Place：Page3

Thank you for your suggestions. We have revised the article according to your suggestions. Please refer to the revised manuscript for details.

5. Place：Figure2

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6. Place：Page5

Thank you for your suggestions. We have revised the article according to your suggestions. Please refer to the revised manuscript for details.

7. Place：Figure3

Thank you for your suggestions. We have revised the article according to your suggestions. Please refer to the revised manuscript for details.

8. Place：Page7

Thank you for your suggestions. We have revised the article according to your suggestions. Please refer to the revised manuscript for details.

9. Place：Figure4

Thank you for your suggestions. We have revised the article according to your suggestions and rearranged the pictures of the article. Now the pictures have become clearer.

10. Place：Page8

Thank you for your suggestions. We have revised the article according to your suggestions and rearranged the content format of the article. Now the article has become clearer.

11. Place：Page11

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12. Place：Figure8

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13. Place：Page13

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14. Place：Page14

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15. Place：Figure9

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16. Place：Page15

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17. Place：Figure10

Thank you for your suggestions. We have revised the article according to your suggestions and rearranged the pictures of the article. Now the pictures have become clearer.

18. Place：Whole paper

Thank you for your valuable comments. We have carefully read the article you recommended and cited it in the article. Our article is a review of mine cooling technology in China. All data are from public documents.

47. AAnagnostopoulos, C. A., Chrysanidis, T., & Anagnostopoulou, M. (2020). Experimental data of cement grouting in coarse soils with different superplasticisers. Data in Brief, 30, 105612. doi:10.1016/j.dib.2020.105612.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Fine