Mechanism of Carbon Monoxide (CO) Generation and Potential Human Health Hazard during Mechanized Tunnel Driving in Organic-Rich Rocks: Field and Laboratory Study
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe title of this paper is “Carbon Monoxide (CO) Generation during Mechanized Tunnel Driving in Organic-rich Rocks: Field and Laboratory Study”. The release mechanism of CO and CO2 from sedimentary rocks containing organic matter in mechanized tunneling is studied. It is found that frictional heat and "cold" combustion at 50-70℃ at the drill bit of shield machine can promote the formation of CO and CO2. The paper has a good scientific. Overall, this is a well written manuscript with the results clearly laid out. Besides, s In addition, some issues need to be discussed.
1. In the Batch alteration experiments of clay and sandstone, is there CO and CO2 that have been generated and not dissolved into the background electrolyte in the Teflon-lined steel reactors.
2. The researchers sealed the hydrothermal reactors and placed it in the laboratory oven. Was the water and the material in contact in a completely closed environment during the tunneling process.
3. This paper proposes that the shield-based TBM has three excavation modes, and the amount of CO and CO2 produced by using these three activation modes is not the same.
4. The contents of 3.1 and 3.2 of the article seem to be two independent parts, and no obvious quantitative argumentation relationship is found. Please explain.
Comments on the Quality of English LanguageThe language of the paper needs to be further streamlined.
Author Response
Dear reviewer,
please see the attachment for our detailed point-by-point response.
Best regards,
The Authors
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsAttached
Comments for author File: Comments.pdf
Minor editing of English language required.
Author Response
Dear reviewer,
please see the attachment for our detailed point-by-point response.
Best regards,
The Authors
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsHowever, it would be necessary to clarify a number of comments that are available to the article:
1. In the introduction, it should be noted that sustainable development issues are directly related to the widespread use of clean energy and the modernization of the mining and quarrying industry. The issue of ecology of production and the content of greenhouse gases in the extraction of minerals is increasingly being raised. One of the key aspects of sustainable development is the assessment of the impact of mining enterprises on the environment, namely the assessment of the carbon footprint - an indicator. It is necessary to take into account the relationship between environmental and economic factors affecting technologies that allow maintaining production efficiency, jobs, and at the same time reducing the environmental burden, as well as complying with the agreements in accordance with the Paris Climate Agreement.
2. Has a comparative analysis of sedimentary rock samples (mudstones and sandstones) been carried out with similar rocks in other regions of the world?
3. According to the data in section "2.2. Experimental Set-up", the methodology for conducting experimental studies should be provided in the form of a block diagram with the equipment used in the tests highlighted.
4. The characteristics of the X-ray diffraction method, which is one of the most common and most accurate when conducting similar studies, are not fully described.
5. Were the capabilities of the geoinformation system used to analyze the geological characteristics of the area under consideration and build the corresponding models (Figure 1)?
6. According to the data provided in tables 1-4, it is necessary to conduct a correlation and regression analysis and present the corresponding mathematical models and determination coefficients.
7. It would be possible to provide predicted values for the reduction in carbon dioxide emissions as a result of the studies carried out for short-term and long-term periods of time.
8. The conclusions should show the prospects for further research on the topic under consideration.
Author Response
Dear reviewer,
please see the attachment for our detailed point-by-point response.
Best regards,
The Authors
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe article: “Carbon Monoxide (CO) Generation during Mechanized Tunnel Driving in Organic-rich Rocks: Field and Laboratory Study”, provides experimental studies based on the generation and release of CO emissions and CO2 emissions during mechanized tunnel driving when drilling in sedimentary rocks which contain significant amount of organic matter.
In the Introduction section, in line 84, please provide the reference for the Austrian CO emissions limit value.
Materials, Experimental Set-up and Method section is well written with clear description of materials and procedures for experimental approach and analysis. However, the numbering of sections and sub-sections should be revised: section 2.3 Analytical Methods instead of 2.2 and further sub-sections accordingly (2.3.1 and 2.3.2). Furthermore, in line 141 should be described which standard mathematical procedures were used and where this deviation is related among the experimental studies.
It is mentioned in line 282 the legal daily average value (DAV: 30 ppm) and the legal short-term average value (STAV: 60 ppm) of CO to which tunnellers are allowed to be exposed, please provide a reference for these limit emissions values.
In the Results section, in line 324, the sub-section numbering is 3.2.2. instead of 3.3.2 and 3.2.3 in line 383.
Please format tables according to the Journal guidelines. Table 1 provides the mineral composition, OM content and should be mentioned TOC in line 317. Table 3 format should be revised and should provide a description for EC. In line 377 and according to Figure 4 please describe the reason for a 2-month experimental approach.
In line 474, recommendations such as on-site monitoring of CO and CO2 in the tunnel atmosphere to ensure a safe working environment, maintain sustainability and standards could be included in the Conclusions section.
Author Response
Dear reviewer,
please see the attachment for our detailed point-by-point response.
Best regards,
The Authors
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsMy comments were taken into account. The conclusions were adjusted, the introduction was corrected. The necessary corrections were also made to the main text of the article.
