Study on Dust Distribution Law in Open-Pit Coal Mines Based on Depth Variation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors conducted a numerical simulation study on dust distribution around the open-pit mine with depth. It is an interesting topic to investigate the interaction between air flow and solid particles. However, more discussion should be included based on the numerical simulation results. For instance, what are the suggestions for dust control based on the results? What would be the dust control measures on the surface? Using various particle sizes would be more practical rather than simplifying them to a uniform size and density. The authors should include more comprehensive work before this manuscript can be published. Below is the detailed comments. 

Line 70: Respirable dust (RD?)

Line 108: It is not clear why previous models are 2D. Don't they consider the gravity of the particles in the numerical simulation? It is not mentioned in the literature review. 

Line 129: Designed stripping ratio and primary topsoil composition should be included. 

Figure 1: Putting scale marks in the image would be helpful.

Line 155: How to define the undisturbed area. 

Line 167: Mark the dump locations in Figure 1. 

Section 3.2: Air flow pattern description in this section is vague. Are these conclusive statements from the lab test, field monitoring or other literature? It is not convincing with these random numbers. 

Line 221: What does minor forces refer to? The gravity of finer particles could be a super-small force.

Line 237: The turbulence is not a random effect. Seems you adopt the k-epsilon turbulent equation in your model.

Line 260: Which software was used to refine the model and why was that needed?

Line 266: It is vague here which retrieval techniques were used. 

Table 2: Was compressive areflow adopted and gravity assigned to the particles? It is not shown in the table. 

Line 291: Simplify the section title. 

Line 293: In the table, the velocity listed is 1m/s. 4m/s was used here.

Figure 9: It seems the primary air pollution is trapped due to localized circulation. How can this dust be emitted to the upper level? Showing a turbulent energy contour would be helpful.

Line 341: What is the boundary conditions of dust particle emission in the model? It is not mentioned anywhere in the manuscript. 

 

 

 

 

 

 

 

 

 

 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

MAJOR COMMENTS
It is necessary to improve the structure of the manuscript, since it is currently unclear where the description of methods and materials ends, and where the presentation of the author's results begins. It is best to clearly indicate the Materials and Methods as well as Results sections.

References should be added: the facts and patterns presented in sections 2 and 3 are not supported by literature data. If these facts and patterns are new results obtained by the authors, then they should be placed in the Results section and the corresponding phrases should be added to the Conclusions section. Some discussion of these new results is also necessary, as well as their comparison with the results of similar studies in other locations (if any). 
  
Links must be formatted in accordance with the journal's rules.

MINOR NOTES
Line 115: is the FLUENT your own software? If non please add reference.
Lines 118-144: please move these lines into Material and Methods section.
Lines 121-122: please illustrate the location of the coal mine at a map of China. The map could be the right part of Figure 1.
Lines 127 and 128: please add ASL after 1490 m and 1232 m, respectively.
Line 132: it seems it is AI-corrected or AI- generated figure (?) since the greens look like too artificial. If so please provide real photo.
Lines 145-210: please move these lines into Results section.
Line 168: really ideal is not achievable else it is not ideal. Please replace "ideal" with another word, for instance with "excellent" word.
Lines 211-253: it seems this section should be moved into Material and Methods chapter.
Lines 217 and 218: please add references after "Euler method" and "Lagrangian method".
Line 224: please check unit consistency of the left and the right parts of the equation: it seems du/dt (unit is m/s²) should be in the left part since right part has unit as of gravity acceleration (g_x) in the second term of right part of the equation. Here and after please use proper denotement of an equation (see the journal's rules for authors).
Line 225: please add exact unit of the drug force.
Line 227: please specify the unit of the drug coefficient (C_d).
Line 234: please check left part of the equation.
Line 239: please add reference of the k-ε model. Please specify what the k and ε variables mean.
Line 252: please add reference for the discrete coordinate method.
Line 256: Antaibao or An Tai Bao?
Line 258 and 259: please add references of the Global Mapper and SketchUp software.
Line 260: what were the refinements?
Line 265: please add link and reference to the GDEMV330M data.
Line 269 and 294: please add references to the SolidWorks and CFD-Post software.
Line 297: maximal outlet wind at Figure 7 surpasses the inlet wind of 4 m/s specified at Line 293. How it could be? Please specify (in Figure's caption) that wind flows from left to right at the diagram.
Line 336: what is the dust concentration, PM10 or PM2.5?
Lines 359-365: these lines do not represent any conclusions so they could be eliminated. 
Line 366: please check fonts.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,
article deals with the ventilation of an opencast mine and the formation of the air velocity field and dust concentration in an opencast mine. However, it is in need of improvement.

Detailed comments

1. Please add information about daily extraction in opencast mine.
2. It is worth expanding the literature review.
3. Has the effect of solar irradiation of slopes been investigated?
4. Information about the model grid should be added. A test of the independence of the model grid should be added.
5. Has an outflow boundary condition been provided on the model sidewalls (in the Z-axis direction Figure 6)? If not, why not.
6. Why the assumed air velocity of 4 m/s in the model?
7. Section 3.2 - describe the methodology and measuring instruments adopted in measuring the air velocity in the mine.
8. Explain the meaning of g_x in equation 1.
9. The marking of plane c in Figure 6 should be checked. The position of lines a, b, c and d should also be checked due to the description in lines 278-280.
10.  Have numerical calculations been carried out on the extent of the zone with increased dust in the excavation surroundings?

Regards
Reviewer

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have properly addressed my primary concerns. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors took int account my comment so the manuscript can be published after minor revisions (please see below).

Line 280: please replace "du_p/d_t" with "du_p/dt".

Line 285: please specify here in brackets that C_D coefficient is dimensionless (as it follows from Response 12 of authors' coverletter).
Line 286: since C_D coefficient is dimensionless, the unit of F_D force must be s^-1. Only with this unit of F_D force the left and the right parts of Equation 1 can have one and same unit of m/s^-2 (i.e. unit of acceleration).

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,
thank you for taking my comments into consideration. I recommend that the article be accepted.

Regards
Reviewer

Author Response

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