Fragmentation Size Distribution Measurement by GNSS-Aided Photogrammetry at Real Mine Site

Round 1

Reviewer 1 Report

Dear Authors, 

The presented paper 'Fragmentation size distribution measurement by GNSS-AIded photogrammetry at real mine site' provides interesting information about the SfM technique. 

First of all submitted paper can be published in the journal, however, I would recommend including some information.

Remark 1.  Line 47 I would also include Split desktop, considering that a lot of analysis regarding cumulative size fragmentation was made in this software.

Remark 2. Images (Image dataset and Scale 3D model) in Fig. 1. are too small. I would leave this information as a normal block. 

Remark 3.  I would recommend adding papers where SfM technique was used to evaluate the results of blasting works. Used to establish models of the product heap.

Remark 4. Fully agree about scaling line 68. I would like to include that in the case of typical fragmentation analysis made in e.g. Split, crucial factors were also how the photos of blasted rocks were taken (with SfM it is also important), as well as the automatic delineation (and adjustment of the factors). Considering the results the error could be up to 30%. 

Remark 5. Please include in the methodology more information about guidelines on how photographs were taken. 

Remark 6. With fragmentation analysis, a lot of the research is made with round scaling objects (e.g. ball and with dual object mode). Please reply why did you decide to use cuboid and do you perhaps investigate if the shape of the scaling object can have an influence on the results?

 

Best regards

Reviewer

Author Response

Thank you very much for your careful review. We appreciate your competent and helpful suggestions for this paper.

Our responses for comments are listed as follows:

• Remark 1. Line 47 I would also include Split desktop, considering that a lot of analysis regarding cumulative size fragmentation was made in this software.

[Response] Thank you for your comment. We added the “Split desktop” software as references since it should be cited but we didn’t.

• Remark 2. Images (Image dataset and Scale 3D model) in Fig. 1. are too small. I would leave this information as a normal block.

[Response] Thank you for your suggestion. Indeed, the images are too small and meaningless. Therefore, we removed them from Fig. 1.

• Remark 3. I would recommend adding papers where SfM technique was used to evaluate the results of blasting works. Used to establish models of the product heap.

[Response] Thank you for pointing this out. The use of SfM for fragmentation distribution estimation for blasting is an original topic that the authors' research team is working on. It is also cited in this manuscript. (Reference [9,10] in the resubmitted manuscript.)

• Remark 4. Fully agree about scaling line 68. I would like to include that in the case of typical fragmentation analysis made in e.g. Split, crucial factors were also how the photos of blasted rocks were taken (with SfM it is also important), as well as the automatic delineation (and adjustment of the factors). Considering the results the error could be up to 30%.

[Response] Thank you for your comment. Does that mean we should do a comparison experiment and parametric study? In this study, we think the contributions of this paper are to show that a 3D photogrammetric method can be used to estimate rock size, to show that the estimation is valid for real mining sites, and to show that the accuracy of the method is practical, as the last paragraph in Introduction says. Comparative experiments and parametric studies are expected to be necessary in the future, but are not within the scope of this paper.

• Remark 5. Please include in the methodology more information about guidelines on how photographs were taken.

[Response] Thank you for your suggestion. We added how to take images from line 133. And in the last paragraph of Section.3, we added the way of using drone videos for reducing capturing time.

• Remark 6. With fragmentation analysis, a lot of the research is made with round scaling objects (e.g. ball and with dual object mode). Please reply why did you decide to use cuboid and do you perhaps investigate if the shape of the scaling object can have an influence on the results?

[Response] Thank you for your comment. The reason was that it was unclear whether a round scale could be set up stably at the mining site, and an object with a definite length in the form of a rectangle would be easier to measure the actual scale. It also has the advantage of allowing us to observe the accuracy of the shape reconstruction.

Reviewer 2 Report

 

The authors proposed a method of creating an accurately scaled 3D model and can be used to measure the fragmentation size. The manuscript is well organized and the method is clearly describe and calibrated. However, I recommend the author to add a section to discuss the advantages and limitations of the proposed methods with the similar techniques.

Author Response

Thank you very much for your careful review. We appreciate your competent and helpful suggestions for this paper.

Our responses for comments are listed as follows:

• The authors proposed a method of creating an accurately scaled 3D model and can be used to measure the fragmentation size. The manuscript is well organized and the method is clearly describe and calibrated. However, I recommend the author to add a section to discuss the advantages and limitations of the proposed methods with the similar techniques.

[Response] Thank you very much for your comment. Indeed, the advantage and the limitation are not enough described. We added the advantage of the proposing 3D fragmentation measurement method in the second paragraph of Introduction, and the limitation in the last paragraph in Section.3.

Reviewer 3 Report

After reading the manuscript “Fragmentation Size Distribution Measurement by GNSS

Aided Photogrammetry at Real Mine Site”, my comments are below;

1. Briefly discuss the existing difficulties with the traditional methods.
2. Try to avoid the sentences, starting with symbol.
3. Improvement needed for the Figure 3 description.
4. Application of the method for the blasted mucked covered size distribution?
5. Limitation of the method required for the practical use.
6. Parametric study?
7. Results discussion is very briefly.
8. Conclusion must be based on the study results and avoid the references in the conclusion.
9. Minor editing is needed; i.e. line 284.
10. Comparing the results of this study with the exiting methods will be required.

Author Response

Thank you very much for your careful review. We appreciate your competent and helpful suggestions for this paper.

Our responses for comments are listed as follows:

• Briefly discuss the existing difficulties with the traditional methods.

[Response] Thank you for your suggestion. Indeed, the discussion was not enough, so we added the difficulty of conventional methods, and the advantage of the proposed method. (Please see the last sentence of the first paragraph in Introduction, and second paragraph in Introduction.)

• Try to avoid the sentences, starting with symbol.

[Response] Thank you for pointing this out. We found that many sentences in section 2.1 are starting with symbol. We fixed them.

• Improvement needed for the Figure 3 description.

[Response] Thank you for your comment. Indeed, the description was too simple. Therefore, we added the detail of the process in the paragraph just before Figure 3.

• Application of the method for the blasted mucked covered size distribution?

[Response] Thank you for your comment. The application is described in Figure 1. The study is a part of a mining process (Planning for blasting > Blasting > Checking (this study) > Reviewing the result > Planning for blasting > ...). The fragmentation size distribution is used for planning next blasting.

• Limitation of the method required for the practical use.

[Response] Thank you for your suggestion. We agree with you. We added the limitation in the last paragraph in Section.3.

• Results discussion is very briefly.

[Response] Thank you for pointing this out. Referring to the result, we found some limitations to solve. So the discussion and limitation are added in the last paragraph in Section.3.

• Conclusion must be based on the study results and avoid the references in the conclusion.

[Response] Thank you for your comment. Indeed, we should have avoided the reference in the conclusion, so we removed it.

• Minor editing is needed; i.e. line 284.

[Response] Thank you for pointing this out. We carefully checked the manuscript again. We are so sorry. It should have been done before first submission.

• Comparing the results of this study with the exiting methods will be required.
• Parametric study?

[Response to the two comments] Thank you for your suggestion. In this study, we think the contributions of this paper are to show that a 3D photogrammetric method can be used to estimate rock size, to show that the estimation is valid for real mining sites, and to show that the accuracy of the method is practical, as the last paragraph in Introduction says. Comparative experiments and parametric studies are expected to be necessary in the future, but are not within the scope of this paper.

Round 2

Reviewer 3 Report

Only one minor comment is:

1. scope of the work is written twice in Figure 1.

Author Response

Thank you very much for your careful review. We appreciate your competent and helpful suggestions for this paper.

Our responses for the comment:

• 1. scope of the work is written twice in Figure 1.

[Response] Thank you for pointing this out. As you mentioned, both of the figure and caption had "scope of this work." We remained the figure's one, and removed the other. (Please see line 59.)