The Steady Seepage Line Equation of Ionic Rare Earth Ore (IREO) In Situ Leached with Long Strip Bare Feet and Its Application
Round 1
Reviewer 1 Report
This paper made the Analysis of steady seepage line of linear barefoot type rare earth mine in-situ leaching. Overall, the structure of this paper is well organized, and the presentation is relatively clear. However, there are still some minor issues that need to be addressed before a possible publication. For example,
(1) In the introduction part, a detailed introduction and description about whether the machine learning or deep learning techniques can be used for the study of linear barefoot type rare earth mine should be given, e.g., 10.1109/TGRS.2020.3015157, 10.1109/TGRS.2020.3016820.
(2) A time complexity should be given to show the effectiveness and superiority of the designed system.
(3) Quantitative performance comparison on the imaging products should be given and discussed.
(4) The future research direction should be given.
Author Response
Reply to the Comments of Reviewer 1
Comments to the Authors:
This paper made the Analysis of steady seepage line of linear barefoot type rare earth mine in-situ leaching. Overall, the structure of this paper is well organized, and the presentation is relatively clear. However, there are still some minor issues that need to be addressed before a possible publication. For example,
(1) In the introduction part, a detailed introduction and description about whether the machine learning or deep learning techniques can be used for the study of linear barefoot type rare earth mine should be given, e.g., 10.1109/TGRS.2020.3015157, 10.1109/TGRS.2020.3016820.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. Due to the authors’ negligence, the machine learning or deep learning techniques used for the study of linear barefoot-type rare earth mine were not given in the original paper. As the reviewer mentioned, the authors should not overlook some typical research work that has significant use for reference. The authors have provided a detailed introduction following the reviewer’s suggestion. The details revised were given in lines 46 to 49 as
“The topographical and geological conditions of the mine are the prerequisite for carrying out mine production. The terrain of the mine can be accurately mapped by digital remote sensing technology combined with machine learning and depth learning algorithms[12-13], and the geological structure of the mine can also be accurately determined by resistivity tomography technology[14].”
(2) A time complexity should be given to show the effectiveness and superiority of the designed system.
Reply:
To the reviewer is not clear whether a time complexity is given to show effectiveness and superiority. This paper has given the steady seepage line equation’s engineering verification and error analysis in the third section.
(3) Quantitative performance comparison on the imaging products should be given and discussed.
Reply:
Thanks for the comments. The parameter analysis of this model shows that it has good calculation accuracy. Detailed quantitative analysis details are in the fourth section.
(4) The future research direction should be given.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The future research direction has given a detailed description in lines 369 to 373 as
“The steady seepage line equation has many parameters, some parameters are not easy to obtain, and the model and parameters have been simplified to a certain extent. The calculation results should be fully evaluated before use. The equation can be further studied and improved in terms of accurately determining the topographic and geological conditions of the mine and the permeability coefficient of materials.”
Reviewer 2 Report
This paper aims to introduce a method of rare earth mine in-situ leaching, especially the steady seepage line of linear barefoot type mine, using calculation and experiments. In view of the writing and novelty, this paper can be published after minor revision. The comments are as following:
1. The abstract expression needs to be modified. The main conclusions of this paper mentioned in the abstract should not be expressed in this way, because there is a separate conclusion part in the text. The abstract should describe the research methods used in this paper, and the main research results obtained, and appropriately introduce the main work value of this paper.
2. Does the model shown in Figure 1 include the change of permeability coefficient in the ore body? Please explain the main simplified assumptions of the model, especially the basis for meeting Dupuit assumptions.
3. It is suggested to delete the derivation process of "horizontal floor stability phreatic line equation", which is a special case of "inclined floor stability phreatic line equation", β = 0 °.
4. It is inappropriate to mark "roadway" in Figure 3. It is suggested to change it to "tunnel".
5. The reference style should be corrected. For example, [22] and [19] are different.
6. After reading the whole paper, I found the title could be improved. Now I only know “Analysis” but readers don’t know what the conclusion is.
Author Response
Reply to the Comments of Reviewer 2
Comments to the Authors:
This paper aims to introduce a method of rare earth mine in-situ leaching, especially the steady seepage line of linear barefoot type mine, using calculation and experiments. In view of the writing and novelty, this paper can be published after minor revision. The comments are as following:
- The abstract expression needs to be modified. The main conclusions of this paper mentioned in the abstract should not be expressed in this way, because there is a separate conclusion part in the text. The abstract should describe the research methods used in this paper, and the main research results obtained, and appropriately introduce the main work value of this paper.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The abstract has been revised following the reviewer’s suggestion, simplifying the conclusions in the abstract and increasing the work objectives and value of this paper. The revised abstract is as follows:
“Without a reliable design method for the leaching and seepage step of in-situ leaching (ISL), problems such as low comprehensive resource recovery rate and frequent geological disasters such as landslides are prominent. This study established a simplified “liquid injection-collection” plane model of ISL with linear barefoot type rare earth mine as the research object. The steady seepage line equation was derived based on groundwater dynamics and Dupuit assumption. Then, engineering verification and calculation error analysis were performed. The seepage line equation is expressed as a piecewise function, where the seepage line in the liquid injection area is the upper half of the ellipse line, and the one in the non-liquid injection area is a parabola. The calculation error increases along the flow field direction. The seepage gradient, bedrock gradient, liquid injection range, and relative permeability coefficient have limited influence on the calculation error of the equation. The seepage line equation can be fairly applied in ISL. The seepage line equation can provide a theoretical basis for the “prior prediction (design)” of the “liquid injection-collection” leaching and seepage process in ISL.”
(2) Does the model shown in Figure 1 include the change of permeability coefficient in the ore body? Please explain the main simplified assumptions of the model, especially the basis for meeting Dupuit assumptions.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The research object of this manuscript is a rare earth mine with a large scale (tens to hundreds of meters). Because the mine soil has different weathering degrees at different depths, the permeability coefficient of soil must have spatial variability and isotropy, but the change of permeability coefficient is not the focus of this study. In order to simplify the study, a fixed value of the permeability coefficient is used to measure the permeability of the whole mine. To avoid similar confusion for readers, the authors have given a detailed description of mainly simplify the content of assumptions in lines 76 to 104 as
“(1) It was assumed that the watershed of surface runoff and underground runoff coincide on the plane. A vertical H-axis was plotted along the watershed at the ridgeline (often the highest point of the bedrock floor), and the horizontal x-axis intersected with the outcrop point of the collection trench floor at the foot of the mountain (point C in Figure 1, coordinate: L3, m).
(2) In-situ leaching process requires the collection trench to drain the outflowing mother liquid in time, and point C was taken as the head reference point (Hc = 0).
(3) The gradient of the bedrock floor is generally small and taken as the average β (°) in this paper.
(4) Since the surface clay at the foot of the slope is excavated when constructing the liquid collection trench, the gradient α (°) at the seepage point B (coordinate: L2, m) is large.
(5) The movement of groundwater in Figure 1 is divided into two parts: 1) The liquid injection area above the seepage line is the unsaturated area, which belongs to the category of soil water movement, where the water flow is mainly vertical downward seepage under the action of gravity. 2) During single-hole injection, the solution infiltrates from the injection hole to the surrounding unsaturated ore body. The further away from the hole, the lower the saturation of the ore body. The wetting body is similar to an ellipsoid[30-32]. During the hole network injection, the interaction between the holes uniforms the infiltration of the solution into the unsaturated ore body beyond a certain range below the bottom of the hole[28]. Therefore, the boundary condition of the injection area (the injection range is L1, m) in Figure 1 is simplified to the uniform infiltration intensity W (the amount of water supplementing the groundwater by infiltration per unit horizontal area in unit time, m/d).
(6) As the liquid injection continues, the interior of the ore body is gradually saturated upwards from the bedrock floor, and the seepage line becomes higher and higher until it stabilizes. In general, the production cycle of ISL is 6–8 months, and the leaching agent solution is injected in the first 40 days or so[4]. Then, after the supernatant is injected, the seepage line within the ore body is close to the steady seepage line (shown by the dashed line in Figure 1). Therefore, the actual highest seepage line can be approximated by the steady seepage line.
(7) This paper does not consider the spatial variability and isotropy of the permeability coefficient of mine soil mass.”
(3) It is suggested to delete the derivation process of "horizontal floor stability phreatic line equation", which is a special case of "inclined floor stability phreatic line equation", β = 0 °.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. Section 2.2 in the manuscript was modified following the reviewer’s suggestion, and section 2.4 was deleted. Please find and check. Thanks very much for the suggestion which makes the manuscript more concise.
(4) It is inappropriate to mark "roadway" in Figure 3. It is suggested to change it to "tunnel".
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The figure was modified following the reviewer’s suggestion in line 246.
- The reference style should be corrected. For example, [22] and [19] are different.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The reference [22] and [19] in the manuscript was modified following the reviewer’s suggestion. Please find and check.
- After reading the whole paper, I found the title could be improved. Now I only know “Analysis” but readers don’t know what the conclusion is.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The title was modified following the reviewer’s suggestion. Please find and check.
“The steady seepage line equation of ionic rare earth ore (IREO) in situ leached with long strip bare feet and its application”
Author Response File: 
Author Response.doc
Reviewer 3 Report
Review
Dear Authors,
The manuscript entitled „Analysis of steady seepage line of linear barefoot type rare earth mine in-situ leaching” presents a liquid injection-collection plane simplified model of ISL was established with linear barefoot type rare earth mine as the research object. The subject taken up by the authors is an interesting one, especially in relation to the prediction of the disasters mentioned.
My first comment relates to layout - shouldn't the journal's guidelines be followed? By this I mean, among other things, formatting (especially the first page), figure captions, typeface, italics and bold, how to cite, etc.
Dear Authors, what is the main aim of this paper? In my opinion, the abstract, firstly, lacks an indication of the explicit purpose of the work; please complete it. One short sentence will be sufficient. And secondly, the abstract does not require such a detailed conclusion.
The data and calculations are presented correctly. The Figures (and Tables) illustrate the content of this paper well, but Figure 2 is a little illegible. The results of the research carried out are satisfactory.
The earliest paper („References”) is from 2000 up to articles from 1019, but most are from the last few years. Why is the literature from 2020-2022 not included in the paper?
Unfortunately, I see some drawback. The major drawback is the lack of „Discussion” (either as a separate, penultimate chapter or jointly with the „Conclusions” chapter).
My overall recommendations is to accept the manuscript after revisions - after introducing the discussion. Some mistakes can be found below.
Minor mistakes:
- please avoid repetition – words from the title of the paper should not be duplicated in Keywords and vice versa – it is better to avoid such repetition and change some of the repeated keywords while leaving the title unchanged;
- please underline the main goal of the paper (aim – some short info in the Abstract, optionally in the Introduction, 1 sentence is enough).
Major mistake:
- one serious error is the lack of the "Discussion", which I have already mentioned. "Discussion" should have been written as a separate, penultimate chapter or jointly with the "Conclusions" chapter; in my opinion, in this particular case, the elements of the "Introduction" chapter, especially the literature discussed in that chapter, can be used partly as background for the discussion.
My best regards,
Reviewer
Author Response
Reply to the Comments of Reviewer 3
Comments to the Authors:
The manuscript entitled „Analysis of steady seepage line of linear barefoot type rare earth mine in-situ leaching” presents a liquid injection-collection plane simplified model of ISL was established with linear barefoot type rare earth mine as the research object. The subject taken up by the authors is an interesting one, especially in relation to the prediction of the disasters mentioned.
(1) My first comment relates to layout - shouldn't the journal's guidelines be followed? By this I mean, among other things, formatting (especially the first page), figure captions, typeface, italics and bold, how to cite, etc.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. the manuscript’s layout was modified following the reviewer’s suggestion.
(2) Dear Authors, what is the main aim of this paper? In my opinion, the abstract, firstly, lacks an indication of the explicit purpose of the work; please complete it. One short sentence will be sufficient. And secondly, the abstract does not require such a detailed conclusion.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The main purpose of this manuscript is to provide a theoretical basis for the “prior prediction (design)” of the “liquid injection-collection” leaching and seepage process in ISL. The abstract has been revised following the reviewer’s suggestion, simplifying the conclusions in the abstract and increasing the work objectives and value of this paper. The revised abstract is as follows:
“Without a reliable design method for the leaching and seepage step of in-situ leaching (ISL), problems such as low comprehensive resource recovery rate and frequent geological disasters such as landslides are prominent. This study established a simplified “liquid injection-collection” plane model of ISL with linear barefoot type rare earth mine as the research object. The steady seepage line equation was derived based on groundwater dynamics and Dupuit assumption. Then, engineering verification and calculation error analysis were performed. The seepage line equation is expressed as a piecewise function, where the seepage line in the liquid injection area is the upper half of the ellipse line, and the one in the non-liquid injection area is a parabola. The calculation error increases along the flow field direction. The seepage gradient, bedrock gradient, liquid injection range, and relative permeability coefficient have limited influence on the calculation error of the equation. The seepage line equation can be fairly applied in ISL. The seepage line equation can provide a theoretical basis for the “prior prediction (design)” of the “liquid injection-collection” leaching and seepage process in ISL.”
(3) The data and calculations are presented correctly. The Figures (and Tables) illustrate the content of this paper well, but Figure 2 is a little illegible. The results of the research carried out are satisfactory.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The figure was modified following the reviewer’s suggestion in line 195.
(4) The earliest paper („References”) is from 2000 up to articles from 1019, but most are from the last few years. Why is the literature from 2020-2022 not included in the paper?
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The authors rearranged the research status in the introduction and added some references from 2020 to 2022.
(5) Unfortunately, I see some drawback. The major drawback is the lack of „Discussion” (either as a separate, penultimate chapter or jointly with the „Conclusions” chapter).
My overall recommendations is to accept the manuscript after revisions - after introducing the discussion. Some mistakes can be found below.
Minor mistakes:
- please avoid repetition – words from the title of the paper should not be duplicated in Keywords and vice versa – it is better to avoid such repetition and change some of the repeated keywords while leaving the title unchanged;
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The keywords were modified following the reviewer’s suggestion in lines 22-23 as
“Keywords: in-situ leaching of ionic rare earth ore (IREO); barefoot type mine; seepage law; groundwater level; leaching and seepage step”
- please underline the main goal of the paper (aim – some short info in the Abstract, optionally in the Introduction, 1 sentence is enough).
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The main purpose of this manuscript is to provide a theoretical basis for the “prior prediction (design)” of the “liquid injection-collection” leaching and seepage process in ISL. The abstract has been revised following the reviewer’s suggestion, simplifying the conclusions in the abstract and increasing the work objectives and value of this paper.
(6) Major mistake:
- one serious error is the lack of the "Discussion", which I have already mentioned. "Discussion" should have been written as a separate, penultimate chapter or jointly with the "Conclusions" chapter; in my opinion, in this particular case, the elements of the "Introduction" chapter, especially the literature discussed in that chapter, can be used partly as background for the discussion.
Reply:
The authors agree with and appreciate the reviewer’s suggestion. The authors have improved the discussion part following the reviewer’s suggestion and added a discussion of the model’s shortcomings and suggestions for further research in the future. The relevant details are described in lines 335-339 as
“In this study, a simplified “liquid injection-collection” plane model of ISL was established with a linear barefoot-type rare earth mine as the research object. Based on the groundwater dynamics and Dupuit assumption, the steady seepage line equation was derived under the known mine topographic conditions and liquid injection conditions, and the engineering verification and error analysis are carried out.”
and lines 370-374 as
“(5) The steady seepage line equation has many parameters, some parameters are not easy to obtain, and the model and parameters have been simplified to a certain extent. The calculation results should be fully evaluated before use. The equation can be further studied and improved in terms of accurately determining the topographic and geological conditions of the mine and the permeability coefficient of materials.”
Author Response File: Author Response.doc
Round 2
Reviewer 1 Report
The authors have well addressed the reviewer's concerns. No more comments.
