Laboratory Measurements of Zeta Potential in Fractured Lewisian Gneiss: Implications for the Characterization of Flow in Fractured Crystalline Bedrock
, Miftah Hidayat 1,2, Yogendra Kumar 3, David Healy 3 and Jean-Christophe Comte 3,*
Round 1
Reviewer 1 Report
This study investigated the zeta potential in fractured Lewisian gneiss in laboratory measurements by the characterization of flow in fractured crystalline bedrock.
1.This study only designed the two levels of confining pressures to investigate the influence of confining stress on zeta potential values. I think the three cases should be considered to find the corresponding laws at least.
2.The curve figure shown in Figure 1g should be marked the associated number.
3.The Conclusions should be simplified, and the valuable recommendations can be given to show the usage of this study for rock engineering.
Author Response
We thank the journal and the editor for a very prompt revision process and the decision made on the manuscript – minor revisions only.
We have carefully addressed all comments and suggestions outlined by the reviewers and modified the manuscript accordingly. The detailed responses are provided below.
Reviewer 1
This study investigated the zeta potential in fractured Lewisian gneiss in laboratory measurements by the characterization of flow in fractured crystalline bedrock.
1.This study only designed the two levels of confining pressures to investigate the influence of confining stress on zeta potential values. I think the three cases should be considered to find the corresponding laws at least.
We are grateful to the reviewer for the comment with which we agree. Unfortunately, due to technical issues we are unable to carry out additional experiments in the coming months to confirm the reported trends. The data reported in the paper are novel and reported as a proof-of-concept investigation. As such, we believe that the conclusions drawn based on our laboratory results (although only 2 pressure values) and supported by previously published trends (https://doi.org/10.1038/srep39882) are still valid. We added a short statement to clarify that additional experimental work to investigate other gneiss samples and other confining pressures is planned (lines 507-514).
2.The curve figure shown in Figure 1g should be marked the associated number.
Implemented. We thank the reviewer for the suggestion.
3.The Conclusions should be simplified, and the valuable recommendations can be given to show the usage of this study for rock engineering.
We expanded our conclusions to include some reference to potential application of our results to rock mechanics/physics/engineering (lines 539-543). The preface to the conclusions was rephrased following a suggestion by the 2nd reviewer. However, it was unclear from the above comment how the current conclusions should be simplified, and the phrasing of the conclusions was highly appreciated by the 2nd reviewer, so for these reasons we kept the conclusion unchanged. If the reviewer provided more specific requirements on ‘simplification’ of the conclusions we would be more than happy to address and implement the requirements.
Reviewer 2 Report
The submitted manuscript "Laboratory measurements of zeta potential in fractured Lewisian gneiss implications for the characterisation of flow in fractured crystalline bedrock" by Jan Vinogradov and collaborators is presenting an experimental investigation of the zeta potential on gneissic rocks and proposes nice results on how to use zeta potential to increase the knowledge gained from SP logs in fractured rock media.
The quality of the paper is overall good, but references are missing in many parts, and the results/discussion section should be reorganised, it is too confusing for the moment.
For these reasons, I recommend minor revisions for this manuscript.
Comments for author File: 
Comments.pdf
Author Response
We thank the journal and the editor for a very prompt revision process and the decision made on the manuscript – minor revisions only.
We have carefully addressed all comments and suggestions outlined by the reviewers and modified the manuscript accordingly. The detailed responses are provided below.
Reviewer 2
The submitted manuscript "Laboratory measurements of zeta potential in fractured Lewisian gneiss implications for the characterisation of flow in fractured crystalline bedrock" by Jan Vinogradov and collaborators is presenting an experimental investigation of the zeta potential on gneissic rocks and proposes nice results on how to use zeta potential to increase the knowledge gained from SP logs in fractured rock media.
The quality of the paper is overall good, but references are missing in many parts, and the results/discussion section should be reorganised, it is too confusing for the moment.
We are grateful to the reviewer for the high appreciation of the paper and will carefully address all the comments.
For these reasons, I recommend minor revisions for this manuscript.
Below are selected point-by-point responses, while the rest of our responses are provided in the annotated PDF.
- The reviewer suggested to change the title from ‘Laboratory measurements of zeta potential in fractured Lewisian gneiss: implications for the characterization of flow in fractured crystalline bedrock’ to ‘Laboratory measurements of zeta potential in fractured Lewisian gneiss: implications for the characterisation of fracture parameters’. Although we agree with the reviewer that some of our results can be used to characterize fracture parameters, broader implications are associated with characterizing flow through fractured systems in real geological setting. Since, this suggestion was not strict (as evidence by a ‘?’ mark added by the reviewer at the end of the suggestion) we would like to keep the title as is.
- We have not addressed the reviewer’s multiple comments on format, size, layout, etc. of the paper (and its ingredients such as figures, tables) as we believe the journal’s team will take over the formatting (note, that using the Applied Sciences template for the paper was not a strict requirement but a recommendation). This future formatting carried out by the journal will convert reference styles, change margin size, move figures and table to appropriate places, etc. Since we submitted a ‘raw’ WORD file, the editing team will be able to use all original figures and tables as they seem appropriate.
- Wording was thoroughly improved following the reviewer’s suggestions throughout the text, required references added (see the marked version) and replies were added to comments in the annotated PDF (attached).
Author Response File: Author Response.pdf
