Surface-wave tomography for mineral exploration:  a successful combination of passive and active data  (Siilinjärvi phosphorus mine, Finland)

Colombero, Chiara; Papadopoulou, Myrto; Kauti, Tuomas; Skyttä, Pietari; Koivisto, Emilia; Savolainen, Mikko; Socco, Laura Valentina

doi:https://doi.org/10.5194/se-13-417-2022

Articles | Volume 13, issue 2

https://doi.org/10.5194/se-13-417-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

State of the art in mineral exploration

https://doi.org/10.5194/se-13-417-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 13, issue 2

Research article

|

01 Mar 2022

Research article |

| 01 Mar 2022

Surface-wave tomography for mineral exploration: a successful combination of passive and active data (Siilinjärvi phosphorus mine, Finland)

Chiara Colombero, Myrto Papadopoulou, Tuomas Kauti, Pietari Skyttä, Emilia Koivisto, Mikko Savolainen, and Laura Valentina Socco

Download

Final revised paper (published on 01 Mar 2022)
Preprint (discussion started on 01 Oct 2021)

Interactive discussion

Status: closed

RC1:
'Comment on se-2021-121', Anonymous Referee #1, 01 Nov 2021

Dear authors,

Thank you for the submission of this article. I have completed my evaluation of your manuscript and will send it out for review.

The work presents a very interesting methodology that can help mineral exploration in hard rock sites in an effective and sustainable way. The work has a certain originality, since there are few similar works published until the moment. Still taking into account the originality of this research, an important factor is that the present study developed a semi-automatic workflow for application of active and passive surface wave tomography, which is quite interesting and worthwhile.

The work is well presented. However, in my opinion, the text requires the insertion of some information that I believe is important. All comments have been detailed throughout the text in the attached file (pdf).

Kind regards.

Citation: https://doi.org/10.5194/se-2021-121-RC1
- AC1: 'Reply on RC1', Chiara Colombero, 24 Jan 2022
  
  We are thankful to the reviewer for the work done to improve the manuscript and the positive evaluation.
  We have carefully considered all the comments and suggestions that were given in the attached file. In particular, we have better motivated all our choices about the data processing and interpretation and added references where possible. We have refined the introduction of the paper following the reviewer’s suggestion and updated two figures to fulfill the comments.
  We have replied to all the comments, point by point, in the attached commented pdf provided by the reviewer.
  
  Citation: https://doi.org/10.5194/se-2021-121-AC1
RC2:
'Comment on se-2021-121', Anonymous Referee #2, 06 Jan 2022

I read your manuscript with great attention and interest as it is an essential topic about applying the seismic potential (active and passive surface-wave tomography) in solving or dealing with mining exploration problems, especially about the estimation of phosphorus-bearing reserves, which is a critical point from which important management decision are relied on. I found this article not only written in a clear language but also well structured so potential readers are going to be pleased to read that. From a more technical point of view, I could see that a significant number of seismic data were gathered from different seismic sources, which are well described, and also using a high number of geophones. I found particularly interesting the excellent agreement among the seismic anomalies and the potential deep ore-bearing structures that could help support those decision stages for further drilling works. So that makes this methodology too promising for other mining areas where it is crucial to have a precise understanding of the geological structures from which the ores are mined. The authors even suggest an appropriate and tested workflow that could be implemented by potential practitioners.

So, I would suggest the paper to be considered for publishing.

Citation: https://doi.org/10.5194/se-2021-121-RC2
- AC2: 'Reply on RC2', Chiara Colombero, 24 Jan 2022
  
  We are grateful to the reviewer for the positive feedback on the manuscript.
  We fully agree on the potentialities of this robust and automatic workflow for future mineral exploration applications in a wide variety of geological contexts.
  We have now slightly revised the paper to improve the quality of the manuscript following the comments and fruitful suggestions of another reviewer.
  
  Citation: https://doi.org/10.5194/se-2021-121-AC2

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by Chiara Colombero on behalf of the Authors (24 Jan 2022) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (27 Jan 2022) by Juan Alcalde

Dear authors,

It has been a pleasure for me to edit this manuscript. The paper is interesting, concise and well presented, and it will make an excellent contribution to this Special Issue. The two reviewers considered it interesting and valuable, and the authors have done an excellent job answering their minor comments.

The paper is almost ready, but I have a few minor comments that I would like you to address before it is taken into the publication stage (see below). Once again, congratulations for this great piece of work.

*Please note that the line numbers refer to the manuscript with tracked changes*

-Please add the sampling rate of the recordings and the estimation of the total size of the data raw data - this is to inform the readers and to link back to the introduction ("leading to large datasets") to support why it is important to automatize this type of processing flows. I can see you have this information in the conclusions, but it may be worth repeating it in the main text too.

-What is the reason behind the passive DC alignments observed in the wavelength-phase velocity diagram in Fig. 6b? Perhaps you could add a short explanation of this effect in the paragraph in lines 159-167.

-You could show the contribution of passive and active DCs to the path lengths and azimuths in Figure 7 by painting the bars and sectors in two colours. This way you can graphically show how the aggregation of passive+active data provides a more robust and homogeneous (i.e. better) dataset, which is a central issue in the conclusion section.

-The fact that the perturbation zones observed in the inverted checkerboards appear at the edges of the study area could be related to a lack of raypaths/azimuths in these areas? Have you observed anything unusual in these zones for example in the misfit maps?

Very minor comments:
49 - "form" to "from"
Caption figure 2 - spell out SWT
Caption figure 3 - spell out FDBF
Figure 5b shows the active or the passive DC? Please clarify

Hide

AR by Chiara Colombero on behalf of the Authors (01 Feb 2022) Author's response Author's tracked changes Manuscript

ED: Publish as is (02 Feb 2022) by Juan Alcalde

ED: Publish as is (04 Feb 2022) by Susanne Buiter (Executive editor)

AR by Chiara Colombero on behalf of the Authors (04 Feb 2022)

Short summary

Passive-source surface waves may be exploited in mineral exploration for deeper investigations. We propose a semi-automatic workflow for their processing. The geological interpretation of the results obtained at a mineral site (Siilinjärvi phosphorus mine) shows large potentialities and effectiveness of the proposed workflow.