Geologist in the Loop: A Hybrid Intelligence Model for Identifying Geological Boundaries from Augmented Ground Penetrating Radar

Round 1

Reviewer 1 Report

Summary: The authors apply Gaussian processes (GP) on a combination of ground penetrating data (GPR) and shallow borehole data for an enhanced determination of the spatial extend of a lateral bauxit deposit. They discuss the impact of geologists as individual experts in evaluating and interpreting the given data and resulting models.

General comment: The paper presents a case study targeting a close to surface bauxit deposit that is being exploitet mainly using GPR and borehole data. Therefore, the extent of parameters is very limited and a generalisation of the proposed method is restricted as it is described in the given text (although it might be applicable on seismic data and deeper borhole data). The study neither does present new science nor completely innovative approaches. It is well presented feasability study that comparable to many others (as layed out in the references).

Title: The title is well chosen and inviting.

Abstract: The abstract is short and concise. It touches all necessary items of the presented work.

Keywords: With some little extension of the paper "optimised exploration" might be added.

1 Introduction: A brief description of the state of the art and especially the framework of the case / feasabilty study is given. It has a very narrowed focus on the investigated mine site. There are some items in it that need some clarification:

page 2 line 50: assay percentages - this might be interpreted in different ways (you later refer to SiO2 content ?)

The fact why GPR data was apllied was extensively justified, the choice of GP lacks this same extend.

The nature of the available borhole data itself (density, permeability, or such) is not clear. Was only the SiO2 content used? Why that and no other borehole parameter?

2 Fundamentals ...:

page 2 line 90. you meant " anything below this particle size"?

figure 1: Locations, city names are unreadable, coordinates are missing

figure 2: The picture shows oolites, not pisolths

3 Ground penetrating radar:

page 5 line 134: This is not a simply GPR technology but a simple way to explain it.

4 Data collection:

It is important to know how the GPR data was processed and if some image enhancements were apllied.

page 5 line 153: 45 Mhz was chosen for this special exploration, the frequency range for application is larger.

5 Modelling process:

There are quite some algorithms available for seismic and radar horizon tracking based on differential contrast, waveform analysis, etc. How do these compare to your approach? Could they be implemented? It is hard to value your work without comparisons to standard procedures. ( - Future work suggestions)

6 Results and discussion:

This is the most interesting section of the paper. The reaction of a geologist and his individual error estimation will be very much based on how the GPR image was processed and (what featuresn were) enhanced. So please include an explanation of how the GPR data was processed. The same accounts for the representation of the borehole data. Maybe the geologists should have to classify those, that may change their uncertainty levels. How much time did the geologists spent on their task?

7 Future work:

see above

Will other algorithms than GP be tested as well?

8 Conclusions:

Could the results not only be used for exploration but for mining optimisation?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Geologist in the loop: A hybrid intelligence model for identifying geological boundaries from augmented Ground Penetrating Radar

by A. Ball & L. O'Connor 

The manuscript concerns the discussion of a model which combines the human with machine approach for the identification of geological boundaries in lateritic deposits.

In my opinion, the manuscript is quite well written and clear in the purposes.

However, I suggest the following improvements:

a) Introduction: the bibliography relating to GPR applications will be enriched by considering other articles, such as those indicated below; b) Data Collection. To detail how GPR data were acquired (e.g., georadar system, antenna frequency, samples for traces) and how they were processed (e.g., filters, migration);                                                                    c) Future Work. To balance the discussion, the limitations of the method will also be discussed. Furthermore, it would be useful to consider the use of the proposed method in geological contexts other than lateritic ones.

Minor points. In Figure 1 both the true north symbol and the metric scale will be inserted. Figure 2 does not seem relevant to me for the purposes of the article. Figure 3 will report the metric scale.

Bibliography suggested

Crocco and V. Ferrara (2014). A review on ground penetrating radar technology for the detection of buried or trapped victims, Proc. Int. Conf. Collab. Technol. Syst.                                                                                  Gizzi, F.T., Leucci, G. (2018). Global Research Patterns on Ground Penetrating Radar (GPR). Surv Geophys 39, 1039–1068. https://doi.org/10.1007/s10712-018-9475-1                                                                                           Zajícová, K., Chuman, T. (2019). Application of ground penetrating radar methods in soil studies: A review  Geoderma, 343, pp. 116-129. doi: 10.1016/j.geoderma.2019.02.024                                                                Wai-Lok Lai, W., Dérobert, X., Annan, P. (2018). A review of Ground Penetrating Radar application in civil engineering: A 30-year journey from Locating and Testing to Imaging and Diagnosis NDT and E International, 96, pp. 58-78; doi: 10.1016/j.ndteint.2017.04.002

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors made almost all the required changes. However, I recommend a few little integrations.

1) Section 2: Change title from "Fundamentals of background geology and the geological profile" to "Fundamentals of background geology and the geological profile of the test site";

2) Section 7: Change title from "Future work" to "Limitations and future works";

3) the four bibliographic sources suggested with the first revision and relating to the application of GPR were only partially considered by the authors;

4) the text on page 7 stops abruptly to start over on page 8.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.