Gold Mine Tailings: A Potential Source of Silica Sand for Glass Making
Round 1
Reviewer 1 Report
Indicate more references for lines 39-41.
More references are necessary for lines 60 to 68.
The paragraph about the study, between lines 85 and 87 require more detailed information.
Point 2.9 does not indicate the concentration of all reagents
Samples are in duplicate or triplicate?. Please, indicate.
How was pH measured. Table 2.
How many samples were measured to obtain concentration of Table 4?.
How was obtained the information in Table 6?.
More deeply discussion of the results is necessary.
Experimental methodology and discussion sections need more detailed information, the results must be analyzed more deeply.
More references in the manuscript are necessary.
Conclusions about the study are poor.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript describes the utilisation of gold mine tailings for glassmaking. The paper is well written, and the results will be of interest to researchers and scientists looking for ways to “recycle” huge volumes of waste generated by mining and mineral processing like tailings and waste rocks. The manuscript, however, is still not suitable for publication in its current form and should be improved especially with regards to the environmental aspects of the approach as well as the stability of hazardous elements in the product (I will expound on this later in my review). I, therefore, recommend to the editors to accept this work after a major revision.
Major comments
Novelty: This is not the first paper to explore the possible use of mine tailings for ceramics and glassmaking, so I suggest to the authors to provide a summary of previous works on these topics and highlight why their work is still necessary. A review on the recycling of tailings, for example, was recently published by a Japanese group (Park et al., 2019).
Data: If possible, the authors should add the following data to improve the quality of their work.
- Map of the sampling area.
- Particle size analysis of -150 mesh fraction of the tailings.
- Where are the hazardous elements partitioned in the tailings? Although XRF detected Zn, Ni, Cu and Pb, minerals containing these heavy metals were not detected by XRD. My suggestion is to do SEM-EDX and check on pyrite and magnesioferrite because heavy metals are usually partitioned in these minerals (Igarashi et al., 2020; Tabelin et al., 2012). Another way to identify the partitioning of heavy metals in tailings is to conduct sequential extraction (Huyen et al., 2019; Tabelin et al., 2014).
- The glass produced from tailings should be evaluated using standard leaching tests like TCLP (Tabelin et al., 2018) to determine the leachability of hazardous elements in the tailings. Also, these experiments will show whether gold mine tailings is suitable for glasswares typically used for drinking or eating.
Minor comments:
Line 32: Titanium, vanadium, iron and aluminium are not considered as hazardous contaminants.
Lines 60-68: The data used in these sentences were very old (1996, 1997 and 2003). The authors should update these sentences using more recent data and publications.
Line 105: Provide μm equivalents for 10-100 mesh.
Line 197-200: How was this experiment conducted? This should be added to the methodology. Was the pH of the leachate 4.28?
Fig. 1: Provide scales for these photographs
Line 221: “comparism” should be “comparison”
Table 4: Trace heavy metals/hazardous elements are usually reported in “mg/kg” or “ppm”
Table 6: Kindly include the XRD pattern in the main manuscript.
Table 7: Why were Pb and Fe unaffected by both acid treatments?
Fig. 2: Provide scales for these photographs
References
Huyen, D.T., Tabelin, C.B., Thuan, H.M., Dang, D.H., Truong, P.T., Vongphuthone, B., Kobayashi, M., Igarashi, T., 2019a. The solid-phase partitioning of arsenic in unconsolidated sediments of the Mekong Delta, Vietnam and its modes of release under various conditions. Chemosphere 233, 512–523.
Igarashi, T., Herrera, S.P., Uchiyama, H., Miyamae, H., Iyatomi, N., Hashimoto, K., Tabelin, C.B., 2020. The two-step neutralization ferrite-formation process for sustainable acid mine drainage treatment: Removal of copper, zinc and arsenic, and the influence of coexisting ions on ferritization. Sci. Total Environ. 715, 136877.
Park, I., Tabelin, C.B., Jeon, S., Li, X., Seno, K., Ito, M., Hiroyoshi, N., 2019. A review of recent strategies for acid mine drainage prevention and mine tailings recycling. Chemosphere 219, 588–606.
Tabelin, C.B., Igarashi, T., Tamoto, S., Takahashi, R., 2012a. The roles of pyrite and calcite in the mobilization of arsenic and lead from hydrothermally altered rocks excavated in Hokkaido, Japan. J. Geochem. Explor. 119–120, 17–31.
Tabelin, C.B., Hashimoto, A., Igarashi, T., Yoneda, T., 2014a. Leaching of boron, arsenic, and selenium from sedimentary rocks: II. pH dependence, speciation, and mechanisms of release. Sci. Total Environ. 473–474, 244–253.
Tabelin, C.B., Igarashi, T., Villacorte-Tabelin, M., Park, I., Opiso, E.M., Ito, M., Hiroyoshi, N., 2018. Arsenic, selenium, boron, lead, cadmium, copper, and zinc in naturally contaminated rocks: A review of their sources, modes of enrichment, mechanisms of release, and mitigation strategies. Sci. Total Environ. 645, 1522–1553.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Some corrections are necessary. Put attention in the format of concentration or data.
Conclusions should be more specific.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Minor comments:
1. Table 4: Include the results for all four tailings samples.
2. Tables 4 and 7: There is a convention followed when reporting the results of XRF analysis (e.g., the order of oxides) (for an example, see Tabelin and Igarashi, 2019), so I suggest to the authors to correct these tables. Also, only trace elements like Pb, Zn and Cu are reported as (mg/kg) while the main components (e.g., SiO2, Al2O3, etc) should still be reported as wt%.
3. Fig. 3: Change the title of the y-axis to "Intensity (A.U.)". Also, add the scale of the Y-axis.
Reference
Tabelin, C.B. and Igarashi, T., 2009. Mechanisms of arsenic and lead release from hydrothermally altered rock. Journal of Hazardous Materials 169(1-3), 980-990.
Author Response
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Author Response File: Author Response.pdf
