Environmental Impact Assessment of Mine Tailings Spill Considering Metallurgical Processes of Gold and Copper Mining: Case Studies in the Andean Countries of Chile and Peru

Round 1

Reviewer 1 Report

The manuscript is well written and well organized, providing an overview of the environmental impacts caused by the spilling of mine tailings. It is a very serious topic, and the way it is presented is very informative, and I think the paper will be useful to the broader scientific community.

It is not necessary to change the text significantly. The number of significant figures should be revised (to three significant figures; e.g. 0.123; 3.45; 45.6 or 1090)... I think that writing excess decimals in 11,389.00 are not really useful (11389)

And I would delete the word "materialized" from the first sentence of the conclusion.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

 

This manuscript reviewed the environmental impact assessment of mining tailings spill of gold and copper mining. Two case studies in the Andean countries of Chile and Peru were also presented. Tailings spill is a disaster, which extremely destroys ecological environment, especially for non-ferrous mining tailings. Thus, I think the review is significant. Even so, I have some specific comments, listed below, which can help authors to improve the quality of the paper.

 

Specific comments:

1         Why cadmium (Cd) did not list in Table 1? As we know, Cd is a common toxicity metal in ore. In addition, I think some flotation agents also should be presented in Table.

2         “According to the table above, it is possible to find heavy metals in a tailings spill such as: (i) Arsenic, (ii) Chromium, (iii) Molybdenum, (iv) Mercury, (v) Copper, (vi) Cobalt, (vii) Chromium, (viii) Selenium, (ix) Iron, (x) Manganese, among others.” Chromium appeared twice.

3         In the conceptual model, the kinds of minerals of ores and the properties of surrounding rock should be included, because the release rates of heavy metals and bugger capacity of acidity are important for mobility of heavy metals.

4         Some figures’ quality is not enough, such as Figure 5, Figure 6.

5         Table 2. Some key heavy metals in water samples in A-02, A-03, A-04 and A-05 sample points did not shown in Table 2. I think their concentrations are important for understanding pollution levels and region of the Escalera River.

6         Page 12. I think the pollution heavy metals were not only Zn, Fe, As, Cd, Mn and Pb. Cu, which is the main element in the ore, should be included. At least, the concentration of Cu also should be included in Table 2.

7         Table 3. The flow direction of the river must be given. Why some soil heavy metals in M-R3 were highest?

8         Page 15. The sampling sites of soils, waters and sediments were the same sites? I suggest merging some maps of sampling sites. In the present manuscript, there are so much figures.

9         Table 4. Why Canada quality guide was used in this study? Why not located quality guide?

10     I suggest giving the concentrations of heavy metals in soils, water and sediments and PM 2.5 before tailing dam failing. The comparison with the current pollution levels is bound to be interesting.

11     Page 15. “Considering the conceptual model of sites contaminated with tailings presented above (Figure 3), it is possible to mention the following characteristics that affect the natural environment called water”. Called “water”?

12     5.1.8. High level Pb were found in human blood? Or hair? What are the other heavy metals levels in human body?

13     The aim of this manuscript is to study the environmental impact of gold and copper mining. However, I cannot find the case of tailing spillage of a gold mine? Although the title of the section 5.2 is “Gold tailings in Las Palmas Creek, Pencahue, Maule Region-Chile”, the mineralogical composition of the materials mined by MLPS consisted of: blende (zinc sulphide, ZnS), galena (lead sulphide, PbS), pyrite (iron sulphide, FeS2), chalcopyrite (copper iron sulphide, CuFeS2), and specularite (specular hematite, Fe2O3) (Page 20).

14     I suggest giving the sampling time of water samples, which is very important for the concentrations of heavy metals in water samples. The pH values seem to not be affected.

15     Lack environmental impact on sediment in Las Palmas Creek.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Authors have reviesed carefully based on the comments. I think it can be accepted in present form.