Simulation Study on the Environmental Impact of Rare Earth Ore Development on Groundwater in Hilly Areas: A Case Study in Nuodong, China
, Sanxi Peng 4,*, Yaping Cheng 1, Meng Chen 1 and Zhiwei Yan 1,2
Round 1
Reviewer 1 Report
This paper introduced a simulation study on the environmental impact of rare earth
ore development on groundwater. The results provide a theoretical basis and reference for groundwater monitoring and pollution control after mining in this area. Along with English editing the following comments should be addressed:
1. Line 44-46: The description about the in-situ leaching technology is not quite accurate
2. Line 55 and line 64: The name of rare earth ores should be expressed uniformly. I think ion-adsorbed rare earth mining areas is appropriate.
3. What is the relationship between Part 3.1 and Part 3.2, 3.3, 3.4, 3.5? In abstract, there are two models, a ground water flow model and a solute transport model. Thus, I think it would be good to present the two models in the title.
4. What is the relationship between the ground water flow model and the solute transport model?
5. Figure 10: The horizontal heading should start with a capital letter.
6. What dose “mine” mean in line 431?
7. Please the authors cite relevant references including high-impact journals to make the manuscript to a broad range of readers. The following specific articles may take note in the revision stage such as Separation and Purification Technology, 2019, 217: 24-30; Minerals Engineering, 2018, 129, 63-70.
8. The English language needs to check carefully in the revision stage because of many careless mistakes in many positions, such as line 269-271.
Comments for author File: 
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Author Response
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Author Response File: 
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Reviewer 2 Report
Dear authors,
In your manuscript you have shown well, based on field research and experiments, that GOCAD software can be applied to establish a geological model, combined with GMS numerical simulation software to build groundwater flow models and solute transport models. Furthermore, to control pollutant transport, two pumping stages were adopted to intervene NH3-N concentrations in groundwater. Following the adoption of the first stage pumping measures, the peak concentration in the flow area monitoring wells was significantly reduced, with the maximum peak concentration reduced from 27.9 mg/L to 5.51 mg/L. Based on the first phase of pumping out treatment, the second phase was adopted. Model results showed that the peak concentration of NH3-N pollutants released into the stream was less than 0.5 mg/L. Okay, I agree.
I think the following should be done:
1. You describe: The recharge, runoff, and discharge characteristics of each sub-hydrogeological unit are similar. Therefore, they were combined into one large hydrogeological unit in the groundwater modeling process. Explain this similarity of sub-hydrogeological units.
2. State: The accuracy of the streams, rivers, and observation wells is set to a 10 ×10 m cell size, respectively, and the rest is set to a 50 × 50 m cell size. The accuracy of streams, rivers and observation wells is set to a cell size of 10 × 10 m, and the rest is set to a cell size of 50 × 50 m. How realistic is this? Explain.
3. In table 1 below the line of the table to write the meaning of КХ and Кy , KX/Kz. You can also write Hydraulic conductivity above these marks in the table.
4. Analytical methods for determining the presence of nitrogenous compounds should be presented in the manuscript. Furthermore, you do not specify in the manuscript which elements are represented in the specific area and how the composition affects the model shown.
5. The results shown in the tables and pictures are correctly done. However, all this does not give enough confidence without discussing the analytical methods of determining the quantification of pollutants. That should be inserted into the manuscript.
Best regards
Author Response
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Author Response File: Author Response.pdf
