The effect of mulch in controlling erosion and dust originated from Chadormalu iron mine tailings

Introduction:
Chadormelo iron deposit is located in Bafaq-Saghand iron ore region. This mine is located in Yazd province, 180 km east-northeast of Yazd city, 65 km north of Bafaq city and 50 km north of Chagharat mine. Chadormelo consists of two separate iron deposits.
There are large amounts of tailings soil around Chadormello mine and its processing refractories. Wind, rain and weather changes cause the dispersion and release of soil particles in these accumulations. Some of these soils contain heavy elements such as nickel, vanadium and chromium, which are harmful to human health and the environment, and their distribution in the environment should be prevented.
Materials and methods:
In general, 10 variables (montmorionite, lignin sulfonate, perlite, zeolite, molasses, magnesium chloride, calcium chloride, potassium chloride, calcium carbonate, water) were investigated and used in order to conduct research and prepare mulch suitable for the environmental conditions of the region. . In this study, the method of conducting experiments was used randomly and the experiments were conducted in 6 stages with the construction and application of different mulches. Molasses and lignin sulfate are used for dust control, these additives are non-toxic and have low cost.
Results and discussion:
There have been various methods such as using water, polymer materials, petroleum mulches, and potash waste to stabilize dust, each of which has specific weaknesses such as durability and shelf life. In this research, the combination of lignin sulfonate, molasses, and calcium chloride has been used to stabilize the waste accumulations of Chadormello mine. The tests carried out to check the efficiency of the manufactured mulch include ICP-OES, SEM, granulation, shear strength, wind tunnel and thickness determination, and the operation of stabilizing waste piles with mulch leads to an increase in the shear strength of the samples. The mulched sample is higher than the non-mulched sample. Increasing the vertical load on the samples led to an increase in the strength of the samples, which is normal in shear behavior.
One of the most important characteristics of the mulch used in this research is the thickness of the mulch on the samples. The thickness of the mulch layer is one of the evaluation indicators of the mulch strength criterion. The strength of soil stabilizing materials has a direct relationship with the thickness of the created pile, but it should be noted that the thickness of the pile may increase the compressive strength and also decrease the permeability of the soil. The measurement of the thickness of the mulch layer on the samples of Chadormelo showed that the thickness of the mulch layer varies from 2 to 4 cm.
Conclusion:
The results of ICO-OES analysis on mulch samples showed that the concentration of heavy metals is lower than the permissible limit. The results of SEM analysis clearly show the creation of a coating layer on the soil surface and the creation of adhesion and continuity between soil particles due to the use of mulch. As a result of the stabilization process, the shear strength and adhesion of the samples show a significant increase. The results of the wind tunnel test showed that the stabilization and mulching operations have led to a significant reduction in the concentration of sediment particles, and the increase in the amount of mulch spraying causes more penetration of the mulch in the soil and an increase in the concentration of the mulch despite the decrease in the depth of its penetration in the soil, due to the increase in the amount Adhesion between soil particles makes it more resistant to wind erosion.