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Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mining & Metallurgical Engineering is the property of Mining & Metallurgical Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the heap leaching process, the free particles in the heap leaching system move with the flow of the solution, which affects the speed and efficiency of the leaching. For small grain-size particles, although it is difficult to clog the interparticle pores, a large amount of them attached to the pore wall also affects the infiltration of solution into the ores, which decreases the leaching efficiency. In this work, based on the real pore structure, Fluent software was applied to perform simulations, and the influences of particle size, particle density, and fluid flow velocity on the migration and adhesion behavior of fine particles in the pore were examined. The simulation results reveal that when the particle size is 1×10−6 m, almost no particles are deposited in the pores. With increasing particle size from 1×10−6 to 1×10−4 m, the number of particles attached to the surface of the pore wall first increases and then decreases. For particles with different densities, the number of attached particles accounts for more than 90% at the peak. The main adhesion sites of particles are the outer walls of curved pores and the small pores with low flow velocity and low slope. The analysis shows that the larger the particle size and density, the greater the influence of gravity and inertia on its trajectory, the smaller the influence of fluid on its trajectory, and the easier it is to become close to the pore wall during migration, leading to particle attachment. Moreover, the large particle size and large density particles primarily migrate in the large pores, and the trajectories are relatively concentrated. However, when small particle size and small density particles migrate in high flow velocity fluid, their horizontal motion amplitude is larger, the migration trajectory distribution is more dispersed, and the distribution is also in small pores. The adhesion of fine particles is not conducive to mineral leaching in the actual heap leaching process. In this study, the migration and adhesion laws of fine particles in pores were examined by simulations. The results reveal that it is necessary to take measures to decrease the content of fine particles when the content of fine particles is too high in the actual production process to avoid the adverse effects of particle adhesion on leaching.

In response to the slow gold leaching rate and low gold leaching rate during the heap leaching process of a fine-grained dissemination, slimy, oxidized gold ore in Guizhou, the on-site production process was optimized. Based on ore process mineralogy research and heap condition experiments, combined with the actual production on-site, the main reasons hindering the gold recovery during the heap leaching process were diagnosed. These included the presence of gold minerals in fine particle form, low dissociation degree of mineral monomers, high content of easily sliming minerals, poor permeability of ore heaps, low pH value and cyanide mass fraction in leaching solution, and high spray intensity. Corresponding optimization measures were formulated to address the problems in the production process. After on-site renovations, the gold leaching rate increased from 35% to 57%, achieving the expected optimization effect and providing significant economic benefits for the company. [ABSTRACT FROM AUTHOR]

In the case study of the pollution control over the heap leaching cyanide residue left by historical gold mines in arid areas of western China. Based on a thorough analysis of climate, hydrogeology, and the characteristics of heap leaching cyanide residue pollutants, in-situ closure operation is employed to verify the pollution control effect over the pollutant such as heavy metals in heap leaching cyanide residue. The paper in detail describes the in-situ sealing and isolation scheme, control and monitoring scheme, and auxiliary schemes. After implementation, the environmental pollution risks are effectively controlled, and the peripheral environment is evidently improved, achieving anticipated engineering goals. The control technology can provide references for the pollution control of heap leaching cyanide residue generated from similar gold mines. [ABSTRACT FROM AUTHOR]

In this paper, the mechanism of biological metallurgy technology, commonly used metallurgical micro-organisms and the classification of biological metallurgy technology are introduced. The application of biological metallurgy technology in the gold industry and the main technical types of biological stirring oxidation process and biological heap oxidation process are summarized, the research status of biological oxidation pretreatment of high arsenic, high impurity gold concentrate, and electronic waste resources, as well as the purification and utilization of oxidation solution are introduced emphatically, the future key research directions of biometallurgical technology are pointed out, providing a basis for better promotion and application of biometallurgical technology in the gold field. [ABSTRACT FROM AUTHOR]

Inner Mongolia Pacific Mining Co., Ltd. uses a heap leaching process for gold extraction. The large area of ore heap leaching and high sodium cyanide consumption result in high production costs. To further reduce costs and increase efficiency, the company has optimized the process and implemented the effective area dripping method. This paper introduces in detail the application conditions of the effective area dripping method in heap leaching process and the control of various indexes. The successful application of the method effectively reduces the dosage of reagents, saving 55.14 million yuan in reagent costs with significant results. [ABSTRACT FROM AUTHOR]

BACKGROUND: As the significant factor of the accumulation of heavy metals in farmland soils, mineral activities such as mining, traffic and mineral processing and smelting allow heavy metals to spread into the surrounding environment by water or atmospheric deposition, and finally collected into the soil, causing heavy metal pollution in the surrounding farmland soil. Heavy metals pollution in soils especially in farmland soils around the mining area thus has received great attention in the field of environmental pollution. Located in the middle reaches of the Yellow River watershed, the gold mining area in western Henan is an extremely important gold deposit area with great prospecting potential in China for the strong late Yanshan acidic magmatic activity and the extremely favorable metallogenic geological conditions, in which more than 40 large, medium or small gold deposits have been discovered. Under the background of ecological protection and high - quality development in the Yellow River watershed, the western Henan gold mining area, with a long history of gold mining development, lacks more attention to the accumulation, spatial distribution and ecological risk of heavy metals in farmland soil around the mining area during the years of mining, beneficiation and processing. It is particularly necessary to study the heavy metal pollution in soil, find out the impact of mining activities on heavy metals in surrounding farmland soil, and provide a scientific basis for prevention and control of heavy metal pollution in farmland soil. OBJECTIVES: To clearly understand the impact of mining activities in the western Henan mining area on heavy metals in the surrounding farmland soil, provide necessary basic data for supporting the safe production of key mineral resources, the surrounding agricultural safety, and prevent and control heavy metal pollution in farmland soil. METHODS: 375 topsoil samples from the farmland around the western Henan gold mining area at a depth of 0-20cm were systematically investigated and analyzed with reference to Code of Practice for Soil Geochemical Survey (DZ/ T 0145—2017). The contents and spatial distribution characteristics of Cd, Cu, Zn, Pb, Hg, As, Cr, Ni were analyzed. The heavy metal pollution and ecological risk were evaluated by the geo-accumulation index method and potential ecological risk index method. RESULTS: (1) The contents variation range of Cu, Pb, Zn, Ni, As, Hg, Cd, Cr are 1. 00- 71. 72, 2. 00 - 524. 79, 8. 00 - 320. 37, 2. 00 - 52. 77, 2. 29 - 24. 64, 0. 0067 - 0. 268, 0. 04 - 1. 30, 28. 20 - 107. 93, respectively, and the average are 35. 33, 74. 43, 137. 69, 31. 60, 12. 39, 0. 064, 0. 43, 76. 27, respectively, showing significant differences between the 8 heavy metals. Compared with the soil background value in the middle reaches of the Yellow River, the average contents of Cu, Pb, Zn, Ni, As, Hg, Cd, Cr are 1. 47, 3. 24, 2. 06, 1. 05, 1. 03, 1. 52, 2. 77 and 1. 07 times of them, respectively, but lower than the value of risk screening values for soil contamination of agricultural land. (2) The characteristics of coefficients of variation show that Pb(90. 72%) >Hg(85. 25%) >Cd(65. 65%) > Zn(44. 0%)>Cu(33. 66%) >As(31. 72%) >Ni(24. 23%) >Cr(13. 61%), the Pb, Hg, Cd are the primary factors causing the soil pollution as the external input by mineral activities for the high coefficients of variation and special relation with mining. The main ore-forming elements in the gold deposit area are Au and Mo, and the associated elements are Cu, Pb, Zn, Ni, As, Hg, Cd, which may diffuse into the surrounding environment during ore transportation, waste rock and slag piling along the river, and processing. Alongside the Daping River, the two gold mining areas and concentrators are distributed around the farmland, and the gold ore heap leaching site on the east side is located at the top of the hillside and hill. The heavy metals produced by mining activities can diffuse in the downstream agricultural areas through atmospheric deposition, rainwater leaching, river drainage, and can accumulate in the surrounding agricultural soil, causing heavy metal pollution in the agricultural soil around the mining area. (3) The geo-accumulation index of 8 heavy metals is -0. 1, 0. 74, 0. 33, -0. 56, -0. 60, -0. 29, 0. 62, -0. 49 with the order Pb>Cd>Zn>Cu>Hg>Cr>Ni>As, in which Cu, Hg, Cr, Ni, As show no influence to the quality of soils for the average geo -accumulation index lower than 0, and Pb, Cd, Zn show moderate pollution for the average geo-accumulation index between 0-1. Among them, the proportion of samples with a Cd element of medium or higher impact grade is 20. 27%, the proportion of samples with medium to strong impact grade is 7. 73%, and the proportion of samples with strong impact grade is 1. 07%. The proportion of samples with a Pb element above the moderate impact level is 18. 93%, and the proportion of samples with moderate to strong impact level is 10. 40%. Hg and Zn also have 7. 46% and 13. 33% of the samples reaching the moderate impact level, indicating that Hg, Cd and Pb in the soil at local sampling sites have different degrees of impact on farmland soil quality. (4) The average value of the single -factor potential ecological risk index of eight heavy metals is between 2. 06 and 83. 62, among which the single-factor potential ecological risk index of As, Cr, Ni, Cu and Zn is a slight potential ecological risk. Pb is mainly subject to slight potential ecological risks for 92% of samples, moderate potential ecological risks for 7. 47% of samples and strong potential ecological risks for 0. 53% of samples. Cd is dominated by moderate potential ecological risks, with 46. 14% of samples, and there are 25. 33% and 10. 93% of samples reaching strong and very strong potential ecological risks respectively. For the ecological risk index of Hg, there are 35. 47%, 11. 46%, 4. 27% and 3. 20% of the samples that reach moderate, strong, very strong and very strong degree. The comprehensive potential ecological risk index (RI) ranges from 51. 66 to 689. 64, with an average of 192. 07. The proportion of samples with slight, moderate, strong and very strong impact degree is 46. 40%, 41. 07%, 11. 20% and 1. 33%, respectively. The overall comprehensive potential ecological risk index shows moderate potential ecological risks. CONCLUSIONS: Compared with the risk screening values for soil contamination of agricultural land, the contents of Cd, Cu, Zn, Pb, Cr, Ni, As, Hg are all lower than the standard, indicating low risk for the soil environment. There were different degrees of accumulation surrounding the intense mining area of Cd, Pb, and Zn by longtime mineral development. Cu, Ni, As, Hg, and Cr were influenced by the natural factor. The farmland area with strong and very strong comprehensive potential ecological risks is 349. 4 hectares and 11. 71 hectares, respectively. Cd and Hg are the main contributing elements, with higher risk to the soil ecology, which should be monitored and controlled from source to avoid the further accumulation of heavy metal elements in the soil. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since 1972, China's uranium mining technology has developed from the first generation of technology system to the third generation of technology system, and has gradually played a leading role in the field of uranium mining and metallurgy. This paper reviews the research progress of uranium mining technology such as conventional mining,heap leaching, in-situ blasting leaching and in-situ leaching, and focuses on the mainstream technology of uranium mining-in-situ leaching technology. The ecological restoration technologies of plants, soil, landscape and groundwater microorganisms in uranium mines were reviewed. It is worth noting that microbial leaching and remediation technology will have broad application prospects in uranium mining and remediation technology because of its economic, environmental protection and high efficiency. [ABSTRACT FROM AUTHOR]

In a case study of the low-grade gold ores from an overseas mine, an experimental study on the cyanidation of high-pressure roller mill and conventional jaw crusher products is carried out and investigates the effect of the 2 comminution and grinding processes on cyanide leaching of gold.The test results show that through the high-pressure roller mill, the fine grain content in the ore products is higher than conventional jaw crusher crushing, and the grindability is better than that of the product from conventional crushing.Besides it helps reduce the cost of grinding and improve the column leaching rate of gold.Under the same leaching conditions, the column leaching rate of high-pressure roller mill products is 11-15 percentage points higher than that of the conventional crushing products.The experimental results can be referred to by the gold mine and similar mines when it comes to high-efficient development and comprehensive utilization of resources. [ABSTRACT FROM AUTHOR]

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ROM grade of certain Inner Mongolia Gold Mine is 1.64 g/t, and gold is the only valuable metal. The mine is featured with big reserve, diversified grades and different types of ores. Through analysis on ore properties and mineral processing test results, it was found that the processing and metallurgical indices vary in a great extent. To ensure the maximum economic benefit of the mime, a process to treat high-grade ores with all-slime cyanidation technique and treat low-grade ores with heap leaching technique was adopted. This paper provided a general illustration on crushing system, all-slime cyanidation system and heap leaching system of the mine, in addition, under the prerequisite to guarantee design indices and process parameters, also discussed selection of high-efficient and energy-conserving processing and metallurgical equipment as well as equipment configuration optimization as per site relief. [ABSTRACT FROM AUTHOR]

Copyright of Mining & Metallurgy (10057854) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To explore the characteristics of the effect of ore particle size on the capillary flow of solution in an ore heap, solution capillary rise experiments of two groups of ore particles, mono-size and non-uniform, were performed with an established capillary rise experimental device. The relationship of solution capillary rise height with time and the corresponding fitting equations were obtained. The regularity of solution rise velocity with time was analyzed. It is found that at the beginning of the experiment, the ore heap solution rises quickly; with the increase of time, the solution rise velocity decreases and eventually drops to zero; the maximum solution rise height and velocity have negative correlation with ore particle size. Immobile solution content inside the ore heap formed by capillary action increases with the decreasing of average particle size, and a wide range area of immobile solution will form when the content of fine particles in the ore heap is too much, which can influence the solution seepage of the ore heap.

Column leaching seepage processes were detected in a non-contact and non-destructive way by magnetic resonance imaging. Column leaching images were obtained when the flow was stationary and running. Mesoscopic seepage velocity field distribution characteristics and velocity field evolution rules inside pores were studied by analyzing the velocity value distribution, flow velocity distribution uniformity, and relationship between evenness index and spray intensity. The research shows that the velocity distribution has obvious inhomogeneity, and the flow velocity value is not in accordance with the pore size strictly. The flow velocity distribution is similar for different spray intensities. There is a positive correlation between the maximum velocity and spray intensity. A spray intensity threshold can he obtained by analyzing the relationship between velocity field uniformity and spray intensity. The value of 0.7 L·cm-2 h-1 is the intensity threshold of the designated graded distribution. Field applications of dynamic spray intensity can obviously improve the permeability of dumps and the leaching rate of copper.