Heap Leaching Process Research Articles

The combined leaching of copper, gold and uranium in chloride solutions. II. Concentrate leach tests

This study of the simultaneous leaching of copper, gold and uranium from a flotation concentrate is aimed at establishing the conditions that could be applied in a possible heap leach process that would recover all three metals (plus silver, if present) in a single step. The results obtained in this study confirm the results obtained in Part I (Nicol et al., 2024) that enhanced rates for leaching of chalcopyrite from flotation concentrates from two different sources can be obtained in acidic chloride solutions in the presence of chlorate ions. The measurements of the solution potentials during leaching with chlorate are similar to those obtained previously and confirm that chlorine generated by the chlorate-chloride reaction is the active oxidant.Uranium is dissolved even in the absence of chlorate by iron(III) as the oxidant. The latter is re-generated by reaction of iron(II) with chlorate. The dissolution of gold requires higher potentials, and it is only leached when the potential approaches 1.0 V in concentrated chloride solutions. At low chloride concentrations (1 M), gold is not dissolved because of apparent passivation.An electrochemical study of the behaviour of gold in chloride solutions in the presence of sulfide ions has shown that the passivation is probably the result of the formation of a layer of Au2S on the gold surface at low potentials before the addition of chlorate to the leach solutions i.e., before the generation of sufficient chlorine concentrations. At potentials above about 0.95 V Au2S is unstable being oxidised to AuCl2− and elemental sulfur thereby eliminating passivation.

Analisis Pendekatan Nilai %Ekstraksi Ore North Mainrigde Dengan Metode Bottle Roller Test Di PT. J Resources Bolaang Mongondow

The heap leach method is one of the cyanidation processes suitable for low-grade ore and PT J Resources Bolaang Mongondow uses this method in its processing. Column test is the most representative testwork of the heap leach process, but this testwork requires a long time so a faster testwork is needed and can provide %extraction value even though it is less representative and bottle roll test (BRT) is a solution for this. This study aims to estimate the % extraction obtained in cells by the BRT method. From the experimental results, it was obtained that the %extraction value of HG 01 samples at +12, +6, and -6 sizes was 67.1%, 79.2%, and 92.4%, respectively. for LG 02 samples of 68.3%, 81.5%, and 93.9%, for LG 03 samples of 54.5%, 90.6%, and 89.6%, respectively, these three samples are categorized as med-high extraction. While the LG 04 sample was 67.3%, 66.3%, 84.8% and categorized as low extraction.

Analysis and Prediction of the Leaching Process of Ionic Rare Earth: A Data Mining Study with Scarce Data

To unveil the impact of each condition variable on the leaching efficiency index during the heap leaching process of rare earth ore and establish a prediction model for leaching conditions and efficiency, common parameters in the heap leaching process of rare earth ore were selected. In addition, the pilot-scale test data were collected over 50 days. Based on the collected data, the Ordinary Least Squares (OLS) linear regression method was used for fitting analysis to determine each variable’s influence on the change in leaching efficiency. The results indicated a linear relationship between the flow rate of the leaching solution and leaching efficiency. In contrast, no obvious linear relationship was observed between other condition variables and leaching efficiency. Spearman’s rank correlation coefficient was calculated to analyze the nonlinear correlation between the abovementioned variables and the leaching efficiency index. The correlation coefficients were found to be −0.78, 0.88, −0.93, −0.53, 0.71, and −0.93 for ammonium content in the leaching agent, pH of the leaching agent, rare earth content, ammonium content in the leaching solution, pH of the leaching solution, and the flow rate of the leaching solution, respectively. This suggests that the flow rate of the leaching solution, rare earth content, and pH of the leaching agent significantly influence leaching efficiency, thus affecting the rare earth leaching efficiency index. Based on the correlation analysis results of leaching conditions and efficiency, a dataset with limited data trained by the common Ordinary Least Squares model, linear regression model, random forest model, and support vector machine regression model was selected to develop a prediction model for the leaching process data. The results indicated that the random forest model had the lowest mean square error of 7.47 among the four models and the coefficient of determination closest to 1 (0.99). This model can effectively analyze and predict condition variables’ data and leaching efficiency index in the heap leaching process of rare earth ore, with a prediction accuracy exceeding 90%, thus providing intelligent guidance for the heap leaching process of rare earth ores.

Fluorescence-Based Image Analysis of Seepage Behavior in Drip Irrigation: Exploring Varied Fractal Grading in Media Permeability

In the recycling of low-value metallic elements, heap leaching is commonly employed. The particle size distribution is a crucial parameter in heap leaching implementation, and the percolation behavior of a heap has always been a focal point in heap leaching technology. This paper utilizes a novel form of ultraviolet fluorescence image acquisition and fluorescence image analysis to investigate the percolation process with different fractal dimension particle size distributions, where the maximum particle diameter is 10 mm. The ore used was low-grade copper ore. The results indicate that the new fluorescence image analysis method can reveal different percolation regions during the heap leaching process, aiding in a better understanding of heap leaching behavior. The combined study found that under irrigation conditions of 10 mL/min, seepage was more uniform under the heap structure formed by a particle gradation with a fractal dimension of 2.2.

The dynamics of two iron-oxidizing Acidithiobacillus strains in industrial copper sulfide heap-leaching

Several species within the Acidithiobacillus (At.) genus can derive energy from oxidizing ferrous iron and sulfur. Two bacterial strains according to their 16S rRNA gene sequences closely related to At. ferridurans and At. ferrivorans were obtained from the industrial sulfide heap leaching process at Minera Escondida (SLH), named D2 and DM, respectively. We applied statistical and data mining analyses to the abundance of At. ferridurans D2 and At. ferrivorans DM taxa in the industrial process over 16 years of operation. In addition, we performed phylogenetic analysis and genome comparison of the type strains, as well as culturing approaches with representative isolates of At. ferridurans D2 and At. ferrivorans DM taxa to understand the differential phenotypic features. Throughout the 16 years, two main operational stages were identified based on the D2 and DM taxa predominance in solution samples. The better suitability of At. ferrivorans DM to grow in a wide range of temperature and in micro-oxic environments, and to oxidize S by reducing Fe(III) revealed through culturing approaches can, in a way, explain the taxa distribution in both operational stages. The isolate At. ferridurans D2 could be considered as a specialist in aerobic sulfur oxidation, while isolate At. ferrivorans DM is a specialist in iron oxidation. In addition, the results from ore samples occasionally obtained from the industrial heap suggest that At. ferridurans D2 abundance was more related to its abundance in the solution samples than At. ferrivorans DM was. This dynamic coincides with previously obtained results in in-lab cell-mineral attaching experiments with both strains. This information increases our knowledge the ecophysiology of Acidithiobacillus and of the importance of diverse physiological traits at industrial bioleaching scales.

Mass transfer in heap leaching of weathered crust elution deposited rare earth ore with Al2(SO4)3 solution

In order to increase efficiency and avoid NH4+–N pollution in the leaching process of weathered crust elution-deposited rare earth ores, the mass transfer in heap leaching with Al2(SO4)3 solution was simulated with column elution and experimentally optimized. The results indicate that the leaching yield is also up to 99 % for leaching with aluminum sulfate instead of ammonium sulfate. The optimal flow rate is 60 mL/h, the height equivalent to a theoretical plate (HETP) is 1.29 mm correspondingly. The peak value position of RE3+ is 60 mL/h, Fe3+ is 100 mL/h, however, Al3+ is 150 mL/h, and the heap leaching process has kinetic separation effect.

Bioleaching and Chemical Leaching of Lateritic Ore in Percolators

This work presents results of an initial exploration of nickel and cobalt bioleaching from lateritic ores in small percolators, which serve as simulations of the heap leaching process. Heap leaching offers an attractive alternative to high-pressure acid leaching of laterites, owing to its relatively simple technology, reduced capital and operational expenses, and lower carbon dioxide emissions. Conventional heap leaching of laterites relies on sulfuric acid leaching. Typically, this process consumes 400-500 kg/t of ore, necessitating the construction of a costly on-site sulfuric acid plant. However, the metabolic activity of sulfur-oxidizing bacteria can generate sulfuric acid while reducing ferric to ferrous iron, facilitating mineral dissolution through a combined protonation and reduction effect. Implementing this process eliminates the need for a sulfuric acid production plant, as the bacteria oxidize sulfur within the leaching heap. The results presented in this paper demonstrate comparable efficiencies between bioleaching and chemical leaching with sulfuric acid for nickel extraction, underscoring the importance of ferrous iron in enhancing leaching efficiency.

Dynamic of Mining Systems: Impact of Cl− Ion Concentration on Heap Copper Leaching Process at Industrial Scale

Analytical models are of vital importance to study the dynamics of complex systems, including the heap leaching process. In this work, a methodology to study the dynamics of copper recovery in the heap leaching by means of fit of analytical models that capture the leaching dynamics product of variations of leaching agents as a function of the feeding is proposed, establishing a first mode of operation keeping the leaching agent fixed (H2SO4) and a second operation mode, where Cl− is added to accelerate the reaction kinetics of sulfide minerals (secondary sulfides). Mineral recovery was modeled for the different modes of operation, dependent on the independent variables/control parameters time, heap height, leach flow rate, and feed granulometry. The results indicate that the recovery of ore from sulfide minerals is proportional to the addition of Cl−, reaching recovery levels of approximately 60%, very close to 65% recovery in conventional oxide leaching, using only H2SO4 as leaching agent. Additionally, high copper recoveries from sulfide ores are achieved at medium Cl− concentrations, but the increase in recovery at high Cl− concentrations is marginal.

Research into heap leaching technology of gold-bearing ores at the Vasilkovsky gold ore deposit (Kazakhstan)

Purpose. To study gold-bearing ores subjected to heap leaching technology to identify both free gold particles, as well as gold in aggregates and adhesions, which makes it possible to obtain data on the distribution of gold by its occurrence forms. Methodolgy. Leaching process studies are conducted at the laboratory setup of the Institute of Metallurgy and Ore Beneficiation of the Ministry of Education and Science of the Republic of Kazakhstan. The gold particles are studied using an AxioScope A1 optical microscope on the polished thin section surface. The sample materials are taken from the heap leaching site of the Vasilkovsky gold ore deposit. Findings. As a result of a microscopic test of a sample taken from the heap leaching site, ultrafine-dispersed and finely-dispersed gold particles have been found both in free form and in aggregates with waste rock and arsenical pyrite, as well as the fact of Au particles adhesions, accumulated on a grain of the host waste rock. The size class of detected Au particles varies from 0.35 to 9.5 m. Originality. For the first time, according to the samples of gold-bearing ores of the Vasilkovsky gold ore deposit, a pattern of the gold distribution according to the forms of its occurrence has been revealed. Practical value. The data obtained as a result of the research make it possible to predict the distribution of the gold form occurrence in other areas of the deposit. This can greatly simplify the conditions for its development, as well as adjust the technological process of leaching the gold-bearing ores and the main technological parameters of the heap leaching process.

Research into electro-hydraulic blasting impact on ore masses to intensify the heap leaching process

Purpose. Substantiating the main explosive impulse parameters and determining the dependences of metal recovery during forced loosening and shaking of the ore mass by an electro-hydraulic blasting to intensify the heap leaching process. Methods. The experimental laboratory studies have revealed the dependences of the discharge energy influence on the blasting pressure at various parameters of the discharge capacity and inductance, as well as the change in the metal content in the productive solution when the ore mass is exposed to an electro-hydraulic blasting. Findings. A research methodology using the models of the electro-hydraulic blasting impact on the ore mass is proposed. In addition, the similarity criteria have been substantiated, which make it possible to study the nature of shaking and loosening under various loading parameters. It has been determined that using the method of influencing the ore mass with an electric discharge in a liquid increases the degree of metal recovery from the ore during heap leaching and increases the rate of the solution penetration into the depth of the ore mass. When using the method of loosening the ore mass by artificial shaking, the recovery of copper increases by 10-15% and the leaching time decreases by 1.5 times. Originality. It has been determined that due to the possibility of regulating the electric discharge capacity in the required range during blasting operations, loosening and additional crushing of the ore mass occurs; fractures are formed in lumpy ores, which contribute to an increase in the rate of leaching solution infiltration. Practical implications. The proposed technology makes it possible, without dismantling the equipment and irrigation communications, to perform additional loosening of the ore mass and increase the rate of the leaching process, as well as significantly reduce the time of the technological process.

Kazmekhanobr's technologies in the field of processing of low-grade gold-bearing ores and technogenic raw materials

The Republic of Kazakhstan has been increasing gold production annually for the last 10–15 years. According to the results of 2019, Kazakhstan ranks 13th in the world in terms of gold production (77 tons), in terms of reserves — 16th in the world (377.5 tons). The article presents information about the innovative developments of Kazmekhanobr in the field of processing of poor goldbearing ores and man-made raw materials. Information on implemented technologies and projects in Kazakhstan for recent years is given. Kazmekhanobr’s deve lopments cover the whole complex of technological stages of processing of poor gold-bearing ores and man-made raw materials by heap leaching technology: ore preparation, leaching process, sor ption extraction of gold from productive solutions, desorption of gold from saturated sorbents and electrolytic extraction of gold from rich eluates. In particular, the company for the first time in Kazakhstan in 1998 developed and implemented pre-pelleting of ore and laying it in a pile leaching stack using a stacker at the mines “Suzdal”, “Mukur”, “Mizek”, “Komarovsky”, etc. It was also developed the highly efficient innovative technology of gold heap leaching from poor gold-bearing ores, complex gold-copper ores and technogenic wastes, which is characterized by low consumption of water and reagents and accordingly low negative load on the environment at the mines “Zhanan”, “Mukur”, “Miyali” “Balazhal”, “Aksu”,“Bestyube”,“Uzboy”, etc. Patents were obtained and a three-stage cascade scheme of sorption extraction of gold by ion exchange resin, original design of sorption columns and binding of columns were introduced, which allowed to maximize the heap leaching process and increase its efficiency, minimize processes of resin pumping processes and, accordingly, the mechanical impact on them, will increase saturation of the resin with gold and reduce the turnover of gold with working solutions at the Zhaltyrbulak, Uzboy, Vasilyevskoye deposits. Innovative processes of highefficiency technology of gold desorption and ion exchange resin regeneration, electrolytic extraction of gold from commodity regenerates have been introduced, in which the duration of gold desorption and resin regeneration together with gold electrolysis does not exceed 18–24 h. According to the projects developed by Kazmekhanobr with the use of innovative technologies, plants for the production of Dore alloy in Ust-Kamenogorsk, Semey and Stepnogorsk, Makmala (Kyrgyzstan) and the Asi gold mining plant (China) were built and successfully operate.

Understanding gangue acid consumption in copper sulfide heap leaching: Predicting the impact of carbonates, silicates and secondary precipitates

A geometallurgical model, linked to simple ore body characteristics, was established to understand short- and long-term gangue acid consumption (GAC) variability for a new copper sulfide chemical heap leaching process under standard metallurgical conditions, including an acid dose of 12 kg/t sulfuric acid during agglomeration at a particle size of 80% passing ¾”. Carbonate availability, or liberation, defined as a function of feed grade and alteration type, enabled the calculation of short-term GAC when combined with mineral abundance, assuming stoichiometric behavior. An adjustment to the acid balance needed to be applied for jarosite formation, which was made possible via a linear correlation, again related to carbonate feed content. The long-term GAC component of the ore could then be determined by difference, comparing data from the column program to the estimation of the two previous variables, resulting in the identification of biotite and chlorite as key drivers of long-term acid consumption during leaching. Final inputs for the three-stage approach to predict overall GAC were simplified to carbonate (CO3), magnesium (Mg), and iron (Fe), facilitating implementation in the 3D resource block model. Application of this methodology indicated that the magnitude of long-term GAC is reduced when higher levels of acid are consumed during the initial phases of processing. The study clearly shows how a holistic knowledge of the ore body can provide an in-depth understanding of future processing response, enabling key investment decisions to be made appropriately, prior to mine construction.

A Decision Support System for Changes in Operation Modes of the Copper Heap Leaching Process

Chilean mining is one of the main productive industries in the country. It plays a critical role in the development of Chile, so process planning is an essential task in achieving high performance. This task involves considering mineral resources and operating conditions to provide an optimal and realistic copper extraction and processing strategy. Performing planning modes of operation requires a significant effort in information generation, analysis, and design. Once the operating mode plans have been made, it is essential to select the most appropriate one. In this context, an intelligent system that supports the planning and decision-making of the operating mode has the potential to improve the copper industry’s performance. In this work, a knowledge-based decision support system for managing the operating mode of the copper heap leaching process is presented. The domain was modeled using an ontology. The interdependence between the variables was encapsulated using a set of operation rules defined by experts in the domain and the process dynamics was modeled utilizing an inference engine (adjusted with data of the mineral feeding and operation rules coded) used to predict (through phenomenological models) the possible consequences of variations in mineral feeding. The work shows an intelligent approach to integrate and process operational data in mining sites, being a novel way to contribute to the decision-making process in complex environments.

Extraction of vanadium and associated elements from black shale ores by hydrodynamic activation technology of sulfuric acid solutions

The purpose of the work was to justify the possibility of converting vanadium in ore mainly into a readily soluble form in the form of hydrated oxides — vanadyls of the general formula VO2+ X (X is an anion) due to the hydrodynamic activation of sulfuric acid solution. Leaching tests were carried out in several stages and by various methods, the duration of which depended on the final indicators of vanadium extraction into the productive solution and its residual content in ore, as well as side components (Mo, W, rare earth metals). The article for the first time is examined the extraction of vanadium and associated elements from black shale ores (Kurumsak deposits, Kyzylorda oblast, the Republic of Kazakhstan) by the hydrodynamic activation of sulfuric acid. The activation of sulfuric acid solutions is carried out in the cavitation mode in a circulating type hydrodynamic apparatus at a pressure of 5 atm supplying a fluid flow to the cavitation nozzle by means of a centrifugal pump. It was found that the hydrodynamic activation of sulfuric acid leads to a significant increase in the degree of extraction of vanadium from 6 to 87% and related components depending on the decreasing in granule size. The technological parameters of leaching, such as pH, redox potential, salinity, acid intensity and filtration, are significantly improved. The results of chemical analysis of productive leaching solutions of the ore for the total contents of V2O5, uranium and rare earth concentrates were equal to 0.62 and 0.95 g/l, 47.26 and 41.43 mg/l and 62.44 and 37.26 mg/l irrespectively, that indicate the technological possibility of carrying out the heap leaching process.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ КУЧНОГО ВЫЩЕЛАЧИВАНИЯ ЗОЛОТА В РУДНОМ ШТАБЕЛЕ (НА МЕСТОРОЖДЕНИИ «ДЕЛЬМАЧИК»)

Recently, due to the clearly expressed tendency to involve poor ores with a low content of a valuable component in the exploitation, heap leaching technology has been increasingly used. As a rule, it is sold on small reserves and sizes of ore deposits. For example, in the Transbaikal Territory, the number of developed gold-bearing de posits and potentially suitable for the development by heap leaching technology of a valuable component today is about 31. Moreover, deposits, as a rule, are located on the territory represented by frozen and permafrost soils. They are characterized by harsh climatic conditions and low-snow winters. One of the promising areas of the research is the method of block modeling, which, with the development of information technology, acquires special significance and is aimed at solving the urgent problem of three-dimensional modeling. Its main advantage is that it allows you to quantify the spatial distribution of factors, as well as the dynamics of their changes over time. The object of research is an ore stack of a technogenic deposit. The subject of the study is mathematical modeling of gold heap leaching. The purpose of the study is to develop a method for block modeling of gold heap leaching in an ore stack and a methodology for its implementation. The research methodology is the use of the regularities of filtration and physico-chemical seepage of leaching solutions through the porous medium of the ore stack. Research methods are the following: physical and mathematical methods modeling of heap leaching processes; use of statistical methods to identify patterns of spatial distribution of factors affecting the heap leaching process; use of software products (geoinformation systems) for data visualization

Studies on heap leaching of gold with the addition of sodium acetate as an intensifying reagent

One of the cheapest methods of extracting gold is heap leaching. However, the recovery of gold by this method is relatively low, compared with cyanidation of the crushed material, so the search for the ways to intensify leaching and increase gold recovery is an urgent task. Investigations on heap leaching of gold from the gold-bearing ore of the Sari Gunay deposit were conducted using a promising reagent sodium acetate to intensify the heap leaching process. The results of assay-gravimetric, chemical, mineralogical and granulometric analyses of oxidized ore are presented. The average gold content in the ore was 2.90 g/t. According to the electron probe analysis, gold in the ore is present in the form of fine (micron) inclusions in minerals and ore rocks. Comparative studies on heap leaching of gold from the crushed ore with a grain size of –20 + 0 mm with the addition of sodium acetate and without that were carried out. The degree of gold recovery with sodium acetate at a flow rate of 0.5 kg/t was 58.74%, that without sodium acetate was 54.69%, i.e. the addition of the reagent provides an increase in recovery of more than 4%. Leaching with the addition of the reagent also reduces sodium cyanide consumption from 0.65 to 0.59 kg/t. The research results have shown that sodium acetate can be used to intensify the process of heap leaching of gold when the ore size is –20+0 mm.

Deconstructing the Leaching Ratio

The heap leaching process has been widely used for recovering different metals since its first application at the end of the 1960s. In Chile, copper production via heap leaching has accounted for between 30 and 40% of annual copper production over the past 10 years. This level of production has been achieved through and supported by the use of a mathematical relation, known as the leaching ratio (LR) or irrigation ratio (IR), which relates operational parameters with metal extraction in a heap leaching operation. This ratio has been used to develop leaching column tests, to scale up results from the laboratory to industrial operations, to design new heap leaching plants, and in metallurgical control and production estimation. In spite of the widespread industrial use of this relation, few scientific studies mention it. This is due to its simplicity and basic theoretical foundations. This disparity between industrial practice and scientific research could lead to operational decisions which lack substantial theoretical support, and to scientific studies which have limited industrial impact. Against this background, several questions arise about the use of the LR: What are the constraints on the use of the LR? Are there practical advantages with respect to reported kinetic models? What is the main reason that industry prefers the use of the LR over kinetic models, which enjoy greater theoretical support? In order to guide its future use, this paper describes the leaching ratio and its current uses and limitations, through a literature review and case studies.

Зависимость скорости выщелачивания от температуры продуктивного раствора

Modern methods of heap leaching process intensification, which make it possible to increase efficiency of metal conversion into productive solution by means of mechanical activation, which will ensure metal extraction increase without additional leaching costs considered and analyzed. Mechanical activation of leaching solution - leads to increase of solution chemical activity after its treatment in activation plant. Leaching solution activation increases conversion of commercial component into liquid phase with simultaneous reduction of leaching time.

Optimization of the Heap Leaching Process through Changes in Modes of Operation and Discrete Event Simulation

The importance of mine planning is often underestimated. Nonetheless, it is essential in achieving high performance by identifying the potential value of mineral resources and providing an optimal, practical, and realistic strategy for extraction, which considers the greatest quantity of options, materials, and scenarios. Conventional mine planning is based on a mostly deterministic approach, ignoring part of the uncertainty presented in the input data, such as the mineralogical composition of the feed. This work develops a methodology to optimize the mineral recovery of the heap leaching phase by addressing the mineralogical variation of the feed, by alternating the mode of operation depending on the type of ore in the feed. The operational changes considered in the analysis include the leaching of oxide ores by adding only sulfuric acid (H2SO4) as reagent and adding chloride in the case of sulfide ores (secondary sulfides). The incorporation of uncertainty allows the creation of models that maximize the productivity, while confronting the geological uncertainty, as the extraction program progresses. The model seeks to increase the expected recovery from leaching, considering a set of equiprobable geological scenarios. The modeling and simulation of this productive phase is developed through a discrete event simulation (DES) framework. The results of the simulation indicate the potential to address the dynamics of feed variation through the implementation of alternating modes of operation.

A Brief Note on the Heap Leaching Technologies for the Recovery of Valuable Metals

Heap leaching is a low-cost technology used in industrial mining to recover precious metals such as gold and uranium, along with several other highly sought after metals like copper, from their primary resources (ores and minerals). For many decades, there has been a growing demand for heap leaching due to its environmental benefits. Heap leaching provides mining operators with a benign, effective and economical solution for the environment and produces only minor emissions from furnaces. The cost of the heap leaching process is low, making this process an attractive option from a financial standpoint. Here, we shall present a brief review of the heap leaching process when applied to the extraction of different metals from primary resources (ores and minerals). This paper presents a roadmap to satisfy future national demands for rare earth elements (REEs). This heap leaching process is applicable for the recovery of REEs from secondary resources such as mining and coal residues. Heap leaching plays a significant role in the recovery of critical elements which are used in clean and green energy applications. In the mining sector, heap leaching is a distinguished method for the recovery of valuable/beneficial metals from low-quality ore. In the present study, we shall report briefly on the heap leaching technologies for valuable metal recovery with economic advantages.