Thiousulfate Leaching in Carbonaceous Gold-Bearing Ores in Ethiopia

Thiousulfate Leaching in Carbonaceous Gold-Bearing Ores in Ethiopia | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Thiousulfate Leaching in Carbonaceous Gold-Bearing Ores in Ethiopia Kaleb Chaka, Steven Rupprecht This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4248503/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 03 Oct, 2024 Read the published version in Scientific Reports → Version 1 posted 8 You are reading this latest preprint version Abstract One of the main unit operations in metallurgical processing plant designs is gold leaching. The traditional cyanidation process was chosen and is currently in widespread use. However, the mining sector is looking for lixiviants other than cyanide. Cyanide's effects on the environment have made it difficult for humans and other biotic creatures to survive. There is now research to discover a substitute for this cyanide. It is currently argued that thiosulfate is a preferable substitute for cyanide. The effectiveness of thiosulfate as a leaching agent in carbonaceous gold-bearing ores in Ethiopia is discussed in this paper compared to cyanide. The study has looked into the advantages of employing thiosulfate over cyanide from a technical, environmental, and economic standpoint. The leaching effects of both lixiviants on carbonaceous gold-bearing ores extracted from MIDROC Legadembi Open Pit mine in Southern Ethiopia, Oromia region, were examined in a laboratory experiment. After 48 hours of leaching, it was discovered that thiosulfate has a better and quicker recovery of 91.54% over 61.70% of cyanide recovery. Tables and graphs are used to demonstrate thiosulfate's technical advantage over cyanide. As a result, this paper provides evidence regarding the Legadembi gold mine in Ethiopia's amenability to thiosulfate leaching on carbonaceous gold-bearing ores. A further research perspective is also sought for thiosulfate leaching in other refractory ores. Earth and environmental sciences/Biogeochemistry Earth and environmental sciences/Environmental sciences Earth and environmental sciences/Solid earth sciences Physical sciences/Chemistry Physical sciences/Engineering Gold leaching Carbonaceous Gold-Bearing Ores Thiosulfate Figures Figure 1 Introduction Over the past 20 years, there has been an increase in research into alternative lixiviates such as the halogens (Iodine, Bromine, and Chlorine), ammonia, thiocyanate, thiourea, thiosulfate, polysulfides, sulfite, and diethylamine for the treatment of problematic ores (Sparrow & Woodcock, 1995). Increased environmental pressure to ban or limit the use of cyanide in metallurgical plants throughout the world is a prime motivator for research into alternatives to cyanide. Some of these alternatives offer a safer and environmentally sound extraction method and, for some ores, these lixiviants can also increase the recovery of gold (Block-Bolten & Torma, 1986 ; Yen, et al., 1998). Except for chlorine, little commercial use has been made of alternative lixiviants, but several have been tested in pilot-scale plants. The most favoured current alternative to cyanide for the treatment of problematic ores is thiosulfate (Abbruzzese et al., 1995; Michel and Frenay, 1999). Before these lixiviants, the international mining community used highly toxic sodium cyanide (NaCN) to extract gold and other precious metals through milling high-grade ores and heap leaching of low-grade ores (Korte et al. 2000 ). The process to concentrate gold using cyanide was developed in Scotland in 1887 and was used almost immediately in the Witwatersrand gold fields of the Republic of South Africa. Heap leaching with cyanide was proposed by the U.S. Bureau of Mines in 1969 as a means of extracting gold from low-grade ores. The gold industry adopted the technique in the 1970s, soon making heap leaching the dominant technology in gold extraction (Da Rosa and Lyon, 1997). The process of gold dissolution in cyanide (and consequently the extraction of gold from its ores by cyanide) involves heterogeneous reactions at the solid-liquid interfaces. Hence, the following sequential steps may be assumed to lead to the dissolution of gold (from its ores) by cyanide: Absorption of oxygen in solution, Transport of dissolved cyanide and oxygen to the solid-liquid interface, Adsorption of the reactants (CN - and O 2 ) on the solid surface, Electrochemical reaction, Adsorption of the soluble gold-cyanide complexes and other reaction products from the solid surface, Transport of the adsorbed products into the bulk of solutions. The dissolution of gold is an oxidation-reduction process in which cyanide ions form a strong complex with Au + ions. The stable complex ion is (Au (CN) 2- ). The overall reaction, where oxygen is reduced and hydrogen peroxide is formed to be the oxidizing agent in the second step, is presented below: \(2\varvec{A}\varvec{u}+4\varvec{C}{\varvec{N}}^{-}+{\varvec{O}}_{2}+{\varvec{H}}_{2}\varvec{O}=2\varvec{A}\varvec{u}{\left(\varvec{C}\varvec{N}\right)}^{-2}+{\varvec{H}}_{2}{\varvec{O}}_{2}+20{\varvec{H}}^{-1}\) (Eq. 1) \(2\varvec{A}\varvec{u}+4\varvec{C}{\varvec{N}}^{-}+{\varvec{H}}_{2}{\varvec{O}}_{2}=2\varvec{A}\varvec{u}{\left(\varvec{C}\varvec{N}\right)}^{-2}+20{\varvec{H}}^{-}\) (Eq. 2) \(4\varvec{A}\varvec{u}+8\varvec{C}{\varvec{N}}^{-}+{\varvec{O}}_{2}+2{\varvec{H}}_{2}\varvec{O}=4\varvec{A}\varvec{u}{\left(\varvec{C}\varvec{N}\right)}^{-2}+40{\varvec{H}}^{-}\) (Eq. 3) However, in recent years, thiosulfate has been considered the most attractive alternative to cyanide for leaching gold, with many investigations taking place worldwide. This is primarily based on its low toxicity and potential use on ‘preg-robbing’ carbonaceous ores that conventional cyanidation cannot readily treat. It has been known for over a hundred years that gold can be leached with thiosulfate. Thiosulfate was the main competitor to cyanide in the 1880s when there was an increase in research to improve gold leaching and recovery from the existing gravity and mercury amalgamation processes. Thiosulfate is a structural analogue of sulfate, replacing one oxygen atom with a sulfur atom. This gave thiosulfate its former name of hyposulfite (Hiskey & Alturi, 1988; White, 1905 ). The structure S-SO 3 -2 is dominated by the sulfur atom, which gives thiosulfate its reducing properties, strong complexing tendencies, and sulfide-forming capabilities (Hiskey & Alturi, 1988). The proposed mechanism for the dissolution of gold in ammoniacal thiosulfate solutions is more complex than portrayed here. It has been suggested that gold is oxidised by copper (II), and the gold diamine complex is subsequently converted to the gold thiosulfate complex as shown below (Deschene, 1998; Breuer et al., 2000): \(\mathbf{A}\mathbf{u}+\mathbf{C}\mathbf{u}{\left(\mathbf{N}{\mathbf{H}}_{3}\right)}_{4}^{+2}+2{\mathbf{S}}_{2}{\mathbf{O}}_{3}^{-2}=\mathbf{A}\mathbf{u}{\left(\mathbf{N}{\mathbf{H}}_{3}\right)}_{2}^{+}+\mathbf{C}\mathbf{u}{\left({\mathbf{S}}_{2}{\mathbf{O}}_{3}\right)}_{2}^{-3}+2\mathbf{N}{\mathbf{H}}_{3}\) (Eq. 4) \(\mathbf{A}\mathbf{u}{\left(\mathbf{N}{\mathbf{H}}_{3}\right)}_{2}^{+}+ 2{\mathbf{S}}_{2}{\mathbf{O}}_{3}^{-2}= \mathbf{A}\mathbf{u}{\left({\mathbf{S}}_{2}{\mathbf{O}}_{3}\right)}_{2}^{-3}+ 2\mathbf{N}{\mathbf{H}}_{3}\) (Eq. 5) This paper aims to examine the environmental and economic implications of utilising thiosulfate for gold leaching in ores that are carbonaceous (preg-robbing) and contain gold. The technical feasibility has been demonstrated in connection with an improved leaching recovery or efficiency compared to the conventional cyanidation process. As there are few publications on the topic, this paper will add to the current body of knowledge on utilising thiosulfate for gold leaching in carbonaceous ores. The authors hope this study will provide the reader with information about the economic, environmental, and technical aspects of employing thiosulfate lixiviants instead of cyanide leaching, specifically in Ethiopia's gold ore. The findings will be particularly important to Ethiopia's gold metallurgical environment and future thiosulfate leaching research undertaken by other academics. Study Methodology First, a comprehensive analysis of the characteristics of carbonaceous ores and how they could be processed using conventional cyanidation methods was conducted. Numerous books, journals, and research papers were examined for this purpose. Next, research was done on the use and technical feasibility of thiosulfate as a gold-leaching agent. Studies have also been conducted on the effects of associated reagents used in leaching. In light of this, the authors have attempted to validate their findings by performing laboratory experiments on the leaching process. This has aided in establishing the effect of some of the parameters under study. To amplify the non-environmental effect of thiosulfate leaching, the environmental effects of the cyanidation process are then investigated. The paper has attempted to demonstrate why a restriction on the use of cyanide (CN - ) in the mining industry is desired and how it poses an environmental risk to bio species. Lastly, the economics of employing thiosulfate leaching over conventional cyanidation methods for carbonaceous gold-bearing ores have been examined. The findings of the technical inquiry are then presented, together with the economic conclusions. A. Experimental Method In a laboratory, the amenability of carbonaceous gold-bearing ores to thiosulfate leaching was tested. The test aimed to demonstrate the technical benefits of thiosulfate leaching over conventional cyanidation. MIDROC Legadembi’s operating conditions provided for the ideal cyanidation settings and optimal leaching conditions for thiosulfate lixiviants were taken from literatures. Broken ore from the Legadembi Open Pit gold mine was obtained for testing from two locations on the North-East Footwall side, which contained 30kg carbonaceous gold bearing ores with grades greater than 1g/t. The following is a presentation of the test findings and laboratory experiments. The samples were oven-dried for over 20 hours to evaporate the surface moisture of the ore, then ground to P80 (80% passing) of 75µm in a pulverizer for five minutes. To create a typical sample ore, the two ore samples were mixed to a 1:1 ratio; then the samples were mixed in a tumbler machine for 30 minutes to guarantee that they were distributed evenly. B. Leaching Experiment Before the leaching test, a sample of the ore was sent to the Analytical laboratory for gold analysis by fire assay; and it was found through triplet sample analysis that the ore sample had a gold grade of 1.25g/t. Please see Table 1 below: Table 1 Sample Gold Assay Triplet Analysis Sample No. Grade (gm/ton) Average Grade (g/t) Sample No. 1 1.34 Sample No. 2 1.19 1.25 Sample No. 3 1.22 The combined ore sample was subjected to a series of bottle leach tests to ascertain the reagent concentration needed to recover the largest amount of gold. All the regents were dissolved in a beaker, and quick lime (CaO) was used to raise the pH from 10.0 to 11.5. The pH of the solution was measured using a pH meter. While Tests 3 and 4 had one parameter changed from the base case scenarios and were also conducted in parallel, Tests 1 and 2 were the base case scenarios. The tests that were run and the parameters examined for this study are briefly shown in the following summary. Laboratory Test Summary Activity Thiosulfate leaching Vs. Cyanide leaching in Carbonaceous Gold Bearing Ores Duration April 12th − 22nd 2016 Venue MIDROC Gold Mine Legadembi Laboratory Services Laboratory Test Conditions : Keep the pulp density constant at 50% solid (pulp density) and vary the concentration of the lixiviants Keep the pH range 10.0-11.5 Keep the leaching process going for 48 hrs. residence time (or leaching time). General test conditions, which are common for both lixiviants, such as % solid, pH, residence time, etc., were kept constant as ground for comparing the two leaching agents. The initial solution strength will vary, and the focus will be on the free cyanide in the solution to see the preg-robbing effect and to make up for the lost cyanide for assisting the leach. See Table 2 below for the summary of laboratory test conditions. Procedure : Take a sample and crush it to a size of -10 mm with a jaw crusher Take the crushed sample and crush it again to a size of -1 mm with a Boyd crusher (for 5 mins) Then pulverize (grind) the crushed material to a size of -75 microns to liberate the metal (Au) inside the ore Then, with a manual splitter, obtain a representative sample of about 2 Kg for the tests (four samples) Prepare the reagents to be added with the appropriate concentration strength Prepare a 50% solid sample by adding two litres of water to the prepared 2kg samples Adjust the pH of the pulp to a range between 10.0 and 11.5 by adding lime (CaO) accordingly Finally, add the reagents to their respective leach bottles into the prepared pulp and start agitating the mix to 200 rpm to promote homogeneity and increase the kinetics of the reaction, thereby increasing the leaching process Take leaching samples to check the progress of the dissolution of gold with the proposed lixiviants Table 2 Laboratory Test Conditions No. Experimental Conditions First Run Second Run 1 Head Grade 1.25 g/t 1.25 g/t 2 NaCN strength 0.5 g/l 0.25 g/l 3 Thiosulfate strength 9 gm/lit 8 g/l 4 Ammonia 13.6 g/l 13.6 g/l 5 Copper Sulfate 0.8 g/l 0.8 g/l 6 Sample size 2 kg 2 kg 7 Pulp density 50% Solid 50% Solid 8 pH 10.0 11.5 9 Leaching time 48 hours 48 hours 10 Temperature 20–25 0 C (Room temp.) 20-25 0 C (Room temp.) Result and Discussion This paper has attempted to demonstrate the technical superiority of thiosulfate over cyanide through laboratory testing. Table 3 provide the results of the two test runs, considering the variations in general leach circumstances. A conclusion has been reached by comparing the chemical properties of cyanide and thiosulfate lixiviants in order to illustrate the economic aspects of leaching. I. First Run Table 3 First Run Laboratory Results Test-1 Thiosulfate (9 g/l) Time (hr.) Au in solution (g/t) Percent Recovery (%) pH Free TS (ppm) 0 0.00 0.00 10.0 ND 2 0.32 25.64 11.18 ND 4 0.40 32.05 10.90 ND 8 0.52 41.67 10.62 ND 24 0.71 56.89 10.07 ND 30 0.74 59.29 9.79 ND 48 1.13 90.54 10.24 ND Test-2 Sodium Cyanide (0.5 g/l) Time (hr.) Au in solution (g/t) Percent Recovery (%) pH Free CN − (ppm) 0 0.00 0.00 10.0 500 2 0.26 20.83 10.26 460 4 0.35 28.04 10.24 450 8 0.51 40.87 9.97 350 24 0.63 50.48 9.86 300 30 0.72 57.69 10.65 285 48 0.77 61.70 10.24 200 For the two leaching agents mentioned above, comparable test circumstances were employed. Therefore, as Table 3 illustrates, thiosulfate exhibits more technical superiority over cyanide, producing a gold recovery in a solution of approximately 90.54% compared to cyanide's 61.70% after 48 hours of leaching. This suggests that in carbonaceous preg-robbing gold-bearing ores, thiosulfate has a far superior leaching recovery than cyanide. II. Second Run Table 4 Second Run Laboratory Results Test-3 Thiosulfate (8 g/l) Time (hr.) Au in solution (g/t) Percent Recovery (%) pH Free TS (ppm) 0 0.00 0.00 11.50 ND 2 0.41 32.85 11.67 ND 4 0.46 36.86 11.61 ND 8 0.52 41.67 11.44 ND 24 0.74 59.29 11.59 ND 30 0.78 62.50 11.51 ND 48 0.83 66.51 11.18 ND Test-4 Sodium Cyanide (0.25 gm/lit) Time (hr.) Au in solution (gm/ton) Percent Recovery (%) pH Free CN − (ppm) 0 0.00 0.00 11.92 250 2 0.22 17.63 11.69 150 4 0.30 24.04 11.60 35 + 150 8 0.37 29.65 11.42 150 24 0.33 26.44 11.72 100 + 150 30 0.45 36.06 11.35 200 48 0.48 38.46 11.21 150 The outcome of the fourth test as depicted in Table 4 demonstrates the preg-robbing impact of carbonaceous gold-bearing ores as leaching progresses and eliminates the free cyanide in the solution. Due to the nature of the ore, which absorbs free cyanide in solution to form other undesirable cyanide complexes, there is a significant loss of free cyanide in solution, as demonstrated by the cyanide leaching, which shows 35 ppm of free cyanide in solution at the beginning of the leaching process. Nonetheless, it is essential to note that for the gold dissolution reaction to occur, the solution must include at least 100–150 ppm of free cyanide. To make up for the lost cyanide in the solution, 0.15g/l of free cyanide was added to the leach solution on the fourth and twenty-fourth hours. This has increased the processing costs of the cyanidation leaching for carbonaceous gold-bearing ores and have a negative economic impact due to overdosing on cyanide dosage. The result implies a faster leach recovery by thiosulfate, which also demonstrates a higher leaching recovery of 66.51% of thiosulfate over 26.44% cyanide leach in 24 hours of residence time. The results presented here solely demonstrate thiosulfate's technical advantage over cyanide. However, greater recovery may be obtained if conditions could be improved to a better state with a thorough study to be conducted by adjusting reagent concentrations and other leach conditions. The result also shows a superior leaching recovery of 66.51% of thiosulfate over 26.44% cyanide leach in 24 hrs. of residence time, implying a faster leach recovery by thiosulfate. The figures here only indicate the technical superiority of thiosulfate over cyanide. But, if conditions could be optimized to a better state with rigorous research to be undertaken by varying reagent concentrations and other conditions for leach, a much better recovery and sound figures could be obtained. The preg-robbing effect, in which the leached gold in solution is stolen by the free carbon and other hydrocarbons from the carbonaceous ore, is further demonstrated by the lower percent recoveries and changes in recovery for cyanide in Test 4. This resulted in a significant drop of gold in the solution. The other thing the authors noticed in the test results was the status of the solution's alkalinity for the best thiosulfate recovery. Test-1, conditioned at pH 10.0, produced a higher recovery of around 90.54%, while Test 3, conditioned at pH 11.5, produced a solution recovery of 62.5%. This study unequivocally demonstrated that the lower alkaline bound, or pH range of 9–10.5, yields a better and faster recovery of gold in thiosulfate solution. This pH range allows for the best possible recovery of gold in thiosulfate solutions. Figure 1 below, displaying Residence time vs. Percent recovery clearly illustrates the discussions surrounding the aforementioned leaching results. Finally, the gold left in the solid as residue after being fire assayed on finalizing the leaching process was examined in the laboratory, and the result is shown in Table 5 : Head grade = 1.25 g/t Table 5 Gold grade in the solid residue Test No. Solid Grade (Residue, g/t) Au in Solution after 48hrs. (g/t) Head Grade (g/t) Test-1 (TS) 0.12 1.13 Test-2 (CN) 0.50 0.77 1.25 Test-3 (TS) 0.45 0.78 Test-4 (CN) 0.68 0.48 A. Economic result This section compares the costs of cyanidation with thiosulfate leaching of gold ores. In addition to the primary operational expenses incurred during the conventional cyanidation process of detoxifying the cyanide from the tailing management facility, expenditures related to direct chemical consumption are also utilised for both lixiviants. Table 6 lists the costs along with the process for analyzing them. The Legadembi metallurgy plant at MIDROC Gold Mine provided the following reagent cost, which is based on the current market pricing in Ethiopian Birr. Table 6 Leaching Reagent Consumption and Costs Chemical Name Unit Unit price (ETB) Specific Consumption (Kg/t) Amount (ETB/t) Sodium cyanide Kg 81.69 0.80 65.35 Sodium thiosulfate Kg 16.60 9.00 149.40 Ammonia Kg 9.00 13.60 122.40 Copper sulfate Kg 44.00 0.80 35.20 Hypochlorite Kg 79.64 0.02 1.59 Taking a particular case for MIDROC Legadembi mine, a facility which processes 1,100,000 tons of gold ore annually with the conventional cyanidation method to estimate operating costs; the detox plant uses a minimum of 20 tonnes of hypochlorite per annum for treating cyanide in tailing solution and taking an average power consumption charge of 0.60 ETB/KWh by EEPCO. Table 7 provides information about operating cost analysis for the detox process, with cost details depicted on Table 7 a and Table 7 b. Table 7 Detoxification Operating Cost Analysis Item No. Major Items Costs Per Annum (ETB) 1 Detox plant operating items ( Details : Table 7 a ) - 1.1 Spare part replacements 950,000.00 1.2 Running items and Utilities 446,266.80 2 Tailing dam operating items ( Details : Table 7 b ) - 2.1 Spare part replacements 2,610,000.00 2.2 Running items and Utilities 549,564.00 3 Supervisory fee for two Units (One person working for 8hrs/day with monthly salary of 10,000ETB) 120,000.00 Grand Total 4,621,080.80 Annual Budgeted Plant Processing Capacity 1.1 million tons Unit Cost for Detoxification of Cyanide Tailings (ETB/t) 4.20 Table 7a Detox Plant Operating Items Item No. Spare part Replacements Costs per Annum (ETB) 1 Electrical parts (breakers, contactors, cables etc.) 200,000.00 2 Pump parts 300,000.00 3 Pipes and Valve replacements 250,000.00 4 Tank spare parts (gearbox and others) 200,000.00 Total 950,000.00 Item No. Running items and Utilities Costs per Annum (ETB) 1 Consumables for Cyanide titration & pH determination 54,750.00 2 Power consumption for: 2.1 Mixing tank agitator at 11KW capacity working for 24 hours per day 57,816.00 2.2 Transfer pump at 11KW capacity working for 24 hours per month 1,900.80 2.3 Dozing pump at 10KW capacity working for 20 hours per day 43,800.00 3 Man power (four operators with 6,000 ETB monthly salary each) 288,000.00 Total 446,266.80 Table 7b Tailing Dam Operating Items Item No. Spare part Replacements Costs per Annum (ETB) 1 Electrical parts (breakers, contactors, cables etc.) 100,000.00 2 Pump parts 1,200,000.00 3 Return pipe and fitting replacements 1,100,000.00 4 Hose and Valve parts 150,000.00 5 Bearing replacements 60,000.00 Total 2,610,000.00 Item No. Running items and Utilities Costs per Annum (ETB) 1 Consumables for Cyanide titration & pH determination 54,750.00 2 Power consumption for: 2.1 Two Return pumps at 11KW capacity working for 23 hours per day 110,814.00 3 Man power (Eight operators with 4,000 ETB monthly salary each) 384,000.00 Total 549,564.00 Pre-treatment of ores is mandatory for refractory ores before leaching with cyanide. Thus, roasting of ores as pre-treatment method has been adopted for this economic analysis. The roasting cost for carbonaceous ores here has been estimated with taking a particular case of Derba Cement’s clinker production kiln (Table 8 ), a major cement producing company in Ethiopia. The Derba kiln uses around 735 KCAL of energy to produce 1 Kg of clinker The cement plant mostly uses lignite coals as energy source with caloric value of around 2310 KCAL/Kg Lignite coal types are sold with 938.40 ETB per tons at international market including 20% for overhead cost Table 8 Roasting Cost Estimation Pre-treatment (Roasting cost ) Economic output Kiln coal requirement 0.32 Kg/Kg of clinker 300.80 ETB/t of clinker Lignite unit price 0.94 ETB/Kg The cement plant kiln for clinker production could here be taken as equivalent to a kiln used for roasting of refractory ores to produce pre-treated ores for cyanide leaching for estimating roasting cost; which resulted in 300.80 ETB/t of ore pre-treated. In summary, the above cost analysis gives the following summarised costs for both lixiviants as shown in Table 9 : Table 9 Leaching Economics Result Leaching Method Total Unit Cost (ETB/t) Cyanide Leaching 371.94 Thiosulfate Leaching 307.00 The result demonstrates that thiosulfate leaching of gold also benefits the economy. By improving the thiosulfate leach process for refractory ores, which would probably reduce the requirement of higher concentrations of reagents in the leach system, this economic benefit of thiosulfate might be further utilised. The increased cost of the conventional cyanidation process demonstrates why such types of refractory ores are not treated using this method. Thiosulfate recovery offers a considerable advantage over cyanide, as can be seen from the test results. This means that there will be an increase in revenue as the recovery is increased by utilising thiosulfate. Furthermore, quantifying the non-environmental benefits of thiosulfate vs cyanide in monetary terms would undoubtedly increase the thiosulfate leach system's economic advantage for carbonaceous ores. Conclusion and Recommendation The results of this paper support the hypothesis that thiosulfate will improve and speed up the recovery when leaching carbonaceous gold-bearing ores. The following observations and conclusions are made. The current study indicates that thiosulfate, at a concentration of 9 gm/l, has a higher recovery (90.54%) in carbonaceous gold-bearing ores than cyanide (61.70%). If more research were conducted on the general test circumstances, altering the crucial factors such as pulp density (% solid), reagent concentration, pH, and so on, the results could be enhanced even more. The results also indicate that, with a minimum residence time of 24 hours, thiosulfate could dissolve gold in carbonaceous gold-bearing ores more quickly than other chemicals, with a 66.51% recovery rate. This phenomenon might be further exploited to reach the 73% recovery within four hours of residence time. Because the primary chemical agents in the leaching process (sodium thiosulfate and ammonia solution) are popular fertilizers, using mine tailings in agricultural applications is also possible in countries where environmental regulations are very stringent. Since environmental concerns are no longer regarded luxury items in the twenty-first century and permission for any new gold project using cyanide is highly unlikely in certain parts of the world, thiosulfate may soon replace cyanide as the major leaching agent. The increased regulatory scrutiny of new gold projects and the reduction in allowed cyanide discharge levels are of great concern to mining companies. Due to cyanide's inefficiency with some refractory ore types, the decrease in free milling ore also increases the need for thiosulfate leaching. Thiosulfate lixiviants can be used for various purposes in these and related illnesses. To ascertain the precise circumstances in which thiosulfate could benefit the mining industry, a thorough investigation of the electrochemistry of the leach process and concepts related to the reduction potential and Gibbs free energy are necessary and should be studied seriously. Declarations We hereby declare that this work presented for publication is a true account of our own work except where particularly all sources of information have been acknowledged by means of reference. Author Contribution Kaleb Jia Chaka conducted the research and wrote the manuscript.Steven Rupprecht reviewed and corrected the manuscript to fit with publication standards. 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The cyanide leaching gold recovery process is a nonsustainable technology with unacceptable impacts on ecosystems and humans: the disaster in Romania. Ecotoxicology and environmental safety , 46 (3), pp.241-245. Helm, M., Vaughan, J., Staunton, W.P. and Avraamides, J., 2009, October. An investigation of the carbonaceous component of preg-robbing gold ores. In World gold conference (pp. 139-144). Aylmore, M.G., 2005. Alternative lixiviants to cyanide for leaching gold ores. Developments in Mineral Processing , 15 , pp.501-539. Molleman, E., 1998. The treatment of copper-gold ores by ammonium thiosulfate leaching (Doctoral dissertation, University of British Columbia). O'Malley, G.P., 2002. Recovery of gold from thiosulfate solutions and pulps with anion-exchange resins (Doctoral dissertation, Murdoch University). Oraby, E.A., 2009. Gold leaching in thiosulfate solutions and its environmental effects compared with cyanide (Doctoral dissertation, Curtin University). Wan, R.Y. and LeVier, K.M., 2003. Solution chemistry factors for gold thiosulfate heap leaching. International Journal of Mineral Processing , 72 (1-4), pp.311-322. La Brooy, S.R., Linge, H.G. and Walker, G.S., 1994. Review of gold extraction from ores. Minerals Engineering , 7 (10), pp.1213-1241. Keskinen, S., 2013. Comparison of Cyanide and Thiosulphate Leaching for Gold Production (A Literature Review). Block-Bolten, A. and Torma, A.E., 1986. Thiosulfate leaching of gold from sulfide wastes. Metall (Berlin);(Germany, Federal Republic of) , 40 (7). Tykodi, R.J., 1990. In praise of thiosulfate. Journal of chemical education , 67 (2), p.146. Eisler, R. and Wiemeyer, S.N., 2004. Cyanide hazards to plants and animals from gold mining and related water issues. Reviews of environmental contamination and toxicology , pp.21-54. Xia, C., Yen, W.T. and Deschenes, G., 2003. Improvement of thiosulfate stability in gold leaching. Mining, Metallurgy & Exploration , 20 , pp.68-72. Yannopoulos, J.C., 2012. The extractive metallurgy of gold . Springer Science & Business Media. Zhang, J., Lan, X.Z., Yu, N.W., Ding, F., He, H., Huang, Y., Yu, R. and Zhang, S., 1993. Leaching gold and platinum group metals by the LSSS method. Precious Metals 1993 , pp.281-288. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 03 Oct, 2024 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 11 Jun, 2024 Reviews received at journal 06 Jun, 2024 Reviewers agreed at journal 16 May, 2024 Reviewers invited by journal 14 May, 2024 Editor assigned by journal 14 May, 2024 Editor invited by journal 22 Apr, 2024 Submission checks completed at journal 22 Apr, 2024 First submitted to journal 10 Apr, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4248503","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":294499200,"identity":"fc8c58cb-4de0-47b7-b905-fab09444591d","order_by":0,"name":"Kaleb Chaka","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYBACxmYGZgaGAoYEfhAvoYBoLQYMCZINIC0GxFkE0WJwAMQmRgtzO/Njgx8GNnnG51cnfnhgwCDPL3aAkMPYjBN7DNKKzW683SwBdJjhzNkJhLQwGB/gMTicuO3G2Q0gLQkGtwlqYf988I/B/8TNM85u/kGkFh7jZB6DA4kb+Hu3EWsLT7GxjEFyscQN3m0WCQYShP1i2H98s+SbCrs8/v6zm2/+qLCR55cmpKUBxpIAq5TArxwE5OEs/gOEVY+CUTAKRsHIBACdmkNAvV1BYQAAAABJRU5ErkJggg==","orcid":"","institution":"Unity University College","correspondingAuthor":true,"prefix":"","firstName":"Kaleb","middleName":"","lastName":"Chaka","suffix":""},{"id":294499202,"identity":"e461642b-c84d-4397-bf9c-4fe42156d9ac","order_by":1,"name":"Steven Rupprecht","email":"","orcid":"","institution":"Southern African Institute of Mining and Metallurgy","correspondingAuthor":false,"prefix":"","firstName":"Steven","middleName":"","lastName":"Rupprecht","suffix":""}],"badges":[],"createdAt":"2024-04-10 16:35:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4248503/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4248503/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-69646-3","type":"published","date":"2024-10-03T15:56:54+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":55381931,"identity":"a7594932-5b1f-4aae-935b-a842e72156fb","added_by":"auto","created_at":"2024-04-26 13:55:19","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":96921,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003ePercent recovery Vs residence time graph\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4248503/v1/5bcf898515b697f2ca868501.jpg"},{"id":66096671,"identity":"dea535e3-f5b2-4d20-a0a9-ba9f8f048629","added_by":"auto","created_at":"2024-10-07 16:06:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":973639,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4248503/v1/8bad35b1-22d2-4158-a67c-c20ce5c57345.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Thiousulfate Leaching in Carbonaceous Gold-Bearing Ores in Ethiopia","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOver the past 20 years, there has been an increase in research into alternative lixiviates such as the halogens (Iodine, Bromine, and Chlorine), ammonia, thiocyanate, thiourea, thiosulfate, polysulfides, sulfite, and diethylamine for the treatment of problematic ores (Sparrow \u0026amp; Woodcock, 1995). Increased environmental pressure to ban or limit the use of cyanide in metallurgical plants throughout the world is a prime motivator for research into alternatives to cyanide. Some of these alternatives offer a safer and environmentally sound extraction method and, for some ores, these lixiviants can also increase the recovery of gold (Block-Bolten \u0026amp; Torma, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e1986\u003c/span\u003e; Yen, et al., 1998). Except for chlorine, little commercial use has been made of alternative lixiviants, but several have been tested in pilot-scale plants. The most favoured current alternative to cyanide for the treatment of problematic ores is thiosulfate (Abbruzzese et al., 1995; Michel and Frenay, 1999).\u003c/p\u003e \u003cp\u003eBefore these lixiviants, the international mining community used highly toxic sodium cyanide (NaCN) to extract gold and other precious metals through milling high-grade ores and heap leaching of low-grade ores (Korte et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). The process to concentrate gold using cyanide was developed in Scotland in 1887 and was used almost immediately in the Witwatersrand gold fields of the Republic of South Africa. Heap leaching with cyanide was proposed by the U.S. Bureau of Mines in 1969 as a means of extracting gold from low-grade ores. The gold industry adopted the technique in the 1970s, soon making heap leaching the dominant technology in gold extraction (Da Rosa and Lyon, 1997).\u003c/p\u003e \u003cp\u003eThe process of gold dissolution in cyanide (and consequently the extraction of gold from its ores by cyanide) involves heterogeneous reactions at the solid-liquid interfaces. Hence, the following sequential steps may be assumed to lead to the dissolution of gold (from its ores) by cyanide:\u003c/p\u003e \u003cp\u003e \u003col style=\"list-style-type:upper-roman;\"\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAbsorption of oxygen in solution,\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eTransport of dissolved cyanide and oxygen to the solid-liquid interface,\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAdsorption of the reactants (CN\u003csup\u003e-\u003c/sup\u003e and O\u003csub\u003e2\u003c/sub\u003e) on the solid surface,\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eElectrochemical reaction,\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAdsorption of the soluble gold-cyanide complexes and other reaction products from the solid surface,\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eTransport of the adsorbed products into the bulk of solutions.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eThe dissolution of gold is an oxidation-reduction process in which cyanide ions form a strong complex with Au\u0026thinsp;+\u0026thinsp;ions. The stable complex ion is (Au (CN) \u003csup\u003e2-\u003c/sup\u003e). The overall reaction, where oxygen is reduced and hydrogen peroxide is formed to be the oxidizing agent in the second step, is presented below:\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(2\\varvec{A}\\varvec{u}+4\\varvec{C}{\\varvec{N}}^{-}+{\\varvec{O}}_{2}+{\\varvec{H}}_{2}\\varvec{O}=2\\varvec{A}\\varvec{u}{\\left(\\varvec{C}\\varvec{N}\\right)}^{-2}+{\\varvec{H}}_{2}{\\varvec{O}}_{2}+20{\\varvec{H}}^{-1}\\)\u003c/span\u003e \u003c/span\u003e \u003cb\u003e(Eq.\u0026nbsp;1)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(2\\varvec{A}\\varvec{u}+4\\varvec{C}{\\varvec{N}}^{-}+{\\varvec{H}}_{2}{\\varvec{O}}_{2}=2\\varvec{A}\\varvec{u}{\\left(\\varvec{C}\\varvec{N}\\right)}^{-2}+20{\\varvec{H}}^{-}\\)\u003c/span\u003e \u003c/span\u003e \u003cb\u003e(Eq.\u0026nbsp;2)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(4\\varvec{A}\\varvec{u}+8\\varvec{C}{\\varvec{N}}^{-}+{\\varvec{O}}_{2}+2{\\varvec{H}}_{2}\\varvec{O}=4\\varvec{A}\\varvec{u}{\\left(\\varvec{C}\\varvec{N}\\right)}^{-2}+40{\\varvec{H}}^{-}\\)\u003c/span\u003e \u003c/span\u003e \u003cb\u003e(Eq.\u0026nbsp;3)\u003c/b\u003e\u003c/p\u003e \u003cp\u003eHowever, in recent years, thiosulfate has been considered the most attractive alternative to cyanide for leaching gold, with many investigations taking place worldwide. This is primarily based on its low toxicity and potential use on \u0026lsquo;preg-robbing\u0026rsquo; carbonaceous ores that conventional cyanidation cannot readily treat. It has been known for over a hundred years that gold can be leached with thiosulfate. Thiosulfate was the main competitor to cyanide in the 1880s when there was an increase in research to improve gold leaching and recovery from the existing gravity and mercury amalgamation processes.\u003c/p\u003e \u003cp\u003eThiosulfate is a structural analogue of sulfate, replacing one oxygen atom with a sulfur atom. This gave thiosulfate its former name of hyposulfite (Hiskey \u0026amp; Alturi, 1988; White, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1905\u003c/span\u003e). The structure S-SO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-2\u003c/sup\u003e is dominated by the sulfur atom, which gives thiosulfate its reducing properties, strong complexing tendencies, and sulfide-forming capabilities (Hiskey \u0026amp; Alturi, 1988). The proposed mechanism for the dissolution of gold in ammoniacal thiosulfate solutions is more complex than portrayed here. It has been suggested that gold is oxidised by copper (II), and the gold diamine complex is subsequently converted to the gold thiosulfate complex as shown below (Deschene, 1998; Breuer et al., 2000):\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\mathbf{A}\\mathbf{u}+\\mathbf{C}\\mathbf{u}{\\left(\\mathbf{N}{\\mathbf{H}}_{3}\\right)}_{4}^{+2}+2{\\mathbf{S}}_{2}{\\mathbf{O}}_{3}^{-2}=\\mathbf{A}\\mathbf{u}{\\left(\\mathbf{N}{\\mathbf{H}}_{3}\\right)}_{2}^{+}+\\mathbf{C}\\mathbf{u}{\\left({\\mathbf{S}}_{2}{\\mathbf{O}}_{3}\\right)}_{2}^{-3}+2\\mathbf{N}{\\mathbf{H}}_{3}\\)\u003c/span\u003e \u003c/span\u003e \u003cb\u003e(Eq.\u0026nbsp;4)\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\mathbf{A}\\mathbf{u}{\\left(\\mathbf{N}{\\mathbf{H}}_{3}\\right)}_{2}^{+}+ 2{\\mathbf{S}}_{2}{\\mathbf{O}}_{3}^{-2}= \\mathbf{A}\\mathbf{u}{\\left({\\mathbf{S}}_{2}{\\mathbf{O}}_{3}\\right)}_{2}^{-3}+ 2\\mathbf{N}{\\mathbf{H}}_{3}\\)\u003c/span\u003e \u003c/span\u003e \u003cb\u003e(Eq.\u0026nbsp;5)\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThis paper aims to examine the environmental and economic implications of utilising thiosulfate for gold leaching in ores that are carbonaceous (preg-robbing) and contain gold. The technical feasibility has been demonstrated in connection with an improved leaching recovery or efficiency compared to the conventional cyanidation process. As there are few publications on the topic, this paper will add to the current body of knowledge on utilising thiosulfate for gold leaching in carbonaceous ores. The authors hope this study will provide the reader with information about the economic, environmental, and technical aspects of employing thiosulfate lixiviants instead of cyanide leaching, specifically in Ethiopia's gold ore. The findings will be particularly important to Ethiopia's gold metallurgical environment and future thiosulfate leaching research undertaken by other academics.\u003c/p\u003e"},{"header":"Study Methodology","content":"\u003cp\u003eFirst, a comprehensive analysis of the characteristics of carbonaceous ores and how they could be processed using conventional cyanidation methods was conducted. Numerous books, journals, and research papers were examined for this purpose. Next, research was done on the use and technical feasibility of thiosulfate as a gold-leaching agent. Studies have also been conducted on the effects of associated reagents used in leaching. In light of this, the authors have attempted to validate their findings by performing laboratory experiments on the leaching process. This has aided in establishing the effect of some of the parameters under study.\u003c/p\u003e\n\u003cp\u003eTo amplify the non-environmental effect of thiosulfate leaching, the environmental effects of the cyanidation process are then investigated. The paper has attempted to demonstrate why a restriction on the use of cyanide (CN\u003csup\u003e-\u003c/sup\u003e) in the mining industry is desired and how it poses an environmental risk to bio species.\u003c/p\u003e\n\u003cp\u003eLastly, the economics of employing thiosulfate leaching over conventional cyanidation methods for carbonaceous gold-bearing ores have been examined. The findings of the technical inquiry are then presented, together with the economic conclusions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eA. Experimental Method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn a laboratory, the amenability of carbonaceous gold-bearing ores to thiosulfate leaching was tested. The test aimed to demonstrate the technical benefits of thiosulfate leaching over conventional cyanidation.\u003c/p\u003e\n\u003cp\u003eMIDROC Legadembi\u0026rsquo;s operating conditions provided for the ideal cyanidation settings and optimal leaching conditions for thiosulfate lixiviants were taken from literatures. Broken ore from the Legadembi Open Pit gold mine was obtained for testing from two locations on the North-East Footwall side, which contained 30kg carbonaceous gold bearing ores with grades greater than 1g/t. The following is a presentation of the test findings and laboratory experiments.\u003c/p\u003e\n\u003cp\u003eThe samples were oven-dried for over 20 hours to evaporate the surface moisture of the ore, then ground to P80 (80% passing) of 75\u0026micro;m in a pulverizer for five minutes.\u003c/p\u003e\n\u003cp\u003eTo create a typical sample ore, the two ore samples were mixed to a 1:1 ratio; then the samples were mixed in a tumbler machine for 30 minutes to guarantee that they were distributed evenly.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eB. Leaching Experiment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBefore the leaching test, a sample of the ore was sent to the Analytical laboratory for gold analysis by fire assay; and it was found through triplet sample analysis that the ore sample had a gold grade of 1.25g/t. Please see Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e below:\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eSample Gold Assay Triplet Analysis\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSample No.\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eGrade (gm/ton)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eAverage Grade (g/t)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSample No. 1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.34\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSample No. 2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.19\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e1.25\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSample No. 3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.22\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe combined ore sample was subjected to a series of bottle leach tests to ascertain the reagent concentration needed to recover the largest amount of gold. All the regents were dissolved in a beaker, and quick lime (CaO) was used to raise the pH from 10.0 to 11.5. The pH of the solution was measured using a pH meter. While Tests 3 and 4 had one parameter changed from the base case scenarios and were also conducted in parallel, Tests 1 and 2 were the base case scenarios. The tests that were run and the parameters examined for this study are briefly shown in the following summary.\u003c/p\u003e\n\u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eLaboratory Test Summary\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eActivity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThiosulfate leaching Vs. Cyanide leaching in Carbonaceous Gold Bearing Ores\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDuration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eApril 12th \u0026minus;\u0026thinsp;22nd 2016\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVenue\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMIDROC Gold Mine Legadembi Laboratory Services\u003c/p\u003e\n\u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eLaboratory Test Conditions\u003c/span\u003e:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eKeep the pulp density constant at 50% solid (pulp density) and vary the concentration of the lixiviants\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eKeep the pH range 10.0-11.5\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eKeep the leaching process going for 48 hrs. residence time (or leaching time).\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eGeneral test conditions, which are common for both lixiviants, such as % solid, pH, residence time, etc., were kept constant as ground for comparing the two leaching agents. The initial solution strength will vary, and the focus will be on the free cyanide in the solution to see the preg-robbing effect and to make up for the lost cyanide for assisting the leach. See Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e below for the summary of laboratory test conditions.\u003c/p\u003e\n\u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eProcedure\u003c/span\u003e:\u003c/p\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cp\u003eTake a sample and crush it to a size of -10 mm with a jaw crusher\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eTake the crushed sample and crush it again to a size of -1 mm with a Boyd crusher (for 5 mins)\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eThen pulverize (grind) the crushed material to a size of -75 microns to liberate the metal (Au) inside the ore\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eThen, with a manual splitter, obtain a representative sample of about 2 Kg for the tests (four samples)\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003ePrepare the reagents to be added with the appropriate concentration strength\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003ePrepare a 50% solid sample by adding two litres of water to the prepared 2kg samples\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eAdjust the pH of the pulp to a range between 10.0 and 11.5 by adding lime (CaO) accordingly\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eFinally, add the reagents to their respective leach bottles into the prepared pulp and start agitating the mix to 200 rpm to promote homogeneity and increase the kinetics of the reaction, thereby increasing the leaching process\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eTake leaching samples to check the progress of the dissolution of gold with the proposed lixiviants\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ol\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eLaboratory Test Conditions\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNo.\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eExperimental Conditions\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFirst Run\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSecond Run\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eHead Grade\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.25 g/t\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.25 g/t\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNaCN strength\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.5 g/l\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.25 g/l\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eThiosulfate strength\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e9 gm/lit\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8 g/l\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eAmmonia\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e13.6 g/l\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e13.6 g/l\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCopper Sulfate\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8 g/l\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.8 g/l\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSample size\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2 kg\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2 kg\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePulp density\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50% Solid\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50% Solid\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003epH\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e11.5\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e9\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLeaching time\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e48 hours\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e48 hours\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTemperature\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e20\u0026ndash;25 \u003csup\u003e0\u003c/sup\u003eC (Room temp.)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e20-25 \u003csup\u003e0\u003c/sup\u003eC (Room temp.)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e"},{"header":"Result and Discussion","content":"\u003cp\u003eThis paper has attempted to demonstrate the technical superiority of thiosulfate over cyanide through laboratory testing. Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e provide the results of the two test runs, considering the variations in general leach circumstances. A conclusion has been reached by comparing the chemical properties of cyanide and thiosulfate lixiviants in order to illustrate the economic aspects of leaching.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eI. First Run\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eFirst Run Laboratory Results\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\"\u003eTest-1\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\"\u003eThiosulfate (9 g/l)\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(hr.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAu in solution\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(g/t)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003ePercent Recovery\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003epH\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eFree TS\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(ppm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e56.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.07\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\"\u003eTest-2\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eSodium Cyanide (0.5 g/l)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(hr.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAu in solution\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(g/t)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003ePercent Recovery\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003epH\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eFree CN\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e\u0026minus;\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(ppm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e500\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e460\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e450\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e350\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e300\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e285\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e200\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eFor the two leaching agents mentioned above, comparable test circumstances were employed. Therefore, as Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e illustrates, thiosulfate exhibits more technical superiority over cyanide, producing a gold recovery in a solution of approximately 90.54% compared to cyanide\u0026apos;s 61.70% after 48 hours of leaching. This suggests that in carbonaceous preg-robbing gold-bearing ores, thiosulfate has a far superior leaching recovery than cyanide.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eII. Second Run\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eSecond Run Laboratory Results\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\"\u003eTest-3\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\"\u003eThiosulfate (8 g/l)\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth colspan=\"3\" align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(hr.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAu in solution\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(g/t)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003ePercent Recovery\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003epH\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eFree TS\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(ppm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e62.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eND\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\"\u003eTest-4\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eSodium Cyanide (0.25 gm/lit)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003cp\u003e(hr.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAu in solution\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(gm/ton)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003ePercent Recovery\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003epH\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eFree CN\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e\u0026minus;\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(ppm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e250\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e150\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35\u0026thinsp;+\u0026thinsp;150\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e150\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u0026thinsp;+\u0026thinsp;150\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e200\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e38.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" align=\"left\"\u003e\n \u003cp\u003e11.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e150\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe outcome of the fourth test as depicted in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e demonstrates the preg-robbing impact of carbonaceous gold-bearing ores as leaching progresses and eliminates the free cyanide in the solution. Due to the nature of the ore, which absorbs free cyanide in solution to form other undesirable cyanide complexes, there is a significant loss of free cyanide in solution, as demonstrated by the cyanide leaching, which shows 35 ppm of free cyanide in solution at the beginning of the leaching process. Nonetheless, it is essential to note that for the gold dissolution reaction to occur, the solution must include at least 100\u0026ndash;150 ppm of free cyanide. To make up for the lost cyanide in the solution, 0.15g/l of free cyanide was added to the leach solution on the fourth and twenty-fourth hours. This has increased the processing costs of the cyanidation leaching for carbonaceous gold-bearing ores and have a negative economic impact due to overdosing on cyanide dosage.\u003c/p\u003e\n\u003cp\u003eThe result implies a faster leach recovery by thiosulfate, which also demonstrates a higher leaching recovery of 66.51% of thiosulfate over 26.44% cyanide leach in 24 hours of residence time. The results presented here solely demonstrate thiosulfate\u0026apos;s technical advantage over cyanide. However, greater recovery may be obtained if conditions could be improved to a better state with a thorough study to be conducted by adjusting reagent concentrations and other leach conditions.\u003c/p\u003e\n\u003cp\u003eThe result also shows a superior leaching recovery of \u003cstrong\u003e66.51%\u003c/strong\u003e of thiosulfate over \u003cstrong\u003e26.44%\u003c/strong\u003e cyanide leach in 24 hrs. of residence time, implying a faster leach recovery by thiosulfate. The figures here only indicate the technical superiority of thiosulfate over cyanide. But, if conditions could be optimized to a better state with rigorous research to be undertaken by varying reagent concentrations and other conditions for leach, a much better recovery and sound figures could be obtained. The preg-robbing effect, in which the leached gold in solution is stolen by the free carbon and other hydrocarbons from the carbonaceous ore, is further demonstrated by the lower percent recoveries and changes in recovery for cyanide in Test 4. This resulted in a significant drop of gold in the solution.\u003c/p\u003e\n\u003cp\u003eThe other thing the authors noticed in the test results was the status of the solution\u0026apos;s alkalinity for the best thiosulfate recovery. Test-1, conditioned at pH 10.0, produced a higher recovery of around 90.54%, while Test 3, conditioned at pH 11.5, produced a solution recovery of 62.5%. This study unequivocally demonstrated that the lower alkaline bound, or pH range of 9\u0026ndash;10.5, yields a better and faster recovery of gold in thiosulfate solution. This pH range allows for the best possible recovery of gold in thiosulfate solutions.\u003c/p\u003e\n\u003cp\u003eFigure 1 below, displaying Residence time vs. Percent recovery clearly illustrates the discussions surrounding the aforementioned leaching results.\u003c/p\u003e\n\u003cp\u003eFinally, the gold left in the solid as residue after being fire assayed on finalizing the leaching process was examined in the laboratory, and the result is shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHead grade\u0026thinsp;=\u0026thinsp;1.25 g/t\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab5\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eGold grade in the solid residue\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTest No.\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSolid Grade (Residue, g/t)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAu in Solution after 48hrs. (g/t)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eHead Grade\u003c/p\u003e\n \u003cp\u003e(g/t)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTest-1 (TS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.13\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTest-2 (CN)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.50\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.77\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.25\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTest-3 (TS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.45\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.78\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTest-4 (CN)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.68\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.48\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cstrong\u003eA. Economic result\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis section compares the costs of cyanidation with thiosulfate leaching of gold ores. In addition to the primary operational expenses incurred during the conventional cyanidation process of detoxifying the cyanide from the tailing management facility, expenditures related to direct chemical consumption are also utilised for both lixiviants. Table \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e lists the costs along with the process for analyzing them.\u003c/p\u003e\n\u003cp\u003eThe Legadembi metallurgy plant at MIDROC Gold Mine provided the following reagent cost, which is based on the current market pricing in Ethiopian Birr.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab6\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eLeaching Reagent Consumption and Costs\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eChemical Name\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eUnit\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eUnit price (ETB)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSpecific Consumption (Kg/t)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAmount (ETB/t)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSodium cyanide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e65.35\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSodium thiosulfate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e149.40\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAmmonia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e122.40\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCopper sulfate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e44.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e35.20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHypochlorite\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e79.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.59\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eTaking a particular case for MIDROC Legadembi mine, a facility which processes 1,100,000 tons of gold ore annually with the conventional cyanidation method to estimate operating costs; the detox plant uses a minimum of 20 tonnes of hypochlorite per annum for treating cyanide in tailing solution and taking an average power consumption charge of 0.60 ETB/KWh by EEPCO. Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e provides information about operating cost analysis for the detox process, with cost details depicted on Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003ea and Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003eb.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cp\u003eTable 7\u003c/p\u003e\n \u003cp\u003eDetoxification Operating Cost Analysis\u003c/p\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eItem No.\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMajor Items\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCosts Per Annum (ETB)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eDetox plant operating items (\u003c/strong\u003e\u003cem\u003eDetails\u003c/em\u003e: Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003ea\u003cstrong\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSpare part replacements\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e950,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRunning items and Utilities\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e446,266.80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eTailing dam operating items (\u003c/strong\u003e\u003cem\u003eDetails\u003c/em\u003e: Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003eb\u003cem\u003e)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSpare part replacements\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2,610,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRunning items and Utilities\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e549,564.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSupervisory fee for two Units (One person working for 8hrs/day with monthly salary of 10,000ETB)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e120,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eGrand Total\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003e4,621,080.80\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnnual Budgeted Plant Processing Capacity\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.1\u0026nbsp;million tons\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eUnit Cost for Detoxification of Cyanide Tailings (ETB/t)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e4.20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tab8\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 7a\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDetox Plant Operating Items\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eItem No.\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSpare part Replacements\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCosts per Annum (ETB)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eElectrical parts (breakers, contactors, cables etc.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e200,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePump parts\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e300,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePipes and Valve replacements\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e250,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTank spare parts (gearbox and others)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e200,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eTotal\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003e950,000.00\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eItem No.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eRunning items and Utilities\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eCosts per Annum (ETB)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eConsumables for Cyanide titration \u0026amp; pH determination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e54,750.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePower consumption for:\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMixing tank agitator at 11KW capacity working for 24 hours per day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57,816.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTransfer pump at 11KW capacity working for 24 hours per month\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,900.80\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDozing pump at 10KW capacity working for 20 hours per day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43,800.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMan power (four operators with 6,000 ETB monthly salary each)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e288,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eTotal\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003e446,266.80\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable id=\"Tabb\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cp\u003eTable 7b\u003c/p\u003e\n \u003cp\u003eTailing Dam Operating Items\u003c/p\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eItem No.\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSpare part Replacements\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCosts per Annum (ETB)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eElectrical parts (breakers, contactors, cables etc.)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePump parts\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,200,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReturn pipe and fitting replacements\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,100,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHose and Valve parts\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e150,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBearing replacements\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eTotal\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003e2,610,000.00\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eItem No.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eRunning items and Utilities\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eCosts per Annum (ETB)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eConsumables for Cyanide titration \u0026amp; pH determination\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e54,750.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePower consumption for:\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTwo Return pumps at 11KW capacity working for 23 hours per day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e110,814.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMan power (Eight operators with 4,000 ETB monthly salary each)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e384,000.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003eTotal\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"BoldUnderline\"\u003e549,564.00\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003ePre-treatment of ores is mandatory for refractory ores before leaching with cyanide. Thus, roasting of ores as pre-treatment method has been adopted for this economic analysis. The roasting cost for carbonaceous ores here has been estimated with taking a particular case of Derba Cement\u0026rsquo;s clinker production kiln (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e), a major cement producing company in Ethiopia.\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eThe Derba kiln uses around 735 KCAL of energy to produce 1 Kg of clinker\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eThe cement plant mostly uses lignite coals as energy source with caloric value of around 2310 KCAL/Kg\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eLignite coal types are sold with 938.40 ETB per tons at international market including 20% for overhead cost\u003c/p\u003e\n \u003c/li\u003e\n\u003c/ul\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab9\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRoasting Cost Estimation\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth colspan=\"2\" align=\"left\"\u003e\n \u003cp\u003ePre-treatment (Roasting cost )\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eEconomic output\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKiln coal requirement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.32 Kg/Kg of clinker\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e300.80 ETB/t of clinker\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLignite unit price\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.94 ETB/Kg\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe cement plant kiln for clinker production could here be taken as equivalent to a kiln used for roasting of refractory ores to produce pre-treated ores for cyanide leaching for estimating roasting cost; which resulted in 300.80 ETB/t of ore pre-treated.\u003c/p\u003e\n\u003cp\u003eIn summary, the above cost analysis gives the following summarised costs for both lixiviants as shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e:\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab10\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eLeaching Economics Result\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLeaching Method\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTotal Unit Cost (ETB/t)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyanide Leaching\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e371.94\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThiosulfate Leaching\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e307.00\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe result demonstrates that thiosulfate leaching of gold also benefits the economy. By improving the thiosulfate leach process for refractory ores, which would probably reduce the requirement of higher concentrations of reagents in the leach system, this economic benefit of thiosulfate might be further utilised. The increased cost of the conventional cyanidation process demonstrates why such types of refractory ores are not treated using this method. Thiosulfate recovery offers a considerable advantage over cyanide, as can be seen from the test results. This means that there will be an increase in revenue as the recovery is increased by utilising thiosulfate. Furthermore, quantifying the non-environmental benefits of thiosulfate vs cyanide in monetary terms would undoubtedly increase the thiosulfate leach system\u0026apos;s economic advantage for carbonaceous ores.\u003c/p\u003e"},{"header":"Conclusion and Recommendation","content":"\u003cp\u003eThe results of this paper support the hypothesis that thiosulfate will improve and speed up the recovery when leaching carbonaceous gold-bearing ores. The following observations and conclusions are made.\u003c/p\u003e \u003cp\u003eThe current study indicates that thiosulfate, at a concentration of 9 gm/l, has a higher recovery (90.54%) in carbonaceous gold-bearing ores than cyanide (61.70%). If more research were conducted on the general test circumstances, altering the crucial factors such as pulp density (% solid), reagent concentration, pH, and so on, the results could be enhanced even more.\u003c/p\u003e \u003cp\u003eThe results also indicate that, with a minimum residence time of 24 hours, thiosulfate could dissolve gold in carbonaceous gold-bearing ores more quickly than other chemicals, with a 66.51% recovery rate. This phenomenon might be further exploited to reach the 73% recovery within four hours of residence time.\u003c/p\u003e \u003cp\u003eBecause the primary chemical agents in the leaching process (sodium thiosulfate and ammonia solution) are popular fertilizers, using mine tailings in agricultural applications is also possible in countries where environmental regulations are very stringent.\u003c/p\u003e \u003cp\u003eSince environmental concerns are no longer regarded luxury items in the twenty-first century and permission for any new gold project using cyanide is highly unlikely in certain parts of the world, thiosulfate may soon replace cyanide as the major leaching agent. The increased regulatory scrutiny of new gold projects and the reduction in allowed cyanide discharge levels are of great concern to mining companies. Due to cyanide's inefficiency with some refractory ore types, the decrease in free milling ore also increases the need for thiosulfate leaching. Thiosulfate lixiviants can be used for various purposes in these and related illnesses.\u003c/p\u003e \u003cp\u003eTo ascertain the precise circumstances in which thiosulfate could benefit the mining industry, a thorough investigation of the electrochemistry of the leach process and concepts related to the reduction potential and Gibbs free energy are necessary and should be studied seriously.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eWe hereby declare that this work presented for publication is a true account of our own work except where particularly all sources of information have been acknowledged by means of reference.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eKaleb Jia Chaka conducted the research and wrote the manuscript.Steven Rupprecht reviewed and corrected the manuscript to fit with publication standards.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eWe, the authors, consent that the datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMarchbank, A.R., Thomas, K.G., Dreisinger, D. and Fleming, C., Barrick Gold Corp, 1996. \u003cem\u003eGold recovery from refractory carbonaceous ores by pressure oxidation and thiosulfate leaching\u003c/em\u003e. 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U.S. Patent 5,246,486.\u003c/li\u003e\n\u003cli\u003eYang, H.Y., Qian, L.I.U., Song, X.L. and Dong, J.K., 2013. Research status of carbonaceous matter in carbonaceous gold ores and bio-oxidation pretreatment. \u003cem\u003eTransactions of Nonferrous Metals Society of China\u003c/em\u003e, \u003cem\u003e23\u003c/em\u003e(11), pp.3405-3411.\u003c/li\u003e\n\u003cli\u003eByerley, J.J., Fouda, S.A. and Rempel, G.L., 1975. Activation of copper (II) ammine complexes by molecular oxygen for the oxidation of thiosulphate ions. \u003cem\u003eJournal of the Chemical Society, Dalton Transactions\u003c/em\u003e, (13), pp.1329-1338.\u003c/li\u003e\n\u003cli\u003eLi, J., Miller, J.D., Le Vier, M. and Wan, R.Y., 1995. \u003cem\u003eThe ammoniacal thiosulfate system for precious metal recovery\u003c/em\u003e (No. CONF-9510120-). Society for Mining, Metallurgy, and Exploration, Inc., Littleton, CO (United States).\u003c/li\u003e\n\u003cli\u003eQian, G. and Jiexue, H., 1989. 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Solution chemistry factors for gold thiosulfate heap leaching. \u003cem\u003eInternational Journal of Mineral Processing\u003c/em\u003e, \u003cem\u003e72\u003c/em\u003e(1-4), pp.311-322.\u003c/li\u003e\n\u003cli\u003eLa Brooy, S.R., Linge, H.G. and Walker, G.S., 1994. Review of gold extraction from ores. \u003cem\u003eMinerals Engineering\u003c/em\u003e, \u003cem\u003e7\u003c/em\u003e(10), pp.1213-1241.\u003c/li\u003e\n\u003cli\u003eKeskinen, S., 2013. Comparison of Cyanide and Thiosulphate Leaching for Gold Production (A Literature Review).\u003c/li\u003e\n\u003cli\u003eBlock-Bolten, A. and Torma, A.E., 1986. Thiosulfate leaching of gold from sulfide wastes. \u003cem\u003eMetall (Berlin);(Germany, Federal Republic of)\u003c/em\u003e, \u003cem\u003e40\u003c/em\u003e(7).\u003c/li\u003e\n\u003cli\u003eTykodi, R.J., 1990. In praise of thiosulfate. \u003cem\u003eJournal of chemical education\u003c/em\u003e, \u003cem\u003e67\u003c/em\u003e(2), p.146.\u003c/li\u003e\n\u003cli\u003eEisler, R. and Wiemeyer, S.N., 2004. Cyanide hazards to plants and animals from gold mining and related water issues. \u003cem\u003eReviews of environmental contamination and toxicology\u003c/em\u003e, pp.21-54.\u003c/li\u003e\n\u003cli\u003eXia, C., Yen, W.T. and Deschenes, G., 2003. Improvement of thiosulfate stability in gold leaching. \u003cem\u003eMining, Metallurgy \u0026amp; Exploration\u003c/em\u003e, \u003cem\u003e20\u003c/em\u003e, pp.68-72.\u003c/li\u003e\n\u003cli\u003eYannopoulos, J.C., 2012. \u003cem\u003eThe extractive metallurgy of gold\u003c/em\u003e. Springer Science \u0026amp; Business Media.\u003c/li\u003e\n\u003cli\u003eZhang, J., Lan, X.Z., Yu, N.W., Ding, F., He, H., Huang, Y., Yu, R. and Zhang, S., 1993. Leaching gold and platinum group metals by the LSSS method. \u003cem\u003ePrecious Metals 1993\u003c/em\u003e, pp.281-288.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Gold leaching, Carbonaceous Gold-Bearing Ores, Thiosulfate","lastPublishedDoi":"10.21203/rs.3.rs-4248503/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4248503/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eOne of the main unit operations in metallurgical processing plant designs is gold leaching. The traditional cyanidation process was chosen and is currently in widespread use. However, the mining sector is looking for lixiviants other than cyanide. Cyanide's effects on the environment have made it difficult for humans and other biotic creatures to survive. There is now research to discover a substitute for this cyanide. It is currently argued that thiosulfate is a preferable substitute for cyanide.\u003c/p\u003e \u003cp\u003eThe effectiveness of thiosulfate as a leaching agent in carbonaceous gold-bearing ores in Ethiopia is discussed in this paper compared to cyanide. The study has looked into the advantages of employing thiosulfate over cyanide from a technical, environmental, and economic standpoint. The leaching effects of both lixiviants on carbonaceous gold-bearing ores extracted from MIDROC Legadembi Open Pit mine in Southern Ethiopia, Oromia region, were examined in a laboratory experiment.\u003c/p\u003e \u003cp\u003eAfter 48 hours of leaching, it was discovered that thiosulfate has a better and quicker recovery of 91.54% over 61.70% of cyanide recovery. Tables and graphs are used to demonstrate thiosulfate's technical advantage over cyanide. As a result, this paper provides evidence regarding the Legadembi gold mine in Ethiopia's amenability to thiosulfate leaching on carbonaceous gold-bearing ores. A further research perspective is also sought for thiosulfate leaching in other refractory ores.\u003c/p\u003e","manuscriptTitle":"Thiousulfate Leaching in Carbonaceous Gold-Bearing Ores in Ethiopia","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-26 13:55:15","doi":"10.21203/rs.3.rs-4248503/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-11T08:21:11+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-06T19:07:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"260988941852500313497241489995260294484","date":"2024-05-16T14:11:38+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-14T18:07:04+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-14T18:03:51+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-04-23T03:56:50+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-04-23T03:48:59+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-04-10T16:34:11+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"79c6d200-5f49-4956-91ec-ce0f30a75d18","owner":[],"postedDate":"April 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":31044274,"name":"Earth and environmental sciences/Biogeochemistry"},{"id":31044275,"name":"Earth and environmental sciences/Environmental sciences"},{"id":31044276,"name":"Earth and environmental sciences/Solid earth sciences"},{"id":31044277,"name":"Physical sciences/Chemistry"},{"id":31044278,"name":"Physical sciences/Engineering"}],"tags":[],"updatedAt":"2024-10-07T15:58:57+00:00","versionOfRecord":{"articleIdentity":"rs-4248503","link":"https://doi.org/10.1038/s41598-024-69646-3","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-10-03 15:56:54","publishedOnDateReadable":"October 3rd, 2024"},"versionCreatedAt":"2024-04-26 13:55:15","video":"","vorDoi":"10.1038/s41598-024-69646-3","vorDoiUrl":"https://doi.org/10.1038/s41598-024-69646-3","workflowStages":[]},"version":"v1","identity":"rs-4248503","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4248503","identity":"rs-4248503","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}