Estimation of Soil Leachable for Gold Recovery Using 1000 Kilograms of Cyanide

Estimation of Soil Leachable for Gold Recovery Using 1000 Kilograms of Cyanide

1. Introduction

The extraction of gold from its ores has evolved significantly over time, with cyanide leaching, also known as cyanidation, emerging as the dominant technology since the 1970s.¹ This method surpassed earlier techniques like mercury amalgamation due to its superior efficiency in dissolving and separating gold from ore. ²Cyanide leaching involves using a dilute solution of sodium cyanide to selectively dissolve gold, and it is primarily implemented through two main processes: heap leaching and milling, which includes methods like Carbon-in-Leach (CIL) and Carbon-in-Pulp (CIP).¹ Heap leaching is typically applied to lower-grade ores, where the crushed ore is piled into large heaps and the cyanide solution is sprayed over them. Milling, on the other hand, is often used for higher-grade or more complex ores, involving grinding the ore into a fine slurry and then mixing it with a cyanide solution in agitated tanks.³ This report aims to estimate the amount of soil that can be effectively leached to recover gold using 1000 kilograms of cyanide. To achieve this, the report will analyze typical cyanide concentrations and gold recovery rates, delve into the chemical reactions and factors influencing the leaching process, consider relevant regulatory aspects, and finally, provide an estimation based on various scenarios. The analysis will highlight the inherent variability in gold mining operations and the importance of site-specific conditions in determining the actual amount of soil that can be processed.

2. Typical Cyanide Solution Concentrations in Gold Leaching

The concentration of cyanide solutions employed in gold leaching operations varies depending on the specific method used and the characteristics of the ore being processed. In heap leaching, a dilute solution of sodium cyanide, typically ranging from 250 to 500 parts per million (ppm), which is equivalent to 0.025% to 0.05%, is commonly used.⁴ However, it is noteworthy that many mining operations strive to achieve even lower cyanide concentrations in their tailings facilities, often below 10 ppm, to minimize environmental impact.¹ Regulations at the local, state, and national levels further limit the amount and concentration of cyanide permitted in discharged solutions, generally ranging from 0.2 to 0.5 ppm (0.00002% to 0.00005%).¹ For economic, safety, and environmental reasons, mines prioritize using the minimum amount of cyanide necessary for effective gold recovery.²

In milling processes such as CIL and CIP, the cyanide content in the ore pulp typically ranges from 0.03% to 0.08%.⁵ Some sources indicate that an average concentration of approximately 250 ppm (0.025%) sodium cyanide is often used.² Research on specific gold ores has suggested optimal cyanide concentrations in the range of 600 to 800 ppm for maximizing gold leaching rates.⁶ Generally, increasing the cyanide concentration tends to improve the gold dissolution rate up to a certain threshold, around 0.15%, beyond which the rate may become independent of the cyanide concentration or even decrease due to cyanide hydrolysis.⁵

Several factors influence the selection of the appropriate cyanide concentration. The properties of the ore play a crucial role; for instance, the presence of minerals like copper, arsenic, antimony, and bismuth can lead to increased cyanide consumption as these minerals may also react with cyanide.⁵ The size of the gold particles also matters, as finer particles generally require shorter leaching times and can influence the optimal cyanide concentration.⁵ Maintaining the pulp pH within the range of 10.0 to 11.0 is essential to prevent the formation of highly toxic hydrogen cyanide gas.³ The pulp concentration, typically between 25% and 50% solids, affects the diffusion rates of cyanide and oxygen in the slurry.⁵ The chosen leaching time can also impact the required cyanide concentration; longer leaching periods might allow for the use of lower concentrations.⁵ Finally, the temperature of the leaching process, generally maintained between 15 and 30°C, can influence the reaction kinetics and thus the optimal cyanide concentration.⁵

3. Average Gold Recovery Rates Using Cyanide Leaching

The percentage of gold recovered from ore using cyanide leaching can vary considerably depending on factors such as the leaching method, the grade and mineralogy of the ore, and the efficiency of the operation. With finely ground ore in vat leaching processes, recovery rates can be as high as 96%.^12^ Heap leaching, which is often employed for processing large volumes of low-grade ores (sometimes with gold grades as low as 0.5 g/t), typically achieves lower recovery rates, generally in the range of 60% to 80%.^11^ The initial concentration of gold in the ore significantly impacts the overall economics and the choice of leaching method.^11^ Low-grade ores (less than 1 g/t) are often processed using heap leaching due to its lower capital and operating costs, even though the recovery rates might be lower compared to more intensive methods.^16^ Conversely, ores with higher gold content (greater than 20 grams of gold per ton of ore) may be treated using vat leaching.^18^

Pretreatment methods can substantially improve gold recovery, especially from refractory ores, where gold is locked within other minerals like sulfides or associated with carbonaceous materials that can interfere with the leaching process.⁹ For instance, ultra-fine grinding of pyritic concentrates before cyanidation has been shown to increase gold extraction from 45% to 85%.⁹ Similarly, fine grinding to around 10 microns followed by leaching with higher cyanide concentrations and longer leach times can achieve gold recoveries of 80-90% from certain types of ore.^13^ The presence of \“preg-robbing\” materials, such as some forms of carbonaceous matter in the ore, can adsorb dissolved gold and reduce the overall yield.⁷ However, under optimized conditions, including fine grinding to achieve sufficient gold liberation and using appropriate cyanide concentrations, pH levels, and oxygen supply, recovery rates exceeding 90% are achievable.^13^ In some cases, gravity concentration or flotation methods are used to recover coarse gold particles or to concentrate the ore before cyanide leaching, which can improve the overall efficiency and reduce reagent consumption.⁵

4. Chemical Reaction and Stoichiometry of Gold Cyanidation

The fundamental chemical reaction governing the dissolution of gold in cyanide solutions is described by the Elsner equation: 4 Au + 8 NaCN + O2 + 2 H2O → 4 Na[Au(CN)2] + 4 NaOH.⁶ This equation illustrates that metallic gold (Au) reacts with sodium cyanide (NaCN) in the presence of oxygen (O2) and water (H2O) to form sodium aurocyanide (Na[Au(CN)2]), a water-soluble complex, and sodium hydroxide (NaOH). The reaction is electrochemical in nature, with oxygen acting as the electron acceptor and cyanide ions forming a stable complex with the gold ions.^26^ While sodium cyanide is the most common reagent, potassium cyanide (KCN) and calcium cyanide (Ca(CN)2) can also be used in the process.⁶

Based on the stoichiometry of the Elsner equation, 4 moles of gold react with 8 moles of sodium cyanide. The molar mass of gold (Au) is approximately 197 g/mol, and the molar mass of sodium cyanide (NaCN) is approximately 49 g/mol. Therefore, to dissolve 4 * 197 = 788 grams of gold, 8 * 49 = 392 grams of sodium cyanide are theoretically required. This translates to a theoretical consumption of approximately 392 / 788 ≈ 0.497 kg of NaCN per 1 kg of gold dissolved.

The presence of dissolved oxygen is crucial for the reaction to proceed, as it acts as an oxidizing agent, accepting electrons from the gold.⁵ Maintaining alkaline conditions with a pH above 10.5 is essential to prevent the hydrolysis of cyanide ions and the release of highly toxic hydrogen cyanide (HCN) gas.³ This is typically achieved by adding lime (calcium hydroxide) or sodium hydroxide to the leaching solution.⁶ It is important to note that the presence of other minerals in the ore, such as copper and sulfides, can lead to side reactions that consume cyanide and oxygen, thereby reducing the efficiency of gold leaching and increasing the overall cyanide consumption.⁵

5. Factors Influencing the Efficiency of Cyanide Leaching

The efficiency of gold extraction using cyanide leaching is influenced by a multitude of interconnected factors. The type and mineralogy of the ore are paramount. Free-milling ores, where gold is readily accessible, generally exhibit higher leaching efficiencies compared to refractory ores, in which gold is encapsulated within other minerals or associated with substances that interfere with the cyanidation process.⁹ The presence of cyanicides, such as sulfides of copper and iron, as well as arsenic and antimony-bearing minerals, can significantly reduce efficiency by consuming cyanide and oxygen.⁵ The size and liberation of gold particles are also critical; finer grinding to expose more gold surface area typically leads to improved leaching rates.⁵

The pH of the leaching solution must be carefully controlled within the optimal range of 10.0 to 11.0 (or 10.5 to 11.0 in some cases) to maximize gold dissolution and minimize the formation of toxic HCN gas.³ Deviations from this range can slow down the leaching process or lead to cyanide loss.⁵ The temperature generally influences the kinetics of the reaction; while higher temperatures can increase the dissolution rate, they can also decrease the solubility of oxygen in the solution and promote cyanide decomposition, making a range of 15-30°C generally suitable.⁵ An adequate oxygen concentration is essential as it is a reactant in the gold dissolution process; higher dissolved oxygen levels typically enhance leaching rates.⁵ Techniques like aeration and the addition of oxidants such as hydrogen peroxide can be employed to increase oxygen availability.⁵

The cyanide concentration itself is a key parameter, with optimal ranges varying depending on the leaching method (e.g., 100-500 ppm for heap leaching, 0.03-0.08% for CIL/CIP) and the ore characteristics.¹ Too low a concentration can result in slow dissolution, while excessively high concentrations might be wasteful or lead to increased consumption due to reactions with other minerals.⁵ The particle size and the degree of gold liberation achieved through grinding directly impact the accessibility of gold to the cyanide solution.⁵ The pulp density or slurry concentration affects the diffusion of reagents and products within the leaching environment, and an optimal density needs to be determined for each ore type.⁵ Leaching time is another important factor; longer durations generally improve gold recovery, although the rate of dissolution tends to decrease over time.⁵ In tank leaching methods like CIL and CIP, agitation or mixing is crucial to ensure proper contact between the cyanide solution and the ore particles, thereby enhancing the efficiency of the process.⁶

6. Regulations and Guidelines Regarding Cyanide Use in Gold Mining

The use of cyanide in gold mining is subject to various regulations and guidelines aimed at ensuring environmental protection and the safety of both workers and the public. Local, state, and national regulations often impose limits on the permissible amounts and concentrations of cyanide in mining operations and in any wastewater discharged from these sites.¹ These regulations can vary significantly by jurisdiction, but they generally aim to minimize the potential for environmental contamination and harm to wildlife.¹ Many regions mandate that discharged solutions contain very low levels of cyanide, typically in the range of 0.2 to 0.5 ppm.¹

In addition to mandatory regulations, the mining industry has developed and promoted voluntary initiatives like the International Cyanide Management Code (Cyanide Code).¹ This code represents a set of best practices for the manufacture, transport, and use of cyanide in gold production, with the primary goals of protecting human health and reducing environmental impacts.¹ Companies that adopt the Cyanide Code are subject to independent third-party audits to verify their compliance with the program\’s requirements.¹ This initiative has gained international recognition and has been implemented in numerous countries.^36^

The regulatory landscape often includes specific limits on cyanide concentrations in tailings storage facilities, with some regions requiring levels below 50 ppm or even 10 ppm.¹ The emphasis across the industry is on minimizing cyanide usage not only to comply with regulations and reduce environmental risks but also for economic and safety reasons.² Some jurisdictions have gone as far as banning the use of cyanide in certain gold mining applications, such as heap leaching, reflecting the ongoing concerns about its potential hazards.^36^ Overall, mining companies are encouraged to adhere to comprehensive regulations and to seek certification through the International Cyanide Management Code to ensure safe operational practices and maintain transparent community relations.¹

7. Estimation of Cyanide Solution Volume from 1000 kg of Cyanide

To estimate the volume of cyanide solution that can be prepared from 1000 kg of cyanide, we need to consider the typical concentration ranges used in gold leaching. Assuming sodium cyanide (NaCN) is the cyanide salt used, 1000 kg is equivalent to 1,000,000 grams.

For heap leaching, the typical concentration ranges from 250 to 500 ppm (0.025% to 0.05%).⁴ Let\’s also consider the broader range of 100 ppm to 500 ppm mentioned in some sources.¹

Lower end (100 ppm or 0.01%): This means 1 gram of NaCN per 1,000,000 grams (1000 liters) of solution. Therefore, 1,000,000 grams of NaCN can produce (1,000,000 g NaCN) * (1000 L solution / 1 g NaCN) = 1,000,000,000 liters, or 1,000,000 cubic meters of solution.
Typical lower range (250 ppm or 0.025%): This means 2.5 grams of NaCN per 10,000 grams (10 liters) of solution, or 1 gram of NaCN per 4000 grams (4 liters) of solution. Therefore, 1,000,000 grams of NaCN can produce (1,000,000 g NaCN) * (4 L solution / 1 g NaCN) = 4,000,000 liters, or 4,000 cubic meters of solution.
Typical higher range (500 ppm or 0.05%): This means 5 grams of NaCN per 10,000 grams (10 liters) of solution, or 1 gram of NaCN per 2000 grams (2 liters) of solution. Therefore, 1,000,000 grams of NaCN can produce (1,000,000 g NaCN) * (2 L solution / 1 g NaCN) = 2,000,000 liters, or 2,000 cubic meters of solution.

For milling processes (CIL/CIP), the cyanide content in the pulp is typically 0.03% to 0.08%.⁵

Lower end (0.03% or 300 ppm): This means 3 grams of NaCN per 10,000 grams (10 liters) of solution, or 1 gram of NaCN per approximately 3333.33 grams (3.333 liters) of solution. Therefore, 1,000,000 grams of NaCN can produce (1,000,000 g NaCN) * (3.333 L solution / 1 g NaCN) ≈ 3,333,333 liters, or approximately 3,333 cubic meters of solution.
Typical concentration (0.05% or 500 ppm): As calculated above for heap leaching, this yields 2,000 cubic meters of solution.
Higher end (0.08% or 800 ppm): This means 8 grams of NaCN per 10,000 grams (10 liters) of solution, or 1 gram of NaCN per 1250 grams (1.25 liters) of solution. Therefore, 1,000,000 grams of NaCN can produce (1,000,000 g NaCN) * (1.25 L solution / 1 g NaCN) = 1,250,000 liters, or 1,250 cubic meters of solution.

It is important to note that these calculations represent the theoretical volumes of cyanide solution that can be prepared. They do not account for the cyanide that will be consumed during the leaching process through reactions with gold and other minerals in the soil.

8. Calculation of Approximate Leachable Soil Amount

Estimating the amount of soil that can be leached with 1000 kg of cyanide requires considering the cyanide consumption rate per ton of ore, which varies significantly based on the ore\’s characteristics and the leaching method. The following table presents several scenarios based on different assumptions for heap leaching, which is typically used for processing large quantities of soil.

Scenario	Cyanide Concentration (ppm)	Gold Grade (g/ton)	Recovery Rate (%)	Cyanide Consumption (kg/ton ore)	Total Cyanide Available (kg)	Estimated Soil Leached (tons)	Estimated Gold Recovered (g)
1	250	0.5	60	0.3	1000	3333	999.9
2	250	0.5	70	0.3	1000	3333	1166.55
3	250	1.0	60	0.3	1000	3333	1999.8
4	250	1.0	70	0.3	1000	3333	2333.1
5	500	0.5	60	0.5	1000	2000	600
6	500	0.5	70	0.5	1000	2000	700
7	500	1.0	60	0.5	1000	2000	1200
8	500	1.0	70	0.5	1000	2000	1400
9	250	0.5	60	0.1	1000	10000	3000
10	250	0.5	70	1.0	1000	1000	350
11	250	1.0	60	1.0	1000	1000	600
12	250	1.0	70	1.0	1000	1000	700

Assumptions for the table:

Cyanide Concentration: Two typical concentrations for heap leaching are considered: 250 ppm (0.025%) and 500 ppm (0.05%).
Gold Grade: Low-grade ore with gold grades of 0.5 g/ton and 1.0 g/ton are assumed, which are common for heap leaching operations.^11^
Recovery Rate: Gold recovery rates of 60% and 70% are considered, which are within the typical range for heap leaching.^14^
Cyanide Consumption: The cyanide consumption rate per ton of ore is a critical factor and can vary widely. For these scenarios, consumption rates of 0.1 kg/ton, 0.3 kg/ton, 0.5 kg/ton, and 1.0 kg/ton are used, based on the range observed in the research material.⁵

The table illustrates the significant variability in the estimated amount of soil that can be leached. For instance, if the cyanide consumption is low (0.1 kg/ton), 1000 kg of cyanide could potentially leach 10,000 tons of soil (Scenario 9). However, if the cyanide consumption is higher (1.0 kg/ton), the same amount of cyanide might only be sufficient to leach 1000 tons of soil (Scenarios 10, 11, 12). The estimated gold recovered also varies depending on the gold grade and recovery rate.

9. Conclusion

The amount of soil that can be leached using 1000 kilograms of cyanide to recover gold is highly dependent on a complex interplay of factors, primarily the cyanide concentration used in the leaching solution, the method of leaching (heap leaching vs. milling), the grade of gold in the soil, the efficiency of gold recovery, and, most importantly, the rate of cyanide consumption per ton of soil. Based on the scenarios presented, the estimated amount of soil that can be leached with 1000 kg of cyanide can range from approximately 1000 tons to 10,000 tons, assuming heap leaching is the method employed for such large quantities of soil.

Key factors that significantly influence this estimation include the mineralogy of the soil, particularly the presence of cyanicides that can increase cyanide consumption, and the desired gold recovery rate. Site-specific ore characteristics and operational parameters are crucial in determining the actual amount of soil that can be processed effectively. Regulatory and environmental considerations also play a vital role in dictating the permissible cyanide concentrations and the overall management of the leaching process.

In conclusion, while 1000 kg of cyanide can prepare a substantial volume of leaching solution, the actual amount of soil that can be leached to recover gold is primarily constrained by the consumption of cyanide during the process. The calculations provided in this report offer an estimated range, and the precise figures will vary considerably based on the specific conditions of the gold mining operation. It is recommended that detailed metallurgical testing be conducted on the specific soil in question to accurately determine the optimal cyanide concentration, gold recovery rate, and cyanide consumption, thereby providing a more precise estimate of the leachable soil amount.

Works cited

The Safe and Effective Use of Cyanide - Society for Mining, Metallurgy & Exploration, accessed April 9, 2025, https://www.smenet.org/What-We-Do/Technical-Briefings/The-Safe-and-Effective-Use-of-Cyanide-in-the-Minin
The Safe and Effective Use of Cyanide in the Mining Industry, accessed April 9, 2025, https://www.smenet.org/docs/public/SafeAndEffectiveUseOfCyanideInTheMiningIndustry.pdf
Measuring pH in Cyanide Leaching | Emerson, accessed April 9, 2025, https://www.emerson.com/documents/automation/application-data-sheet-measuring-ph-in-cyanide-leaching-en-68418.pdf
HEAP-LEACH GOLD MINES: WHERE DOES THE CYANIDE GO?, accessed April 9, 2025, https://www.westmont.edu/sites/default/files/2025-01/Todd%20Silverstein_appendix_final.pdf
gold cyanide leaching - Xinhai, accessed April 9, 2025, https://www.xinhaimining.com/newo/1087.html
Study on the Effect of Cyanide Concentration on Gold Leaching Recovery in Ore at PT Indo Muro Kencana, accessed April 9, 2025, https://jurnal.uns.ac.id/equilibrium/article/download/77833/42867
Cyanide Leaching Chemistry & Gold Cyanidation - 911Metallurgist, accessed April 9, 2025, https://www.911metallurgist.com/blog/cyanide-leaching-chemistry-gold-cyanidation/
Predicting Cyanide Consumption in Gold Leaching: A Kinetic and ..., accessed April 9, 2025, https://www.mdpi.com/2075-163X/8/3/110
Effect of leaching time and cyanide concentration on the extraction of gold and silver (d80 - ResearchGate, accessed April 9, 2025, https://www.researchgate.net/figure/Effect-of-leaching-time-and-cyanide-concentration-on-the-extraction-of-gold-and-silver_fig2_310793955
A Review of the Cyanidation Treatment of Copper-Gold Ores and Concentrates - MDPI, accessed April 9, 2025, https://www.mdpi.com/2075-4701/10/7/897
All You Need To Know About Cyanide Gold Leaching - Core Resources, accessed April 9, 2025, https://coreresources.com.au/the-metallurgy-of-cyanide-gold-leaching/
Gold cyanidation - Wikipedia, accessed April 9, 2025, https://en.wikipedia.org/wiki/Gold_cyanidation
Six Factors Affecting Gold Cyanide Leaching Process, accessed April 9, 2025, https://www.cnlitereagent.com/news/six-factors-affecting-gold-cyanide-leaching/
Heap leaching - Wikipedia, accessed April 9, 2025, https://en.wikipedia.org/wiki/Heap_leaching
The Ultimate Guide to Gold Cyanidation, accessed April 9, 2025, https://www.cnlitereagent.com/special-guide/ultimate-guide-gold-cyanidation/
Precious Metal Heap Leach Design and Practice - Ore-Max, accessed April 9, 2025, https://ore-max.com/pdfs/resources/precious_metal_heap_leach_design_and_practice.pdf
Gold Recovery 101 - Sepro Systems, accessed April 9, 2025, https://www.seprosystems.com/gold-recovery-101/
Gold processing | Refining, Smelting & Purifying - Britannica, accessed April 9, 2025, https://www.britannica.com/technology/gold-processing
The Basic Economics Of Gold Mining - Numismatic News, accessed April 9, 2025, https://www.numismaticnews.net/coin-market/the-basic-economics-of-gold-mining
WO2004042094A1 - Reducing cyanide consumption in gold recovery from finely ground sulphide ores and concentrates - Google Patents, accessed April 9, 2025, https://patents.google.com/patent/WO2004042094A1/en
gold cyanide leaching process - Xinhai Mining, accessed April 9, 2025, https://www.xinhaimining.com/newo/794.html
Technology for Aiding the Cyanide Leaching of Gold Ores - MDPI, accessed April 9, 2025, https://www.mdpi.com/2297-8739/11/8/228
Developments in gold leaching using hydrogen peroxide | 911 Metallurgist, accessed April 9, 2025, https://www.911metallurgist.com/wp-content/uploads/2016/10/Gold-cyanidation-using-hydrogen-peroxide.pdf
Cyanide Amenability Studies of Gold Ores-The Use of Design of Experiment (DOE) - ARC Journals, accessed April 9, 2025, https://www.arcjournals.org/pdfs/ijms/v4-i3/2.pdf
en.wikipedia.org, accessed April 9, 2025, https://en.wikipedia.org/wiki/Gold_cyanidation#:\~:text=The%20chemical%20reaction%20for%20the,of%20cyanide%20ions%20and%20oxygen.
Gold cyanidation - chemeurope.com, accessed April 9, 2025, https://www.chemeurope.com/en/encyclopedia/Gold_cyanidation.html
Cyanide in Gold Mining. And why it\’s a problem. | by Harsh Desai | Scientia - Medium, accessed April 9, 2025, https://medium.com/scientia-blog/the-use-of-cyanide-in-gold-mining-2c6cd63d7389
Chemistry of Cyanidation of Gold & Silver - 911Metallurgist, accessed April 9, 2025, https://www.911metallurgist.com/blog/chemistry-gold-silver-cyanidation/
Optimizing Gold Cyanidation: Key Factors Influencing Gold Extraction Efficiency - Xinhai, accessed April 9, 2025, https://www.xinhaimining.com/newo/optimizing-gold-cyanidation-key-factors-influencing-gold-extraction-efficiency.html
5 Factors Affecting Gold Extraction Efficiency by Cyanide - Xinhai, accessed April 9, 2025, https://www.xinhaimining.com/newo/5-factors-affecting-gold-extraction-efficiency-by-cyanide.html
(PDF) Optimizing and evaluating the operational factors affecting the cyanide leaching circuit of the Aghdareh gold processing plant using a CCD model - ResearchGate, accessed April 9, 2025, https://www.researchgate.net/publication/287995268_Optimizing_and_evaluating_the_operational_factors_affecting_the_cyanide_leaching_circuit_of_the_Aghdareh_gold_processing_plant_using_a_CCD_model
Factors Affecting Gold Leaching Effects: A Comprehensive Overview | Mining Pedia, accessed April 9, 2025, https://www.miningpedia.cn/cyanidation/a-comprehensive-overview-of-factors-affecting-gold-leaching-effects.html
Factors Affecting Gold Heap Leaching Efficiency - CNLITE Eco-friendly Gold Dressing Agent, accessed April 9, 2025, https://www.cnlitereagent.com/news/factors-affecting-gold-heap-leaching-efficiency/
Gold Leaching, CIP & CIL Process | Role Of Agitators, accessed April 9, 2025, https://dynamixinc.com/gold-leaching-cip-cil-process/
CYANIDE MANAGEMENT - Department of Industry Science and Resources, accessed April 9, 2025, https://www.industry.gov.au/sites/default/files/2019-04/lpsdp-cyanide-management-handbook-english.pdf
Can gold miners say \‘sayonara\’ to cyanide? - Canadian Mining Journal, accessed April 9, 2025, https://www.canadianminingjournal.com/featured-article/can-gold-miners-say-sayonara-to-cyanide/
[Request] How many loads of ore to pay this thing off? Let\’s assume gold, and cobalt for comparison. : r/theydidthemath - Reddit, accessed April 9, 2025, https://www.reddit.com/r/theydidthemath/comments/1i87noe/request_how_many_loads_of_ore_to_pay_this_thing/
Ore treatment hydrogen peroxide during heap leaching of gold | Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex use of mineral resources, accessed April 9, 2025, https://kims-imio.com/index.php/main/article/view/36
INFLUENCE OF ORE PROCESSING BEHAVIOR ON HEAP-LEACH CYANIDATION AND AGITATION LEACHING EFFICIENCY, accessed April 9, 2025, https://rudmet.net/media/articles/Article_EM_01_22_pp.55-58.pdf
Consumption of sodium cyanide in the leaching process - ResearchGate, accessed April 9, 2025, https://www.researchgate.net/figure/Consumption-of-sodium-cyanide-in-the-leaching-process_fig3_350237529
Integra Reports Excellent Heap Leach Recoveries in DeLamar Project Metallurgical Test-Work Update, accessed April 9, 2025, https://integraresources.com/news/integra-reports-excellent-heap-leach-recoveries-in-delamar-project-metallurgical-test-work-update/
Cyanide Destruction in Gold Heap Leach - 911Metallurgist, accessed April 9, 2025, https://www.911metallurgist.com/blog/cyanide-destruction-leach-heaps/
FLOTATION AND LEACHING AT ANGLO ASIAN MINING\’S GEDABEK GOLD AND COPPER MINE IN AZERBAIJAN A.J. Monhemius*, F. Hedjazi and H., accessed April 9, 2025, https://www.angloasianmining.com/wp-content/uploads/2019/09/TECH_PAPER_2.pdf
Optimization of cyanidation process for gold-bearing ores from Central Kazakhstan, accessed April 9, 2025, https://rudmet.net/media/articles/Article_NFM_02_24_pp.39-44.pdf
Gold CIL & CIP Gold Leaching Process Explained CCD - 911Metallurgist, accessed April 9, 2025, https://www.911metallurgist.com/blog/gold-cil-process-explained/
Comprehensive Guide to CIL Process - JXSC Machine, accessed April 9, 2025, https://www.jxscmachine.com/new/comprehensive-guide-cil-process/
Estimating process design gold extraction, leach residence time and cyanide consumption for High cyanide-consuming gold ore | Request PDF - ResearchGate, accessed April 9, 2025, https://www.researchgate.net/publication/282265774_Estimating_process_design_gold_extraction_leach_residence_time_and_cyanide_consumption_for_High_cyanide-consuming_gold_ore
AU2003273610B2 - Reducing cyanide consumption in gold recovery from finely ground sulphide ores and concentrates - Google Patents, accessed April 9, 2025, https://patents.google.com/patent/AU2003273610B2/en
Gold Mining Operations Summary Audit Report - The Cyanide Code, accessed April 9, 2025, https://cyanidecode.org/wp-content/uploads/2021/06/AuraErnestoSAR2022.pdf
cyanide recovery | SGS, accessed April 9, 2025, https://www.sgs.com/-/media/sgscorp/documents/corporate/brochures/sgs-min-wa016-cyanide-recovery-comparison-en-11.cdn.en.pdf