Can we extract gold from old mining waste? New research reveals potential

A new study of tailings from Tanzania's Golden Pride Project proves that even low-grade ores (just 0.72 g/t Au) can become profitable thanks to modern technology! Scientists analyzed 1.4 million tons of old waste deposits — long considered worthless — and found they could now be economically viable to process.

Key findings:
✔️ Average gold content: 0.72 g/t, with 74% of the gold concentrated in the fine –75 µm fraction after grinding.
✔️ Dominant minerals: quartz, muscovite, and kaolinite—typical of gold-quartz ore types.
✔️ Minimal harmful impurities (copper <0.05%, sulfur <0.5%), making extraction easier.

How can it be processed?
🔹 Heap leaching — the most cost-effective method for such ores. Similar deposits (e.g., Russia's Mayskoe) achieve 70–80% gold recovery.
🔹 For finer fractions, carbon-in-pulp (CIP) with grinding and classification works best.

Why does this matter now?
With rising gold prices and advancing tech, yesterday’s waste could become tomorrow’s gold source — boosting profits while reducing environmental impact.

For more information, see the article:

📌 Shirima J., Wikedzi A., Rasskazova A.V. Investigation of old waste dump composition of lean gold-bearing ores from the Golden Pride Project (GPP) mining operation in Nzega district, Tanzania. Mining Science and Technology (Russia). 2024;9(1):5-11. https://doi.org/10.17073/2500-0632-2023-07-130

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❓ Can the setback distance of a mine ventilation duct be increased without losing efficiency?

New research has proven: even with a 21-meter setback from the working face, the air jet maintains its effectiveness, fully ventilating the dead-end drift.

🔹 Key findings:

✔️ Experiments conducted in an actual 29.2 m² cross-section drift with five setback variants (10-21 m)
✔️ 21.75 m/s jet velocity ensured proper ventilation even at maximum distance
✔️ Results verified through computer modeling
✔️ Derived equation correlates face velocity with drift geometry

🔹 Why it matters:

The discovery allows safely increasing duct setback to 20m for large cross-section drifts, simplifying mining operations.

For more information, see the article:

📌 Kamenskikh A.A., Faynburg G.Z., Semin M.A., Tatsiy A.V. Experimental study on forced ventilation in dead-end mine working with various setbacks of the ventilation pipeline from the working face. Mining Science and Technology (Russia). 2024;9(1):41-52. https://doi.org/10.17073/2500-0632-2023-08-147


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How to Optimize Ventilation in Mines Using Diesel Equipment?

🔹 Problem: Modern mines utilize high-power diesel equipment, significantly increasing ventilation load. Traditional airflow calculation methods overestimate requirements by 50%, leading to substantial costs.

🔹 Solution: Researchers developed a novel methodology based on field measurements of actual emissions and numerical simulation. This enables precise determination of airflow needed to dilute harmful substances to safe concentrations.

🔹 Key Results:
✅ Reduced ventilation costs through accurate emission accounting
✅ Optimized air distribution in mine workings
✅ 3.5× decrease in CO and NO₂ concentrations with proper ventilation

For more information, see the article:

📌 Senatorov V.A. Determining airflow requirements in mine workings based on field measurements of actual emissions from internal combustion engine equipment. Mining Science and Technology (Russia). 2024;9(1):53-59. https://doi.org/10.17073/2500-0632-2024-01-203

💡 Conclusion: Innovative calculation methods represent a breakthrough in cost efficiency and environmental safety for mining operations!

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We present the articles of the first issue of scientific journal "Mining Science and Technology” (Russia) for 2025:

Scientists investigated a novel method for reinforcing sandy soils using polyurethane compounds. During construction of engineering structures and mineral deposit development, strengthening loose rock formations often becomes necessary, yet conventional polymer reinforcement techniques provide insufficient strength. Experimental studies introduced a two-solution treatment technology: initial mixing of sand with a slow-reacting highly elastic compound followed by addition of 5% rapid-curing single-component resin. Triaxial compression tests demonstrated that this approach creates cured polymer aggregates that bind mineral grains without complete void filling, increasing sand strength by 5-fold. The resulting geomaterial exhibits superior deformation resistance under axial stress, while maintaining strength independence from rapid-curing additives when the resin-to-rock volume ratio exceeds 0.3. The research confirms that the dual-solution method significantly enhances soil stability even with minimal polymer consumption, offering important practical applications for construction and mining operations.

For more information, see the article:

📌 Shilova T.V., Serdyukov S.V., Drobchik A.N. Experimental research of stress-strain properties of sandy soil when strengthened with polyurethane compounds. Mining Science and Technology (Russia). 2025;10(1):15-24. https://doi.org/10.17073/2500-0632-2024-08-303


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How to improve power quality in variable-frequency drives for scraper conveyors?

🔌 Challenge:
Modern mines are actively implementing VFDs for scraper conveyors. However, this introduces voltage and current distortions, reducing energy efficiency and safety.

📊 Research:
Scientists from MISIS analyzed harmonic distortions in MPDS and evaluated the effectiveness of HFs, reactors, and SFs.

🔹 Key Findings:
✔️ HFs and reactors reduce harmonics upstream of the FC by 70–90%.
✔️ SFs mitigate distortions downstream of the FC but require precise tuning.
✔️ Harmonics in leakage circuits (especially 3rd, 5th, 7th) impact RCDs and personnel safety.
✔️ Combined use of HFs, reactors, and SFs delivers optimal results but needs technical-economic justification.

⚠️ Risks:
Higher harmonics in leakage circuits pose safety hazards and disrupt protective devices.

💡 Recommendations:
1️⃣ Deploy HFs and reactors to suppress harmonics upstream of the FC.
2️⃣ Carefully select SF parameters.
3️⃣ Account for harmonics when configuring RCDs.
4️⃣ Implement real-time power quality monitoring.

📌 Conclusion:
Enhancing power quality in VFD-driven scraper conveyors demands a holistic approach and adaptive protection systems.

For more information, see the article:

📌 Petrov V.L., Pichuev A.V. Assessing the efficiency of measures to enhance electric power quality in variable-frequency drive for scraper conveyors. Mining Science and Technology (Russia). 2024;9(1):60-69. https://doi.org/10.17073/2500-0632-2024-01-198

How do you address these challenges? Share your insights below!

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We present the articles of the first issue of scientific journal "Mining Science and Technology” (Russia) for 2025:

Scientists have determined how relative air humidity affects the size of hygroscopic salt dust aerosols – a key factor in addressing ventilation challenges in potash mines. With the expansion of mining operations, the issue of fresh air shortages in mines has become critical. Traditional ventilation methods are no longer sufficient, giving way to recirculation and "ventilation on demand" systems. However, their effective operation requires a precise understanding of how salt dust behaves in a humid atmosphere. When rock is fractured, it generates NaCl and KCl aerosols, which absorb moisture, increase in size, and settle. Accurate models are needed to predict their dispersion. Researchers studied the mechanisms of hygroscopic growth, hysteresis, deliquescence, and recrystallization of salt particles. Due to the challenges of conducting experiments in mines, data on oceanic aerosols of the same composition were used. These models were adapted to mine conditions, yielding average values for the hygroscopic growth factor of salt dust. Remarkably, the particle growth dynamics in mines and over the ocean were found to be very similar! To predict changes in aerosol size, Young's model was proposed, which effectively describes the process in log-log coordinates. These findings will help improve dust condition calculations in salt and potash mines, enhancing ventilation systems and miner safety.

For more information, see the article:

📌 Chernyi K.A., Faynburg G.Z. Evaluation of variation of salt dust hygroscopic aerosol particle size as a function of relative air humidity. Mining Science and Technology (Russia). 2025;10(1):34-44. https://doi.org/10.17073/2500-0632-2024-07-283

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We present the articles of the first issue of scientific journal "Mining Science and Technology” (Russia) for 2025:

Scientists have developed a new method for producing adsorbents to extract heavy metals from mining wastewater. Mining and metallurgical operations generate large volumes of liquid waste containing valuable components. Processing copper-zinc ores produces metal-laden effluents with a wide range of accompanying elements, complicating treatment due to low concentrations of individual components and pH fluctuations. Heavy metals such as Cu²⁺, Zn²⁺, and Fe²⁺ are highly toxic, non-biodegradable, and can accumulate in living organisms, posing risks to ecosystems and human health. Researchers proposed using zeolites based on kaolin and bentonite as an efficient alternative to chemical precipitation. These adsorbents exhibit high ion-exchange capacity, are easily regenerated, and release non-toxic Na⁺ cations into the environment. The novelty of the method lies in using waste Al₂O₃–NaAlO₂ suspension to adjust the composition of the alkaline alloy during zeolite synthesis, ensuring a specific crystalline structure. The technology involves alkaline fusion of bentonite or kaolin with sodium hydroxide, followed by dissolving the alloy in water, filtration, and hydrothermal crystallization. Optimized synthesis conditions achieved a metal recovery rate of 95% from model solutions with initial concentrations of 150 mg/L Cu²⁺, 180 mg/L Zn²⁺, and 125 mg/L Fe²⁺. The resulting zeolite adsorbents can be used to treat metal-contaminated water in closed-loop water systems, reducing environmental impact and conserving resources.

For more information, see the article:

📌 Mirzaeva E.N., Isaeva N.F., Yalgashev E.Ya., Turdiyeva D.P., Boymonov R.M. Preparation of adsorbents for the extraction of heavy metals from mining wastewater. Mining Science and Technology (Russia). 2025;10(1):45-55. https://doi.org/10.17073/2500-0632-2024-02-224

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We present the articles of the first issue of scientific journal "Mining Science and Technology” (Russia) for 2025:

Scientists studied finely ground tailings from the flotation processing of slags at the Sredneuralsky Copper Smelter ("SUMZ technical sands"), which contain zinc (3.3–3.9%) and copper (0.4–0.5%). These wastes can serve both as a source of valuable metals and as a potential environmental hazard. The study examined the material composition of the magnetic fractions of the "technical sands" and evaluated the efficiency of wet magnetic separation for extracting valuable components. Chemical and phase analyses revealed that zinc and copper were distributed relatively evenly across the fractions, with a slight increase in copper in the non-magnetic fraction and zinc in the weakly magnetic fraction. The application of wet magnetic separation under standard conditions proved insufficiently effective, indicating the need for further research to optimize the technology. The results are important for developing new methods of processing copper smelting waste and reducing its environmental impact.

For more information, see the article:

📌 Kotelnikova А.L., Zolotova E.S. Material composition of magnetic fractions of copper-smelting slag flotation tailings. Mining Science and Technology (Russia). 2025;10(1):56-66. https://doi.org/10.17073/2500-0632-2023-08-142

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We present the articles of the second issue of scientific journal "Mining Science and Technology" (Russia) for 2025:

Scientists have proposed a new approach to calculating the optimal width of a dredge front bank, which reduces the cost of placer deposit mining. The study demonstrates that existing methods, focused solely on maximizing dredge productivity, fail to minimize costs when the depth of the placer and overburden thickness increase. The authors developed a methodology for determining the front bank width that accounts not only for dredge performance but also for stripping costs and the extraction of valuable components. The research analyzed the influence of placer parameters (peat thickness, productive layer thickness, front bank width) on economic efficiency, evaluated over 100 process flow sheets for equipment operation, and provided their economic assessment. The results include recommended correction factors for calculating the optimal front bank width, serving as a methodological foundation for designing dredge mining systems.

For details, see the article in Mining Science and Technology:

📌 Talgamer B.L., Meshkov I.A., Murzin N.V., Roslavtseva Yu.G. Justification of the optimal width of a front bank. Mining Science and Technology (Russia). 2025;10(2):99-108. https://doi.org/10.17073/2500-0632-2024-11-332

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