| 1. |
- Bahrami, Ataallah, et al.
(författare)
-
Combined Effect of Operating Parameters on Separation Efficiency and Kinetics of Copper Flotation
- 2019
-
Ingår i: Mining, metallurgy & exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 36:2, s. 409-421
-
Tidskriftsartikel (refereegranskat)abstract
- This study aims to investigate the effects of operational variables on concentrate grade, recovery, separation efficiency, and kinetic parameters of the copper flotation process. For this purpose, the effects of the pulp solids content, collector and frother dosage, and preparation and concentrate collection time were studied using a Taguchi experimental design. The results of statistical analyses indicated that the concentrate collection time and pulp density were the most influential parameters on concentrate grade. Considering copper recovery, concentrate collection time, collector dosage, and pulp density were the most significant variables, in decreasing order of importance. Also, the separation efficiency was mostly influenced by the concentrate collection time. Furthermore, kinetic studies showed that the second-order rectangular distribution model perfectly matched the experimental flotation data. The highest kinetic constant of 0.0756 s−1 was obtained from the test, which was performed with 35% solids content and 40 and 20 g/t collector and frother, respectively. The highest predicted copper recovery of 99.57% was obtained from the test at 30% solids content, and the collector and frother dosages of 40 and 15 g/t, respectively.
|
|
| 2. |
- Bahrami, Ataallah, et al.
(författare)
-
The Evaluation of Starch-Based Flocculant on the Thickener Operation in the Molybdenum Processing Plant and Competency of Molybdenite Flotation
- 2022
-
Ingår i: Mining, Metallurgy & Exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 39:3, s. 1255-1266
-
Tidskriftsartikel (refereegranskat)abstract
- The type and dosage of flocculants used in the middle thickener of the copper-molybdenum plant, in addition to adjusting the quality of recycled process water, is very effective on the floatability of molybdenite. In this study, the effect of starch-based flocculant (wheat starch) was investigated on the efficiency of middle thickener and molybdenite flotation, in the molybdenum processing plant. First, sampling from overflow and underflow of the middle thickener in Mo processing circuit (in industrial scale), in the presence and absence of starch, were collected. The polished sections of samples from the overflow and underflow of the thickener were studied in order to determine the effect of starch on particles settling with different shapes. Microscopic studies show that molybdenite plate-like coarse particles are transferred to the thickener overflow (process water) in the presence of starch flocculant, whereas molybdenite fine particles present in the underflow are often needle-shaped. In addition, in terms of grade distribution, the grade of molybdenum in the thickener overflow is higher than that of copper and iron. Then, after sedimentation tests (in laboratory scale) with different concentrations of flocculant, flotation tests were performed on test samples. According to the results from laboratory studies, increasing the dosage of starch from 0 to 1000 g/t increased the recovery of molybdenite flotation and reduced the access of copper minerals to molybdenite concentrate. In this case, molybdenum recovery (in lab tests) is increased by about 5% compared to the case of not using starch. While the increase in the recovery of molybdenum by adding starch to the middle thickener in the industrial scale is about 10%. In higher dosages of starch (2000 g/t), the trend is reversed (in the lab and industrial scale) and molybdenum recovery decreased sharply due to the decrease in contact angle and depression, whereas the amount of copper transferred to the molybdenum concentrate increased.
|
|
| 3. |
- Bahrami, Ataallah, et al.
(författare)
-
The Order of Kinetic Models, Rate Constant Distribution, and Maximum Combustible Recovery in Gilsonite Flotation
- 2019
-
Ingår i: Mining, Metallurgy & Exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 36, s. 1101-1114
-
Tidskriftsartikel (refereegranskat)abstract
- Kinetic models are the most important tool for predicting and evaluating the performance of flotation circuits. Gilsonite is a natural fossil resource similar to an oil asphalt, high in asphaltenes. Here, in order to determine the kinetic order and flotation rate of a gilsonite sample, flotation experiments were carried out in both rougher and cleaner stages. Experiments were conducted using the combinations of oil–MIBC and gas oil–pine oil, with one test without collector and frother. Five kinetic models were applied to the data obtained from the flotation tests using MATLAB software. Statistical analysis showed that the results of the experiment with oil–MIBC were highly in compliance with all models. Kinetic constants (k) were calculated as 0.1548 (s−1) and 0.0450 (s−1) for rougher and cleaner stages, respectively. Rougher and cleaner tests without collector and frother also matched all models well (R2 > 0.98), with kvalues of 0.2163 (s−1) and 0.284 (s−1), respectively. The relationship between flotation rate constant, maximum combustible recovery, and particle size showed that the maximum flotation combustible recovery and flotation rate were obtained in the size range of −250 + 106 μm in the rougher and cleaner stages. The combustible recovery and flotation rate were higher in the rougher flotation process than in the cleaner stage.
|
|
| 4. |
- Gyamfi, S., et al.
(författare)
-
Development of Strategies to Reduce Ventilation and Heating Costs in a Swedish Sublevel Caving Mine—a Unique Case of LKAB’s Konsuln Mine
- 2022
-
Ingår i: Mining, Metallurgy & Exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 39:2, s. 221-238
-
Tidskriftsartikel (refereegranskat)abstract
- This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine 2018–2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 3 Mtpa in the future, and this requires the primary fans to be upgraded. Therefore, a study was carried out to determine whether using ventilation on demand (VOD) could avoid this fan upgrade and reduce Konsuln’s ventilation and heating power costs in the future. The study also investigated whether using battery electric vehicles (BEVs) along with VOD or as a standalone strategy could further reduce these power costs. In addition, the study analyzed the suitability of heating power reduction strategies presently or previously used in the Nordic countries and Canada to investigate potential additional strategies to reduce the heating power cost, the largest portion of Konsuln’s ventilation and heating power costs. The study found using VOD can avoid the expensive upgrading of the existing primary fans and reduce Konsuln’s ventilation and heating power costs in the future. Using BEVs can further reduce these costs. Finally, none of the Nordic and Canadian heating power reduction strategies is suitable for Konsuln because they require unique conditions that do not exist in Konsuln.
|
|
| 5. |
- Halim, Adrianus, et al.
(författare)
-
Do Refuge Chambers Represent a Good Strategy to Manage Emergencies in Underground Coal Mines?
- 2019
-
Ingår i: Mining, Metallurgy & Exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 36:6, s. 1191-1199
-
Tidskriftsartikel (refereegranskat)abstract
- The 2006 Sago, Darby, and Aracoma mine disasters in the United States (US) forced the US government to implement the 2006MINER Act and additional regulations that require all US underground coal mines to install and maintain refuge chambers tomanage entrapment emergencies, in particular, fires and explosions. However, there is a debate on whether barricading in refugechambers is a good strategy to survive such emergencies. Australian coal mines are not required to use refuge chambers and,instead, have adopted a strategy that focuses on instructing and training miners to self-escape to the surface. This paper analyzesmerits and problems of using refuge chambers and self-escape to the surface to manage emergencies in fires or explosions in anunderground coal mine. The authors found that the use of refuge chambers may not be the best strategy during extensive fires orwhen multiple explosions happen. In these situations, mine rescuers are unlikely able to extract miners who are sheltered inchambers and conversely, self-escape may save more lives than sheltering. Chances for successful self-escape are furtherimproved by regular, externally assessed training such as Level 1 Emergency Exercises required in the Australian State of Queensland. These exercises put pressure on mine operators to ensure and maintain the effectiveness of their emergencymanagement system.
|
|
| 6. |
- Halim, Adrianus, et al.
(författare)
-
Improvement of Working Conditions and Opinions of Mine Workers When Battery Electric Vehicles (BEVs) Are Used Instead of Diesel Machines — Results of Field Trial at the Kittilä Mine, Finland
- 2022
-
Ingår i: Mining, Metallurgy & Exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 39:2, s. 203-219
-
Tidskriftsartikel (refereegranskat)abstract
- A major part of the European Union’s (EU) project Sustainable Intelligent Mining System (SIMS) is investigating the development of diesel-free/carbon-neutral underground mines in order to ensure sustainable underground mining in the future. Replacing diesel machines with electric vehicles in underground hard rock mines has been widely acknowledged by the mining industry worldwide as a critical step to improve working conditions by reducing diesel exhaust related contaminants, to reduce mine ventilation electrical power cost by reducing mine airflow quantity, and to reduce mine greenhouse gas emissions. All of these are major requirements to achieve sustainable future underground mining practices. A field trial of Epiroc’s 2nd generation of Battery Electric Vehicles (BEVs) at Agnico Eagle Finland’s Kittilä mine was conducted during 2019 – 2020. Vehicles tested were MT42 mine truck, ST14 Load-Haul-Dump (LHD), and Boomer E2 jumbo drill rig. This paper outlines the improvement of the working conditions observed in the field trial, and the opinions of the mine personnel at Kittilä mine on using BEVs instead of diesel machines. Measurements of atmospheric contaminants and air temperatures taken during the field trial clearly demonstrated a significant improvement of working conditions when BEVs were operating as opposed to diesel machines. This field observation was supported by the opinion of the majority of the Kittilä mine workers. However, some remaining concerns must be addressed before BEVs can replace diesel machines.
|
|
| 7. |
- Ikumapayi, Fatai, et al.
(författare)
-
Recycling process water in sulfide flotation, Part A: Effect of calcium and sulfate on sphalerite recovery
- 2012
-
Ingår i: Minerals & metallurgical processing. - : Springer Science and Business Media LLC. - 0747-9182. ; 29:4, s. 183-191
-
Tidskriftsartikel (refereegranskat)abstract
- In order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the influence of major species, calcium and sulfate in process water on sphalerite flotation was investigated through Hallimond tube flotation, zeta potential, diffuse reflectance Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements using sphalerite mineral sample. Assessment of process water species in flotation was done using deionized water, process water and simulated water containing calcium and sulfate ions in experiments. Hallimond flotation shows increased sphalerite floatability in process water compared to deionized water, but no significant effect on the presence of calcium and sulfate ions in deionized water using isobutyl xanthate as a collector. The presence of calcium ions reduced the sphalerite's negative zeta potential, while at higher concentrations, a charge reversal occurred, at about pH 11. FTIR and XPS studies revealed the presence of surface-oxidized sulfoxy and carbonate species on sphalerite at pH 11.5 in deionized water, process water and water containing calcium and sulfate ions. These surface species do not influence xanthate adsorption.
|
|
| 8. |
- Ikumapayi, Fatai, et al.
(författare)
-
Recycling process water in sulfide flotation, Part B: Effect of H2O2 and process water components on sphalerite flotation from complex sulfide
- 2012
-
Ingår i: Minerals & metallurgical processing. - : Springer Science and Business Media LLC. - 0747-9182. ; 29:4, s. 192-198
-
Tidskriftsartikel (refereegranskat)abstract
- Hydrogen peroxide production was measured during the grinding of a complex sulfide ore, and its oxidizing effect on solid surfaces was investigated using Fourier transform infrared spectroscopy (FTIR) with diffuse reflectance attachment measurement. In turn, an attempt was made to correlate the formation of hydrogen peroxide, surface oxidation and sphalerite flotation. Additionally, in order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the effects of major components of calcium and sulfate species present in recycled process water and the effect of temperature on sphalerite flotation were investigated through bench-scale flotation tests using complex sulfide ores. The significance of process water species in flotation was studied using tap water, process water and simulated water containing calcium and sulfate ions. Formation of hydrogen peroxide was revealed during the grinding of the complex sulfide ore, and its formation was counteracted by diethylenetriamine (DETA). The FTIR spectrum of the pulp solid fraction showed varying degrees of oxidized surface species, which are related to the concentration of H2O2 analyzed in pulp liquid. Bench-scale flotation using two different complex sulfide ores showed that sphalerite recovery is better in process water than in tap water. Flotation results also indicated a varied recovery of sphalerite at different temperatures in either tap water or process water.
|
|
| 9. |
- Jonsén, Pär, et al.
(författare)
-
Validation of tumbling mill charge induced torque as predicted by simulations
- 2013
-
Ingår i: Minerals & metallurgical processing. - : Springer Science and Business Media LLC. - 0747-9182. ; 30:4, s. 220-225
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding mill charge motion is important. In the charge, the center of gravity is shifted from the rotational center of the mill system, and its motion is induced by rotation of the mill, while at the same time the charge creates a torque into the mill system. Breakage of ore particles and wear of liners/ball media are closely linked to this motion. To study these phenomena in a physically correct manner, numerical models for different parts of the mill system are needed. Validations of such models are scarce, because of the difficulty to measure inside a tumbling mill.Experimental measurements in a lab mill were done for a number of load cases: varying feed material, mill filling, mill speed and pulp liquid. The mill is set up to measure the charge-induced torque. The accuracy is good with relative uncertainty smaller than ±2% for relevant load cases.A full three dimensional numerical model of the whole mill is used to predict induced torque. Agreement between predicted and measured torque at steady-state is good. In addition, the model can accurately predict the mill start-up behavior for torque and mill power. This proves that the model is physically correct, and can be used for modeling large-scale mills.
|
|
| 10. |
- Larsson, I. A. Sofia, et al.
(författare)
-
Simulation of Thermal Effects on the Flow Field in a Pilot-Scale Kiln
- 2021
-
Ingår i: Mining, Metallurgy & Exploration. - : Springer. - 2524-3462 .- 2524-3470. ; 38:3, s. 1487-1495
-
Tidskriftsartikel (refereegranskat)abstract
- The flow field and coal combustion process in a pilot-scale iron ore pelletizing kiln is simulated using a computational fluid dynamics (CFD) model. The objective of the work is to investigate how the thermal effects from the flame affect the flow field. As expected, the combustion process with the resulting temperature rise and volume expansion leads to an increase of the velocity in the kiln. Apart from that, the overall flow field looks similar regardless of whether combustion is present or not. The flow field though affects the combustion process by controlling the mixing rates of fuel and air, governing the flame propagation. This shows the importance of correctly predicting the flow field in this type of kiln, with a large amount of process gas circulating, in order to optimize the combustion process. The results also justify the use of down-scaled, geometrically similar, water models to investigate kiln aerodynamics in general and mixing properties in particular. Even if the heat release from the flame is neglected, valuable conclusions regarding the flow field can still be drawn.
|
|
