Journal of Mining Engineering نشریه مهندسی معدن

Rare earth elements are generally separated from the leaching solution by concentration as a by-product of the processing plants. Among the main problems of their separation and extraction is the low level of them in the leaching stage. This study aimed to recover available rare earth elements from leaching solution of the non-magnetic sample of the Gazestan iron ore. The solution under investigation contained low concentrations of the rare elements cerium, lanthanum, neodymium, and yttrium, along with significant impurities including ferric ions, calcium, and phosphorus. Therefore, the removal of impurities, especially iron, were investigated. In this regard, it was tried to precipitate rare earth elements as fractional. The two main methods examined, 1) fractional precipitation of rare elements, iron and phosphate, and 2) precipitation of rare elements and calcium while increasing the solution temperature and remaining iron in the solution. Finally, the results of the two methods showed that rare earth elements were concentrated effectively. The REEs concentrated around two to three times higher than their initial level in the concentration step. After that, the adsorption experiments were performed on a batch scale by the Dowex50 WX4 cationic resin. Some experiments were also considered to investigate the effect of temperature enhancement on the adsorption of REEs on resin from the concentrated solution. As the temperature increased, the adsorption of the REEs from the solution increased significantly. In this case, the removal of iron was around 98%. The maximum adsorption of cerium, lanthanum, neodymium, and yttrium on the resin was, 99.11%, 98.67%, 99.0%, and 97.27%, respectively.

The phenomenon of dilution is one of the undesirable consequences of mining that is caused by the unwanted mixing of tailings and minerals. Adverse effects of dilution include increased costs of extraction, transportation, processing, mining grade, and environmental degradation. Dilution control requires identifying the causes of the dilution. Field surveys of the East Azerbaijan Sungun copper mine, which is extracted by the open-pit method, show that factors such as dyke infiltration, contact of tailings blocks and mineral at the borders, sample error Vector and Murphy's errors (human error) are the factors influencing the dilution. In this study, in order to estimate the amount of external dilution (dilution due to dykes) of Sungun copper mine, geostatistical modeling (index kriging) was used. The external dilution rate of the mine (11.3%) was calculated. The amount of external dilution seemed to be higher than the maximum initial estimate of dilution in open-pit mines with ma...

A mine closure plan is implemented while mine’s deposit is totally exhausted. It is necessary to precisely identify and analyze these factors and their impacts on mine’s life. In this research, with the purpose of identifying and analyzing the factors affecting the premature closure of Chadermaloo Iron ore mine, a comprehensive risk closure model of Chadormalou mine was developed based on the Laurence’s closure risk model. With this respect, in order to assess the probabilities and consequences of broad and sub-issue closure risks, questionnaires have been provided and distributed through the seven experts in case study mine site and filled questionnaires based on experts’ judgment collected to obtain certain values of risks. In the next step, identification and ranking of the factors affecting the premature closure of surface mines was designed in a hierarchical structure in order to predict and take appropriate measures. The model at the level of criteria includes four main components consists of probability of occurrence, consequence, uncertainty of estimation and ability of the organization in responding to risk. The alternatives comprises risk factors in the social, political, economic, environmental, legal, technical, safety and health issues. Whole calculations were performed in accordance with Chang approach through Fuzzy Analytical Hierarchy Process (FAHP) to evaluate and rank relative and final weights of each criterion involved in premature closure risk assessment. The results of application of closure risk model to Chadormaloo mine demonstrated that the mine is classified as "moderate" from premature closure point of view. The closure probability of 30 percentage shows the mining activities are able to be continued. This implies more attention should be paid to eliminate or minimize the impacts of these issues within mine’s planning and design.

Given the high importance of hydraulic failure in the oil and gas industry in order to stimulate and increase the capacity of oil reservoirs, the analysis of crack propagation in these environments during this process is very important. Although the amount of porosity in such reservoirs may be low, but these porosities and cracks, are considered as weaknesses and discontinuities of the environment and a determining factor in the number and propagation path of the cracks. In the present paper, using the linear elastic fracture mechanics, initiation, propagation and spread of cracks in porous samples are modeled by the finite element method (XFEM) developed in Abacus software, based on the criterion of the maximum principle stress and the criterion of independent of the failure. In order to validate the proposed method,, the results were compared with the KGD method and with an error of 0.04% in the maximum crack opening size and 4.87% in the maximum crack length, an acceptable agreement was obtained. The results showed that the use of spring elements as elastic support to simulate the elastic properties of the environment can be useful and effective. The hydraulic fracture modeling process is performed on microscopy-CT scan images of three real sandstone samples and the crack growth path is analyzed. Also, the amount of energy absorbed per unit length in each sample is calculated and the final path of crack propagation with increasing injection pressure is presented. Then, by calculating the percentage of empty space before and after failure in each sample, absolute and relative failures in each case are calculated and the results are compared with each other. The results show that due to compression and reduction of porosity, the absorbed energy per unit length decreases and a lower level of the sample is affected by hydraulic failure.

Due to the increasing number of accidents while working in the mines, studies related to maintaining the safety and health and improving safety management are expanding today. To reduce accidents and injuries, risk assessment should be performed continuously in the mines. For this purpose, two gold mines of Ardestanِ Dareh Ashki and Isfahan Moteh were examined. In the first stage of risk assessment, information on hazards in the mines was collected and in the second stage, the probability of occurrence and severity of its effect were evaluated. The two gold mines were then developed using methods similar to the ideal option and fuzzy logic to assess the risks The total hazards of the ore mining and concentrating operations in these mines were 136, which were classified into 8 groups. Finally, after completing the necessary calculations, several groups with different risks were obtained. The first group with the highest risk included unpredictable explosions, non-standard explosives, tailings dam failure, cyanide leakage, people falling into the tailings dam, electrocution while working with equipment, slipping or slipping, not wearing safety clothing, unauthorized entry It was in the area of ​​extraction and explosion during firefighting. Based on the obtained results, it is possible to plan and take appropriate action to prevent the occurrence of undesirable results.

lead and zinc mine of Gole zard is located in ALigudarz city of Lorestan province and the grade of galena and sphalerite minerals in this sulfide ore is 5.4% and 23.7%, respectively. Research has shown that lead in ores is complexed by chlorine ions. For this purpose direct lead leaching was performed on the ore of this mine by mixing hydrochloric acid and NaCl solution and the effect of each of the parameters of temperature, time, pulp density, stirring and hydrochloric acid concentration on lead leaching was investigated. The results showed that the parameters of hydrochloric acid concentration, pulp density and time had the most effect and pulp stirring time and temperature had the least effect on lead recovery and finally under optimal conditions of 60 minutes, temperature 50 ° C, pulp density 10%, hydrochloric acid concentration 15% and the stirring speed 1000 rpm, the lead recovery was obtained about 91.7%.

Identification of the element dispersion patterns and relating them to the geochemical anomalies is one of the exploration tools, especially in the semi-detailed and detailed phases. Methods that can simultaneously analyze samples and elements are recommended for this purpose. In this paper, two methods namely, correspondence cluster analysis (CCA) and density-based clustering algorithm (DENCLUE) and the geochemical data of Khoynaroud region have been used. Clustering of 165 soil samples, along with the results of the 7 elements analysis associated to the porphyry copper-gold mineralization, namely As, Au, Cu, Hg, Pb, S and Zn, shows that four A, B, C and D areas are visible with mineralization potential in the study area. In CCA method, the data are divided into 6 clusters. These clusters contain S with 57 samples, 61 samples, Pb with 16 samples, Cu with 8 samples, As with 7 samples and Au, Hg and Zn with 17 samples, respectively. While in DENCLUE method include 5 clusters in the form of S with 66 samples, 43 samples, Pb and Zn with 38 samples, Au and Cu with 10 samples and As and Hg with 8 samples, respectively. Part C2 of area C and part D2 of area D are proposed as the best areas with the possibility of porphyry mineralization and as well as area A with the possibility of hydrothermal vein mineralization. Area B and part D1 with the possibility of vein mineralization and the need for additional exploration are also likely to be the next proposals. The results also show the better clustering of the elements, better adaptation of the proposed areas for mineralization with multi-element geochemical anomalies and geological conditions of the study area are the advantages of DENCLUE algorithm. Therefore, this algorithm can be used to relate the element dispersion pattern with their geochemical anomaly.

فرآیند تخریب در روش استخراج جبهه‌کار طولانی به طور مستقیم بر پایداری و پیوستگی عملیات استخراج تاثیر می‌گذارد. از این رو پیش‌بینی رفتار تخریبی سقف از دو دیدگاه گام‌های تخریب و مقدار تنش‌های القایی ایجاد شده در طی آن مساله‌ای ضروری در طراحی پروژه‌های استخراج جبهه‌کار طولانی است. در این راستا فرآیند تخریب اول که در آن گام تخریب و تنش‌های القایی بیش از تخریب دوره‌ای است، اهمیت ویژه‌ای دارد. بر این اساس در این مقاله به بررسی تنش‌های القایی ناشی از فرآیند تخریب اول از طریق شبیه‌سازی عددی گسسته پرداخته شده است. برای این منظور تاثیر تغییرات 5 پارامتر مقاومت کلی سقف بلاواسطه به صورت تابعی از مقاومت فشاری تک محوری لایه‌ها و ضخامت آن‌ها، ارتفاع سقف بلاواسطه، فاصله لایه‌بندی در سقف بلاواسطه، عمق معدنکاری و نسبت تنش‌های برجا بر روی بیشینه تنش‌های القایی قائم و افقی جلو و پشت جبهه‌کار با استفاده از نرم‌افزار UDEC مجموعا برای 62 مدل تحلیل شده است. نتایج حاصل شده نشان می‌دهد که به ‌جز برای نسبت تنش‌های برجا، روند تغییرات فشارهای پایه‌ای قائم و افقی جلویی و عقبی نسبت به تغییرات پارامترها یکسان است. همچنین رابطه تمام پارامترها با تنش‌های پایه‌ای به ‌جز ارتفاع سقف بلاواسطه به صورت مستقیم است.