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By Ralph W. M. Lai

The liquid membrane separation process was first patented in 1968 for separating hydrocarbons.(1-4) This stimulated many researchers to join in the area of separating organic compounds. l Since then, its applications have been extended to the removal of contaminants from waste water,(12-33) encapsulation of enzymes and/or microorganisms for reaction and/or separation, (24-28) oxygenation of blood (artificial lung),(19) removal of toxins from blood (artificial kidney)(26,20) and metal extraction.(31-63) This paper discusses the possible process schemes for using liquid membranes to separate and concentrate copper ion from its acidic leaching solution.

Jan 1, 1982

By Richard E. Beane

For several decades, the minerals industry has used leaching techniques to extract metals from rocks whose grade was too low to be treated profitably using conventional metallurgical techniques, and, as of 1972, about 15% of domestic copper production was derived using leaching methods (Beall 1). Increasing interest is currently being directed toward solution mining, particularly with respect to copper, for basically two reasons. In the first place, geological exploration has outlined several copper deposits of large tonnage and 1m', grade which are buried at sufficient depth to preclude open-pit mining which would make such mineral deposits ore deposits. Nevertheless, these occurrences provide significant potential if they could be treated by chemical leaching in situ. Secondly, the porphyry deposits of the western united States, which provide by far the largest percentage of domestic copper, do not terminate geometrically with sharp borders. These large disseminated bodies commonly decrease in grade laterally away from volumes of rock containing ore grade metallization, and the distinction between ore and waste is strictly economic. In order to extract ore grade material from the ground, a significant amount of rock containing sub-ore-grade copper must also be removed which, when placed on dumps, is amenable to solution mining. These two considerations clearly indicate the reasons for the growing interest in solution , leaching techniques--namely the ability to exploit deeply buried low grade deposits and the expansion of reserves in deposits currently under production.

Jan 1, 1977

By William C. Dixon

Since the mid 60's, several haul cycle simulation programs have been developed. However, most of these programs are believed to employ the continuous, rather than the discrete, event-oriented simulation approach to determine the haul cycle times. This paper describes the recently developed haul cycle simulation approach where time is advanced in varying amounts only as the system changes occur. This approach results in greater computational accuracy and increased computational efficiency. The program is written in FORTRAN and requires equipment performance curve and haul road profiles as input. Unique program capabilities include the handling of switchbacks and intersections. The program uses a master data file concept in which various haul road profiles found during the mine life can be simulated all in one job submission. The results of the model validation using the actual time study data provided by an open pit mine operator near Tucson, Arizona, are also described in this paper.

Jan 1, 1978

By Bob Munz, Ry Stone

To facilitate the installation of the longwall equipment for each extraction panel, West Elk mine develops set-up room roadways that are between 26.5 and 30.5 feet wide. Historically at the mine, the set-up room roadways have been driven in a single 20-foot-wide pass, then incrementally widened to the required width during installation of the longwall shields. The first pass roof is supported with a generic roof support plan consisting of partially encapsulated roof bolts and point-anchored cables. This ground support plan was utilized regardless of the geotechnical conditions encountered in the roadways or consideration of the required stand-up time of the roadway before the longwall shields were installed. This "blanket" approach tends to result in over-conservative or inappropriate roof support designs, particularly in changing geotechnical environments. Guided by the desire to optimize the ground support plans and increase mining efficiency for future set-up rooms, the West Elk mine and Agapito Associates, Inc. have developed and implemented a strata management program. Strata management, as a formal and structured process, allows ground support and mining methods to be tailored to the anticipated and encountered geotechnical environment in a con- trolled manner (Thomas 2007). To arrive at adequate site-specific ground support plans for the set-up rooms at the mine, several struc- tured processes were utilized. Firstly, the geotechnical environment was characterized by examining the roof lithology and geomechanical properties from nearby rock core obtained from exploration boreholes. To increase both mining efficiency and continuity, and to achieve longer stand-up times before the longwall shields are installed, a multi-pass approach was implemented into the design. During mining, the geotechnical conditions of the roadway are mapped, and the roof is strategically surveyed with a borescope. This process was used to ensure that the encountered ground behavior was in alignment with the design standards used for the roof support design. To support this process with measured data, roof extensometers were strategically installed throughout the roadway. This data was used to monitor the magnitude of roof displacement at various horizons and record displacement rates up until the longwall shields were installed. Lastly, a Trigger Action Response Plan (TARP) was used during mining to cater for any unforeseen changes in ground conditions that would warrant additional con- trols such as increased monitoring or the installation of additional ground support. This paper presents two case histories at the mine where the above strata management approach was implemented to arrive at a site-specific ground support plan. The main changes to the mine's ground control plan included a multi-pass mining approach, the utilization of fully encapsulated roof bolts, and the transition to a stiffer roof support system. The geotechnical mapping, the roof borescope results, and the roof extensometer data will be presented to demonstrate the effectiveness of the ground support system up until the longwall shields were installed in both presented cases.

Jun 25, 2024

By Diler Katircioglu-Bayel, Oner Yusuf Toraman, Safak Gokhan Ozkan

Calcite has found many applications in the industrialized countries recently, such as filler for paper, paint, plastics, rubber and food. Furthermore, calcite separates many toxic elements, and thus it is used in water treatment, and it is also used to raise the pH of drinking water. Due to its special features, calcite has been characterized as a useful coating and reinforcement filler for applications. Finer particle size of calcite has been determined to provide improved features for all of these applications. For submicron particle production, wet milling is selected over dry milling to produce finer particle sizes. Wet stirred media mills are also used in many industries. For that reason, this study investigated the effects of operating parameters on particle size reduction in the wet grinding process. The knowledge acquired by this study will allow the finding of optimal operating parameters for a stirred media mill to optimize specific energy consumption and reduce particle size.

By MEHMET KIZIL, PETER KNIGHTS, ROYAL REA

A 1/20 scale experimental dozer push test rig was designed and constructed to quantify the expected production rates (loose cubic metres per hour) for dozers operating in hard rock bulk push applications. The particle size distribution of the material employed in the test rig was modelled on a fragmented muckpile representative of that for a typical surface copper/gold mine overburden. A commercially available road base material was found to be highly representative of site conditions. Buckingham Pi theory was applied to mathematically develop factors for scaling up dozer productivity parameters, including blade loads and push times. Dozer production rates were investigated for various dozing distances and slope angles. A series of instantaneous productivity curves were produced which are applicable for use in hard rock dozer push operations. Currently, it is difficult to estimate dozer push productivity in hard rock environments due to dozer productivity correction factors that are empirical in nature and provide only discrete, end-point values for a range of operating conditions. The productivity curves produced demonstrate that dozer productivity declines rapidly over the range of 10 m to 40 m. As such, it is recommended that efficient bulk dozing operations in hard rock mining blocks should not exceed 40 m dozing distance. Further testing of muckpile conditions with increased clay and moisture content would be beneficial in order to better understand and quantify the effects of cohesion on hard rock dozer push productivity.

Nov 23, 2021

By R. M. Parlman

Interest is increasing in obtaining incremental improvements in mineral recoveries in flotation processes because of changing world economic conditions. Research on collector reagents, long indispensable components in flotation systems may provide the cheapest and simplest route to higher metal recoveries. Sulfhydryl group - containing compounds (-SH) and their salts, e.g., dithiophosphates, xanthates and a few other derivatives are commonly used to promote the flotation of sulfide minerals. Alkyl mercaptans, another class of sulfhydryl compounds, have long been known to have collecting properties but have been relegated to dormancy for one reason or another. This paper reports results from new investigations of alkyl mercaptans, trithiocarbonates, and a petroleum oil with a variety of western domestic and Canadian ores for copper and molybdenum sulfides recovery. Specific opportunities are pointed out to the industry for mineral recovery enhancement through the use of the proper reagent combination.

Jan 1, 1980

By D. C. Yang

A practical and economical flowsheet has been developed and demonstrated by integrating the packed column flotation with the GranuFlow process for fine coal recovery. Orimulsion, which was used as an additive, served a dual purpose: first in the flotation and second in the dewatering and granulation steps. The test results on the coal preparation effluent sample show that Orimulsion is flexible and compatible with fuel oil and various frothers used in the packed column. Clean coal with ash contents of 3.0, 3.7, 4.3 and 5.1% were produced from a head sample of 33% ash at combustible matter recoveries of 72.4, 81.1, 87.5, and 89.2%, respectively. Other advantages include high throughput, low moisture, improved handleability, and reduced dustiness of the dewatered coal, thus providing a very significant economic Incentive for the integrated process.

Jan 1, 1998

By C. Vasilescu

Phytotechnologies use plants to remediate various media impacted with different types of contaminants. These technologies can be implemented either in situ or ex situ. The affected media in which phytotechnologies can be applied include soil, sediments, groundwater and surface water. They are best applied at sites with shallow contamination of organic, nutrient, or metal pollutants that are amenable to one of five treatment options: phytoextraction, phytotrans-formation, rhizosphere, bioremediation, phyto-stabilization or rhizofiltration. Phytoremediation can be used along or, in some cases, in place of mechanical cleanup methods. Phytoremediation can be used to clean up metals, pesticides, solvents, explosives, crude oil, polycyclic aromatic hydrocarbons and landfill leachates.

Jan 1, 2006

By A. Jahedsaravani, M. Massinaei, M. Zarie

Deep learning is a subset of machine learning that uses artificial neural networks for extracting high-level features from image data. In the present study, a soft sensor is proposed for the prediction of the flotation performance through froth features generated by the use of pre-trained convolutional neural networks. Several state-of-the-art convolutional neural networks (AlexNet, GoogLeNet, VGGNet, ResNet, and SqueezeNet) pre-trained on the ImageNet database are used to predict the metallurgical performance of two flotation systems. The first case study is a batch copper flotation system video-captured over a wide range of process conditions. The second case study is an industrial coal flotation column equipped with a continuous video recording system. The pre-trained networks are used to extract features from the froth images, and these features are subsequently used to predict the flotation conditions and performance. The prediction results by the pre-trained algorithms were compared with the traditional image processing algorithms. This demonstrates the ability of the pre-trained structures to generalize to images outside the ImageNet database. GoogLeNet outperforms other network architectures and provides more accurate predictions of the flotation process behavior and performance.

May 5, 2023

By S. Mischler, J. Noll, G. Schnakenberg, A. Bugarski, M. Crum

Diesel particulate filter (DPF) systems and biodiesel fuels are two of the most promising technologies available to the mining industry to reduce the exposure of underground miners to diesel particulate matter (DPM). A study has been conducted to estimate the potential of DPF systems and biodiesel blends to reduce DPM emissions from production vehicles. Results of testing three DPF systems in an isolated zone showed 88% to 99% reductions in elemental carbon concentrations. The test results also show that biodiesel blends, B20 and B50, reduced the elemental carbon concentrations in the mine air by 26 and 48 percent, respectively.

Jan 1, 2004

By R. S. Jurani

Sunshine Mining Company's Kellogg operation is the primary silver producer in the United States, and maintaining a comfortable working environment in this deep underground mine historically has been a complex and costly problem. To improve the ventilation and cooling systems at a time of declining and uncertain silver market, it was proposed to optimize the performance of existing facilities at minimum cost. This paper discusses a 2-year, $400 000 optimization program that resulted in increased total mine airflow, cooler ambient temperatures, reduced compressed air usage, and lower energy consumption by primary fans, air compressors, and refrigeration plants, thereby saving the company approximately $650 000 per year.

Jan 1, 1987

By Miguel Reyes, Chenming Zhou, MATTHEW GIRMAN

Electromagnetic energy emitted from electronic devices has been known to interfere with other electronic systems, hindering their ability to function properly. Mines have many electronic devices critical to the health and safety of mine workers that could be negatively affected by electromagnetic interference (EMI). To ensure that devices are electromagnetically compatible, tests must first be conducted to measure emissions and check for immunity. There are many standards available across multiple industries that prescribe emission limits and test methods for electronic devices. Due to the unique environment of an underground mine, it may not be enough to simply adopt a standard from another industry to mining. A literature review has been conducted, and an overview of EMI standards in other industries will be provided in this paper. Also, an example of how a standard can be applied to mining equipment is presented. Finally, recommendations on standards which could potentially be applied to mining will also be included. This work will inform the mining industry of EMI standards in other industries so that mine workers and technology manufacturers have guidance of the steps that can be taken to investigate and reduce the impact of electromagnetic interference and potentially work toward electromagnetic compatibility. The findings and research involved in this effort can also be used to explore the need to develop mining-specific EMI recommendations and standards.

Nov 25, 2021

By Xuezhong Wang, Hao Guo, Tao Tu, Qingsheng Liu

The scheelite concentrate was leached with a mixture of sulfuric and oxalic acids. Chemical compositions, mineral phases, and morphology were characterized by XRF, XRD, and SEM–EDS. Based on the results of the single-factor experiments, the response surface methodology (RSM) was chosen to optimize the leaching parameters: temperature, time, and concentrations of sulfuric and oxalic acids. The RSM results indicate that the optimum values for those parameters are as follows: temperature 72 ℃, sulfuric acid concentration 1.48 mol/L, oxalic acid concentration 0.96 mol/L, and reaction time 2 h. Under the optimal leaching conditions, the model predicts a maximum leaching yield of 99.5%, compared to the value of 99.1% obtained experimentally, that is, a discrepancy of only 0.04%. This good correlation shows that the quadratic polynomial equation obtained by the RSM optimization is reliable. The importance on leaching parameters of scheelite is, in decreasing order, temperature, time, sulfuric acid concentration, and oxalic acid concentration.

Oct 11, 2021

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

6.1 PRINCIPLES OF PLANNING GROUTING OPERATIONS FOR SHAFTS, DRIFTS AND TUNNELS The planning of integrated grouting of vertical, inclined or horizontal underground workings in saturated, fractured rock includes the following phases: 1. Planning for the collection and analysis of geological information concerning the characteristics of the struc¬tural deformation(s) that produced the details of the frac¬ture system being studied. 2. Planning for the acquisition of initial hydrogeological information produced by the flowmetric and hydrody¬namic investigations (described in Chapters 2 and 3). 3. Computing the initial engineering calculations of the ex¬pected or planned dimensions of the isolation curtains for each water-producing stratum (fracture zone) and the expected areal spreading pattern of the grout in each of these water-producing horizons. The selection of the lo¬cations, the initial optimal number of holes and the vol¬ume of grout needed to create each isolation curtain also are included in this phase. 4. The selection or development of a grout formula for the specific hydrogeological conditions that exist at the site. 5. Identification of a resource (deposit) required to produce the grouting clay. The planning of grouting operations must be supported by the acquisition of all necessary initial data, which in¬cludes: 1. The geographic location and administrative responsibil¬ity (ownership and regulatory constraints) of the mineral deposit and any peculiar features of the area where ex¬cavation of the underground workings is planned. The surface relief, the hydrographic network of the region, and the local climatic conditions must be evaluated prior to planning for buildings and waste discharges if any. 2. The economic status of the region, the available trans¬portation, the nature of the energy base, the water and heat supply sources, the location of construction mate¬rials suitable for making the grout all must be deter¬mined. 3. The geological and hydrogeological characterization of the work site must be accomplished. 4. The technical features of the shaft(s) and underground works must be characterized. 5. The organization's principal initial design plan features and the construction sequence of all buildings and struc¬tures must be developed. These must be correlated with the organization and schedule for excavating the under¬ground works. The technical characterization of a shaft or of other un¬derground workings must contain information about the purpose of the workings, the design depth, the planned excavation procedures along with cross-sections, and the parameters of the lining, if a lining is required. The geology of the section to be penetrated must include geological data obtained from existing exploration activities at the mineral deposit and conclusions about the shaft ex¬cavation conditions obtained from drilling technical moni¬toring holes and exploration drillholes. The interpreted stratigraphic regime, including the thickness, strike and dip of each stratum, must be shown in cross-section. The tec¬tonics, including all geologic structures, must be presented by cross-sections. The bedding orientations must be used to identify anticlines, synclines, monoclines and faults. The lithologic composition and the drillability of the rock com¬prising the section must be examined. The character of the rock's fracture pattern must be presented. Finally the per¬meability, porosity and storage characteristics of each aqui¬fer must be determined by in situ hydraulic property testing (injection tests or pumping tests, as described in Chapter 3). The fracture pattern of the indurated rock is presented in reports derived from geo-exploration borehole studies and from studies of outcrops on the surface and in all nearby underground workings. The extent of each fracture zone is mapped in three dimensions. The distribution of fracture apertures, the nature of the fractures according to each litho¬logic stratum, and the relationship of bedding planes to each fracture system are all determined. Acoustic logs, downhole cameras, caliper logs, oriented core, and any other appro¬priate geophysical tools available are used to construct the data base for this purpose. The hydrogeological characterization of the geologic section to be penetrated by the workings is based on the analysis of hydrogeological data collected during the drill¬ing and testing of technical monitoring holes and from in¬formation on ground water inflow collected during the ex¬cavation of nearby underground workings, if such workings exist. The hydrogeologic characterization must contain the following information: 1. The identification of all aquifers, their thicknesses and their locations in the section, 2. The distribution of hydrostatic head in the ground water in three dimensions, 3. The coefficient of saturated hydraulic conductivity (per¬ meability) of each aquifer, 4. The porosity and storativity of each aquifer, and 5. The projected rate of water inflow into the shaft, drift or tunnel for each aquifer prior to grouting. This step is used to identify the zones to be grouted.

Jan 1, 1993

By Cheng Xie, Zhihu Li, Xiaoming Sun, Linsen He, Jiaxu Ding, Jinkun Yang, Yong Zhang, Zhenmin Qi

To solve the problem of large deformation of deep soft rock roadway, taking the soft rock roadway of no. 1 coal mine in New Shanghai as an engineering example, the deformation mechanism of surrounding rock of deep soft rock roadway is analyzed by combining theoretical analysis, numerical simulation and field test, and the control countermeasures centering on deep and shallow dense drilling are put forward. Through theoretical derivation, based on the masonry beam theory, surrounding rock structure S-R stability principle and composite beam principle, the length, angle, and spacing of deep and shallow dense drilling are determined. Through numerical simulation, the deformation evolution process of soft rock roadway surrounding rock after dense drilling pressure relief is reproduced, and the influence of drilling parameters (drilling spacing, dip angle) on pressure relief effect is analyzed and compared. The field application test and monitoring verify that the deformation control measures of deep and shallow dense drilling broken roof surrounding rock have a good effect of large deformation control of soft rock roadway, and provide a new support means for the safety and stability control of soft rock roadway.

Mar 2, 2024

By Qingming Feng, Jinhong Zhang

A study has been carried out to apply fly ash as a high strength, water-resistant precast construction material through geopolymerization. Experiment results show that the working conditions such as water content, the concentration of NaOH, curing temperature, and curing time significantly affect the mechanical property of geopolymermatrix. Through optimization, an above-100MPa compressive strength has been achieved with the geopolymerization products. The optimum working conditions involves 10MNaOH concentration, 14–15% water content, and curing at 90 °C in an oven for 1 day or at ambient condition for 3 weeks. Adding Ca(OH)2 does not help to increase the compressive strength of the specimen.Water soaking tests show that the geopolymerization product has a very high water resistance without losing noticeable compressive strength, even after a 1-month soaking time. To elucidate the geopolymerization mechanism, microscopic techniques such as SEM/EDS (scanning electron microscopy and energy-dispersive X-ray spectroscopy), XRD (X-ray diffraction) and ATR-FTIR (attenuated total reflectance Fourier transform infrared) are also applied to investigate the microstructure, the elemental and phase composition of geopolymerization products. The findings of the present work provide a novel method for applying fly ash as a high-strength water-resistant precast construction material.

Aug 17, 2020

By Jr. Matthews

The Candelaria copper-gold deposit is located in Region m of Chile, 805 kilometers north of the capital, Santiago. Candelaria was discovered in 1987, following a six month exploration program. In late 1986, induced polarization (IP) surveys outlined an anomalously high response within the area of interest. The first test hole bad three intersections totaling 49 meters, with an average grade of 1.97% copper. Drilling eventually outlined approximately 390 million tonnes, grading 1.09010 copper and 0.26 grams/tonne gold. Production began in early 1995 and is estimated at 120,000 tonnes copper and 80,000 ounces gold annually.

Jan 1, 1996

By N. Moelans, I. Bellemans, K. Verbeken

Metallic droplets can remain attached to solid particles within liquid slags, resulting in production losses in several movement of solid particles in the liquid slag in a system, considering the attachment of liquid metal droplets to solid slag and on the resulting microstructures is investigated as a function of the velocity of the particles. For all wetting For the amount of metal attached to the particle, a clear trade-off was found between the speed of motion of the solid particle and the wetting regime.

By J. Stawovy, A. Fourie, J. D. Quaranta

Coal refuse impoundments are disposal facilities specifically designed for the coal mining industry. Re-purposing refuse impoundments for co-disposal with natural gas flowback water and waste rock overburden has been investigated. The aims of this study were to investigate properties of coal refuse classification under the influence of co-disposed wastes as geochemical material exposure pathways from hydraulically exposed sodium and calcium ( Na+, Ca2+) cation loading from disposal of flowback water produced during the development of horizontal drilled natural shale gas frack wells, and waste rock having limestone characteristics. The geotechnical index classification of saturated cohesionless refuse is required to evaluate the liquefaction potential for strain or strength loss contributing to ground movements. This study is relevant to identifying changes in the coal refuse geotechnical index classification as sand-like, clay-like, or a borderline transitional material from the effects of ion and waste exposure in the impoundment’s reservoir porewater. Laboratory geotechnical tests were performed on fine coal refuse blended with different cations to classify the altered plastic behavior and index classification. Following determination of the index classification, the specimen’s stress–strain responses were investigated through isotropically consolidated undrained (ICU) triaxial compression tests. This experimental study culminated with two salient findings: the first is that introduction of ions alone into the refuse tailings or impoundment porewater resulted in significant material changes in property index classification, and the second finding was that the difference in refuse index classification did not correlate into noticeable effects of the monotonic undrained triaxial strength parameters.

Jul 5, 2022