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By Manoj Khandelwal, Jian Zhou, Yingui Qiu, Peixi Yang, Pingan Peng

Rockburst prediction is crucial in deep hard rock mines and tunnels to make safer working conditions. Due to the complex interaction of many factors involved in rockburst prediction, such as multi-variable and multi-interference factors, three hybrid support vector machine (SVM) models optimized by particle swarm optimization (PSO), Harris hawk optimization (HHO), and moth flame optimization (MFO) are proposed to predict rockburst hazard level (RHL). The RHL is determined according to four kinds of microseismic characteristic parameters including angular frequency ratio, total energy, apparent stress, and convexity radius. Then, six types of microseismic characteristic parameters are taken as input variables in 343 sets of data, including angular frequency ratio and total energy, etc.. And the RHL is taken as the output target of rockburst prediction. The classification performance of PSO-SVM, HHO-SVM, and MFO-SVM hybrid models is evaluated by accuracy (ACC), precision (PRE), and kappa coefficient. Findings reveal that the MFO-SVM model performs best in terms of accuracy, with ACC, PRE, and kappa coefficients reaching 0.9559, 0.9063, and 0.9094 respectively, while PSO-SVM and HHO-SVM have similar performances. However, the PSO-SVM, HHO-SVM, and MFO-SVM all perform better than the unoptimized SVM model. This confirms that the three optimization algorithms significantly enhance the rockburst prediction capacity of the SVM model to help mine practitioners apply machine learning methods to rockburst prediction problems appropriately.

Feb 3, 2023

By Earle Faig

Earle Faig Along with other transportation modes, the barge industry will be greatly affected by trends in domestic coal production. Traditionally, coal has been one of the major commodities moved by barge. Now, because of events in the international energy market, coal is finally getting the recognition it deserves as a major component of the country's energy program. Perhaps even more significantly, a series of events has caused other countries to turn to the United States as a source of coal. Although the outlook for coal demand is optimistic, it will be greatly influenced by the ability of the transportation sector to handle the additional traffic. Because of its long experience in moving large quantities of coal, the barging industry is in an excellent position to capitalize on coal's increased popularity. A brief description of the barging industry should facilitate the discussion of coal as it relates to that industry. Barge companies operate on a river system that is over 40 Mm (25,000 miles) long. It includes the East and West Coasts and the Mississippi River System comprised by the Allegheny, Monongahela, Kanawha, Ohio, Illinois, Missouri, Tennessee, Cumberland, Arkansas, Warrior-Tombigbee, and Mobile Rivers, and some smaller tributaries. The Gulf Intracoastal Waterway stretching along the Gulf Coast from Brownsville, TX, to Apalachicola, FL, also is considered part of the inland waterway system. Approximately 1,800 companies operate on the inland river system and have a combined fleet of about 4,400 towboats and 28,000 barges. The fleet of towboats represents 4.8 GW (6.4 million hp) of power. The towboats comprising this fleet vary in size from a small harbor boat to a large line haul boat with 7.5 MW (10,000 hp) of power. The choice of size and power of the boat depends on a number of factors, including the size of the river and operational constraints, such as lock size, river-current rate, and water level. The choice also depends on the tow size. A single tow on a river capable of locking through 15 barges at a time handles up to almost 20 kt (22,000 st), whereas a tow on the lower Mississippi, which has no locks, can accommodate up to 41 kt (45,000 st) of cargo. Because the quality of coal is not typically damaged by exposure to the elements, it is usually moved in open hopper barges, although covered barges are used occasionally. The most frequently used size is the jumbo barge that measures 59 m (195 ft) long by 11 m (35 ft) wide by 4 m (12 ft) deep and can handle up to 1.4 kt (1,500 st) of coal. Advantages of Barge Transportation Barging offers several inherent advantages in transportation of bulk commodities like coal. First, barges can carry large quantities of product. A single jumbo hopper barge can handle 1.4 kt (1,500 st) of cargo while it takes 15 91-t (100-st) capacity rail cars or 57 trucks hauling 24 t (26 st) each to move an equivalent amount of cargo. Thus, barges can move more tonnage with less equipment than competing forms of transportation. Second, barging offers the most fuel efficient means of transportation. Less energy is required to push a load over water than to pull a similar load over land. The amount of pollution attributable to barge traffic is minimal because barges consume less fuel. Third, barging is an inexpensive form of transportation. The inland waterway industry transports about 12% of the nation's freight for about 2% of the total freight bill. This can be attributed to competition between the large number of companies on the river system and competition with other transportation modes. Fourth, barging is an environmentally safe method of transportation. Inland river routes expose fewer urban areas to hazardous substances than rail or truck. And barge spills occur less frequently than rail or truck spills. The industry does pose some disadvantages. The waterway system is constrained by the natural river network, so barges cannot travel on the most direct straight-line route. This means that barging is usually an incomplete form of transportation requiring interface with truck or rail. The industry's market is limited to those geographical areas that are located on or near the rivers. In addition, it is a time-consuming transportation mode, making it impractical for many types of commodities.

Jan 10, 1982

By Zhiguo Chang, QINGXIANG CAI, Ebelia Manda, IZHAR MITHAL JISKANI, XIANG LU, Wei Zhou, Saleem Raza Chalgri

The concept of mine safety is highlighted in the literature of sustainable mining but not extensively discussed. This study analyzes various aspects of underground and surface mine safety and emphasizes its importance in the context of sustainable mining. More specifically, this research attempts to find the relationship between mine hazards and demographic characteristics, examine and compare the perceptual difference among miners, and determine the impact of mine hazards on workplace safety and safety climate. Descriptive analysis, chi-square test, independent samples t test, and linear regression modeling were conducted to achieve study objectives. Results confirmed that mine hazards were significantly associated with age and experience. Miners perceived lower levels of management safety practices, followed by supervisor safety, coworker safety, and job safety. The analysis showed that underground miners reported lower safety scores than surface miners. There was a statistically significant difference between miners’ perception of safety climate (p < 0.05). The results showed that the higher prevalence of mine hazards predicts poor workplace safety and a low safety climate. The regression models revealed that mine hazards have a significant effect on workplace safety (p < 0.05) and safety climate (p < 0.05). In conclusion, the distinctive model of mine safety presented here contributes to the monitoring and design of comprehensive safety interventions and helps to better understand how certain factors interact on multiple levels to influence the overall safety of the industry. In this study, some suggestions are put forward to provide directions to develop a sustainable mine safety system.

Mar 27, 2020

By MUSTAFA ERKAYAOGLU, ENVER YILMAZ

Coal mining is likely to sustain its critical role as energy requirements are increasing. While surface mining exploits coal seams near the surface, underground mining techniques are crucial for extracting deep coal reserves. Longwall mining is one of the most common methods used in underground coal mining operations. This paper introduces a data-based framework — including data collection, data analysis and the interpretation of operational data — for understanding the system efficiency of a longwall shearer. Operational performance is evaluated by the time between arrivals (TBA) and duration of the shearer stoppages, shearer drums’ reversal time, cutting speed and flit speed on daily production in a longwall top coal caving (LTCC) mine. A discrete event simulation model is developed to represent the bidirectional cutting sequence of a longwall shearer.

By Ricardo Oliveira Gallart de Menezes, Claudio Gerheim Porto, Reiner Neumann

The Jiboia heavy mineral sands deposit is a new discovery associated with the São Francisco River delta on the northern coast of Sergipe state. The identified resources are part of the much larger mineralized trend. Mineralization is hosted in paleodunes deposited on Holocene marine terraces (Fig. 1). The dunes are up to 30 m above sea level, and mineralization occur from 6 m above sea level upward. The main ore minerals constitute pseudorutile, ilmenite, zircon, rutile and monazite. This work presents a thorough characterization of the mineralogy and granulometric distribution of the Jiboia orebody.

Apr 1, 2024

By A. E. Foscolos

British Petroleum (BP, 2005), indicates that world reserves for oil to be 1198 billion barrels, for natural gas the equivalent of 1156 billion barrels of oil and for coal the equivalent of 3219 billion barrels of oil. If we take into consideration the mean aver-age annual increase in demand of the last three years for oil, 2.6%, for natural gas, 3.9%, and for coal, 6.6%, then their respective reserves? lifespan are calculated to be 27, 34 and 38 years. Without taking into account their annual increase in demand, lifespan increases to 38, 67 and 161 years respectively. Since zero increase or perpetual increase in energy demands on finite resources is unrealistic the selection of the most suitable energy commodity for power generation rests upon the law of supply and demand of each commodity. This defines its price hence its selection for the production of cheap electricity. When the ratio of supply to demand is less than one, peak production is achieved. Any further increase in demand results in price increase to quench its demand. The Association for Oil and Gas Peak (ASPO) has calculated that when oil demand exceeds 84 million barrels/day, Peak Oil Production will be attained thus prices will start to increase in order to even demand with supply. Correspondingly, Gas Peak Production is expected to take place when demand exceeds 9.1 or 10.2 billion cubic meters/day. Peak Oil production has been calculated to take place in the current year, 2006, while Gas Peak production is estimated to take place between 2020 and 2025 provided that gas will not cover the energy deficit created from the lack of oil otherwise Gas Peak production could arrive as early as 2010. The use of coal for power generation is considered a better alternative than oil and gas if new combustion technologies with an energy efficiency of 43%, Germany, and 47%, Denmark, are adopted. These not only extend the lifespan of coal reserves but reduce also CO2 emissions by 25% and 31%, respectively. In the very near future CO2 sequestration and fixation in deep geological strata will eliminate its emissions thus rendering the use of coal the cheapest feedstock for power generation.

Jan 1, 2006

By S. M. Bulatovic

The western industrial world has to rely more and more on complex polymetallic sulphide ores as sources for base metals. These ores are composed of fine grained sulphide minerals such as chalcopyrite, galena, sphalerite, pyrite, pyrrhotite and marcasite. The liberation sizes of the individual minerals can range between 30 um and 5 um. Therefore, applying conventional techniques to recover these finely disseminated minerals usually results in unsatisfactory metallurgical performances with high losses of the valuable mineral to the slime , fraction of the tailing. New concepts for treating these polymetallic complex ores are discussed in this paper. Beneficiation techniques utilizing new reagents and a new approach to pulp preparation are described. Some of these techniques were applied to ores from existing concentrators as well as to new ores. The results of these studies are discussed in the following sections.

Jan 1, 1990

By C. Feng, W. Song, B. Moudgil, P. Zhang, W. Xiao

Separation of dolomite from phosphate is the most challenging problem in phosphate mineral processing. Over 50% of the future phosphate reserves in Florida contains too much dolomite to process using the current industry practice. The FIPR Institute has collaborated with worldwide experts in the field to address this issue. As a result, the industry is now offered with three feasible options. Optional 1 involves crushing and grinding of high-dolomite phosphate pebbles followed by dolomite flotation at slightly acidic pH using a new collector that does not require phosphoric acid as a phosphate depressant, achieving a final concentrate analyzing less than 0.9% MgO at about 87% P2O5 recovery. Option 2 offers three methods for reducing MgO content in the concentrate from the Crago process, including adding a dolomite depressant in the rougher flotation step, dolomite flotation of the cleaner concentrate, and scrubbing the cleaner concentrate in quartz sand. These methods could reduce MgO content in the final concentrate by 20-40%. Option 3 is a gravity separation technique using an innovative separation jig, and may well be the ultimate solution to the problem. INTRODUCTION Magnitude of the Dolomite Problem With the depletion of the higher grade, easy-to-process Bone Valley deposits, the central Florida phosphate industry has moved into the lower grade, more contaminated ore bodies from the Southern Extension. The phosphate deposits in the Southern Extension may be divided into two zones: an upper zone and a lower zone. The upper zone is readily processable using the current technology, but the lower zone is highly contaminated by dolomite. Geological and mineralogical statistics (Hassan and Bogan, 1994) show (Table 1) that more than 50% of the phosphate resource would be wasted if the lower zone is bypassed in mining, and about 13% of the resource would be wasted if the dolomitic pebbles in the lower zone were discarded.

Jan 1, 2019

By P. Conrad, S. Rosenthal

"Engineers remain in demand. Job opportunities in the United States still exceed the number of students graduating from college with degrees in Mining Engineering. Although enrollment is up for freshman studying Mining Engineering, many of those students will either change majors or not complete their degree, maintaining that deficit of available Mining Engineers. What can be done to ensure that enough Mining Engineers will graduate to fill the needs of the mining industry over the next ten to 20 years? The authors believe that this need can be met by recruiting students to Mining Engineering programs who are genuinely interested in working in the mining industry. With this in mind, Montana Tech conducted its first Mining Engineering camp in July 2014 to get junior and senior high school students interested in careers in the mining industry by showing them that Mining Engineering is both an exciting and rewarding career. This paper discusses What a Blast! The 2014 Montana Tech Mining Camp. INTRODUCTION The concept of summer camps for high school students is not new. For example, Missouri University of Science and Technology has offered their “Explosives Camp” for several years. A large percentage of attendees to these camps discover or confirm an interest in Mining Engineering and enroll in the school’s program. The Dean of the Montana Tech School of Mines and Engineering challenged department heads to develop and offer summer camps for prospective high school students to get a taste of engineering with the goal being to improve recruitment for each discipline. Mining Engineering embarked on the concept of a summer camp in 2013 with a concept to provide a week’s experience in Mining Engineering during the summer of 2014. What it takes to progress from concept to reality, with some of the learnings to be shared, follows."

Jan 1, 2015

By PDF

Flotation columns are widely used in mineral processing and coal preparation industry today. Mathematical modeling of flotation columns has conventionally been done using axial dispersion or tank-in-series models. However, for design and scale up purposes these models are not adequate enough because they do not provide detailed information of the flow fields within the column. This paper presents a Two-Dimensional, Two-Phase. Fluid-dynamic Model and its numerical solutions for some cases encountered in column flotation. The MAC (Marker and Cell) method was employed to obtain the numerical solutions, and based on this method a computer code COLUMNFLOW was developed. The simulated flow field reveals the presence of a circulation flow structure in flotation columns, which could be one of the main reasons for mixing in column flotation. The effects of some parameters such as superficial gas and liquid velocities on the characteristics of the flow structure in flotation columns were also tested with the numerical model.

Jan 1, 1994

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

Many modern industries rely on rare earth elements (REEs) to produce products that are essential to both civil and defense applications. In a prior study (Vass et al., 2019), the authors showed that REE grades in acid mine drainage (AMD) and associated byproduct precipitates from AMD treatment (AMDp) warrant evaluation as a feedstock for REE production. The current work extends that effort through a broad survey of 141 AMD treatment sites in Northern and Central Appalachia. In this study, 185 raw AMD and 623 AMDp field samples were obtained and analyzed to assess the REE and major metal concentrations. Results show that an average of 282 μg/L and 724 g/tonne of REEs occur in AMD and AMDp respectively. Additionally, both basins contained similar distributions of REEs, and these distributions tended to favor heavy and critical REEs when compared with traditional REE ore deposits. Geospatial analysis identified a total resource of 340 tonnes stored at the 141 sites sampled in this study. While this analysis did not quantify the basin-wide REE inventory, it does indicate the impact that processing cut-off grades will have on the overall AMDp resource base.

By Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

Many modern industries rely on rare earth elements (REEs) to produce products that are essential to both civil and defense applications. In a prior study (Vass et al., 2019), the authors showed that REE grades in acid mine drainage (AMD) and associated byproduct precipitates from AMD treatment (AMDp) warrant evaluation as a feedstock for REE production. The current work extends that effort through a broad survey of 141 AMD treatment sites in Northern and Central Appalachia. In this study, 185 raw AMD and 623 AMDp field samples were obtained and analyzed to assess the REE and major metal concentrations. Results show that an average of 282 μg/L and 724 g/tonne of REEs occur in AMD and AMDp respectively. Additionally, both basins contained similar distributions of REEs, and these distributions tended to favor heavy and critical REEs when compared with traditional REE ore deposits. Geospatial analysis identified a total resource of 340 tonnes stored at the 141 sites sampled in this study. While this analysis did not quantify the basin-wide REE inventory, it does indicate the impact that processing cut-off grades will have on the overall AMDp resource base.

By Wilson W. Zoogah, Joel G. Burken, Abdullah Al Moinee, Mariam K. Al-Lami, Kwame Awuah-Offei

Soil CO2 flux serves a critical indicator of ecosystem function and carbon cycling in disturbed landscapes. This study measured and quantified temporal patterns and environmental drivers of soil respiration across fifteen revegetated treatment plots over a 12-week period (July-October 2025). Utilizing automated CO2 flux measurements, we investigated differences between treatments and quantified their relationships with soil temperature, moisture, and atmospheric pressure. One-way ANOVA revealed significant treatment effects on CO2 flux (F4, 442 =14.1, p < 0.001, η2=0.113), with amended plots exhibiting 40–50% higher mean fluxes than control plots. Weekly temporal analysis demonstrated distinct temporal patterns, with peak fluxes registering in mid-August before a gradual decline. Multiple regression analyses showed that soil temperature (β=0.043, p < 0.001) and moisture (β=2.31, p < 0.001) are the primary flux drivers, together accounting for 18.2% of total variability (adjusted R2=0.182). Atmospheric pressure had a moderate effect (β=1.13, p < 0.001), detectable only in multivariable analysis. Variance partitioning indicated that environmental factors explained more variability (18.7%) than treatment effect (10.5%), with approximately 71% of flux variability attributed to finer spatial or temporal variability. These results demonstrate that revegetation amendments enhance soil biological activity and impact geochemical cycling, and that temperature and moisture are dominant controls on respiration dynamics in reclaimed mine soils. The findings provide quantifiable benchmarks for ecosystem recovery through altering soil biology and geochemistry and for quantifying carbon sequestration potential in post-mining landscapes.

Feb 22, 2026

By A. Yadav, B. Behera, G. S. P. Singh

The size of chain pillars in the Indian geo-mining conditions is primarily decided in accordance with the regulatory provisions. These provisions are of little help for deep longwall workings, exceeding the cover depth of 360 m. Furthermore, these provisions are primarily meant to support pillars in bord and pillar workings. They may not be suitable for the chain pillars owing to a significant difference in layouts and functional requirements. Hence, it is imperative to develop a method to evaluate the stability of the chain pillar considering the complex loading and geo-mining conditions. To this end, a machine learning-based model was developed in this study to assess the stability of the chain pillars under high depth of cover considering the field-representative conditions. The data for this work was generated by conducting a parametric study using a field-validated numerical model. The strength and deformability parameters of the caved, fractured, and continuous deformation zones were established by calibrating the numerical model outcomes against the site-specific field observations. The developed ML model was used to evaluate the influence of pillar width, pillar height, cover depth, abutment angle, face length, coal strength, moduli ratio of the roof and floor strata to the coal seam, and the elastic modulus and unit weight of the overburden on the chain pillar stability. An interesting finding of this study showed that the factor of safety of the chain pillar increased with the increasing abutment angle, which may be indicative of the confining effect of the abutment angle on the pillar. Eventually, the ML model was verified by comparing its outcomes with the calibrated numerical model for a typical longwall working from Indian geo-mining conditions.

Oct 18, 2023

By Abdelaziz Baçaoui, Imane Aarab, Mohammed Derqaoui, Abdelrani Yaacoubi, Khalid El Amari, Abdelmoughit Abidi, Abderahman Etahiri

Numerous researchers have addressed the complexity of the direct flotation separation of apatite from low-grade phosphate ore. The majority of these studies were limited to the micro-flotation scale. In fact, there is no warranty that a reagent scheme that showed a direct flotation of apatite at a micro-flotation scale on pure minerals would automatically replicate the same expected results on the natural ore in the mechanical flotation cell and so was the case for the phosphate ore studied. The overall trend was concentrating apatite in the non-float product. This study aspired to thoroughly assess the flotation performance of this never-exploited low-grade sedimentary phosphate using design of experiments (DOE). Unveiling new insights on such a strategy twist, various parameters and operating conditions, namely, desliming, type of collector and depressant, reagents dosages, conditioning times, flotation time, and pH, were addressed by multiple-factor screening using asymmetrical fractional factorial design followed by statistical interpretations. The collectors tested were the sodium oleate and a fatty acid mixture (FAM). The depressants tested were sodium alginate (NaAL), corn starch, carboxymethylcellulose (CMC), and sodium silicate. The results of the multivariable analysis revealed that desliming, pH, collector dosage, and flotation time significantly influenced the flotation process. Desliming was beneficial for the yield, P2O5 recovery, and SiO2 removal; however, there was still a compromise between grade and recovery. A strongly alkaline pH value of 12 stood out from the whole range. P2O5, CO2, and SiO2 grades of the products and flotation recoveries were improved, except for P2O5 recovery, which was negatively affected. A collector dosage between 2000 and 3000 g/t increased the P2O5 grade and reduced CO2 grade and recovery, enhancing the apatite/carbonates separation. A flotation time of 15 min was significant for P2O5 grade and CO2 recovery, nevertheless, at the expense of yield and P2O5 recovery. The products having initial concentrates of 28.08% P2O5 with a recovery of 88.96% and 29.41% P2O5 with a recovery of 62.71% were obtained using 25 g/t of NaAL and 2000 g/t of the collector FAM and sodium oleate, respectively, at pH 12.

Jun 5, 2022

By Carla Da Corte, Kagisego Letsoalo, Ashma Singh

Banded Iron Formations (BIF) are sedimentary rock formations ranging in age from 0.8 to 3.8 billion years and consist of alternating layers of silica and iron. The thickness of the alternating layers varies between and within deposits, with this lithology forming approximately two-thirds of South Africa’s future low-grade hematite resources. The production costs for South African iron ore producers are approximately double that of the largest iron ore producers, namely, Brazil and Australia. This in conjunction with volatile commodity prices, necessitated a cost-sensitive beneficiation strategy for low-grade hematite to sustain the industry and extend life of mine. A BIF sample grading at 44% Fe and comprising predominantly of hematite and quartz with minor amounts of magnetite and goethite was subjected to three fines gravity processing routes to establish the amenability of this sample to beneficiation. To provide flexibility for iron ore producers who still have high-grade resources available, two product grades were considered, namely a 60% Fe product for further blending or a 63% Fe product for direct sales.

May 12, 2023

By J. A. Herbst, H. R. Cooper, R. J. Brison, R. W. Harper, K. P. Ananthapadmanabhan, W. C. Hellyer, B. H. Bergstorm, D. M. Hopstock, H. Rush Spedden, W. C. Hellyner

Scope of Section The physical characterization of an ore or mineral mixture in such detail that mineral processing may be effectively applied to create more useful products is one part of the technology of sampling and testing. In addition, the evaluation of the multitude of separation processes, both physical and chemical, combined with ancillary opera¬tions and performed on samples at a laboratory scale, is another part of the testing procedure. Although analytical techniques provid¬ing quantitative determinations of elemental compositions are an im¬portant and necessary supplement to any testing program, that field of endeavor is a well-developed, separate entity beyond the scope of this Section. Sampling procedures cover the practice of selecting representative quantities of test materials in the field to evaluate mineral deposits, and extend to techniques of obtaining process samples in slurry and bulk ore as part of process evaluation. The same techniques are appli¬cable, of course, to standardized methods of metallurgical accounting. Sampling is also an important facet of successful on-line measurement of slurry properties such as assays and particle size in the practice of automation. However, the sampling methods in this case can be different from those needed for precise testing and accounting pur¬poses. Sampling was well defined in Taggart&apos;s Handbook as "the opera¬tion of removing a part convenient in size for testing, from a whole which is of much greater bulk, in such a way that the proportion and distribution of the quality to be tested (e.g., specific gravity, metal content, recoverability) are the same in both the whole and the part removed (SAMPLE). The conditions of the more stringent definition, that the sample shall be completely representative of the whole as regards all aspects save bulk, are practically never fulfilled when heterogenous mineral mixtures are sampled." Taggart&apos;s Handbook of Mineral Dressing, Section 19, "Sampling and Testing," continues to be a very useful compendium of principles and techniques, particularly as applied to manual methods for han¬dling samples. In the intervening years since its last revision, substan¬tial progress has been made in both the theory and the techniques; thus, this current contribution is designed to be an extension of the earlier work, yet complete enough to provide procedural guidelines to methods of continuing validity. Although basic principles of testing remain unchanged, the meth¬ods of applying those principles have undergone great change. New testing equipment has become available, yielding a greater precision of results. Testing methods have been refined which, in many cases, allows for a valid scale up of flowsheet designs without the necessity of costly pilot or prototype plant development. Justification for a Sampling and Testing Program* The proper evaluation of a mineral property is a complicated process. It often is done on a team basis with the exploration geologist, mining engineer, mineral process engineer (extractive metallurgist), economist, and product utilizer (ceramist, chemical engineer, chemist, metallurgist, etc.) all represented. The mineral processing engineer is a key member because he can provide a go no-go answer to the question, "Can this ore be processed economically?" In addition, his judgment on the response of even the initial sample to processing can be an invaluable guide to the proposed process and its mutations. Since the capital investment and operating costs are so sensitive to the type of process used, the judgment of the mineral processing engineer forms an important part of the early evaluation of the profitability of a new mining venture. This early estimation of the processing approach is all the more important since, for some metalliferous ores, the capital investment for mill, smelter, water supply, and tailings disposal exceeds the cost of the mine. At present, for commodities such as coal, the reverse is true. There is a smaller capital investment for the coal preparation plant than for the mine. In general, both the capital and operating costs escalate very rapidly in the following order: gravity concentration of alluvial deposits (e.g., dredging), gravity concentration of lode ores, flotation, simple hydrometallurgical processes, and complicated hydrometallurgical and pyrometallurgical processes. The latter two processes may cost 100 to 1,000 times more per ton treated than processing of a simple alluvial deposit. This dictates that the valuable mineral be concentrated as much as possible to minimize the total tonnage treated in the more expensive operations. Within each of these ore-processing categories there is a wide range of process sophistication and hence of capital and operating costs. Perhaps the greatest variations are in the chemical processing of ores. These range from the simple leaching of a copper waste dump to very sophisticated hydrometallurgical processing of ores in increasing order of cost. Because the overall cost of a mining venture is so sensitive to the process selected, it is essential that the mineral¬ processing engineer evaluate the ore in the initial stages of the development of an ore body. As better samples become available, he must continually revise his estimate of the process to be employed. The sampling and testing process must be a necessary and continuing activity throughout the life of a project. One fundamental aspect of nearly all mineral deposits is the inherent variability of the mineral assemblage and composition. A utopian goal of any processing plant is to have the process so flexible and so well-defined that an automatic process control system can optimize the economic recovery at all times. Since this is rarely possible, a continuing or at least a periodic testing program is desirable. Variables to be considered are: 1) Ore body inconsistencies. 2) Zonal variations. 3) Feed variations from mining plan or methods. 4) Variable performance of processing units due to wear. 5) Seasonal or other changes affecting processing conditions such as water quality, temperature, etc. 6) Changing market conditions for product quality or byproducts. 7) Technological advances in processing methods or equipment. 8) Increasing demands for environmental control. 9) Changing economics of competitive processes, of supplies, of capital investment vs. labor costs, etc. Sampling Procedures Preliminary Guidelines for Sampling Ore Deposit Studies. t At a very early stage, it is essential that the mineral processing engineer receive a sample of the ore. This may be a portion of the diamond drill core or a split from the trench, pit, churn drill, channel, or sheet sample. Even a grab sample may have some value, but it should be selected by the mining engineer or exploration geologist to be as representative of the ore body as possible within his best judgment. The sample delivered to the process engineer should have been subjected to as little prior crushing as is practical since fine sizes are difficult to concentrate. In addition, finely ground ores are readily oxidized and thus may give misleading test results. Furthermore, ground samples may make it impossible to eval¬uate either the comminution or the coarse-gravity concentration pro¬cesses. For an initial evaluation, a good deal may often be learned from a sample of only a few pounds if that is all that is available. To obtain the maximum information from a sample, its selection should be carefully discussed with the mineral processing engineer. In addi¬tion to being as representative as possible, the mineralogically distinct samples should be carefully segregated rather than composited. Since drastically different processes are often needed to process samples of differing mineralogy, considerable care and time must be exercised during this sample collection step. The segregation of samples showing gross mineralogical differences, such as the oxide caping on a sulfide deposit or a laterized zone, is easy. It is the more subtle changes in mineralogy that can often elude the field man. Yet these differences are often sufficient to dictate that an entirely different type of process be used. Obviously, the selection of these initial samples for ore testing and mineralogical studies requires that it be done by a man of consider¬able experience and judgment. While the mining engineer or field geologist is collecting these samples, he should also note and convey to the processing engineer such details as water quality and availabil¬ity, terrain, potential mill location, tailings-disposal areas, case of transportation, etc. As the property is developed with additional drill holes, adits, etc., larger and more representative samples will be required to develop the ore-processing flowsheet more adequately. If pilot-plant studies are required, a very large sample may be necessary. Though the type and amount of sample collected for flowsheet development investigations vary widely, gathering a representative sample of the ore body is a prime requisite for any process development effort. The process developed for any given ore body is only as reliable as the sample on which the flowsheet was based¬

Jan 1, 1985

By A. Anani

The goal of hot mix asphalt (HMA) design is optimal material blending to meet Superpave specifications. HMA cost minimization has being modeled as linear programing (LP) (Awuah-Offei et al 2011) and mixed integer LP problems (Brown et al, 2012) and solved with commercial software such as LINDO and CPLEX. Often these software, which are designed to solve general optimization problems, have licenses that cost thousands of dollars. The objective of this study is to develop a novel solution algorithm to the HMA optimization problem presented by Brown et al. (2012), which will negate the need for expensive commercial packages and is specific to this problem. This novel algorithm is based on the branch and bound algorithm for solving mixed integer problems. The algorithm is incorporated into a software package with an easy-to-use graphical user interface. The developed algorithm is validated using a real-life HMA problem. Using this solution algorithm will save companies thousands of dollars, otherwise used to purchase software licenses.

Feb 23, 2014

By M. SIDDARAJU, Rameshwar Sah, Satendra Kumar, Arvind Jaiswal

The study explores a novel process to sinter porous iron ore with improved productivity and quality. The iron ore is pre-processed with calcined lime to temporarily close pores, preventing water absorption during granulation. This enhances reaction kinetics and early slag formation during sintering, resulting in significant improvements in sinter productivity, product yield, and cold strength property.

Feb 28, 2022

By Lee R. Kump, Sarma V. Pisupati, Peter L. Rozelle, Alan R. Larson, Timothy S. White, Nicholas A. Crescenzo, Maureen D. Feineman

The Mercer Clay bed in central Pennsylvania has produced feedstocks for the refractory industry in the USA and has also been investigated as a source of alumina and lithium. Developments in global markets for these commodities, as well as rare earth elements, have led to their classification as critical minerals in the USA, in turn renewing production opportunities for the Mercer Clay resource. The work reported here includes a review of the clay types and minerals involved, as well as past mineral processing and extractive metallurgy test work, and reports new research results from renewed investigation of the deposit as a polymetallic resource. This renewed work has found lithium contents that exceed 1,000 ppm, lying directly below the overlying Mercer coal, where the alumina content ranged from 32 to 34 wt%. Total rare earth concentrations were somewhat lower than have been found elsewhere in the region, and the highest contents were also found to be stratigraphically close to the coal. Further work is required to establish the mineral hosts for lithium and rare earths and to define the extent of enriched alumina, lithium, and rare earth concentrations.

Jul 22, 2021