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By Mary Nelima Ondiaka, Kayode Henry Talabi, Oladunni Oyelola Alabi, Fatai Olufemi Aramide, Francis Gitau

Iron ore is essential in steel making; however, high-grade ores have diminished, making low-grade ores inevitable. These lowgrade iron ores need further beneficiation to upgrade the iron content. Currently, traditional physical and chemical methods are utilized and are not environmentally friendly. Bio-beneficiation techniques have emerged as a sustainable alternative for mineral recovery. This review delves into recent bio-beneficiation advancements for enhanced low-grade iron ore recovery using microbes. Research has revealed that bio-beneficiation methods such as bio-leaching, bio-flotation, and bio-flocculation have proven successful in iron recovery from ores. The bio-beneficiation process occurs in mild conditions using bio-reagents derived from microbes and offers a reduction of chemicals used in processing. Bio-beneficiation of iron ore potentially offers a relatively energy-efficient, cost-effective, and environmentally friendly method of maximum iron ore recovery. However, this review has identified a scaling-up difficulty in which a future approach for industrial-use applications is offered following a thorough sustainability assessment. Bio-beneficiation, using microbial processes, provides a viable avenue for maximizing iron ore recovery while tackling the constraints of dwindling high-grade iron ore resources and environmental sustainability.

Mar 16, 2024

Market confidence is on the rise and industry leaders turning toward the vast and diverse region of Latin America are faced with abundant, yet daunting, opportunity. From the iron orebodies of Brazil to the renowned copper mines of northern Chile, drilling teams in Latin America are often faced with abrasive, broken ground. These types of ground conditions tear up coring bits rapidly, making it extremely difficult for even the most seasoned drilling teams to maintain effective productivity. The drilling challenges faced in this rich and opportune region are being met today by advanced coring technology, bringing with it the potential for increased productivity in Latin American mineral exploration.

Jan 3, 2010

By R. C. Bratton, R. Q. Honaker

Hindered-bed separators are recognized as low-cost, high-capacity devices for both classification and density separation; however, since their inception, there have been few significant advances in the fundamental technology. Recently, Eriez has shown through modeling and pilot-scale testing that the innovative approach to feed presentation offered in the CrossFlow teeter-bed separator provides improved metallurgy when compared to traditional hindered-bed classifiers or single-stage coal spirals. This design feature prevents excess water from entering the separation chamber and disrupting the overall fluidization flow rate within the teeter zone. Most recently, a side-by-side industrial scale evaluation has verified that this technology improves overall efficiency and simultaneously reduces the separation cut-point. With regards to coal processing, data from full-scale units indicate that the CrossFlow offers good separation efficiency, high unit capacity, and metallurgical results consistent with laboratory- and pilot-scale separators.

Jan 1, 2006

By T. Hudaverdi

Control of the particle size distribution of a muckpile after blasting is always an important subject for mining industry. Blasting has a significant impact on downstream processes such as loading, crushing and grinding. Improvement of blasting results provides increase in loader and excavator productivity due to increased diggability capacity, and increased bucket and truck fill factors. Suitable and uniform particle size distribution results increase in crusher and mill throughput and decrease in energy consumption in size reduction process. Digital image analysis technique has been used for many years in mining industry in order to determine blast fragmentation. The images of muckpile surface can be used to determine the mean fragment size (x50). The source of digital images can also be haul truck, leach pile, waste dump, stockpile, and conveyor belt. The screening that is conventional method to measure blast fragmentation is time consuming and expensive. Digital image analysis is a cost effective and faster method (1).

Jan 1, 2012

By James W. Bass

Introduction Atmospheric fluidized bed combustion (AFBC) is an improvement over coal-fired boiler design. It offers several advantages over conventional boilers. AFBC can meet sulfur and nitrogen oxide emission regulations without the need for add-on flue gas treatment equipment. The relatively low combustion temperature inhibits ash melting, thus reducing slagging and fouling that can in turn increase a boiler's fuel flexibility. AFBC process The fluidized bed boiler that operates at atmospheric pressure on the fire side (AFBC) is relatively simple and no different in purpose from those pulverized coal boilers used by utilities today. Fluidized bed boilers can generate steam at the pressure and temperature needed by modern steam turbines. Only the firing system is different. In fluidized bed combustion, the fuel can be almost any coal or waste fuel. It is burned in the presence of a bubbling bed of limestone. Air is forced through the bed at a velocity sufficient to support the weight of the bed particles. When the bed is fully fluidized, it bubbles like a boiling liquid. Although the burning coal makes up less than 1% of the fluidized bed, all the bed particles are heated quickly by the turbulence. The calcium in limestone reacts with sulfur dioxide produced in coal combustion to form calcium sulfate in a dry solid state. In this way, sulfur emissions regulations can be met without installing flue gas desulfurization equipment. Boiler tubes submerged in the bed absorb heat directly from the turbulent solids. The heat converts water in the tubes to steam or superheats the steam. Because of the intimate contact of the boiler tubes with the fluidized bed, heat transfer is highly efficient. Consequently, less boiler tubing surface is needed to generate the same amount of steam as in a comparable pulverized coal boiler. The optimum temperature for sulfur capture is relatively low, about 815°C (1500°F) as opposed to 1370°C (2500°F) for pulverized coal boilers. This results in the formation of lower levels of NON. Because operating temperatures are below those that fuse coal ash, a single design can burn a variety of coals without slagging or fouling problems. TVA's AFBC development program Tennessee Valley Authority's (TVA) involvement in AFBC development began in 1974 and has addressed the technical uncertainties through a comprehensive program of design, experimental, and analytical studies. In 1979, TVA and the Electric Power Research Institute (EPRI) developed plans for a 20-MW AFBC pilot plant, a 10-fold scale-up over the next largest test facility. Pilot plant design features TVA constructed the pilot plant at the Shawnee Steam Plant near

Jan 4, 1986

By T. R. Paquin

Powerful, easy to manipulate, ventilation modeling software is readily available to most mining engineers. Too often when preparing an initial ventilation model, engineers will go overboard in their design, creating a complex model with hundreds of branches. When, in practice, the creation of a less complicated ?to the point? model, containing a few well-constructed branches, would have delivered the same results. In this paper the author will demonstrate, by using actual feasibility report examples, that when designing a ventilation model, engineers should make more use of the K.I.S.S. (?Keep It Simple, Stupid?) Principle. As mining industry consultants we must continue to improve on, and deliver timely and cost-effective results to our customers.

Jan 1, 2009

By Jon Y. Kaneshiro, Sean A. Menge, M. Luis Piek, Brian Barker

The Lake Hodges to Olivenhain Pipeline project is part of a 40-megawatt pumped storage project linking two reservoirs as part of the San Diego County Water Authority’s $939 million Emergency Storage Project. Seeking to expedite project completion, the project was advertised as Design-Build, a first for the owner. Awarded to Kiewit Pacific with Parsons as designer, the 1,750m (5,700ft) long, 4.25-m (14 ft) horseshoe tunnel was excavated with conventional drill-and-shoot technique. The mining method was well suited to deal with the shear zones, the very abrasive rock, and 13.3% and19.6% grades. At the apex of the alignment, a 60m (200ft) by 3.6m (12ft) diameter raisebore shaft with surge chamber to protect against pump malfunction was constructed. Upon completion of mining, the tunnel was lined with a 3m (10 ft) diameter high strength steel pipe. Scheduled to come on-line by January 1, 2008, the Lake Hodges to Olivenhain pumped storage project is valued at $108 million, delivering a reliable source of water in emergency situations and electricity-generating capability to meet the growing demands of the San Diego region.

Jan 1, 2007

By B. Anderson, P. Churak, S. Dewar, A. Johnson, P. Eger

Although vegetation can be successfully established on fine taconite tailings, innovative approaches are needed to reclaim the coarse tailings used for dam construction. Through a series of cooperative projects with various government agencies and industries, EVTAC has been able to develop a unique closure plan. This plan will not only meet current reclamation standards, but also provide mitigation for a disturbed wetland and possibly create a tree plantation in the interior of the basin. By using waste products and exchanging materials, reclamation of the entire basin will be accomplised in a cost effective manner.

Jan 1, 2002

By Jorgen Elbrond

The capacity calculation of complex transportation systems involving variable activity times such as encountered in the mining industry are often worked out by means of simulation, which reconstructs waiting times and cycle times. The queuing theory, which mathematically calculates waiting times, has been used mainly to describe the, phenomena. This is due partly to the difficulties encountered in modelling complex systems and partly to the difficulty of reconciling the required time distribution laws with the real phenomena by means of the queuing theory. It is, however, obvious that formulas for capacity calculations would be preferable to simulation procedures because of their higher calculation speed, shorter and more flexible programs and shorter programming work. The calculation procedure presented in this paper is composed of some rather simple models, which are based on the queuing theory, and on some probabilistic and some deterministic considerations. The models are supported by observations, and to some extent by simulations. It has been attempted to find all the components of the cycle time and to include them in a comprehensive model. It is the intention to demonstrate that even quite complex mine transportation systems can be treated by means of the queuing theory with the advantages mentionned above and, without sacrificing the precision of the estimates. The speed of calculation of a wide range of parameter combinations is such that the procedure can be used extensively by a project engineer in the search for optimal modifications of the entire transportation system.

Jan 1, 1979

By Faruk Oksuz, Phillip L. Covell, Martin Doll

A series of difficult ground conditions causing high groundwater inflows and hazardous gas intrusion abruptly halted the construction of a 6.4-meter (21-foot) finished diameter and 1,890 meters (6,200 feet) long tunnel planned to serve as a 4-millioncubic meters (1-billion gallon) per day capacity river outfall for treated wastewater. Some 808-meters (2,650-feet) section of the constructed tunnel, TBM, and all other tunneling equipment were completely flooded with hydrogen sulfide laden artesian groundwater. The subsequent pumping and tunnel recovery efforts were unsuccessful and the tunnel was abandoned. In the end, the construction contract was terminated and options to redesign and reconstruct the project were re-evaluated to maximize the use of already constructed tunnel facilities such as the construction access and inter-mediate shafts and six outfall diffuser shafts in the river.

Jan 1, 2007

By M. L. Mellish

The year 1988 unexpectedly turned out to be a good year for the US coal industry. In fact, it was a third consecutive year of record coal production. Accord¬ing to preliminary Energy Information Administration data for 1988, domestic coal consumption went up 5%, or 41 Mt (45 million st), from 1987. Coal exports were up by a surprising 13.6 Mt (15 million st). In 1988, 22.7 Mt (25 million st) of coal were drawn from stockpiles for consumption. Even so, US coal production increased to 862 Mt (950 million st). That was up 28 Mt (31 million st) from 1987. While coal consumption, exports, and production were up, delivered prices for steam coal continued to slide during the year. Metallurgical coal prices, however, firmed up and showed a moderate increase. This reflected tight metallurgical coal markets at home and abroad. Coal consumption US coal consumption reached 800 Mt (882 million st), compared with 759 Mt (837 million st) in 1987. Increased metallurgical coal consumption was one factor. Most of the rise in coal consumption, however, was due to unexpectedly high electricity demand. Unseasonably hot summer weather al lowed added coal-fired electric generation to supplement the drought-related reduction in hydro-electric power supply. Electric utilities consumed 687 Mt (757 million st) of coal in 1988, 35.4 Mt (39 million st) more than in 1987. Coal-fired power plants remained the primary source of US electricity generation, providing 57% of the total in 1988. Coal consumption at coke plants increased 13%, to 38 Mt (42 million st), from the level consumed in 1987. This increase reflects the recent recovery in the iron and steel industry. Metallurgical coal consumption in 1988 could have been greater. But US coke plants reportedly reached their maximum practical production capacity. As a result, net US coke imports amounted to 1.45 Mt (1.6 million st). Despite increased industrial activities, steam coal consumption by industrial plants was up only slightly from the 1987 level, amounting to 69 Mt (76 million st) in 1988. Residential and commercial coal consumption remained virtually unchanged at 6.4 Mt (7 million st). Coal exports and imports US coal exports rebounded in 1988, reaching 86 Mt (95 million st). It was the highest level of annual US coal exports since 1982, when they reached 96 Mt (106 million st). An unusual set of factors led to an opening for US coal exporters in 1988: • a high level of industrial production in Japan and the European Economic Community, • supply disruptions due to labor problems at coal mines in Poland and Australia, • a drought-related reduction in hydro-electric power generation in Canada, requiring increased coal-fired generation, • China's problems in meeting its export commitments, and • a fall in the value of the US dollar. US metallurgical coal exports in 1988 amounted to 56 Mt (62 million st), 9.1 Mt (10 million st) more than the 1987 level. Europe, Japan, and Canada were the principal importers of US metallurgical coal in 1988. European countries, in particu¬lar, increased their take by one-third of US metallurgical coal. The labor problems in Poland and Australia contributed to these higher levels of imports. So did increases in pig iron production of 8% in Japan and 9% in the European Economic Community. US steam coal exports - including bituminous, anthracite, and lignite-increase to 30 Mt (33 million st). This was up from 25.4 Mt (28 million st) in 1987 Contributing to this overall rise were 1.8-Mt (2-million st) increase in shipments to Canada and a 2.7-Mt (3-million st) increase to Europe. Unaffected by the somewhat tighter world coal market, US coal imports showed a slight increase to 1.8 Mt (million st) in 1988. Colombia continue to be the leading exporter to the United States, followed by Canada and Venezuela. Venezuela's entry into the US market is a relatively recent one, having made its first significant shipment in the fourth quarter of 1987.

Jan 1, 1989

By J. D. Morgan

In the first half of the year, lessening of cold war tensions was welcome. But Iraq's invasion of Kuwait in the second half led to the Persian Gulf War in January and February 1991. This caused an oil shock that dampened the economy. So the US gross national product rose only 0.9% to $5,463 billion (US billion = 109). The buildup of military forces in the Persian Gulf area focused greater attention not only on petroleum but also on other strategic materials. The Department of Defense continued to review stockpile goals and to upgrade several mineral materials. In addition, the Bureau of Mines continued to maintain the standby Emergency Minerals Administration. The Defense Production Act, which authorizes priorities, alloca¬tions and supply expansion, lapsed on Oct. 20. So the Selective Service Act of 1967 became the authority for assuring that orders of the armed forces and defense atomic-energy programs were given priority treatment. Consumer demand strongly affects mining worldwide. US citizens carry significant debt, and large stocks of housing and consumer goods are already in place. Some 250 million persons have 188 million licensed motor vehicles and 100 million dwelling units. Consequently, new car production fell 11 %, to 6.1 million units. Truck and bus production fell 8%, to 3.7 million units and new private housing starts fell 13% to 1.2 million units.

Jan 1, 1991

Kidd Mine in Northern Ontario is now producing from Stage 1 of the Mine D expansion project ? mining between 2100 m and 2700 m below surface. Planning for Stage 2 of the Mine D project is already well advanced and will see the mine extended potentially to 3100 m below the surface. To ensure adequate ventilation is maintained at such depths, two large axial fans have been installed on the 6000 Level (1800 m below surface) as exhaust booster fans to operate in series with the surface exhaust fans. The Kidd Mine 6000 Level Booster Fans are a unique installation with unique and often unexpected challenges. These challenges have been met and attacked through the combined efforts of mine and fan manufacturer personnel with a common focus.

Jan 1, 2009

By W. A. Heitbrink, J. D. Ashley, R. E. Gresh, J. A. Organiscak, A. B. Cecala

Many different types of mobile equipment used in surface coal mining utilize enclosed cabs to protect equipment operators. The overburden removal process is extremely dusty and can cause excessive exposure to respirable dust, especially crystalline silica. After equipment is used for years, many components of the enclosure deteriorate and its effectiveness is greatly reduced. This report discusses a cooperative research study performed on an Ingersoll Rand DM45E surface drill, retrofitted with a new Sigma pressurization and filtration system. Respirable dust concentrations were substantially reduced from 0.64 mg/m3 during pre-testing to 0.05 mg/m3 during post-testing with the new system, representing a 92% reduction in dust levels in the drill cab. This new system appears to be a very well-built and sturdy device, well-suited for the mining industry.

Jan 1, 2002

By Allan Sylvester, Paul E. Gabryszak, Diane R. Hirsch, David P. Field

With construction of the first phase of the Automated People Mover (APM) Tunnels nearing completion, this paper will address how knowledge from recent Tunnel Boring Machine (TBM) and New Austrian Tunneling Method (NATM) tunnel construction at the airport was used to refine the methodology for the next phase of tunnels currently in design. The benefits include an enhanced understanding of the ground conditions; allowing optimization of excavation sequences and support requirements; a more effective instrumentation and monitoring program; and improved construction details and related contract provisions.

Jan 1, 2007

By S. Rupprecht

"This article addresses the prevalence of poor public reporting practices of coal exploration results, coal resources and coal reserves in southern Africa. Currently, the reporting of coal tonnage without supporting coal qualities or saleable tonnes and quality is a poor reporting practice that occurs far too often. Not all coal is equal — therefore it is extremely important that investors or potential investors are provided with the full details of both run-of-mine (ROM) and saleable coal tonnage, their associated qualities and other material and relevant information.Competent or qualified persons should note that publicly reported information should be sufficient to enable an informed reader to make a reasonable and balanced assessment of the significance of the information provided. “Companies are encouraged to provide information in their public reports, which is as comprehensive as possible (CRIRSCO, 2013).” However, too often this isn’t the case, and material matters are either not reported or inadequately disclosed.According to the South African National Standard (SANS) 10320:2014 draft document, “tonnage and coal quality that will be available for sale, either in the raw ROM state (raw saleable) at a specified moisture content, or after beneficiation of the ROM coal by processing operations to produce materials at specified qualities, size ranges and moisture contents. The assessments must demonstrate that at the time of reporting, the marketing of the products is reasonably justified. The basis of the predicted practical product yield to achieve the saleable coal reserve must be stated. The moisture basis of reporting shall be stated.” An example as to why coal qualities are so important to the public, the requirements of South Africa’s electric public utility (Eskom) power stations are detailed in the followint paragraphs. The Kendal power station, commissioned in 1988, operates at a calorific value (CV) range of 19 to 20 MJ/ kg, an ash content between 29 and 34 percent and volatiles between 20 to 21 percent. Other power stations, such as Kriel or Hendrina, may require different qualities, such as a CV range of 22 to 23 MJ/kg, an ash content between 20 and 28 percent and volatiles between 22 to 23 percent. Thus, in terms of domestic saleable coal, it is not just about reporting the coal qualities but also informing the investor as to which power station the coal is intended to be sold as “boilers are designed to burn particular qualities of coal” and “it is not always possible to transfer coal between stations because of different quality requirements at each station (Chetty, 2010).” Sulfur content is another important quality with the ideal coal content having a quality of less than 1 percent sulfur."

Jul 1, 2019

In conjunction with steady increases in production levels, longwall operators have applied greater quantities of ventilating air and spray water in an effort to control respirable dust and/or methane. Air velocities greater than 7.6 m/s (1500 fpm) have been measured on longwall faces. Operators have expressed concern over the potential entrainment of respirable dust at these high velocities. The greatest likelihood for entraining dust into the high velocity airstream may occur as shields are advanced allowing relatively dry particles to fall from the shield canopy directly into the airstream. Laboratory tests to simulate dust liberation during shield movement were conducted at the Pittsburgh Research Laboratory of NIOSH at velocities ranging from 2.0 to 8.2 m/s (400 to1600 fpm). Airborne dust samples were obtained with personal impactors to quantify the size distribution and concentration of the dust entrained at the various air velocities. Statistically significant increases in both total and respirable dust concentrations were measured as test air velocities were increased.

Jan 1, 2001

By Akira Tsune, Shingo Sugimoto, Tadayuki Ishiyama, Nadao Saito, Masatsugu Okazaki

"The Deep Ocean Resources Development Co. Ltd. (DORD) of Japan signed a 15-years contract with the International Seabed Authority for exploration of polymetallic nodule in a 75,000 km2 area, consisting of West and East Areas in the Clarion and Clipperton Fracture Zone in 2001. The exploration work is now concentrated in resource estimation of the first generation of mining area, the High Abundance Area.A detail survey of the Model Area, set in the High Abundance Area, was conducted using AUV (Autonomous Underwater Vehicle) equipped with MBES (Multi-Beam Echo Sounder), SSS (Side Scan Sonar), Sub-Bottom Profiler (SBP) and still camera. The seafloor topographic map based on 1 m grid data was produced in an area of approximately 80 km2 (Figure 1). Photographs, continuously covering the seafloor taken by AUV along two west-east trending traverse lines, together with detail seafloor topographic map produced from MBES give an excellent opportunity to observe distribution manner of pollymetalic nodule related to topographic features. This helps to understand more accurate resources estimation of a whole area of the High abundance Area. Furthermore, information of micro-topography gives ideas for conducting ore collecting operation and designing ore collector."

Sep 1, 2014

By G. L. Mowrey

One critical element of the U.S. Bureau of Mines (Bureau) autonomous mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include vibration, passive infrared, radar, and natural gamma radiation (NGR). To establish which CID sensor technologies need to be developed for a given seam, coal and adjacent rock samples (i.e., immediate roof and floor) are being collected from selected major coal seams in the U.S. and are being analyzed in terms of NGR and other geophysical measurements. Results of the NGR measurements indicate that, in general, all shale and shale-like materials (e.g., drawslate, slate, and fireclay) have higher NGR readings than the coal seam. Consequently the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1990

The evolution of surface mine layout configuration is a function of the schedules and sequence of material excavation within the optimized layouts. The production schedules and sequence of materials movement from multi-bench and multi-face operations are difficult to plan and execute. However, the ability to maximize the profit or net present value of an orebody is largely dependent on the mining schedule. The mining schedule will determine the life of the mine, the projected cashflows, and the investment requirements over the mine life. The pit geometries, pit expansion rates and the periodic volume of materials from different benches in a multi-bench, multi-face open pit mine determine the equipment requirements. The volume of materials excavated, as well as pit layout changes from circular and elliptical geometries of an oil sands mine were modeled using analytical geometric and parabolic partial differential equations (PDEs) and solved within Matlab. The results show that the geometric values are almost the same as those obtained from PDEs for different pit configurations. The economic analysis shows that both the current mining system (CMS) and the cyclic excavator conveyor belt control system (CycEx CBCS) are viable with high NPV (= $3.20 × 1010), PI (> 19%) and IRR (> 29.02%) with short discounted payback periods (= 3.24 months). The CycEx CBCS option is more economic than the CMS option. Its NPV is 1.27 times that of the CMS option. The PI and IRR for the CycEx CBCS option are respectively 2.24 and 1.13 times that of the CMS option. As well, the CycEx CBCS option has almost half the DPBP of the CMS option. The CMS option has an operating cost of $1.386 per tonne ($2.774/barrel) while that of the CycEx CBCS option is $0.779/tonne ($1.558/barrel). These results show that the CycEx CBCS option is the better option for mining companies working on oil sands deposits to invest in.

Jan 1, 2011