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By D. M. Ramsey

HIGH-INTENSITY magnetic separation as now practised in the commercial treatment of a large variety of industrial minerals is a com-paratively recent development, having had its practical beginning about ten years ago when it became necessary to devise more effective methods for the purification of the electric furnace abrasives and refractories-silicon carbide and fused aluminium oxide. The fundamentals of magnetic separation are, of course, very well under-stood; bur while very, very old in principle, the process has, in recent years, been developed to a point of far greater usefulness than heretofore. In fact, until the development of the high-intensity process,. magnetic separation was limited largely to the removal of tramp iron? with magnetic pulleys and the removal of the very highly magnetic portions of industrial minerals by means of horizontal conveyor-belt-type separators. All magnetic separation processes depend for their success on the fact that various materials are kinetically influenced to a greater or lesser degree by the force that we speak of as 'magnetism'. We have now come to regard 'magnetic separation' and 'high-intensity magnetic separation' as two different and distinct methods. However, both depend upon the reaction of a particle when placed in a magnetic field. The common types of magnetic separators quite generally operate on the principle that a magnetic particle can be lifted by a powerful magnetic force from a stream of material moving on a belt or other type of conveyor. The application of the force removing magnetic material by this scheme is directly opposed to the force of gravity and is, therefore, limited to sub-stances of a relatively high order of magnetic susceptibility, such as metallic iron and magnetite. Until a few years ago, one very important principle was almost entirely overlooked. Practically every substance is susceptible to some extent, at least, to magnetic attraction, and by the application of a magnetic force great enough, and properly applied, separations of materials heretofore considered 'non-magnetic' can be accomplished.

Jan 1, 1937

By B. Wasmund, M. Parravani, M. Jastrzebski, Z. Coull

"One of the main drivers of overall profitability of pyrometallurgical vessels is refractory lining campaign life. Increased economic pressure to improve vessel life requires innovative solutions to the problem of refractory cooling. Hatch has recently developed a high-intensity, waterless cooling system that bridges the performance gap between external shell cooling and internal water-cooled copper elements. External shell cooling has a limited effectiveness in protecting the refractory lining, because it is thermally insulated from the hotface of the lining by its thickness. This situation does not improve until the lining itself has become worn near the end of the campaign. The patented technology developed by Hatch overcomes this problem by positioning high-velocity air-cooling channels within the lining, closer to the hotface where the cooling benefits can be realized throughout the entire duration of the campaign. The current paper presents the development and application of Internal Air Cooling technology as well as results from the pilot campaign in an operating commercial vessel. Various adaptations for this novel, cost-effective and inherently safe system are also discussed."

Jan 1, 2015

By G. O. Rading, B. O. Odera, M. J. Papo, R. Couperthwaite

"Platinum-based alloys are being developed with microstructures similar to nickel-based superalloys for potential high-temperature applications in aggressive environments. Since the chemistries of nickel and platinum are similar, Pt-based alloys can be made with gamma prime ~Pt3Al precipitates in a gamma (Pt) matrix. Currently, the Pt-Al-Cr-Ru system is one of the bases for developing Pt-based alloys, where Al allows the formation of thePt3Al precipitate and also gives protection from the alumina scale formed, Cr provides oxidation resistance and stabilization for the L12~Pt3Al phase, and Ru provides solid solution strengthening in the (Pt) matrix. Four Pt-Al-Cr-Ru-V and two Pt-Al-Cr-Ru-V-Nb alloys were made, with compositions based on a quaternary alloy, ~Pt82:Al12:Cr4:Ru2, which hadpreviously been identified as having optimum properties. Four of the as-cast alloys had the targeted two-phase structure of ~Pt3Al and (Pt), and two were single-phase ~Pt3Al. Vanadium partitioned more to (Pt) than to~Pt3Al. There was an improvement in hardness compared to the quaternary alloys. The best addition of V was ~15 at.%; higher additions resulted in brittle intermetallic phases of the Pt-V system. The effect of Nbcould not be ascertained because of its high losses."

Jan 1, 2015

By Soseol Kim

A high-performance Emulsion-based booster explosives has been developed that can be used as a booster for bulk explosives. Currently, Pentolite booster, which is mainly used as a booster for bulk explosives, has a high risk of accidents due to the sensitivity of its raw materials PETN and TNT, and has a low melting point, making it impossible to use it in high-temperature ground. The Emulsion-based booster was developed to maximize the Velocity of Detonation (VOD) while elimination the shortcomings of the Pentolite booster. The VOD of the Emulsion-based booster is about 6,500m/s, so it can maximize the performance of the bulk explosive. In addition, it can be used in high-temperature ground and does not cause accidental detonation due to the external environment. In this article, the performance of the Emulsion booster was verifies through comparative test blasting of the developed Emulsion-based booster and Pentolite booster.

Feb 6, 2023

By Yuanfei Chen, Jianfeng Zha

"China is the largest producer and consumer of coal in the world. The mining-induced surface subsidence has bad influences on the surface and structures above the surface. In order to minimize disasters, removal, reinforcement, or maintenance structures are often adopted. In the application of maintenance methods, it is necessary to carry out dynamic surface subsidence prediction to choose maintenance methods, optimize maintenance time, and evaluate the amounts of work. Time series methods and influence function methods are common for dynamic surface subsidence prediction, but the former is difficult to consider with underground mining conditions, and the latter has low prediction precision. Therefore, this paper develops a dynamic subsidence prediction model aided by field-measured data and realizes the model programming. The model could achieve high-precision prediction of dynamic surface deformation through optimizing the parameters in time by using field-measured data of surface subsidence. The research results of engineering cases show that, with the method of dynamic prediction, the standard error can be controlled in the range of 5%, greatly improving the accuracy of dynamic prediction of mining subsidence, which provides strong technical support for the maintenance and management of structures. INTRODUCTION With the rapid economic development and continued industrialization process, the demand for energy is growing in China. Today, China is one of the largest coal, oil, and gas consumers in the world. Coal consumption accounts for 47.7% of the total consumption in the world (Tian, 2016). In order to meet the demand for coal resources in the process of modernization, more and more coal mines carry out coal mining under villages, buildings, highways, and bodies of water. The mining-induced overlying strata and surface subsidence have bad effects on surface and on various structures (such as buildings, railways, highways, high-tension transmission lines) and could even cause various disasters (Williams et al., 1998; Bell et al., 2000; Doyle et al., 2002). Generally, methods, such as removal, reinforcement, or maintenance are taken to eliminate the adverse impacts (Kraatz, 1984; Bell and Genske, 2001; Wang, 1989). When reinforcement or maintenance is selected to remove bad effects, the proper maintenance methods must be chosen. In addition, maintenance time, as well as an evaluation of time it will take to do the work are necessary to predict the surface subsidence with high precision."

Jan 1, 2017

By R. G. Haire

Studies of the f-elements under pressure provide important insights into their solid state chemistry and physics. From such studies, of the elements and their alloys, it has been established that the normally localized f- electrons of several of these elements can become, involved in bonding under pressure. The electronic behavior of f-element compounds under pressure tend to be more difficult to interpret, due to the variety and the nature of electronic orbitals that are present. The 4f-elements and some 60% of the 5f-elements have been studied under The systematic comparisons that have been established for these materials are discussed.

Jan 1, 1992

By K. B. Hodgins, P. Ouellette

"The North American mining industry faces challenging emissions regulations in the coming years with the introduction of new standards for off-road diesel engines. In order to remain competitive, industry stakeholders must invest in new technologies that are economically and environmentally sustainable.Westport Innovations Inc., Vancouver,British Columbia, has developed high-pressure direct injection (HPDI) technology that allows diesel engines to run primarily on natural gas with no intrusive engine modifications while reducing emissions of nitrous oxides (NOx), particulate matter (PM), and CO2 with no loss in performance. This is accomplished through late-cycle, high-pressure direct injection of natural gas into a diesel engine combustion chamber at the end of the compression stroke. A small amount of diesel fuel is injected first to initiate combustion, followed by the natural gas fuel main injection. The diesel cycle and its operating characteristics are fully retained including high combustion efficiency, lowspeed torque, high-power output, no engine knock, and fast response to load changes. Natural gas has not been an attractive fuel alternative in mining operations due to the reduced performance associated with spark ignition engines and the added weight and space required for compressed natural gas tanks. However, liquefied natural gas (LNG) can be stored with less impact on weight and space than compressed natural gas (CNG) by virtue of its increased energy density over CNG.Westport has applied HPDI technology to the Cummins QSK series engines for high horsepower applications such as power generation and mine haul trucking. HPDI can also be applied to other engine manufacturer platforms and market applications. Westport is interested in demonstrating the unique characteristics of HPDI in mine haul trucks to show diesel performance with low emissions levels using low-cost LNG fuel.Retrofitting a Tier 1 engine with HPDI would provide emissions reductions below the EPA 2006 Tier 2 standards while maintaining the performance and efficiency of the Tier 1 platform. The longer-term target is the Blue Sky voluntary standards of 3.8 g/kW-hr (2.8 g/bhphr) of NOx + non-methane hydrocarbons (NMHC), and 0.12 g/kW-hr (0.09 g/bhp-hr) of particulate matter (PM) and future standards. Typically, an HPDI engine is capable of reducing NOx emissions by 40% over diesel operation at the same efficiency. On a mining truck meeting Tier 2 standards, this NOx reduction would translate into NOx emissions approximately 14 t per year lower than under diesel operation. PM emissions are typically reduced by some 60% with HPDI fueling, which would translate into a yearly reduction of 650 kg. Similarly, engine-out greenhouse gas (GHG) emissions are reduced by 21%, resulting in a yearly reduction of approximately 950 t per vehicle.Above those of emissions reduction, efficient natural gas usage in mine haul operations would offer significant benefits in terms of fuel cost savings, which may be further combined with monetary emission credits. HPDI technology would enable operators to exercise environmental stewardship while gaining a competitive advantage in advance of new Tier 2 and Tier 3 emissions regulations. The advantages of natural gas use among mine haul truck operations can be replicated across a broad range of engines and applications."

Jan 1, 2005

By C Harrison, A Bowskill

The Ambuklao hydroelectric dam was originally constructed in the 1950s in the remote and mountainous region of the northern Philippines. Following its construction the dam has suffered heavily due to siltation and a partial collapse of the intake structure due to a 7.8 magnitude earthquake that struck the region in 1990. Between the years 1990 and 1999 the power station progressively lost its capacity to generate power. In 1999 the owner took the power station out of commission. The power station remained idle over the next 12 years. In 2008 the power station was sold to a new owner who commissioned the rehabilitation works.The rehabilitation project restored the operating status of the power station in June 2011 and increased its capacity from 75 MW to 105 MW. The civil contract of the rehabilitation project required the construction of a new intake structure behind an in situ rock coffer dam on the edge of the existing reservoir, new 6.2?m diameter × 124?m deep blind sunk shaft behind the intake structure, which connects to a new 6.8?m horseshoe profile headrace tunnel that ultimately connected onto the existing vertical penstocks which feed three No 35 MW Horizontal Turbines rated at 155?m head.The unique challenge in rehabilitating this existing hydropower station involved finding solutions that would conclusively deal with the challenging geological and hydrogeological conditions associated with excavating new tunnels and a drop shaft beneath a live dam.McConnell Dowell was awarded the civil works package for the rehabilitation works in August 2008. The Ambuklao rehabilitation program took 33 months to complete.Over 600?m of tunnels were excavated in highly weathered and often challenging geotechnical conditions via drill and blast with the extensive use of high-pressure fissure grouting to control groundwater ingress that was surcharged by the dam.This paper focuses on the use of high-pressure fissure grouting that took place to enable the excavation of the new waterway system and intake structure.CITATION:Bowskill, A and Harrison, C, 2014. High-pressure fissure grouting for drill and blast tunnelling, Ambuklao, Philippines, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 141–152 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By L. Thompsen

High-pressure grinding rolls (HPGR) offer capacity increases, savings in operating costs and metallurgical advantages. The first installation of the Polycom HPGR in a copper ore treatment plant occurred in July 1995 at Cyprus Sierrita’s mining complex near Green Valley, AZ (Fig. 1). Until that time, the benefits this technology offers for copper and gold ore were only demonstrated on testwork. In other industries, such as diamonds, HPGR have proven to be reliable in industrial-scale plants and have set a new standard for this kind of ore treatment plant. HPGR are also successfully used for the comminution of coal, blast furnace slag and in cement and pelletizing plants. The installation at the Cyprus Sierrita Mine should prove the economical benefits in commerical-scale copper mining, confirming the results of comprehensive testwork(Fig. 2).

Jan 1, 1996

By Michael von Seebach

High-pressure grinding rolls subject the feed material to pressures of 200 N/mm? During this process considerable size reduction and the Formation of flakes occur. This paper describes the basic consideration For design and operating of this type of mill. It is also shown that the particle size distribution resulting from this process is typical for grinding processes but untypical for crushing processes. High pressure grinding rolls are designed in size of up to 2.8 m roll diameter allowing feed material top sizes of 250 mm. The rigid frame, bearing and drive - train design allows a broad application of the high-pressure grinding rolls operating the machine in open or semi-closed and closed circuit for dry and moist feed materials. Operating results show that capacity increases of up to 100 % can be accomplished with this technology. The high-pressure grinding roll also, allows for lower operating and maintenance costs due to energy savings of up to 20 L and reduction of wear to less than 1 76 for dry and less than 0.1 5 for wet grinding. Other advantages of the high-pressure grinding rolls are smaller equipment sizes than a ball or SAG-mill for a given capacity resulting in lower building sizes with reduced capital in- vestment costs.

Jan 1, 1987

By V. E. Antonov

Hydrides of iron and iron-based alloys are thermodynamically stable only at hydrogen pressures in the gigapascal range and rapidly loose hydrogen under ambient conditions. At low temperatures, however, these hydrides can be retained in a metastable state at atmospheric pressure after being cooled under the high pressure to liquid nitrogen temperature. This review will discuss the current state of studies on phase transformations in the Fe-H and related systems and also on the composition, crystal structure and physical properties of the hydrides, both under high hydrogen pressures and in the "quenched" metastable state at ambient pressure. The studies at ambient pressure include magnetization measurements, X-ray and neutron diffraction, Mossbauer spectroscopy and inelastic neutron scattering. In the sections on Mossbauer and structural investigations of hydrides of Fe-Cr and Ni-Fe alloys new experimental results will be presented.

Jan 1, 2002

By J. K. Brimacombe

Plant trials have been conducted at the Tacoma Smelter of ASARCO to assess the effect on tuyere blockage and refractory erosion at the tuyere line, of increasing the injection pressure of air into a Peirce-Smith con¬verter. Four tuyeres each having an ID of 19.1 mm (3/4 in) were installed toward one end of the tuyere line of the No. 4 Converter. Air and oxygen-enriched air were injected at 414 kPag (60 psig) through these tuyeres and at the usual 83 kPag (12 psig) through the remainder of the tuyeres in an otherwise normal converter campaign. The test campaign consisted of 88 charges and lasted for 89 days. During this period, punching of the high-pressure tuyeres was found to-be unnecessary; and when, as a precaution, the tuyeres were cleaned by hand at the end of a charge, they were always open. Also it was observed that the flow of high-pressure air remained constant. Accretion formation around the tip of the high-pressure tuyeres varied from charge to charge and was influenced by the matte grade and the level of oxygen enrichment.

Jan 1, 1983

Control shearer-generated airborne respirable dust on longwall mining sections. Approach Previous Bureau studies have shown that using high-pressure water can have a significant impact on the amount of airborne dust released into the face airflow while cleaning and controlling the airflow in the immediate cutting zone. The basic concept to improve the drum water spray system was to utilize high-pressure (1,200 psi) inward-facing drum sprays to improve the dust knockdown efficiency of the spray system and confine the dust to the face area. This system would minimize the exposure of the shearer operator through dust avoidance and decrease face dust levels by suppressing the amount of respirable dust that becomes airborne. System Design In-mine tests were designed to provide information that would permit evaluation of the operation with different spray orientations and water spray pressures. This was achieved by comparison with a conventional baseline wet-cutting system consisting of 26 low-pressure bit sprays, located on the hit blocks to provide pick-point flushing. Total drum water flow was 60 gpm and was maintained continuously throughout all tests. The high-pressure inward-facing drum water spray system consisted of sprays located in each bit block, oriented 15° and 30° toward the face. The inward-facing water spray system was operated at either 800 or 1,200 psi.

Jan 1, 1989

Improve the strength and other properties of steel alloys. Approach Research by the U.S. Bureau of Mines indicates that steels melted and solidified under high nitrogen pressure acquire yield and tensile strengths that are up to four times the strengths of comparable stainless steel alloys without nitrogen. Fatigue strength, creep strength, and other mechanical properties are also improved. Strengthening occurs by two mechanisms: (1) increasing dissolved nitrogen in the lattice and (2) formation of dispersed metal nitride phases. Nitrogen Alloying Nitrogen alloying of a steel is generally done by introducing metal nitrides during melting of the steel. The concentration of nitrogen is limited to its equilibrium solubility at 1 atmosphere. For face-centered-cubic (fee) iron, that solubility is approximately 0.4 weight percent (wt%). For body-centered-cubic (bee) iron, solubility is 0.05 wt%. This solubility limitation can be overcome by melting the metal in a pressurized vessel. European steelmakers currently have metal-processing systems that can melt and pour tons of steel under nitrogen pressures exceeding 4 megapascals (MPa) (40 atmospheres). They have achieved nitrogen concentrations as high as 1.0 wt% in these (stainless) steels. The tensile strength is approximately twice the tensile strength of similar steels without nitrogen.

Jan 1, 1992

By Oliver Gutsche

High-pressure roll mill comminution of heterogeneous multicomponent feeds was simulated with artificial limestone-quartzite mixtures using a piston-die press. The influence of heterogeneous interactions between components of the mixture on grinding path, energy utilization and energy split have been examined. Primary fractures are governed by differential fracture strength and attrition resistance of the components at heterogeneous contacts; subsequent secondary and tertiary fracture events are governed by coarse-fine interactions in the particle-bed. The weaker component is preferentially ground out of the feed size fraction and concentrates in the fines. Energy split among the components in the mixture is a function of their relative fracture strengths. It doubles for limestone and decreases by a factor of 5 for quartzite over the entire range of the mixing ratio.

Jan 1, 1995

By Tim Lundquist

Disa Technologies Inc. provides innovative, sustainable solutions for mineral processing and remediation through its patented High-Pressure Slurry Ablation (HPSA) technology. HPSA processes solid feed material in slurry form, propelled by high pressure pumps through opposing nozzles that generate impinging jets within a collision housing. This process induces particle-to-particle collisions in a high energy zone, creating intergranular fractures along grain boundaries. In our batch scale and continuous operating testing, we have found that controlling key processing variables such as nozzle velocity, slurry solids percentage, and the number of passes can allow for controlled size reduction and maximum mineral liberation. Since 2018, Disa Technologies has demonstrated the versatility of HPSA by testing it on diverse materials, including phosphate, copper, uranium, vanadium, zinc, rare earth elements, lithium, nickel, mineral sands, gold tailings, and more. The intent of this paper is to present an overview of our test results describing in detail impacts on size reduction, recovery, and grade with a focus on HPSA's adaptability across ore types. Looking forward, it explores the potential to process materials such as DR-grade iron, clay, PGMs, bauxite, and various tailings. Additionally, it examines planned advancements in HPSA technology, including optimized nozzle spacing, higher capacity models, improved tonnage-to-footprint ratios, enhanced maintenance features, and expanded nozzle configurations.

Jan 1, 2025

By Isobel Yeo, Luca Cocchi, Sven Petersen, Nico Augustin, Sean Plunkett, Ingo Klaucke

Exploration for seafloor massive sulfides is currently mainly focused on investigation for active hydrothermal vent fields. However, most of the resource potential is thought to be related to inactive, large deposits that had enough time to accumulate sufficient tonnage. At the same time, ageing of these deposits will ultimately result also in burial acted by either sediments and/or volcanic deposits. We currently lack the technologies to explore for these deposits in a time- and cost-efficient manner. In the fall of 2012 we used a number of AUV-based technologies to explore and image a sulfide occurrence at the Palinuro Volcanic Complex in the Tyrrhenian Sea (Mediterranean Sea; Fig. 1) where sampling and drilling have documented a buried polymetallic barite-pyrite dominated site (Petersen et al., 2014). Sulfide mineralization is here covered by volcaniclastic and pelagic sediments and only red sediment staining and the presence of few tubeworm bushes indicated recent hydrothermal activity - black smoker venting is absent. We used AUVbased high-resolution bathymetry, sidescan sonar imaging, subbottom profiling, as well as magnetics to describe, in a quantitative way, the previously known sulfide-bearing areas as well as to successfully explore for new hydrothermal sites including large chimney structures (Figs. 2). Additionally chemical sensors (CTD, Eh, turbidity) investigated the water column for signs of hydrothermal activity in areas not previously investigated, but at the end, only weak anomalies were found in the southern part of the summit.

Sep 1, 2014

By R. Howard

"In projects involving resource development and plant optimization, the use of in-mine geophysics can deliver considerable benefit. The value proposition lies in using very high resolution downhole measurements to model process-plant outcomes. The calibration procedure used to convert in-situ physical properties into process engineering parameters is illustrated using two iron ore projects. Data correction was related either to orebody structure or mineral formation. The deliverable from this approach is a series of high-definition sections indicating the variability of ore delivered to a front-end separation plant and parameters for mine scheduling and stockpile design needed for maximum product yield.RÉSUMÉ Dans des projets de développement des ressources et d’optimisation de l’usine, l’utilisation de la géophysique minière peut engendrer des bénéfices considérables. La valeur de la proposition réside dans l’utilisation de diagraphies à très haute résolution afin de modéliser les résultats de l’usine de traitement. La procédure d’étalonnage utilisée pour convertir les propriétés physiques in situ en des paramètres d’ingénierie de procédés est illustrée en se basant sur deux projets de minerai de fer. La correction des données porte sur la structure de la masse minérale ou de la formation minérale. Les livrable attendus de cette approche sont une série de sections à haute définition, signalant la variabilité du minerai livré à une usine de séparation de première ligne, des paramètres pour l’échéancier de la mine et la conception des haldes requis pour une production optimale."

Jan 1, 2016

By B G. Lottermoser

Field and laboratory data combined with computational modelling have been used to predict the pit water quality for the Highway Reward mine. Open pit mining of the Highway Reward copper-gold deposit has produced a final mining void with a diameter of 600 m and a depth of 280 m. This void will be left to fill with ground and surface water once pumping of pit water ceases. Several leaching tables were constructed to simulate weathering reactions and surface water run-off in the major pit wall units during a 200-day leaching experiment. To date, about three-quarters through the experiment, combined run-off from these cells has reached a pH

Jan 1, 2003

By C. Melvin Lepper

High-resolution shallow seismic reflection methods are being used by the Bureau of Mines to map underground geologic features in coal mines. These features include faults, channel sand, washouts, rolls, and steep dips. The seismic method is proving useful for locating all of these at reasonable cost and with better definition than available with drill programs alone. This report provides a capsule description of the techniques and their application to mine planning.

Jan 1, 1976