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By George S. Dulikravich

An advanced semi-stochastic algorithm for constrained multi-objective optimization has been adapted and combined with experimental testing and verification to determine optimum concentrations of alloying elements in heat-resistant and corrosion-resistant H-Series austenitic stainless steel alloys. The objective was to simultaneously maximize a number of alloy's mechanical properties. This research will result in a rigorous tool for the design of high-strength H-Series steels and other types of alloys unattainable by any means existing at the present time. Such a material-by-design tool will also be able to reduce or minimize the need for the addition of expensive elements such as Cr, Ni, Co, Nb, Ti, V, etc. and still obtain the optimum properties of an alloy.

Jan 1, 2003

By P J. Handley

"Predicting how coal seams will be beneficiated through the coal handling processing plant (CHPP) has long been challenging within BHP Coal. Various coal seams from different areas are mined and stockpiled separately, often depending upon a deleterious coal quality parameter; high/low trace elements for example. These stockpiles are then fed in different ratios into the CHPP to produce the desired product/s. In understanding the washability characteristics of the feed source, mine geologists and process engineers work together to improve the beneficiation of different coal materials through the CHPP.For the majority of the BHP Coal deposits, the washability data is available for the coal seams across the deposits. However, no previous standardised modelling and prediction technique existed that could ensure the correct information was available for forecasting and refining CHPP processes. This paper will discuss the steps undertaken to implement a geometallurgical prediction tool that simplified and streamlined the washability modelling and yield estimation process. The value realised to the BHP Coal assets resulting from this process was: improved compliance to plan increased throughput increased CHPP recovery through improved efficiencies and increased revenues.CITATION:Handley, P J, 2017. Washability modelling and estimation techniques used to improve coal handling preparation plant beneficiation, in Proceedings Tenth International Mining Geology Conference 2017, pp 327–336 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By G. V. Henderson

The San Gabriel Valley contains some of the richest and most extensive sand and gravel deposits in California. Operating quarries within the San Gabriel area mine more than 15 million tons of high quality aggregate per year. This represents about 45 percent of the total mined in the greater Los Angeles area, one of the nation's largest aggregate markets and producing regions. Popular opposition to continued aggregate production in the San Gabriel Valley is high, especially in the city of Irwindale where 40 per-cent of the city's property is made up of "excavated holes," some 150-200 feet deep. Reclamation of 70 years of mining is now an almost impossible task. Zoning regulations have the effect of depleting these vast reserves rapidly by changing the definition of total reserves to include only "legally minable reserves." All but two or three of the aggregate mines now operating will be depleted or zoned out of business by the year 2000. Some studies indicate that there will be no aggregate mining operations by 1995. Recent studies show a drastic change in land use patterns within this valuable mineral resource area over the past 20 years. The San Gabriel Valley is a classic example of the lack of adequate regional planning with regard to urban development in MRA's and represents a "too little, too late" effort by local government and industry.

Jan 1, 1978

By M. Matabane, T. Khati

"Accurate delineation of the contact between a kimberlite pipe and country rock at production level depths is a challenge due to limited geological data. Geological information is obtained from widely spaced diamond core boreholes which are drilled either from surface or from higher mining levels within the pipe. Kimberlite pipe/country rock contacts are notoriously irregular and variable, further reducing the confidence in contact positions defined by the drill-holes. At Finsch Diamond Mine (FDM), the opportunity arose to further improve the confidence in the contact positions relative to the planned slot (end) positions of each sublevel cave tunnel during the development stage of these tunnels. As a result, the accuracy of the 3D geological model has improved.The use of diamond drill core for this purpose is expensive due to site establishment requirements. The lengthy time taken during site establishment also delays the development of tunnels and support cycles, thereby extending the completion dates. FDM has reduced delays during development by adopting percussion drilling, in conjunction with gamma ray logging. The S36 drill rig is mounted on a moveable platform and does not require a costly and lengthy site establishment. The holes are generally drilled (0°/flat) on grade elevation, and these holes could also be drilled from the rim tunnels (developed in waste) into the kimberlite pipe. A single-boom production drill rig is normally used to drill holes about 20 m in length.On completion of the contact delineation drilling, gamma logging of the holes is conducted using the GeoVista geophysical sonde (or probe) to log the natural gamma signature of the dolomite/ kimberlite contact. The advantage of this tool is that the readings are continuous within centimetre intervals, and due to contrasting characteristics between kimberlite (rich in clay minerals) and dolomite, the contact position can be determined accurately. The better definition of contact positions also adds value to tunnel stopping distance in terms of developing the tunnel’s slot at the optimum distance from the contact (easier blasting of longhole rings, avoidance of contact overbreak and premature waste ingress, and other matters relating to extraction of ore from these tunnels). This method is highly successful and has reduced development costs (on-time completion), improved definition of the pipe’s contact position for geological modelling, improved blast design, and mitigated early waste ingress by maintaining the contact’s integrity."

Feb 1, 2019

By W. Mirihange

Considerable mechanical property decline is always observed at the Heat Affected Zone (HAZ) of AA 5083, This occurred as a result of the thermal effect on the hardened material, It is highly beneficial to have a prospective metallurgical procedure to overcome this decline of properties. Therefore, experiments were set to evaluate the effectiveness of a quick post weld heat treatment process with the AA 5083, Optimum results were obtained at 473K and with approximately 600 seconds time, The interplay between the time, temperature and mechanical properties are possible to explain by the Lifshitz-Slyozov-Wagner (LSW) theory and by considering the composition of the material.

Jan 1, 2005

In a previous study, various pyrite depressants were examined to improve the flotation performance of a copper-sulfide ore. Optimal results from this study were used to examine the effect of elevation on recovery and grade. Tests were conducted at elevations of 3350, 1735, 610 and -760 metres, consisted of five repetitive experiments for statistical analysis, and were performed both with and without airflow control. Tests were also performed in a glove box at Montana Tech to mimic the pressure conditions. Results indicate that both recovery and grade are dependent on pressure via bubble size and airflow suggesting that pressurised flotation cells should be considered for operations, particularly those at high elevation. Economics are extremely favourable for implementation because ensuing capital expenses are inconsequential with minimal time for return-on-investment.

Jan 1, 2005

By T. Plikas, L. H. Gunnewiek, L. Oshinowo

"Electric furnace smelting is one of the principal unit operations for ferroalloy production, and increased process intensity, improved availability, minimal maintenance and a longer campaign life are common objectives for electric furnace operation in order to obtain favourable economics of production. Furnace designers have continued to develop innovative solutions, e.g., furnace cooling systems, that have allowed these objectives to be realised and CFD modelling plays a key role in the design process. Enhanced understanding of the energy transfer process in the furnace and the ability to develop, evaluate and optimize components of the crucible design to match process requirements are the key motivators for modelling.This paper provides an overview of recent applications of CFD to the design of electric furnaces. The aim is to illustrate what can be done, and identify areas where further work is needed in this field. Examples include furnace bath simulation, crucible cooling system design, taphole design, baking of Soderberg electrodes, off-gas systems, and fume control and building ventilation. It is argued that the trend is for numerical models to become more encompassing while at the same time more accessible, and therefore further improvements in furnace design will be realised with continued and well validated modelling efforts.IntroductionOne of the main processing steps in ferroalloy production is the smelting of ore in electric furnaces. The three-electrode, AC submerged arc furnace is most prevalent method for smelting in the industry, with shielded-arc and DC plasma arc furnaces achieving limited application (1,2). Commercial furnaces range in size from a few megawatts to more than eighty megawatts of supplied power, and operate with the objective of maximising the return on capital invested. Maximising productivity and energy efficiency are two pathways to achieving this objective, through process intensification, increased availability, minimal maintenance, and increased campaign life for the furnace and associated equipment. Concurrently, the need to reduce the environmental impact of metal production by controlling the emission of particulate emissions, greenhouse gases, and other harmful by-products must also be met."

Jan 1, 2004

By III Scotland

Genstar's underground mine at Texas, MD experienced a failure of the mine roof and subsequent damage to an underground backfill caused by surface floodwaters. A hydraulic backfilling program was developed in house to stabilize temporary repairs to the mine roof, replace 2300 yards of pneumatically stowed backfill, and complete a permanent repair to the mine roof. A flowable backfill material was developed, tested, and later marketed as the result of experience gained during this project. In addition, Genstar personnel developed backfilling techniques to meet the requirements of the repairs and completed work without the additional expense of non company services or contractors.

Jan 1, 1992

By Andrew B. Cecala

This U.S. Bureau of Mines report provides a detailed description of the Bureau-designed modified shearer clearer system. Engineering drawings are provided for all major components of this system. The modified shearer clearer system is a revised version of the original system and is intended to improve the ventilation around both cutting drums. The original shearer clearer technique was solely a dust control technique that has been effective in lowering shearer operators' dust exposures. The technique uses a series of water sprays that not only knock down a portion of the dust cloud but also act as small fans that move a substantial amount of air and keep the dust cloud from dispersing over the shearer body. The modified version is composed of two additional spray blocks for improved air movement around both cutting drums, thus lowering methane levels and the likelihood of an ignition. A laboratory study performed with the modified version in a full-scale longwall gallery resulted in a 73-pet reduction in methane concentrations at the shearer machine for both cut directions. The air-moving capabilities of the system provide more turbulence at the cutting drums and reduce methane levels.

Jan 1, 1994

By R. E. Hamilton

"The requirements for effective optimization of a mineral dressing operation are discussed, with specific reference to a flotation system . Also considered are the relation-ships between automatic control and optimization pro-grams. Variables are classified into the following groups, and the significance of the classification is discussed: (a) Directly measurable (b) Directly manipulable (c) Uncontrollable (d) Calculable from measurable variables (e) Affected by changes in manipulable or uncontrol-lable variables. New sensors for measuring variables not normally measured are described."

Jan 1, 1967

By Michael J. McGuire

Rostoker, Inc. has developed a process to smelt solid hazardous/non-hazardous inorganic wastes. Near seven hundred experiments were performed. Actual industrial wastes as well as reagent grade chemicals were used. By mixing a multiplicity of these wastes to proper formulations, then furnacing them, it was determined that saleable end products could be reclaimed; metal, fume and slag. The slag, due to its siliceous structure was tested to be leach resistant (40 CFR). This formed the essence of our patent, #5,180,421 "Method and Apparatus for Recovering Useful Products from Waste Streams". What is unique is that a HTMR (High Temperature Metal Recovery) process has been developed that can treat a multiplicity of wastes within the same furnace. The discussion will include a list of waste streams we have treated, details of proper waste formulation and experimental results.

Jan 1, 1994

By L. M. Dwarkin

Strip mining in Western Canada, though of considerable importance, is a fairly recent development for many of the operators in the district. Adding to the difficulty of unfamiliarity is the fact that a great deal of the stripping is done on pitching seams, for which the engineering and economic principles of setting the most advantageous strip ratio are not readily apparent. The novelty of the operation combined with the complexity of the principles involved can easily lead to misconceptions as to the determination of the economic ratio. Definition of Strip Ration There are two commonly accepted meanings of the term strip ratio: (1) The ratio of feet of overburden to be stripped per foot of coal recoverable. (2) The ratio of cubic yards of overburden per cubic yard or ton of coal. The first definition is inapplicable to pitching seams so, throughout this paper, strip ratio will be taken as the ratio of cubic yards of overburden to be removed per cubic yard of coal recoverable. Economic Ratio In the case of flat seams, the strip ratio is fixed by existing natural conditions, and the magnitude of this ratio determines whether stripping is economically feasible. With pitching seams, however, the strip ratio is a variable. On the outcrop, there is usually some coal which can be obtained with little or no stripping. As the work is carried down the pitch of the coal seam, the proportion of overburden continually increases until a point is reached where it is no longer economical to continue the operation. The question immediately arises as to the location of this point, and this resolves into the problem of determining the most favourable strip ratio, or, to use the accepted term, the economic ratio.

Jan 1, 1949

By G. Nazari

ERAMET, through its subsidiary COMILOG, have rights to a rich niobium and rare earth deposit inGabon. The Mabounié deposit, is located 50 kmfromthe town of Lambaréné, in a fairly remote location. ERAMET has been developing a process to recover value metals for several years, and approached Hatch Ltd. to design a sizeable Demonstration Plant to help them further optimize the process, and prove the flowsheet is technically viable. The process employs concentration techniques to recover an upgraded Nb/REE feed material for processing in the subsequent leach step. Rare earths and niobium are selectively leached, and subsequently precipitated. Following precipitation, rare earths undergo bulk separation and are purified to produce LRE and mixed MRE/HRE products, which will be further processed by Third Parties. This paper provides a high-level overview of the process, summarizes the motivation for a Demonstration Plant in the vicinity of the deposit, and discusses technical challenges faced during the flowsheet definition and design phase. Key challenges are focused on and summaries of the methodologies used to address each challenge, as well as the solutions to overcome the challenges, are discussed. The paper provides motivation for further process simplification and concludes with a project update.

By K Orth

The volcanic successions that host massive sulphide deposits are diverse in composition, facies types and facies relationships. They also show a variety of spatial and temporal relationships to mineralisation. In many examples, such as the Koongie Park Formation in Western Australia, the host succession includes more or less conformable syn-volcanic sills with peperitic contacts. Such sills can be an important source of heat for fluid circulation, influencing patterns of hydrothermal alteration and the location of co-eval and later mineralisation. The impact of syn-volcanic sills on the host succession depends in part on the initial porosity and permeability of the enclosing facies. The special properties of glassy pumice û being highly porous, permeable, and reactive û allow pumice-rich facies to preferentially focus hydrothermal fluid flow. However, the same properties promote early alteration and porosity reduction. Hence, the diagenetic and compaction history of pumiceous facies strongly influences their potential to host massive sulphide mineralisation. In contrast to pumice, dense glass has relatively low porosity, at least initially, and does not compact. Non-vesicular glass is a major component of submarine lavas, syn-volcanic intrusions and some volcaniclastic facies. However, especially in submarine settings, dense glass is commonly intensely perlitically fractured soon after eruption. The fractures greatly increase the porosity and permeability, locally accelerating diagenetic and hydrothermal alteration. In addition to false pyroclastic textures, altered perlite may exhibit false porphyritic textures. Silica- or feldspar-altered perlite kernels surrounded by intensely altered phyllosilicate domains can resemble phenocrysts in a fine grained groundmass.

Jan 1, 1999

By R. Michael

Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response, the National Institute for Occupational Safety and Health (NIOSH) conducts research to reduce the noise emission of underground coal-mining equipment, an example of which is a roof bolting machine. Field studies show that, on average, drilling noise is the loudest noise that a roof bolting machine operator would be exposed to and it contributes significantly to the operators? noise exposure. NIOSH has determined that the drill steel and chuck radiate a significant amount of noise during drilling. NIOSH and the Corry Rubber Corporation have developed a bit isolator that breaks the steel-to-steel link between the drill bit and drill steel and a chuck isolator that breaks the mechanical connection between the drill steel and the chuck. This effectively reduces the noise radiated by the drill steel and chuck and reduces the noise exposure of the roof bolter operator. The paper documents the evolution of the bit isolator and chuck isolator. Laboratory testing confirms that production bit and chuck isolators reduce the A-weighted sound level generated during drilling by 3.7 to 6.6 dB

Jan 1, 2010

By K. Baba

Liberation of valuable minerals from a gangue matrix during size reduction of multiphase mineral particles is an important objective in mineral separation processes. A methodology for the prediction of volumetric grade distribution from one dimensional, linear intercept image analysis is being developed using a transformation function to describe the relations hi p between the linear and volumetric grade distributions. As part of this research effort it has been found that a transformation function, derived from Monte Carlo simulations of irregularly shaped particles, mainly depends on the volumetric grade and the dispersion density, i.e., the number of nuclei (or grains) per particle. A possible mathematical form for the transformation function is described in detail.

Jan 1, 1985

By W. L. Ott, J. E. Hawley, C. L. Lewis

"IntroductionTHE APPLICATION of spectrochemical analysis to metals of the platinum group was advocated by Harvey (3) as follows: ""The spectra of the platinum group metals have been studied less than many of the more common metals. The rarity of occurrence of these elements makes the analysis relatively unusual. Potentially, the analysis of this group is an excellent application of spectrographic methods, particularly in contrast to the tedious chemical procedure"".Wichers (8) divides platinum-metal analysis into three broad divisions as follows :( 1) The detection and estimation of these metals in other materials, e.g., ores, where the amounts present are very small.(2) The detection and estimation of impurities in the refined metals themselves ....(3) The analysis of alloys of the platinum metals .....The present paper deals with the second division: analysis of refined rhodium.Research on spectrochemical techniques for determination of trace contaminants in refined platinum metals was begun at Queen's University in 1949, under the supervision of Professor J. E. Hawley. Since 1953, the work has been continued in the Metallurgical Laboratories of Falconbridge Nickel Mines, Limited. Techniques for spectrochemical analysis of refined platinum and palladium have been published ( 4, 5). A technique for analysis of refined iridium has been developed but not yet published."

Jan 1, 1955

By M. F. Chambers

The U.S. Bureau of Mines conducted experiments on electrowinning of neodymium metal by using a molten-metal cathode at 650° C and an electrolyte of 50 mol pct NdCl3 (neodymium chloride) and 50 mol pct KCI (potassium chloride). The molten-metal cathodes were alloys of magnesium and zinc or magnesium and cadmium. Current efficiencies were 90 pct with a Mg-Zn cathode and 80 pct with a Mg-Cd cathode; The Mg-Cd cathode was easily separated from the electrolyte. In contrast, the Mg-Zn cathode tended to mix with the electrolyte, making separation difficult. The cathode metals were separated from the neodymium by distillation at 1,100° C under a vacuum of 10-3 torr. Neodymium metal of 99.9+ purity was recovered from the Mg-Cd alloy cathode after 30 min distillation time. The neodymium recovered from the Mg-Zn system contained almost 2 pct Zn after vacuum distillation. Continuous operation using the Mg-Cd alloy cathode was demonstrated.

Jan 1, 2010

By James JV, Petho SZ

The South Deep surface shaft system is being sunk to a final depth of 2750 in below surface and on completion will be the deepest single drop haft in the world. The shafts will intersect the target reef horizon at 2650 to below surface. In order to negate the requirement for a shaft pillar, which would he extremely large at this depth, the reef horizon in the vicinity of the intersection is currently being mined. A high quality crushed waste/classified tailings backfill is being placed in the longwall stoping panels around the shaft intersection area. This kill limit closure and ride which following shaft reef intersection could have a detrimental effect on the long term shaft stability. This paper discusses underground instrumentation results and numerical modelling exercises carried out to confirm that the shaft system will he stable throughout the life of the mine. Instrumentation projects include closure and ride measured between backfill paddocks and haulage leveling exercises carried out to determine the far field rockmass response to mining with stiff backfill.

Jan 1, 1998

By B. Berg, J. Stephenson, J. Mansanti, C. Nyikos

"Intrepid Potash, Inc.’s Carlsbad East facility has refined sylvite and produced muriate of potash (MOP) since 1965. In addition to MOP, Intrepid Potash began recovering the mineral langbeinite from a mixed ore reserve in 2005. In 2011 a new langbeinite recovery process for the coarse (+850 micron) size fraction was constructed to enhance the overall langbeinite recovery. Based on the limited mixed ore reserve and an abundance of langbeinite ore reserves the transition of the East plant to a langbeinite only facility was targeted for 2021. Due to a decreasing grade of the mixed ore reserve, declining sales pricing, and high sylvite operating costs a strategic decision was made to accelerate this transition into 2016. To enable a successful transition, a fines recovery system needed to be developed, constructed and implemented. This paper describes the advancement of langbeinite processing at Intrepid Potash and the planning, development and successful execution of the transition to a langbeinite only operation. BACKGROUND Langbeinite (K2SO4·2MgSO4) is a double salt containing potassium sulfate (K2SO4) and magnesium sulfate (MgSO4). It is used as fertilizer and in the industry is described as Sulfate of Potash Magnesia. It is attractive as a specialty fertilizer and in addition to containing a ready source of a primary nutrient potassium, it also provides two secondary essential nutrients, magnesium and sulfur. It is especially attractive for chloride sensitive crops. Langbeinite has a specific gravity of 2.8, a Mohs hardness of 4.2, and is brittle thus very friable. It is the hardest of the saline minerals, and despite its relative softness on the Mohs scale can be very abrasive in process environments and in field applications, probably due to its conchoidal cleavage. Its solubility at 240 g/l is less than the solubility of sylvite (KCl) or halite (NaCl) and due to even slower relative dissolution kinetics washing with cold water has been a common practice for upgrading langbeinite ores. The solubilization/crystallization relationship for langbeinite is different from the majority of other evaporite minerals in that once langbeinite is solubilized it does not form langbeinite again. Instead it gives up one mole of magnesium sulfate, takes on various waters of hydration and precipitates out as either schoenite (K2SO4·MgSO4·6H2O) or leonite (K2SO4·MgSO4·4H2O) depending on temperature. Due to its partial solubility and phase transitions at its surface when exposed to moisture, there is strong cohesion between wetted particles; the resulting stickiness of the upgraded products can create significant materials handling issues unless processed in slurry form or at relatively low moisture levels. Langbeinite has been produced commercially from two locations, the Kalush and Stebnik regions in the Cartpathian Mountains of former Poland and now the Ukraine and from the Permian Basin in New Mexico (Garrett, 1996; Smith 1949). Current production is from two operators in the U.S., Mosaic and Intrepid Potash."

Jan 1, 2017