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By L. Scott, M. A. Goncalves

Effective communication is a sought-after non-technical skill in the health, safety, and environmental (HSE) function and is fundamental in achieving an organization’s safety objectives. While different channels are used to communicate HSE matters, many organizations employ posters, videos, and/ or signs containing images to convey information. Communication through signage and graphical hazard symbols has been regulated in standards, but vast sections of HSE communication are bespoke communications and exist outside the sphere of standards. Effective HSE communication through images requires an understanding of the organizational culture in which the images will be used, as well as an understanding of the semiotics of the images themselves. Creative interpretation within HSE communication can create situations where the message that was received is not the message that was intended, leading to confusion and misinterpretation. This paper is aimed at elucidating the semiotics of South African HSE visual content. It was found that the indexical mode of images was most preferred in visual communication, and text-only designs the least preferred. Senders and receivers of messages differ in their opinions on the complexity of HSE communication.

Feb 2, 2021

By Fredrik Sarvell, Harald. Ihler, Veli-Matti Uotinen, Jukka Rantala

"Many of the valid international building codes state that the lateral support provided by the soil is sufficient to prevent buckling of fully embedded piles. However, the development of small diameter micropiles and especially the use of high strength steel have evolved to applications including high capacity elements. The ultimate structural load bearing capacity of a pile in a cohesive soil is decided by examining which gives the lowest value, the peak buckling load and the resisting moment provided by the surrounding soil medium or the structural capacity of the pile cross section. In both cases, the initial deflection of the pile is a significant factor when the axial load bearing capacity of the pile is determined. Steel micropiles are joined commonly with mechanical splices. A less rigid mechanical splice is often a weaker hinge that allows the pile to bend and deflect more during installation increasing the initial deflection of a pile. In addition the less rigid splice element decreases the bending capacity of a jointed pile section and the ultimate axial load capacity of the entire pile. A series of FE analysis performed for various pile sizes suggest that the steel pipe piles including separate pile sections and mechanical splicing elements should have the combined bending stiffness of EIshaft = 0,75 × EIpile. This requirement yields to the buckling resistance of at least 96 % of the solid reference pile with the sameinitial eccentricity in similar soil conditions.IntroductionMany of the valid international building codes state that the lateral support provided by the soil is sufficient to prevent buckling of fully embedded piles. However, the development of small diameter micropiles and especially the use of high strength steel have evolved to applications including high capacity elements. The potential buckling of these very slender high capacity piles in soft soils may in many cases be the controlling design factor of the pile, especially with end bearing micropiles.A typical sequence of soil strata in Nordic countries, such as Norway, Finland and Sweden, constitutes of friction soil or dry crust clay on top of soft clay followed by till. This soil stratum often rests on solid bedrock of granite or gneiss. Conditions like these are suitable for slender end bearing piles subjected to buckling and especially steel pipe piles where most of the material is located at the edge of the cross section. Other reasons for using slender steel pipe piles are for example fast installation with minimal waste, efficient manufacturing and relatively well established design and execution procedures. Minimum quality criteria’s regarding splices for steel pipe piles are recommended to be set as national provisions to ensure quality and comparable procurements in foundation business."

Jan 1, 2014

By L. P. Teas

As sphalerite is such a common constituent of many types of ore, the present investigation was undertaken to determine what its relations are to the other minerals in the deposits, and also whether these are of any genetic significance. The data presented herewith were obtained from a mineralographic study of about 200 ore specimens from some 43 different localities, represented by suites of specimens in the Cornell University collection. These, grouped according to their genesis, were as follows: I. Contact-Metamorphic Deposits.-Silver City, N. M.; Kelly, N. M.; Silver Bell, Ariz.; Bingham, Utah; Agaguca, Michoacan, Mex.; Matehuala, Mex.; Sombreretti mine, Mex. II. Deep-Vein Zone Deposits.-Mineral, Louisa Co., Va.; Edwards, N. Y.; Chestnut Yard, Va.; Allah Cooper mine, Louisa Co., Va.; Globe, Ariz.; Moyie, B. C.; Rossland, B. C.; Broken Hill, N.S.W.; Weedon, Que.1 III. Intermediate-Vein Zone.-Park City, Utah; Leadville, Colo.; Butte, Mont.; Santa Barbara, Mex.; Red Cliff, Colo.; Burro Mountains, N. M.; Idaho Springs, Colo.; Blue River, Ore.; Rye, Colo.;1 Slocan district, B. C.; Freiberg, Ger.; Clausthal, Ger: IV. Shallow-Vein Zone.-Ouray, Colo.; Goldfield, Nev., Zacatecas, Mex.; Field, B. C.; Kapnik, Austria; Frontenac mine, Kingston, Ont. V. Meteoric Water Deposits.-Joplin, Mo.; Southwest, Wis.; Austinville, Va.; Crittenden County, Ky.; Ridgeburg, Pa.; Moresnet, Belgium. It is not supposed that the investigation of such a limited number of occurrences may warrant conclusive and universal generalizations, but the conclusions reached are believed to be reliable in so far as the specimens, that were examined are concerned.

Jan 11, 1917

By Pinnaduwa H. S. W. Kulatilake, Biao Shu

The intact rock properties and discontinuity properties for both Devonian Rodeo Creek (DRC) and Devonian Papovich (DP) rock formations that exist in the selected open-pit mine were determined from tests conducted on rock samples. Special survey equipment, which has a total station, laser scanner and a camera, was used to perform remote fracture mapping in the research area. From remote fracture mapping data, the fracture orientation, spacing and density were calculated using more refined procedures compared to what exist in the literature. Discontinuity orientation distributions obtained through remote fracture mapping agreed very well with the results of manual fracture mapping conducted by the mining company. The GSI rock quality system and Hoek-Brown failure criteria were used to estimate the rock mass properties combining the fracture mapping results with laboratory test results of intact rock samples. Fault properties and the DRC-DP contact properties were estimated based on the laboratory discontinuity test results. A geological model was built in a 3DEC model including all the major faults, DRC-DP contact and two stages of rock excavation. The built major discontinuity system of 44 faults in 3DEC with their real orientations, locations and three-dimensional extensions were validated successfully using the fault geometry data provided by the mining company using seven cross-sections. Numerical modeling was conducted to study the effect of boundary conditions and lateral stress ratio on the stability of the considered rock slope. For the considered section of the rock slope, the displacements obtained through stress boundary conditions seemed more realistic than those obtained through zero velocity boundary conditions (on all four lateral faces). Stable deformation distributions were obtained for k0 in the range of 0.4 to 0.7. Because the studied rock mass is quite stable, it seems that an appropriate range for k0 for this rock mass is between 0.4 and 0.7. The displacements occurred between July 2011 and July 2012 due to the nearby rock mass excavation that took place during the same period; they were compared between the field monitoring results available from the mining company and the predicted numerical modeling results and a good agreement was obtained. Overall, the successful simulation of the rock excavation during a certain time period indicated the possibility of using the procedure developed in this study to investigate rock slope stability with respect to expected future rock excavations in mine planning.

Jan 1, 2015

The sulphide ores of the principal lodes of the Boulder Mines are mainly composed of a schistose guess with a varying proportion of silica and lime, containing tellurides of gold, silver and mercury, associated with iron pyrites. It is a great difficultyto obtain pure and homogeneous samples of the tellurides for analysis, and from a number of tests made with excellent specimens it was found hardly possible to procure two to agree in analysis, the precious metals being found to be combinedwith tellurium in most varying proportions indeed, a close inspection of a partially crushed specimen will reveal, even to the naked eye, the various shades of colour characteristic...

Jan 1, 1901

By R. E. Lindstrom

The mineral bastnasite is utilized to describe alternate processes for the extraction and separation of the rare-earth elements by solvent extraction. The rare earths can be acid-leached directly or fused with NaOH before acid leaching. Cerium, the major constituent, can be recovered by fractional precipitation, fractional leaching, or solvent extraction with tri-nbutyl phosphate. The latter process is capable of producing 99.5-percent pure CeO2 at 98+ percent recovery. Lanthanum is subsequently recovered by fractional precipitation or solvent extraction with a nitrogen-based extractant. A 20-stage mixer-settler operation with a primary amine extractant results in a 95-percent pure La203 fraction at 96 percent recovery. Europium is amenable to extraction from most of the remaining rare earths with an organophosphate extractant. Selective stripping of the europium, followed by reductive precipitation, produces high-purity Eu203. Another possibility for europium purification involves the differential extraction of europium with an amine followed by a sub- sequent reducing strip. Separation of the remaining elements is more difficult but can be accomplished with amine or quaternary ammonium extracts. Typical separation factors achieved are 3. 8 for praseodymium-neodymium and 10. 5 for neodymium-samarium.

Jan 1, 1967

By J. A. Zimrner, R. J. Tirnko

The roles of main mine fans in underground mines are to induce airflow and continuously re- move hazardous gases and dust. While most larger mines use multiple fans to accomplish these tasks, many smaller mines employ only a single fan. This paper concentrates on those mines having only one fan to provide ventilation needs. If this fan should cease to function, it is likely that methane concentrations will in- crease in some areas of the mine. As a safety precaution, Federal Regulations require that personnel must be- gin evacuating the mine within fifteen minutes after fan stoppage. Powered haulage can be used to transport workers to the mine portal as long as travel is through areas where hazardous levels of methane are not expected. To determine where methane will accumulate along haulageways during a fan stoppage, air samples must be taken at specific areas and analyzed for hazardous gases. During this study, procedures were developed for measuring methane levels along the haulegeways that are used to exit a mine following stoppage of the main mine fan. Methane levels were measured in four different mines at selected underground locations during four planned fan stoppages. In these mines the measurements taken only at the specified locations showed that, if workers had used electrically powered haulage to exit the mine following a fan stoppage, the methane accumulated along haulageways during fan stoppages would not have significantly increased the risk of an ignition.

By J. Dong

"A “green” collector project has been initiated at Vale Base Metals Technology Development to replace xanthate. Bench and miniplant testwork showed comparable metallurgical results between xanthate and DTC (sodium dibutyl dithiocarbamate), a “greener” collector. During the first DTC plant trial, a strong interaction between the process water and DTC negatively impacted the metallurgy. The subsequent investigation showed that the quality of process water including suspended solids and dissolved metal ions had a significant impact on the performance with DTC, while less so with PAX. This paper explains these differences using UV spectrophotometry and batch flotation tests. INTRODUCTIONVale Base Metals is dedicated to sustainable mining and mineral processing. One of the key activities is to find a “greener” collector to replace xanthate (PAX: potassium amyl xanthate), which decomposes during storage and flotation causing CS2 emissions in the work place. As the most promising candidate, DTC (sodium dibutyl dithiocarbamate) was evaluated in the lab and miniplant (Dong & Xu, 2011). Consequently, a plant trial was conducted in the winter of 2010. However, the results were not as good as expected. The subsequent investigation showed that the quality of process water played a significant role in the metallurgical performance with DTC but less so with xanthate.From test work in 1996 and 1997, a series of batch tests were performed at Clarabelle Mill to investigate the winter/summer metallurgical shift with xanthate. As shown in Figure 1, the winter metallurgy was considerably worse than the summer metallurgy (Xu & Wilson, 2000). At 80% pentlandite recovery, the concentrate (Cu+Ni) grade was 21% in the winter and 26% in the summer. At 23% (Cu+Ni) concentrate grade, pentlandite recovery was 85% in the summer and 70% in the winter. In the summer, the process water is much cleaner, with very low concentrations of dissolved metals ions and suspended solids; while in the winter, the water is yellow and cloudy, with much higher suspended solids. Based on these results, it was concluded that the process water in winter has a detrimental impact on metallurgy."

Jan 1, 2012

By Deirdre Bradshaw, Cornelius Vos

"The detailed understanding of the variability in process performance parameters within an ore body forms a key aspect of ensuring that proper decisions are made with regards to the economic viability of that ore body. To gain this understanding, various tools have been developed over the years, of which the batch flotation test is the most well-known and applied technique for investigating the flotation separation of ores. In this paper, the Julius Kruttschnitt Mineral Separability Indicator (JKMSI) is put forward as a small-scale test, suitable for the characterization of the flotation separability of copper porphyry ores. It is demonstrated that the JKMSI can be a complementary technique to the batch flotation test, with the capability to further improve the knowledge of ore body variability. The response from this test has been shown to be sensitive to particle size and modal mineralogy, providing a critical link between flotation and upstream comminution activities. The trade-off between the fineness of grind and the recovery target can thus be evaluated to determine the minimum energy application required for optimal separation economics. The test is designed to utilize small sample quantities of various sizes, providing an opportunity to increase our understanding of ore variability through increased tests. This complements our ore body knowledge and combining this with efforts in comminution (Powell, 2013) provides a platform for extending the concept of flexible circuit design."

Jan 1, 2014

By G Hancock, A Kemp, I Taylor

The mine site is situated south east of Port Hedland in the Pilbara region of Western Australia. A detailed engineering design was undertaken for six irregularly shaped waste rock dumps at the site. The design was undertaken to ensure long-term stability of the dumps and optimise material movements for closure construction. The Watershed Erosion Prediction Program (WEPP) and SIBERIA landscape evolution modelling was undertaken for the landforms using regional and site-specific material characteristics to provide an indication of the maximum allowable slopes and corresponding slope lengths for long-term stability.The majority of the waste materials present in the waste rock dumps are considered likely to be subgrade banded iron formation (BIF) and chert, which is generally competent material. The presence of a large number of dolerite dyke swarms indicates appreciable volumes of dolerite were produced as waste from the pits. Geological records also indicate that the dolerite is logged as being heavily kaolinised in the geological logging, hence kaolinite is very likely to be present within the waste dumps on-site. This material has an elevated risk of being highly erodible/dispersive. Clays and shales are also likely to be present in the dumps and are considered to be less competent material (relative to the BIF/chert).The final design configuration of the largest existing ‘unplanned’ waste rock stockpile is compared to a hypothetical continuous ten degree outer embankment alternative. This paper will present a brief description of the alternatives for closure of three waste dumps in close proximity to each other and how the detailed design based on site-specific materials and conditions compare to an alternative approach blankly assuming that most materials will be erosionally stable at less than ten degrees.CITATION:Kemp, A, Taylor, I?and Hancock,?G,?2014. Landform design for Pilbara mine site – why plan and design waste rock dumps for closure based on site-specific conditions?, in Proceedings Life-of-Mine 2014 , pp 47–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Silvando Vieira dos Santos

O emprego de trabalho mecânico em ligas metálicas associado a aplicações de tratamentos térmicos estão entre os principais métodos para se conseguir alcançar aumento de resistência mecânica e manutenção de boa ductilidade. Este estudo busca avaliar a correlação entre deformação a frio, tratamento térmico, microestrutura e propriedades mecânicas da liga Ti35Nb2,5Sn. Para isso realizou-se laminação a frio empregando níveis de redução equivalentes a 70%, 80% e 90%. Em seguida, as amostras foram analisadas por meio das técnicas de microscopia ótica, difração de raios X e microdureza Vickers. Na sequência, tratamentos térmicos de envelhecimento foram aplicados em diferentes tempos para cada nível de deformação e os mesmos parâmetros foram avaliados. Observou-se significativo aumento de dureza após etapa de envelhecimento e as análises por metalografia e difração de raios X evidenciaram a presença de fases metaestáveis na matriz beta..

Oct 30, 2017

By K. Ihara, T. Yamaguchi, K. Matsumoto

"Al-Fe alloy sheets having layers with different strain components were produced by unlubricated hot rolling and the recrystallization texture formation during annealing was investigated in each layer. In this study, the strain component introduced by rolling was quantitatively evaluated by measuring degree of bending of an aluminum pin embedded in the sheet. The textures before and after annealing were investigated by the SEM-EBSD technique. It was clarified that, in the middle layer, where comparatively small shear strain was introduced, ß-fiber subgrains and cube {001}<100> oriented subgrains were formed before annealing, and cube oriented recrystallized grains grew after annealing. On the other hand, in the surface layer, where large additional shear strain was introduced, shear texture components and cube oriented subgrains were formed before annealing, and shear texture was retained even after annealing, while cube oriented subgrains did not grow and were encroached. It was suggested that introduced strain components influenced the recrystallization texture formation by inducing different distribution of the subgrain size, stored strain energy and orientation relationship with surroundings before annealing.INTRODUCTION The microstructure developed during the hot-rolling process of aluminum and aluminum alloys affect the mechanical properties of the final product sheets. Especially, the crystallographic orientation in the final product sheets affects the r- value and ears during deep drawing (Humphreys & Hatherly, 2004), then the texture control in the hot-rolling process is important. When the friction between the rolling roll and rolled sheet in the hot-rolling is large, both the rolling texture and recrystallization texture tend to be heterogeneous in the thickness direction. It is known in many rolled aluminum alloy sheets that the texture in the surface layer was different from that in the middle layer because of additional shear strain. It was reported that in the vicinity of the surface layer, where large additional shear strain was introduced, the shear texture <1 1 1>//ND and < 1 1 0> // RD which contain components of {1 1 1} <1 1 0> and {0 0 1} <1 1 0> developed during rolling, and the shear texture developed even after recrystallization annealing (Sakai et al., 2002). Particularly, it is thought that the <1 1 1> // ND texture contributes to improve the r-value and press formability (Inoue & Takasugi, 2007). Therefore, asymmetrical rolling and high friction rolling have been applied to improve formability of aluminum alloys by adding shear strain in the rolled sheets as deep as possible (Kamijo et al., 1972; Inoue et al., 2005). However, few researches have been focused on the microstructures and texture before annealing and thus, the detailed mechanism is still unclear how the texture after annealing is affected by the texture before annealing. In this study, the Al-Fe alloy of commercially pure aluminum was chosen as the first material to be studied in order to clarify the fundamental process of the recrystallization texture formation. The main purpose of this study is to clarify the effect of additional shear strain on the rolling and recrystallization textures in the hot-rolled sheets by analyzing the transition of microstructure and orientation distribution through recrystallization annealing."

Jan 1, 2018

By Chu E. Ho

This paper describes a case history involving the use of the Equivalent Driving Energy concept for evaluating timber piles that failed to achieve the termination criterion traditionally based on final driving resistance and minimum pile depth. It was assumed that a pile would be acceptable if the overall energy delivered during pile driving was at least equal to that of an ideal pile that achieved the design pile capacity established during an initial load test. The equivalent driving energy was determined by integrating the cumulative driving resistance profile over the embedded length of the pile within the founding soil strata. The required equivalent driving energy was calibrated using representative restrike PDA capacities of production piles as piling progressed. This approach enabled piles that failed to meet the original acceptance criterion to be re-evaluated, resulting in a significant reduction in the number of rejected piles that would otherwise have to be replaced.

By C. A. Herbert

WITHIN the past few years, considerable development has been made in the coal-mining industry in Illinois and Indiana and it is the purpose of the authors to record its most important phases. Perhaps the two most striking features are the entry into the producing fields of certain large consumers of coal and the magnitude of some of the new operations. Mines are now being equipped by the. Chicago & Northwestern R. R., the Chicago,. Burlington & Quincy R. R., the Standard Oil Co., of Indiana, and the Union Electric Light & Power Co. of St. Louis. Besides, the U. S. Steel Corpn. has increased its coal-mining activities by commencing operations on its large holdings northeast of Benton, Franklin Co., Ill. Until recent years, the supply of coal has commonly been adequate and prices have generally been favorable, especially to large consumers, as the magnitude of their purchases enabled them to obtain satisfactory quotations from producers. In fact, most consumers of coal have believed that they could buy their fuel more satisfactorily in the open market than they could produce it themselves. The entry of the United States into the war was accompanied by various disarrangements of industrial conditions, and a demand for coal in excess of the supply seemed likely to be experienced for an indefinite period. Under these circumstances it seemed that the greatest assurance of a supply of fuel was its production by the operation of mines. In the case of the Chicago & Northwestern R. R. and the U. S. Steel Corpn. the production of coal has been carried on for many years with satisfactory results, but the C. B. & Q. R. R., the Union Electric Light & Power Co. and the Standard Oil Co. of Indiana had not been producers of coal, at least in this district. Apparently the most impressive feature of the newest mines is their capacity, for in some cases it is planned that production shall be in the neighborhood of 1000 tons per hr. There are mine, now in this field having nearly that output, but these were not planned for such

Jan 9, 1919

Discussion of the paper of G. K. Burgess and J. J. Crowe, presented at the New York Meeting, October, 1913, and printed in Bulletin No. 82, October, 1913, pp. 2537 to 2591. HENRY M. Howe, New York, N. Y. :-I think we can hardly rate the importance of the entry of the Bureau of Standards into our field. There is no body in the world that is better fitted to undertake this work than that Bureau, and it is work which really calls for the aid of some national organization. The skill and care with which this work has been done speaks for itself. It is very striking that within a very few months the distinguished English investigator, Professor Carpenter, of whom I spoke before, thought that he had disproved the existence of beta iron by proving that the A2 retardation which Professor Burgess has now demonstrated did not occur. Dr. Burgess&apos;s demonstration of the existence of. this retardation makes the existence of beta iron very probable, in my opinion. Osmond used to call beta iron " decipuum." You knew of its existence as you know of the existence of certain planets, only by the perturbation which it caused. Certain phenomena could not be explained, except by assuming the existence of a third allotropic form, beta iron. The evidence that you got was always evasive and susceptible of other explanations, except that which we have to-day, which it seems to me is not capable of other explanation. Professor Carpenter proceeded in the same way that Dr. Burgess has, by taking the heating and cooling curves of exceedingly pure iron, and thought that he had shown that there was no thermal change, no absorption or evolution of heat at the supposed A2 point, and hence that the A2 point did not exist. This he did by a piece of reasoning which I think seems to most of us rather surprising. That is to say, if of ten witnesses, three have seen a thing and seven have not, the evidence of the seven who have not is set aside, and that of the three who have seen stands. In Dr. Carpenter&apos;s own experiments under certain conditions he found the A2 change, the heat evolution., under certain others he did not. That is like the three witnesses who saw and the seven who did not see. You can arrange your test so that this change will not become visible or so that it is masked. But though an existent change can be masked a non-existent one cannot be shown. So that the reasoning seemed to me wholly fallacious.

Jan 12, 1913

By M. Deutsch, E. González, M. Williams

"There is uncertainty in ultimate pit limits due to geologic variation and unpredictable economic landscapes. In this work we show how this uncertainty affects the ultimate pit and how it can be analyzed to improve the mine planning process. A stochastic framework using geostatistical simulation and parametric analysis is used to model the effects of geologic and economic variation on ultimate pit limits and overall project economics. This analysis is made possible by a new, highly efficient pit optimization implementation which can be automated and set up to calculate ultimate pits for hundreds of different scenarios in a matter of hours. Quantifying ultimate pit uncertainty early in the mine planning process allows mining engineers to make informed decisions regarding infrastructure placement, and to mitigate the possibility of incurring substantial costs relocating critical mine facilities. INTRODUCTION The mining industry is increasingly concerned with the effects of risk and uncertainty. Uncertain prices, unpredictable global markets, and unknown foreign exchange rates can alter the economic viability of a mining project in substantial ways. This economic uncertainty is compounded by geologic uncertainty. The extent and quality of any given deposit cannot be fully measured and is not known before consequential decisions must be made. These two sources of uncertainty are responsible for the majority of deviation between what happens during operation and what was initially planned. Understanding and explicitly quantifying this uncertainty will lead to better decision making and allow mining engineers and investors to be aware of what may occur. It is unrealistic to believe that one model, estimated from sparse measurements, is enough to capture both geologic and economic uncertainty and allow for optimal decisions. The entire breadth of uncertainty should be considered, as both upside and downside risks have large impacts on the investment potential and operational efficiency of mining projects. The workflow presented here uses Monte Carlo simulation and parametric analysis together to explicitly analyze the breadth of geologic and economic uncertainty as it applies to ultimate pit calculation and long range mine planning."

Jan 1, 2015

By F. Schreiter

"One method to increase the exploitation rate of a mine is the use of backfill with residual materials in exploited areas. The backfilled material is meant to support both, the walls of galleries and pillars as well as the roof of mining openings. With increasing depth, the exploitation rate diminishes fast, thus the application of backfill in order to change the layout of the mine is crucial for economic success. In result of using backfill, it is possible to change the layout of the working area with a higher ratio to excavated areas and less area occupied by pillars. Thus it is possible to boost the output of a mine by using backfill. Setting the criteria for the selection of the best possible materials and whose improvement, it is useful to know about their qualities and handicaps. The Mining Department at TU Bergakademie Freiberg is analyzing the parameters of residues from different processing methods, accrued in plants of different potash mines and blending different residues for optimization of material attributes. These were significantly characterized by basically parameters like the size and the distribution of different diameters of the grain material. INTRODUCTION The chair for underground mining methods at TU Bergakademie Freiberg is tasked with the sufficient and sustainable supply of economics with raw materials. The steady high demand, the rising prices and the finiteness of the deposits are reasons for the need of an optimized economic utilization of natural deposits, a continuous improvement of mining technics and technology. From an ecological and economical position the best possible utilization of the resources has to be achieved. Many mining operations are by reasons of the deposit not able to haul valuable minerals only, they have to haul a mixture of valuable minerals and waste rock. This hauled combination is given into the processing plant for separation and enrichment of the valuable mineral. The residuals of the processing are commonly dumped to a waste rock pile. For minimizing the size of such a waste rock pile and also minimizing the ecological footprint of a mining operation the only way is minimizing the quantity of accruing waste rock material. Both, optimization of economic utilization and also minimization of waste rock dumps can be realized in one by backfill with processing waste rock material in mined out areas. Especially in mines, mined by room and pillar method, smaller dimension of the pillars are sufficient for safety and stability. By the way less valuable minerals have to be leaved back in the mine and the mine outcome is increasing."

Jan 1, 2015

By J Guo, K Williams, S Caldwell, W Chen

Mining is increasingly occurring near or below the water table. This has led to a higher rate of handling problems associated with increased moisture and increased adhesion, which lead to a higher rate of blockage events within the materials handling chain. Typically, these ores and minerals are known as ‘wet and sticky materials’.Currently there is very limited knowledge and/or methodologies for effective design of efficient materials handling systems when it comes to handling wet and sticky materials. However, there is one major parameter that significantly affects handleability of a wet and sticky ore; namely, its moisture content. Flow property testing has shown that when moisture is reduced, the adhesive properties of the ore are also significantly reduced, thereby increasing ore flowability.The research embodied in this paper investigates the moisture reduction rate through a loose packed bed of iron ore using dry, ambient temperature airflow. A comparison of the predictive capabilities of a proposed drying model to data obtained from on-site experiments using iron ore fines is made. Building on an assumption made by Hukill (1954), a second term has been proposed to account for rewetting effects in the drying process. From this research, identification of improved moisture reduction approaches is envisaged.CITATION:Caldwell, S, Williams, K, Guo, J and Chen, W, 2017 Aeration induced moisture reduction of iron ore, in Proceedings Iron Ore 2017, pp 455–460 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Sergey Komarov, Manuela Diaz, Sano. Masamichi

"Mixing time, bubble behavior and absorption rate of gas injected into a liquid bath through rotary L-shaped lances have been studied by cold models with an effort to improve refining characteristics of metallurgical processes. Two kinds of the rotary lances were tested, namely the single-hole lance and the multi-hole lance. The effects of gas flow rate, bath depth and rotation speed were examined.It is found that when gas is injected through the rotary lances, the mixing intensity and the gas absorption rate are larger than that for the gas injection through stationary lances. The effect of rotation speed decreases as the bath depth and the gas flow rate increase.The multi-hole lance produces much smaller bubbles, which lead to an increase in the volumetric mass transfer coefficient by 3-4 times as compared with the single-hole lance. However, the effect of rotation speed is smaller for the multi-hole lance. The obtained results are explained in terms of the bubble coalescence and fragmentation, the rate of which depends on the departure bubble size and the power supplied to the liquid bath.IntroductionIn recent years, there has been a growing interest in the development of gas injector for metallurgical processes. The majority of the previous work was focused on modification to the injector design to improve mixing and to increase the of chemical reaction rate. These two goals can not be necessarily achieved by the same way. Bottom nozzles and stationary immersed top lances, which have been widely applied to steelmaking processes, are effective for the bath mixing, but have a limit to decrease in the bubble size. This results from a vigorous coalescence occurring between the bubbles when they rise in the molten bath as a bubble swarm.One of the ways to ensure the small bubble size and the effective bath stirring is the gas purging through rotary injectors. A number of studies have been undertaken to improve the refining characteristics by using rotary injectors. All of them are related to aluminum refining. The SNIF equipment (The Spinning Nozzle Inert Flotation) has significantly improved the quality of aluminum products at National Luxemburg Aluminum [1]. Rotary injectors made in the form of a disc have been applied to the Alcoa 622 [2] and the GBF processes [3]. A study of the gas injection by a rotary impeller has been carried out by C. Leroy and G. Pignacelt [4]. All researchers note the significant improvement in removal of sodium, calcium, hydrogen and non-metallic inclusion."

Jan 1, 1996

By Frank C. Greene

Drilling in Missouri in 1943 continued at a lower rate than in 1942, only 28 wells being completed. Following the completion of the Cities Service Oil Company&apos;s No. I Jim Cook near Tarkio, in the northwest corner, NW. &apos;fi sec. 32, T. 65 N., R. 39, W., Atchison County, four dry holes were drilled by other parties, all a mile or more from the Cook well. Later the Cities Service Oil Co, completed No. 2 Cook for 60 bbl. Table I gives a summary of activities by counties. The total footage drilled was 23,83134 ft., of which 12,802 1/2 ft. was by cable tools and 11,029 by rotary. Four of the dry holes were drilled into Mississippian or older beds.

Jan 1, 1944