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By Morgan L. Race, Matthew R. Glisson

"Most driven pile projects have plumbness limits from 0.25 in/ft (21 mm/m) to 0.5 in/ft (42 mm/m) to control bending stresses. For two projects, the project teams performed static load testing to evaluate performance of piles with sweep. One project, located in Grand Forks, North Dakota, used 9.625-inch (244-mm) diameter piles with a wall thickness of 0.395 inch (10 mm) and lengths ranging from about 130 to 160 feet (40 to 49 m). Measured pile sweep (lateral offset distance of the pile toe from the pile top) was between 12 and 17 inches (305 to 432 mm). Static load testing indicated that the piles could support the design load with axial deflection of less than 1 inch (25 mm) but only provided about 80 to 90 percent of the ultimate resistance at axial deflections of about 1.9 to 1.7 inches (49 to 43 mm), respectively. The other project, located in Shakopee, Minnesota, used 9.625-inch (244-mm) diameter pile but with a wall thickness of 0.352 inch (9 mm) and lengths around 50 to 90 feet (15 to 27 m). The measured sweep varied between about 20 and 63 inches (508 and 1,600 mm) for 9 of 214 piles driven at the site. Load testing indicated that these piles could provide the required design resistance with less than 0.3 inch (8 mm) of axial deflection and support the required ultimate resistance with about 0.5 to 0.6 inch (13 to 15 mm) to of axial deflection.INTRODUCTIONAnyone who has observed a significant number of piles has seen that, inevitably, the pile is not perfectly straight after driving. In spite of the best efforts of contractors, there are a whole host of reasons for piles to end up out-of-plumb or to have a curve, sometimes referred to as pile sweep. Most project specifications set limits for plumbness typically between 0.25 in/ft (21mm/m) and 0.5 in/ft (42mm/m) (USACE, 1991; PDCA, 2007; MnDOT, 2016; MoDOT, 2016). Closed-end pipe piles, including monotube or tapertube, are the only pile type that allow actual measurement of the final alignment of the pile.As Nadeem, et al. (2015) note, buckling failure of long, slender piles is the predominant mode of pile failure in soft soils. Pile sweep is just one source of buckling failure in long, slender piles. The nonlinear buckling analysis showed that increasing slenderness ratio and/or increasing degree of curvature decreases the loadcarrying capacity of a driven pile. Nadeem, et al. (2015) considered solid, steel pile with lengths from 24 to 66 feet (7.5 to 20 m), diameters from 9.75 to 26 inches (244 to 660 mm), initial bends from 2 to 6 inches (50 to 150 mm), and half- and quarter-sine shapes."

Jan 1, 2017

Based on X-ray phase analysis and exploratory experiments, a new technology was developed to recycle multiple valuable elements in spent Al2O3-based catalyst. The experimental results showed that after roasting at 750°C for 30 minutes at an Na2O:Al2O3 mol ratio of 1.2, the leaching recoveries of alumina, vanadium and molybdenum from the spent catalyst were 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by barium hydroxide and barium aluminate. The precipitation recovery of vanadium and molybdenum was 94.8% and 92.6%, respectively. Al(OH)3 is prepared from sodium aluminate solution using the carbonation decomposition process. The purity of Al2O3 is 99.9% after calcinations, and the recovery of alumina can reach 90.6% in the whole process. The Ni-Co concentrate was leached with sulfuric acid, and a nickel recovery of 98.2% and a cobalt recovery of more than 98.5% were obtained under the experimental condition of 30% (w/w) H2SO4, 80°C, a liquid: solid ratio of 8:1 (by weight), a reaction time of 4 hours and a stirring rate of 800 rpm.

Jan 1, 2007

By Peter Wells, Adrian Sabau, Turgut Yalcin

"The nickel ores of Sudbury contain substantial amounts of the gangue mineral pyrrhotite (Fe7S&) which causes certain diflculties in the milling of these ores. This paper proposes a process called “magnetoflotation” as an effective means of dealing with pyrrhotite. The method reduces the pyrrhotite content of concentrates by applying a magneticjield on the path product as it leaves the flotation cell.Successful performance of magnetoflotation requires the optimization of several variables. In this study, three of the variables (air flowrate, collector concentration, pother concentration) were investigated by Box- Wilson experimental design, and others (magnet speed, grind size, pulp density, flotation time) were examined individually. The process was tested on a Falconbridge nickel ore, assaying 1.92% Ni, and under the best operating conditions, a concentrate was obtained with 13.56% Ni grade and 74.32% recovery in a single step. Further improvements to grade and recovery were possible by cleaning and scavenging. The same ore was also tested with conventional methods for comparison, and results indicated that magnetoflotation performed better.INTRODUCTION“Magnetoflotation” refers to the process of carrying out magnetic separation and flotation simultaneously within the same device, and is intended to prevent magnetic minerals from reporting to the froth products while non-magnetic minerals are being floated. Typical cases where this method might be beneficial include the processing of magnetite and nickel ores. Its use on magnetite ores has been reported elsewhere [Yalcin, 1992; Yalcin, 19931. This paper describes its application to nickel ores, more specifically to the nickel ore of Falconbridge Limited in Sudbury."

Jan 1, 1999

By F Linares, B De Waele, K Bischoff, M Lacorde, G Loveday

Recent exploration has identified the presence of detrital iron deposits (DIDs) associated with banded iron formation (BIF) units in the north-west of the Congo Craton, Gabon. The regional geology comprises a complex of granitoids and gneisses assigned to the Archaean Chaillu Complex, within which older slivers of lower amphibolite-grade greenstones are preserved including muscovite-biotite-garnet-bearing felsic schist, amphibolite and BIF. These units are typically overlain by several metres of residuum comprising colluvium, eluvium and duricrust. The residuum is overlain by a regionally extensive loess cover from 2 m to 10 m thick.The DIDs occur within the weathered residuum as mostly unconsolidated gravels with lesser canga (CAN) duricrust draped over deeply weathered hematite. Head grades are in the range of 45 to 52 per cent Fe. Fresh BIF, located from 30 to 50 m below surface, is comprised of magnetite-quartz±amphibole. The detrital iron gravels are comprised of rod- and plate-shaped clasts of hematite (martite)-maghemite-goethite composition, in a ferruginous sand to clay-sized matrix. The DID form ridges and plateaus that coincide with magnetic highs defined using high-resolution ground magnetic surveys.The field relations and petrography indicate that the detrital iron accumulations are the result of weathering (including enrichment) and erosion of primary BIF. This includes removal of quartz, further oxidation and re-cementation of BIF to form ferruginous caprock. This cap and the in situ oxidised BIF were subsequently disaggregated and liberated, and further weathered to form the detrital iron accumulations.Metallurgical test work on bulk detrital iron samples has shown this material can be upgraded to lump and fines iron ore products with grades of 62 to 65 per cent Fe using simple scrubbing and wet screening, followed by dense media separation of the -1 mm fraction, with overall mass yields from 75 to 85 per cent. The test work indicates a high ratio of lump to fines products, sometimes exceeding 50:50.CITATION:De Waele, B, Lacorde, M, Bischoff, K, Loveday, G and Linares, F, 2017. Geological and metallurgical characteristics of banded iron formation associated detrital iron mineralisation in Central West Africa, in Proceedings Iron Ore 2017, pp 259–268 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

Using mines in Canada, Boart Longyear, a leading provider of drilling services and products, has put its Stage 3 Coring Bit to the test and each time the bit has passed the test with great success. After more than a year in the field at a major mine operation in Sudbury, Canada, the Stage3 coring bit broke life records to become recognized as the most productive design in the industry. In addition to the proven advantage seen in regular bit life increases of as much as 300 percent in some cases, the design is quickly being recognized for its cost-saving operational impact. In Sudbury, the mine operation realized actual cash savings of more than C$45,000 within an eight-month period by making the switch to Stage3 bits. For years, the Sudbury Basin team has relied on the Alpha Extended Crown bit with the Express Waterway geometry option, ordering approximately 500 units per year. This 07 COM ECEX configuration performed well in medium-hard, non-abrasive to ultra-hard, non-abrasive formations with an average bit life of 150 m (490 ft). While satisfied with the performance of the Alpha Ex-tended Crown, the team agreed to put the new Alpha Stage3 to the test. Boart Longyear?s field engineers supplied five drill sites with Alpha Stage3 bits in a 07 COM configuration. After thoroughly testing the Stage3, the results were clear. Even with the well-known performance and versatility offered by the previously preferred configuration, the Stage3 set a new standard of bit performance. The new bit maintained its cutting edge for up to three times longer than the Alpha Extended Crown, a significant performance increase when compared to the 07 COM ECEX.

Jan 1, 2009

The applicability of borehole assaying techniques, both conventional and advanced, to orebody evaluation in the mining industry is reviewed and assessed, and the research, development, and demonstration programs necessary to apply the various logging techniques to mining are outlined. At present, the principal method of orebody evaluation in the mining industry is coring. However, coring is costly and time-consuming, and potentially great savings can be realized if all or part of d coring program is replaced by a borehole logging suite specialized to the needs of the particular mining industry. Using a set of 12 minerals, most of which are essential to the U. S. economy, an algorithm is presented for calculating the priority of developing suitable borehole assaying technology to replace all or part of the coring in each mineral industry, The priority is expressed in terms of dollars currently spent for that portion of present orebody evaluation techniques which may eventually be replaceable by in-situ assay techniques. The orebody assay requirements (grades, accuracies, etc.) of the 12 selected mineral industries, as determined from mining industry interviews and published literature, are compiled and represent performance criteria for borehole assaying instruments for the particular industry. Current logging techniques, applied chiefly in the petroleum industry, and advanced assay techniques which are or may be packageable for borehole use are evaluated to determine their performance characteristics. The performance characteristics of the various conventional and advanced techniques are then compared with the performance criteria in each of the 12 mineral industries in order to determine the potential benefit derivable from each technique. Finally, the benefit available from each technique, averaged over the 12 mineral industries, is compared with the cost of development of the technique, to determine the overall priority for investment in research to develop the technique for use in mining. The technology assessment and cost-benefit analysis shows neutron activation analysis in its various forms to have the highest priority for research and development as a borehole logging technique. Other techniques found to be promising include x-ray fluorescence, x-ray diffraction, photoluminescence (optical fluorescence), and infrared spectroscopy. Of the 12 industries considered in the study, those where the need for advanced borehole logging technology is greatest are uranium, copper, gold, and iron.

Jan 1, 1976

By E. R. Palowitch

Two samples of the Lower Hartshorne (Spadra) bed were collected: A sample of the raw coal with the machine cuttings excluded, and a sample of the machine cuttings exclusively. Analysis of the 5-inch by 200-mesh size fraction of the raw coal, excluding machine cuttings, showed that a product meeting minimum quality specifications could be produced by washing at 1.60 specific gravity, yielding a theoretical 93.7 percent of clean coal. A negligible amount of near-gravity material at the separation gravity indicated an easy washing problem. The sample of machine cuttings had a maximum size of 2 inches and contained about 50 percent ash. Washability tests of the 2-inch by 200-mesh size fraction indicated that a theoretical yield of 30.0 percent of specification-grade coal could be achieved by washing at 1.49 specific gravity. As the machine cuttings represent an estimated 10 percent of the total coal mined, their inclusion in the mine output would increase the theoretical net yield of salable coal by only 3.7 percent. Because the machine cuttings contained a high percentage of sink 1.80 specific-gravity material, they had neither an effect on the separating gravity required to clean the raw coal nor on the difficulty of separation. Gabbing underground versus transporting the cut-tings to the surface for disposal or washing either separately or combined with the raw coal involves a number of practical, economic; and intangible factors; hence, no specific recommendations could be made. A discussion of some of the factors involved in dealing with a similar problem is given by Gandrud and Riley.4

Jan 1, 1962

By M. Tangstad, B. Monsen, H. Midtgaard, R. Ishak, M. Syvertsen, I. Solheim

Charcoal is an interesting reducing agent because it is produced from growing wood which is renewable and does not contribute to global warming, provided that there is a balance between the felling of timber and growth of trees. In the biocarbon project the possibilities for using charcoal is investigated as well as other biological based and renewable reductants for ferroalloy production. The background for the project is that the Norwegian ferroalloy producers wish to contribute to reduction of CO2- emissions. This paper focuses on the use of charcoal instead of coke for the production of manganese alloys, and the consequences of doing so. Results from practical SiMn smelting experiments on a pilot scale have previously been reported, where only 12-14 % Si in the metal was obtained when charcoal was used. Recently we have attained satisfactory 18 %Si also for charcoal, but good results are indeed dependant on good furnace performance. There is no tradition for using charcoal for manganese production in Norway. A change from using mainly coke to the use of some charcoal will demand new routines for furnace operation, raw material and off-gas handling. Hence, characteristic properties of charcoal, which may cause change of furnace operation, have been measured and are compared to coke. The following results are presented: ?Thermal abrasion strength together with CO2- reactivity; important parameters for the performance of the upper part of the furnace. ?Coke-bed resistance; it will increase with the use of charcoal (a review of new results). ?Slag reactivity; a relevant method for testing slag reactivity of industrial reductants is of interest. The suggested method can serve for comparing slag reactivities towards graphite.

Jan 1, 2007

By J. E. Rourke, O&apos

This report incorporates a review of available dewatering technology and an evaluation of its relevance to surface coal mines in the Interior Province of the United States. Guidelines for the selection, design and construction of dewatering systems are included. On the basis of documented experience, candidate dewatering systems were selected and evaluated with respect to their anticipated impact on the environment and mine operations. Included in the discussion is a summary of laws and regulations which can impact on dewatering operations. Following this discussion, geologic and hydrogeologic conditions within the Interior Province are described and potential dewatering problems at surface coal mines are identified. Model mines are developed which exhibit the most difficult dewatering problems identified, and it is demonstrated how available technology can be utilized to deal with these problems. Dewatering of coarse-grained, high permeability terrace deposits might be economically feasible today. Low permeability, saturated glacial tills or lake deposits appear to be significantly outside present economic feasibility for dewatering.

Jan 1, 1979

By E. Concha

The concept of an Automated Continuous Explosive Excavation system (ACEE) for the underground mining applications of development drifting and room and pillar mining has been evaluated in comparison with conventional drill, blast and muck operations. The role and possible extent of application as this method was identified. The evaluation examined each element of existing and of proposed ACEE design concepts in a defined mine environment. Step by step procedures were developed to quantify the evaluation process where this appeared feasible. One conclusion drawn was that a system approach to ACEE design is not only feasible but attainable within the state of the art. Several preliminary design concepts were formulated and examined in order to determine what further research or development might be needed to realize them.

Jan 1, 1982

By Hou Shitao

With the development of Wuhan's city planning in China, new buildings of moderate and high store have been increasing day by day. Precast concrete piles or cast-in-site piles were used in the major foundations of the buildings. In process of their design and construction geotechnical engineers are concerned very much about practical bearing capacity and construction quality of pile foundations. In order to grasp accurately the cases static loading or vibration test is used generally to judge them. At present, the major questions in existence are that although a load is applied directly on pile and measured datums are reliable for static loading test, it must take a lot of work and longer time and engineering cost is higher. A vibration test has the advantages of which checking up of pile quality can be performed rapidly, the test is simple and convenient, and scope measured wide. But bigger error exists generally in measured datums. Therefore, it is nesessary to make vibration test on piles more perfect for pile foundation engineering. It is stated in paper that adapted technique of vibration test on piles is quite right in developmental direction sense for pile foundation. There are a great variety of vibration test methods on piles. A few of methods which often are adapted in practice can not meet the need of different practical engineering. It is also an important question whether the instruments of vibration test and relevant computer softewares make a response accurately for practical case. Different sequence of operation and technical requirements comes into being some influence directly on the test results. Meanwhile, different combination of soil stratigraphy, soil texture, groundwater and pile could cause different error of test datum. It is necessary to analyse and judge objectively the results of vibration test. Therefore, on the basis of developing and perfecting further the technique of vibration test, the applied technique of vibration test should be standardized so that better test results can be obtained.

Jan 1, 1991

By D. E. Pollock, J. A. Organiscak

Water sprays and water powered scrubbers have both been utilized in the mining and milling industry to suppress airborne dust. Unconfined water sprays operated at lower water pressures of ?689 kPa (?100 psig) can be very effective at wetting the mine product at the dust source and significantly reducing the amount of respirable dust that becomes airborne. However, unconfined waters sprays can be somewhat ineffective in actually removing airborne dust from the air. On the other hand, water powered scrubbers operating at higher water pressures of ?1,724 kPa (?250 psig) in physical enclosures or ducts have previously been demonstrated to be very effective in removing airborne dust from the air. These higher operating water pressures are uncommon in many mines and mills, so their use is limited. The National Institute for Occupational Safety and Health (NIOSH) recently investigated the performance of a lower-pressure, water powered inline series spray scrubber for removing localized airborne dust emitted at the source. Results showed noticeable improvements in airborne dust capture efficiency through the operation o f multiple inline series hollow cone spray nozzles within a round duct or pipe at the same water pressure as a single spray. Operating hollow cone spray(s) at higher water pressures noticeably improved airflow through the scrubber and yielded some additional scrubber efficiency improvements. Thus, in-line spray scrubber efficiency trade-offs were observed to be made by altering spray power components of water pressure and/or quantity (number of sprays). Results show that, on average, up to 0.23 and 0.32 m3/s (484 and 679 cu ft per min) of airflow at 0.81 and 0.69 dust capture efficiencies can be achieved with three 81° and 33°hollow cone inline series sprays, respectively, operating at 1,655 kPa (240 psig).

By J. W. Town

The Bureau of Mines determined the physical properties of southeastern Idaho phosphate fines as related to mineral composition, particle size and liberation, beneficiation, and potential use in structural clay products. The phosphate mineral in the fines was identified by unit-cell dimensions to be essentially the same as the phosphate mineral fluorapatite identified in the coarser sizes. The mean particle frequency as determined by electron-microscopy and pipet-analyses was between 0.5 and 0.2 micron. Liberation of the phosphate could not be definitely determined because of the weathered condition of the minerals and their extreme fineness. No beneficiation scheme was developed that would concentrate the phosphate into a marketable fertilizer product; therefore, forming and firing tests were made to demonstrate that the fines can be used to manufacture structural clay products.

Jan 1, 1968

In addressing the need for non-degree tertiary training, let us examine some recent reviews of engineering and geoscience education. The Finniston Report (1) criticised the formation of engineers in the UK and stated that this was largely due to the narrow British conception of engineering as a branch of applied science which militates against an effective marriage between theory and application. It also criticised the system for not giving students sufficient grounding in the synthesis of technical, human and financial considerations within their undergraduate courses. As we all know, this report has led to the restructuring of engineering education in the UK. More recently, a Review of the Discipline of Engineering was carried out in Australia by a committee chaired by Professor Sir Bruce Williams (2). The report stated that: Australia has a fairly good system of engineering education that should be made better. more should be done to develop the communication skills of both staff and students. more attention should be paid to changes in engineering practice and the human element in technology. there is a serious shortage of state of the art equipment in most engineering schools. female enrolments in engineering courses should be increased from the current level of about 7% to 20% by 1997. employers should develop a better understanding of the need for continuing education. staff in engineering schools should develop closer relations with employers of engineers. higher education institutions with engineering schools should give financial and other inducements to staff to increase the proportion of study leave or professional development leave spent working as engineers in the business sector. there is considerable room for improvements in the teaching process and in the development of evaluation schemes for assessing the teaching contributions of staff. In its recent report to the Council of the Institution of Engineers, Australia, the Task Force on Engineering Education(3) makes the following points: managerial, entrepreneurial, professional and interpersonal skills should be introduced and integrated into the undergraduate courses but studied in depth as part of continuing education. the continuing education policy of the Institution should be promoted and strengthened with all engineers required to pursue continuing education. the Institution should develop a comprehensive guide to continuing education available from universities, colleges and other public and private sector organisations.

Jan 1, 1989

By Dale S. Preece, J Paul Tidman, Stephen H. Chung

A discrete element computer program named DMC-BLAST (Distinct Motion code) has been under development since. 1987 for modeling rock blasting (Preece & Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions (2-D). DMC-BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993).

Jan 1, 1998

By W. Tom Witherspoon

Many Engineers are skeptical and cautious about skin friction factors for the portion of drilled piers where temporary casing is used. This has led Texas engineers in many cases to eliminate skin friction values for the cased section, which necessitates deepening the drilled shaft to compensate for the loss in the cased section. This paper has provided field test data that supports inclusion of skin friction in the temporarily cased hole section as a contributing factor in total axial capacity as comparable to open hole shafts of the same diameter. Reasons for the resultant friction values are provided including; remolding of the cased clay section and the increased pier circumference necessitated by the oversized casing required for adherence to the engineers shaft diameter specification.

Jan 1, 2009

The development of a robust belt sampling strategy and protocol inunderground gold mines is a fundamental requirement for effective grade quality control, ore accounting and mine-mill reconciliations. As part of the ore management system, a belt sampling system has been developed by the author, which is used to predict monthly gold grade and its error for underground/belt/mill reconciliation and grade control. This paper presents the step-by-step development of the belt samplingstrategy and sample preparation protocol at Target, an underground gold mine in South Africa. The belt sampling system at Target consists of an underground belt transporting run-of-mine material into an underground transfer point, a weightometer, a two stage crushing system, a tube splitter and a catchment device. The design allows run-of-mine ore on the belt to be sampled automatically by a go-belt sampler. GyÆs sampling theory of particulate materials forms the basicframework of the belt sampling strategy. The theory is used to quantify the optimum sample mass of broken material to be taken from the belt and to predict its reliability. It is also employed to determine the Fundamental Sampling Error (FSE), time interval between samples and particle size requirements of the final underground belt sample. Further, GyÆs sampling theory provides the means of analysing the crushing processes, splitting, segregation error, analytical variance, and the best sample preparation protocol. Although the belt sampling strategy developed in this study was forWitwaterstrand gold ore, the process is entirely general and may be very successfully used in any underground or surface mine.

Jan 1, 1999

By J. J. Gusek

There are hundreds of passive treatment systems accepting mining influenced water (MIW) throughout the world. Some systems do not perform to design expectations while others, including volunteer systems, have successfully operated relatively unattended for decades. The primary reasons for this situation include the common misconceptions that (1) a “cookbook” approach to design is valid for a wide array of MIW chemistries and site conditions, and (2) low maintenance means “no maintenance.” Passive treatment systems for MIW are typically manmade ecosystems that are designed to handle a specific range of metal loading conditions and MIW geochemistry. Thus, when design conditions are exceeded, the suite of microbial to macroscopic ecosystems may be slow to recover or mature. This should be no surprise to designers. But when a particular system fails, it may be inappropriately attributed to the technology, not the design. This paper presents a standard “phased” design protocol that appears to work and provides examples of sub-par performance of selected passive treatment systems.

Jan 1, 2002

By Jena Moshen

Underground Bulk Systems (UBS) technology has gained widespread application in tunneling and underground mining owing to its safety, reliability, increased Velocity of Detonation (VOD) and excellent results. However, its application in perimeter blasting is still limited and researchers are looking at ways of harnessing this technology for perimeter control. This simplifies the charging process by using one cost efficient product for charging both the perimeter and grid holes. This paper presents a case study on the application of underground bulk emulsion explosives for perimeter control blasting in underground room and pillar platinum mines. In order to achieve the required coupling ratios in the perimeter holes, the emulsion is loaded into specially formulated smaller diameter polyethylene (poly) pipes. The effectiveness of this method was evaluated using information obtained during routine blast audits and data supplied by the mines on half cast factors, over break and under break as well as analysis of data from Ground Penetrating Radar (GPR) Scans over a period of four years. This method of perimeter control, has given the platinum miners in Zimbabwe a competitive edge in cost effective perimeter charging and blasting by simplifying the previously costly deployment of traditional barrels and other decoupled cartridges. The method has been adopted by all the platinum mines in Zimbabwe as it has proven to be a cost effective alternative of controlling the perimeter walls, along with other key benefits that relate to safety, productivity and effectiveness.

Jan 1, 2018