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By M. Sahoo, P. Burke, Y. Fasoyinu, J. P. Thomson

The effects of grain refinement, mold temperature and chemical composition on the hot tearing resistance of aluminum alloys 535.0 and 206.0 has been studied by pouring constrained rod castings in metal molds. In addition, two prototype components that could be used in automotive applications were also poured from both alloys by gravity tilt-pour and low pressure permanent mold casting processes. This paper summarizes the results and issues encountered during the casting trials. It was shown that grain refinement and mold temperature ::::: 400°C reduced, and sometimes eliminated hot tear cracks in both alloys. The two prototype engineering components could be cast successfully from both alloys in metal molds. The metallurgical issues related to molten metal treatment and processing temperatures were well controlled. However, issues related to the control of hot tearing, casting and mold design must be addressed in future studies to guarantee the production of defect free castings.

Jan 1, 2006

By Oswaldo Delfim

Com o aumento da exportação do minério de ferro para os mercados asiáticos e consequentes novos parâmetros nas especificações, principalmente granulométricas para o minério com maior grau de pureza, viabilizaram-se importantes mudanças no processo produtivo, como por exemplo, a classificação do minério em sua umidade natural. Os ganhos adquiridos nesta nova condição de processo vão desde o aumento da recuperação mássica (de 90 a 95 para 100%), menor investimento no Capex e Opex, além dos ganhos na área ambiental como a eliminação da água na rota do processo e das barragens de rejeitos com consequente facilidade na obtenção do licenciamento ambiental. Neste artigo apresentamos os detalhes técnicos das condições dinâmicas ideais da peneira vibratória dedicada a esta nova aplicação.

Aug 16, 2017

By W. G. Sandell, L. C. Bauerle, K. C. Dean

"INTRODUCTION As a part of the wartime activities of the Bureau of Mines, metallurgical services were extended to other Government agncies engaged in purchasing and stock-piling some of the more critical and strategic materials. At the request of Dr. Alan M. Bateman, special representative of the Metals Reserve Company, metallurgical studies were made on three samples of oxide tin ore from, the States of Zacatecas and Guanajuato, Mexico. The samples were submitted for testing by A. Porraz of the Financiera Miners, S. A., institution Financiera, Edificio Guardiola, Despachos 500-507, Mexico, D. F.The samples as received were marked Nos. 1, 2, and 3 and described as follows:Sample 1. - Origin: Mining camp ""El Naranjo,"" municipality of Sombrerete, State of Zacatecas, Mexico. This sample was partly concentrated by washing and as received was all minus 10-mesh in size.Sample 2. - Origin: Deposits in Sierra. Fria and Juan Cherey, municipality, of Jerez,State of Zacatecas, Mexico. This sample represented run of-mine ore.Sample 3. - Origin: Mine ""La Frontere, "" Ranch of San Pedro del loya, State of Guanajuato, Mexico. This run-of-mine sample was low in tin content but came from a highly mineralized tin field."

Jun 1, 1947

By Shaw-Shong Liew

This paper presents the design concept using floating piles to support 2500Ton oil storage tanks on a very soft alluvial clayey soil of about 40m thick in Riau Province of Sumatra, Indonesia. The floating piles of various penetration lengths were designed to support seven numbers of such storage tanks seating on a 20m diameter and 500mm thick reinforced concrete (RC) circular raft. The pile points have been strategically located at the RC raft. Varying pile penetration lengths have been designed to minimize the angular distortion of the thin RC raft and the out-of-plane deflection at the tank edge. Vibrating wire strain gauges were installed at different levels inside the ø350mm prestressed reinforced concrete piles to measure the load transfer profile during the static load tests and water-loading test. The installation and interpretation of the instrumentation are described and discussed. Boreholes, in-situ tests like piezocones, vane shear tests and standard penetration tests, and laboratory testing were carried out to obtain geotechnical parameters for the pile designs. Static load tests were also carried out on the spun piles of varying lengths of 24m, 30m and 36m respectively. It has been demonstrated that the floating pile system can be a cost effective design to support heavy structures on very soft compressible deposits with satisfactory performance. Finally, the design concept validated with the results of instrumentation is discussed.

Jan 1, 2002

By Rafael Oliveira Sena

A SMS Siemag tem oferecido ao mercado brasileiro novas tecnologias para Lingotamento Contínuo de Placas com objetivo de aumento de desempenho dos equipamentos. A SMS Siemag tem desenvolvido e otimizado o processo de revestimento de placas de cobre do molde que utiliza em conjunto com o processo de eletrodeposição a tecnologia thermal spray que proporciona um produto com alta propriedade de resistência ao desgaste. O revestimento cerâmico, mais conhecido como UniGuardTM, tem obtido resultados excelentes no mercado da América do Norte atingindo valores superiores a 300.000 toneladas. A utilização do revestimento UniGuardTM proporciona um aumento de produtividade e redução dos custos de manutenção do molde bem como redução de aquisição de novas placas de cobre.

Jul 29, 2018

By K Lownie, R Sani, A Sianturi

Part of the PT Freeport Indonesia (PTFI) mine production is in the process of transitioning from the deep ore zone (DOZ) mine to the deep mill level zone (DMLZ) mine. The DMLZ mine is the next lift in the caving series and lies 500 m below the current DOZ footprint.In order to reduce the need for a very expensive additional ventilation system for the DMLZ mine, it was decided to reconfigure some infrastructure and upgrade the performance of the three existing DOZ mixed flow ventilation fans in situ, reducing the new fans required to two. This was far less costly than providing complete new installations.These fans are installed in individual underground chambers in DOZ mine exhaust drifts and connected to the DMLZ mine exhaust drifts system in 7 m × 7 m airways size, through sets of 6 m diameter by 500 m high raises.The upgrade process involved replacement of motors, fan shafts and bearings. The existing 1600 kW DOZ mixed flow fans are 3500 mm diameter and operate at a speed of 595 rev/min and were originally designed to deliver 390 m3/s at 3.3 kPa. Efficiency optimisation may be required at a later date.The upgraded DMLZ fans are required to deliver 425 m3/s at 3.7 kPa and it was necessary to increase in motor size and speed to 2200 kW at 710 rev/min. This paper will discuss the fan upgrade project and in particular the integration of an unusual ventilation system, which is based on the semi parallel operation of multiple large fans.CITATION:Sani, R, Sianturi, A and Lownie, K, 2017. Operation of deep mill level zone mixed flow fans after the first fan upgrade – a parallel fans case study, in Proceedings Australian Mine Vent Conference 2017, pp 285–292 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Jason M. Ryan

"Along with recent advances in computer technology have come cost-effective systems desiiedto evaluate fragmentation distributions through digital images of particles. In mining operations andmineral processing plants, important data from these systems is obtained through monitoring sizedistributions at key stages of the comminution process. Blast engineers apply this technology as atool for the validation of empirical fragmentation models so that predicted results are more meaningful."

Jan 1, 1998

By Finlay, J. S.

THE North Lily Mine started its career in an unusual way it was discovered by a geologist. The remarkable circumstance of driving a 2400-ft. drift into an unexplored country and "hitting her on the nose," indicates that geologists are sometimes numbered among those whom the Lord loves. Diamond- drilling from surface had previously shown the presence and position of the Ophir beds, and surface showings of pebble-dykes, faults, and bleached rhyolite indicated conditions similar to those at the Tintic Standard "Pot-hole." The discovery drift from the Tintic Stand- ard 700-level reached the North Lily orebody in January, 1926, and development and stoping were continued by Tintic Standard men and equipment until the North Lily shaft was sunk and put into service in May, 1928. The discovery drift was run on a cooperative basis by the Tintic Standard and North Lily mining com- panies. Finding the North Lily mine cost the North Lily company $26,000. The Tintic Standard Mining Co. furnished men and equipment to drive this discovery drift at a fraction of what it would have cost to find the orebody from surface. This was the beginning of the friendly cooperation that still exists. Through Tintic Standard ground the Tintic Standard paid two- thirds of the cost and the North Lily one-third; the cost of the drift through Eureka Lily, into North Lily ground, was paid by North Lily. Later, another drift from the Tintic Standard 900-level was run on the same plan, excepting that Eureka Lily paid its share of the cost; that is, the Eureka Lily paid one-third of the expense in Tintic Standard ground, and the Eureka Lily two-thirds and North Lily one-third in Eureka Lily ground. This 900-drift was driven by North Lily from the Eureka Lily line to near the North Lily west side-line. From this point the Chief Consolidated continued the drift well into Tintic Bullion ground.

Jan 1, 1929

By James P. Rider, Charles D. Taylor, Edward D. Thimons

Research was conducted to investigate how ventilation of a mining face is affected when scrubber flow is greater or less than intake flow. Tests were conducted in a full-scale surface test gallery built to simulate a mining entry with a continuous mining ma- chine at the face. Methane gas was released at constant flow at the mining face. Gas measurements taken at six locations near the face were used to evaluate how well the face was being ventilated. Increasing scrubber flow resulted in lower methane levels even when scrubber flow was much greater than intake flow.

By E. W. J. Thornton

During the past six or seven years extensive research has been performed on ore samples procured at the Bruns1,vick Tin Mines which is located in the south-west corner of New Brunswi.ck. This property was originally staked by Mount Pleasant Mines and they did considerable metallurgical and geological work on a small copper, zinc and tin deposit. In 1969, the property was obtained by the Sullivan Mining Group and after much geological and diamond drilling work, an entirely separate ore body \Vas located two miles south of the previous workings. The major economic metals in this ore zone are tungsten, bismuth and molybdenite, but many other metals exist as well. As the ore contains a host of different mineral species, it can be seen that considerable time WRS required to develop a practical flow sheet.

Jan 1, 1977

By Bryan Buchholz, N. Kumar Kittusamy

Previous studies indicate that operators of heavy construction equipment are afflicted by musculoskeletal injuries of the arms, shoulders, neck, and lower back. These injuries appear to be due to excessive periods of sitting (static posture), work intensity, whole-body vibration, high resistance levers, repetitive motions, and awkward postures. (2-5) Although numerous studies have shown an association between operation of heavy construction equipment and symptoms of musculoskeletal disorders, very little research has been performed that systematically characterizes operating engineers' exposure to ergonomic hazards. The objective of this study was to systematically characterize the ergonomic hazards associated with excavating operations. As such, the following were performed: (1) vibrations were measured at the operator/seat interface (X, Y, and Z axes), and at the floor of the cab (Z axis); (2) psychophysical ratings of whole-body vibration (WBV) level and overall seat design were obtained; and (3) postural assessments of the job were made. Methodology This study evaluated an inexperienced female operator performing excavation, utilizing two different pieces of equipment. The operator was 37 years old, 162 cm tall, and weighed 80 kg. She had approximately 15 hours of operation time (experience) on the equipment evaluated. The two pieces of equipment used were: a Case Super 580E (1986) backhoe/loader, and an Insley H-2000 excavator (1975) (see Figures 1 and 2). More evaluations were performed on the backhoe/loader than on the excavator. The following evaluations were performed on the Case equipment: 1) vibration levels at the seat and floor; 2) psychophysical ratings of the overall seat design and vibration levels (for the task duration, and for an 8 hour duration); and 3) postural assessments. For the Insley equipment, all of the evaluations were performed except vibration measurements. When the evaluations were conducted, the following environmental conditions were noted: the temperature was 31°F, and soil and terrain conditions were rough and frozen.

By Paul W. Johnson

A computer program for calculating capital and operating costs from material and energy requirements and equipment costs for use in preparing cost estimates for metallurgical process evaluations has been written by the Bureau of Mines' College Park process evaluation group. The program permits rapid recalculation of processing costs when changes of data or equipment are desired, and produces tables of capital and operating costs suitable for publication. Equipment cost summary tables for each process section end supplemental information for input-data checking is included in the computer printout. The program is written in Fortran IV except for several subroutines which are written in machine assembly language for the IBM 7094.3 With a few modifications, the program can be used on other computers.

Jan 1, 1969

By O. A. Bascur

The lack of integration of mining and metallurgical information with sufficient detail for analysis causes inefficient operation and hence sub-optimal energy and water use. It is difficult to analyze the performance of mining and metallurgical processes without an integrated view of mine transactions, stockpile inventories, process flows and assays. To take action requires real time information from manufacturing assets, corrected for gross errors from trucks, shovels, conveyors, faulty sensors, bad instrument calibration. This paper presents an infrastructure with advanced tools that sift through available data, identify and eliminate gross errors, and transform the data into business information for continuous improvement and optimization. Collaboration is a key component of improving efficiency of energy and water use, and the evolution of Web technology enables collaboration and troubleshooting of plant information to more quickly act on issues to reduce wasteful operation. Keywords: Mine Concentrator Optimization, Real Time Performance Management, Data Unification, Integration of Operational and Business systems, Mass and Energy Balances, Real Time Web Services, Equipment Availability, Efficiency.

Jan 1, 2009

By Jorge Beim

Helical Piles are increasingly being used to support and rehabilitate structures subjected to compressive axial loads. Traditionally, empirical correlations between installation torque and load capacity of helical screw piles are used as the field quality control. Load tests, however, are always recommended to validate the installation process and design methodology. This paper describes a test program performed on helical piles installed at the National Geotechnical Experimentation Site of the University of Massachusetts - Amherst campus (UMass-Amherst), well known for its deep varved clay deposit. Seven of these piles were submitted to Dynamic Load Tests using the Pile Driving Analyzer® (PDA), and also to Static Load Tests. Good agreements were obtained between the results of the dynamic and static load tests, encouraging the use of the former testing method as a viable alternative to the latter for determining the compressive load capacity of helical piles installed in cohesive soils. The results of the load tests were also compared to the predictions based on torque correlations, resulting in correlation coefficients which were higher than the ones traditionally used.

Jan 1, 2012

By Moi Arzamendi, Jose Ramirez, Kenneth Kniss, Sunil Arora, James Gingery

Construction of a new approach embankment for a railroad bridge over a river in Southern California required placing up to 12 ft of fill over soft to medium stiff silts and clays along an approximate 1,500-ft long stretch. The embankment, situated within a narrow railroad right-of-way between an existing live track and existing buildings, would have been susceptible to excessive settlement that could damage existing buildings and numerous underground utilities if regular weight soil fill had been placed over the unimproved ground. To limit total and differential static settlements to tolerable levels, a design was developed using a combination of mechanically stabilized earth wall with lightweight cellular concrete fill and rigid inclusions ground improvement. This paper describes the design of the ground improvement system, construction methods used, and challenges of working next to live railroad traffic. Ground improvement quality control and assurance measures, and verification of performance by settlement monitoring are also addressed. INTRODUCTION AND BACKGROUND The 0.9-mile San Diego River Double Track (SDRDT) project is located on the Los Angeles-San Diego- San Luis Obispo (LOSSAN) Corridor in San Diego, California. The project includes the replacement of the existing 900-ft long single track railroad bridge over the San Diego River with twin double track structures. Construction of the project is phased and closely coordinated with the associated Mid-Coast light rail project (San Diego Trolley Blue Line Extension). The new bridge is a 7-span, twin steel, through girder structure supported by six cast-in-place reinforced concrete pier caps and two abutments. The large diameter cast-in-drilled-hole (CIDH) foundations are up to 9 ft in diameter, with upper portions encased in a 1.5-in.-thick permanent steel casing. The north abutment approach embankment includes a mechanically stabilized earth (MSE) retaining wall up to approximately 10 ft high and 1,520 ft long. This paper focuses on the design and construction of the north approach embankment. The project site is characterized by challenging geotechnical and seismic conditions. The site contains liquefiable soils interbedded with soft cohesive soils, underlain by competent layers of sand/gravel/cobble and other sedimentary formations. Static settlement of the new railroad, crossing utilities and adjacent buildings was a primary design concern for the north approach embankment.

Jan 1, 2018

By Gabriel Esterhuizen

Underground stone mines in the United States make use of the room-and-pillar method of mining. A prerequisite for a safe working environment is that the pillars should adequately support the overburden and the pillar ribs and rooms should remain stable during mining. At present pillar dimensions are either based on experience at neighboring mines or on strength equations that were developed for metal or non-metal mines. This paper presents a pillar design methodology that was developed from a study of pillar performance in operating stone mines. Data were collected that describe the rock mass quality, pillar conditions, mining dimensions and intact rock strength. The results showed that current mining practices have resulted in generally stable pillar layouts with no recent cases of extensive pillar collapses. However, a small number of single failed or failing pillars were observed in otherwise stable layouts. Numerical analyses were used to supplement the observations and develop a pillar strength equation that describes the stable and small number of failed pillars observed. The developed strength equation can be used to design stable pillar layouts provided the factor of safety is greater than 1.8 and the width-to-height ratio of the pillars is greater than 0.8. The paper concludes with guidelines for applying the developed equation and selecting appropriate input parameters.

Jan 1, 2008

By André de Jager, Henk Ludik

Navachab Mine experiences difficulties with pit wall stability in certain areas of the mine. The main reason for the instability is the fact that the geology comprises many joints and faults. Blasting, without impacting negatively on the stability of the pit walls, poses a major challenge. The mine has installed a technologically advanced seismic monitoring system with monitoring sensors positioned at various locations and depths throughout the pit. The electronic data recording system records all relevant information on a continuous basis with early warning signals in cases of potential danger. From the information recorded by this micro-seismic system it was established that the energy release into the high-wall is predominantly influenced by the mining rate, water content and mining tempo and to a lesser extent by the blasting operations. To limit the negative effects of blast vibrations, the use of Electronic Delay Detonators (EDDs) was introduced. The optimal delays were determined through signature trace analysis. The vibrations obtained during blasts initiated by means of electronic delay detonators were monitored and compared to those traditionally obtained when standard pyrotechnic delay detonators had been used. The measured vibration data indicated an improvement of 25% to 100% drop in vibration amplitude compared. The accuracy and programmability of EDDs presented huge potential for blast optimization in terms of limiting the vibrations without compromising fragmentation. The whole project was conducted over a twelve week period with some 4000 EDDs. The average size of a blast was in the order of 350 holes using about 40kg explosives per hole, which equates to 14,000 kg explosives over 12 different blasts. The paper deals in detail with the blast optimization process with regard to: - determining the rock response time; - establishing the signature traces; - analyzing the wave interference patterns; - predicting the direction of constructive and destructive wave interferences; - optimizing of the inter-hole and inter-row delay periods; - measuring the ground vibrations. The results obtained during electronic blasting are compared to those obtained during pyrotechnic blasting. Comparisons are being made with regard to the following: - ground vibration measurements; - pit wall stability measurements; - blast safety.

Jan 1, 2006

By Jerry J. Ran

In open stope mining borehole deviation is one of the main factors affecting the blasting results. Though previous research has identified some actual deviation patterns, these studies are unable to relate the hole deviation pattern with the blasting results and therefore it is not possible to modify the design or take remedial measures based on the prediction of the blasting results. An alternative to the conventional method for borehole surveying is the in-hole probing techniques. With their inherent errors, it is important to evaluate these surveying systems under conditions of different mine sites. The lack of available assessment methods has limited the application of these techniques. In this paper some of the characteristics of the actual hole deviation pattern are discussed based on data from surveying production holes in six stopes. A method of predicting the blasting results is proposed by considering the borehole deviation pattern. Based on the prediction stope design can be modified or further surveying is carried out to improve the blasting results. The tolerable error is introduced to relate the surveying error with the drilling pattern and therefore it is possible to assess various in-hole-surveying techniques.

May 1, 2002

By Albert L. Toenges

[The i~ ortance o~ S3~e, fdequnt, nQ economical tr~n~po~t~t on 8ys~em Th~a bee~ e~~~~siz8d by the introduction of mechanical loading in co 1 mines, pa.rticula:c y \'r~ e::-e ~o?oile loaciine; ~ac~ine!;j rrre u .... ed. This papar i tr_e . eco:1d or' ?. ~eries deGcribi 1{) t:;'~~11>ort:ltion G stems et1-p oyed in mech3JlizeG. f!lincs. Progre,-s ?. epo~ t J...2.t deal t ~~tirel.: ,'Ii th the l:se of rail .laulagr £or c;atl:erine tran~ortc;tion, ailc, in t-!is paper 'Ii 11 be i acuss d c .icilY rub"col'-t? ro ~ t:tto::"ing as Ie _ as ani:naJ., con-",reyor, an ot.he~ systems of rnil gatheri?1.g. ~ho l)urpo~e of this invosti-gation is, as outlined in Progress ,~ort 1, to studT . Q analyz0 v rious systems nov.: in. u"'e El.I1d to derivQ cor..cl :cicn .... tllcrcfrom.]

Jan 1, 1941

By A. Taylor, J. Shelegey, H. Sullivan, J. Doucet

"Historically, performance at Vale’s Clarabelle Mill was measured by Mill throughput and Mill recovery. After the economic collapse in 2008, a series of reviews were performed to drive improvements in business efficiency. These identified that product quality (e.g., concentrate grade, variability in concentrate grade) had a profound impact on downstream processes and suggested that improved control of these parameters would generate the greatest value for the customer (the Copper Cliff Smelter) and the company (Vale). Consequently, a movement was initiated to transform the Mill operating philosophy to consider customer needs as paramount. Systems and strategies used to drive the transformation are described. In 2011, an unexpected furnace failure resulted in decreased capacity at the Copper Cliff Smelter. In response, a two-stage change in production strategy was developed at Clarabelle. The first stage was to modify the ore blend feeding Clarabelle so that the concentrate grade could be significantly increased with minimal impact on recovery. The second stage was a circuit modification to ensure the elevated concentrate grade could be sustained. Execution of the first stage was complete five days after the failure and the second stage was complete within 10 weeks. Steps involved in each stage are outlined and the overall benefits are presented.INTRODUCTION Clarabelle Mill is located in Copper Cliff, Ontario, Canada (approximately 350 km north of Toronto). The Mill treats copper (Cu) and nickel (Ni) sulphide ores. The primary diluents are pyrrhotite (Po) and non sulphide gangue rock (Rk). The process description of the circuits at Clarabelle is documented in the paper by Taylor, Doucet, Blanchette, Barrette & Lawson (2012) in this Proceedings and will not be repeated. The Mill treats ore containing Cu, Ni and platinum group elements (PGE’s) and produces two concentrates; a Cu concentrate and a bulk Cu/ Ni Concentrate (referred to as nickel concentrate). The Cu concentrate is sold to market while the Ni concentrate is thickened at the Mill and pumped to Vale’s smelter complex in Copper Cliff Ontario for further processing. Since commissioning in 1971, Clarabelle Mill has undergone many circuit changes to suit the changing needs and wants of our customers, both internal and external. The Mill processes ores of varying quality, based on mineralogy and size and until 2009 the Mill daily performance was primarily based on throughput. The second key performance indicator (KPI) of “good” or “bad” performance was quality of the concentrate and third; Mill metal recoveries. There were other plant level KPIs such as flotation feed grind size, slurry densities and mass flows to the separation circuit, but for the most part each day was good or bad depending on how many tons were processed through the Mill."

Jan 1, 2012