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By K. Sun, S. A. Argyropoulos

The assimilation and the exothermic behavior of Zn-Zr metallic powder compacts into molten aluminum was studied by measuring simultaneously the temperatures inside at the centerline of the compact, at its surface, and inside the molten aluminum bath, as well as the net downward force acting on the compact. In addition, the exothermic behavior of these compacts was also investigated in an argon protected atmosphere. The temperature rise inside the compact increases significantly with the mass ratio of zirconium in the compact and to a lesser degree with the aluminum bath temperature. Experimental results on the recovery of these compacts in molten aluminum will also be presented.

Jan 1, 2008

By G. Q. Zhou, H. C. Liang, X. D. Zhao

"This study describes the strain behavior in vertical shaft lining (VSL) embedded in thick soil deposits and its application in assessment of concrete deterioration. The observed strain in VSL continuously decreased companied by a sinusoidal fluctuation due to the influences derived from negative skin friction (NSF) and temperature. The increase in strain increment between peak and trough at each year and compressive strain level as the servicing time continued and VSL depth increased implies that the concrete strength was attenuated, and this attenuation was significantly dependent on the existing compressive strain level in VSL. The reliability of the proposed approach was validated by Schmidt Hammer Technique (SHT) – based concrete strength, and is applicable in concrete assessment and then fracturing prediction of VLSs in thick soil deposits.Concrete strength, Field monitoring, Strain behavior, Vertical shaft liningINTRODUCTIONOver 100 VSLs in Southeastern China subjected to an unpredictable fracturing as shown in Figure1, and there are over 1,000 VSLs embedded in thick alluvium su?ering from challenges of damaging and potential fracturing (Cheng, Yang, Zhou, Li, & Hu, 1993; Zhou, Cui, Lv, Huang, & Chen, 1999; Li & Li,2005). Therefore, a reliable assessment of these VSLs is significant to the normal servicing of mine shafts and the recycle of underground space when these mine shafts were closed.The continuous increasing of NSF induced by the drainage of water–saturated deposits well interpreted such extensive fracturing phenomenon, and it is universally regarded as the governing indicator to determine the VSL stabilization (Cheng et al., 1993; Zhou et al., 1999). Based on this recognition, the fracturing prediction and VSL strengthening according to the field monitoring on hydrogeological characteristics, servicing environments, and mechanical behaviors of VSL were carried out (Zhao, Zhou, Zhong, Zhu, & Liang, 2009; Liang et al., 2009; Xie, Lv, & Wu, 2014). As known, the compressive strain level in VSL and the in–situ strength of VSL concrete were the main factors to perform such fracturing prediction. However, the existing studies in literatures were limited to the strain accumulating or releasing behaviors (Zhao, Zhou, Zhao, Kuang, & Hu, 2017), and lack of considering the VSL concrete strength and its attenuation. In this reported study, the in–situ monitoring data on the strain in typical VSLs and the VSL elevations between 2004 and 2014 were initially analyzed. Then, an observed strain behaviors–based approach was developed to quantitatively evaluate the VSL concrete deterioration."

Jan 1, 2019

By L. Chunpongtong

Compared to equipment used in hard rock mines, the lifespan of equipment deployed in oil sands operations tends to be shortened due to the abrasive nature of the material and soft ground conditions in which it operates. One of the challenges of oil sands mine planning is to determine the most cost-effective replacement time for aging equipment. For cost engineers dealing with aging equipment, the options become an economic trade-off between taking the chance of higher frame failure or buying new equipment. Therefore, the ultimate question is: “When is the best time to replace the equipment?”

Jan 1, 2012

By Bill Charbonneau

Lumen, lm The measurement unit of light emitted by a light source 60W incandescent840 lumens 32W T8 linear fluorescent3200 lumens 54W T5HO linear fluorescent5000 lumens 400W metal halide24,000 lumens

Oct 1, 2010

By Ken Musgrave

"A program is described that helps managers and supervisors control maintenance more effectively. Work- order generation, preventive maintenance, repair parts inventory, planning and scheduling, reporting, analyzing costs, printing purchase orders and other functions are covered. Flexibility often permits integration with other programs such as payroll, cost accounting and materials management.The Role of MaintenanceMaintenance provides a service to allow the rest of the operation to do its job effectively. Its success should not be measured by maintenance cost alone, but also by its effectiveness in reducing downtime and maximizing production. It can make sense to spend more maintenance dollars if this results in an even greater contribution from increased production.The Cost of MaintenanceIn mining companies, maintenance costs can be as much as half of operating costs. Maintenance has generally not been given the management attention that an expenditure of this magnitude deserves."

Jan 1, 1986

By E. H. Kranck

Introduction Baffin Island is still too in-accessible to be of interest to the mining industry. However, twenty years ago few people dreamed of mining iron ?ore in Labrador. A journey by air to the most remote places in the Arctic is today no more remarkable than a trip to Europe, and the technical difficulties of mining minerals of high value are not insurmountable. Some ?observations concerning the geology and mineral possibilities of Baffin Island, the largest of the Arctic islands, may therefore interest the members of the Institute, in spite of problematic practical value of the subject. The following short account is mainly based on observations made during the Baird Expedition of the Arctic Institute of North America last summer 1950), and on information available from earlier expeditions. Early Work Baffin Island was one of the first parts of Canada to attract prospectors. Frobisher sent a shipload of rocks, which he believed contained precious metals, from Baffin Island to England. This attempt, however, was a failure and no further serious prospecting work has, so far as I know, been done. During the past few years geological mapping has been carried out by the Geological Survey of Canada (Fortier. Davison, 1949-1950) in the southern parts ?of the island, along the coast of Hudson strait. In 1942, Weeks mapped the coast from Pangnirtung to the head of Cumberland fiord, and Netteling river up to Netteling lake. In the northern parts of the island, only scattered observations have been made ?by Bell, Watkins, Baird, and others.

Jan 1, 1951

By Timothy D. Dreger

In the spring of 2009, Suncor Energy Inc. technical personnel saw an opportunity to improve planning 0and mining of overburden material in order to address aggressive construction goals and increased mining complexity. By tying together current and historical equipment performance, geological model information, and material observation in the field new operating elevations for the shovels were developed. At the same time, methodology of recording and reporting overburden movement through the Modular Mining DISPATCH system was changed. The result of this first stage of improvements was an increase in construction-grade material available at the face. The personnel involved realized that other opportunities were available to build on the initial successes and establish processes that would stand up to attrition and experience levels. A cross-functional technical team was assembled to identify ways of further improving workflows around overburden mining. Some of the opportunities realized include greater alignment between planning, reporting and operations as well as development of reporting tools that help steward Mine Operations to the plan. All of which have resulted in Suncor meeting or beating its forecast overburden targets. The cross-functional technical team continues to seek out new and better ways of doing business so Suncor can continue to deliver on its commitment of outstanding performance and results.

May 1, 2011

An optimization process is described that can be systematically applied by mine planners to produce life-of-mine schedules aligned with their strategic targets, while maximizing the net present value of the mining operation. The software tool employed uses heuristics and an evolutionary algorithm to generate life-of-mine schedules of production and development activities. Generating such schedules is typically a very difficult task due to the large number of operational constraints that must be respected, and the vast number of alternative schedules; as a result the value of the mining operation can be compromised. With an expansion at Newmont?s Leeville mine in Nevada, the mine planners were given the task of producing feasible life-of-mine schedules with significantly increased production rates. Their initial efforts indicated that it would be a considerable challenge to generate such schedules in a timely manner. By systematically applying the proposed optimization process, the mine planners were able to generate optimized life-of-mine schedules with the desired production rate.

Aug 1, 2013

By Xiao Huang, Dongmei Wang, Prakash Patnaik

Further increase in gas turbine engine temperature necessitates continuous development and advancement to thermal barrier coatings. While tremendous effort has been devoted to developing new thermal barrier coating materials and processing methods in order to decrease the thermal conductivity, limited attention has been paid to radiative thermal transport through coatings. It is the purpose of this study to develop a new layered coating structure that can be used to effectively reduce the both radiative thermal transport as well as thermal conductivity, and to demonstrate the mechanism and effectiveness of the proposed multilayered structure. Mathematical modeling based on the multilayer quarterwave stack and simulation results are presented.

Jan 1, 2004

By Kenneth L. Graham

Horizontal directional drilling from existing underground workings will greatly reduce, if not replace, surface exploration drilling. Diminishing ore reserves along with increasing difficulty in acquiring access and permitting of drilling surface holes requires a change in procedure. The length and direction of the required long holes is site specific, but once determined could be quickly mobilized. Data would be available for a much more timely evaluation without any surface disturbance and required reclamation issues. Preplanned directional drilling from underground will also provide an evaluation of already inconsistent uranium deposits located under surface terrain that is inaccessible to surface drilling.

Aug 1, 2010

By A. Diaz, Minera Los Pelambres, C. G. Salinas, G. Leinenweber, F. Diaz, D. Rojas, R. Bernal, O. Jimenez

"Los Pelambres Mine (MLP) is located in the IV Region of Chile, a semi-arid region where water plays a key role in operations as a scarce resource and is vital for the sustainability of human life, animals and ecosystem. The conventional flow meters installed on pipes at MLP can fail to provide an accurate measurement due to corrosion and/or fouling on the inner wall or presence of elements in the water such as acids, salts and suspended solids. Conventional flow measurement methods require the inner diameter to be known, however it is not always possible to assess its real value due to scaling, fouling, corrosion, etc. Here we present a novel methodology to solve these problems, which consists of the measurement of flow by a method that does not require the internal area of the pipes: the fluorescent tracer dilution method. In addition, the fluid velocity can be determined by the transit time of a radioactive tracer method. With the flow rate and velocity, the equivalent area is determined and thus the equivalent internal pipe diameter as well. This methodology was applied in a recirculation pump station, for mineral processing from the El Mauro tailings dam.This work demonstrated adequate correlation between measurements from fluorescent tracers and velocity measurements from radioactive tracers, both of which lead to the assessment of the internal diameter of pipes with scaling. The results of both methods disagree with the data provided by the flowmeter installed on the line due to its miscalibration. This information is useful in validating and correcting the information provided by online flowmeters of all water and solutions transport processes in filled pipes.INTRODUCTIONPresently, the need to optimize water resources is increasingly ever important, due to various reasons such as water scarcity, community empowerment, an increased use of water for mining processes and environmental considerations. Taking into account those main considerations, Los Pelambres Mine decided to focus on water conservation to avoid losses of this vital element. They decided to demonstrate that all of the systems that used water (flow meters, pipes, pumping stations, lagoons, etc) were in good condition and that no evitable loses of this important resource occurred. A plan was proposed to conduct a “hydraulic assessment” of fluid flux and water speed at different points and courses at the mine, with the purpose of obtaining hard data to support, verify and correct the information provided online from specific instrumentation dedicated to those purposes. The final goal was to manage the water resource basin in a sustainable way, based on cross-checked information. The chosen points are representative of the processes present in the mine, such as recirculating water stations at different operating conditions and surface water courses, where the fresh water capture systems operate."

Jan 1, 2016

By C. A. Pickles, K. Mackowiak

Black Thor chromite ore from the Ring of Fire deposit in Northern Ontario was carbothermically reduced in a microwave system to produce a ferrochromium alloy. The as-received ore contained 43.0% Cr2O3, 19.9% Fe2O3, 14.5% MgO, 13.4% Al2O3, and 7.0% SiO2. Activated charcoal was utilized as the reducing agent. Firstly, TGA/DTA and permittivity studies were carried out in order to determine the relationship between the reduction process and the microwave susceptibility. Secondly, microwave reduction experiments were performed on the chromite ore. The variables investigated were; the amount of carbon, processing time, input power and type of atmosphere. A maximum chromium grade of 76.1% and a chromium metallization of 82.7% were obtained for a processing time of 20 minutes, a power input of 800 W, and a carbon addition of 15% in an argon atmosphere.

Jan 1, 2017

By B. Farabi Khoshmehr

In the present study the effect of Silicate Sodium oxidation agent concentration and Plasma Electrolytic Oxidation (PEO) treatment time were investigated on properties of oxide layer on Aluminum alloy. The phase composition and surface morphology of PEO films were evaluated through x-ray diffraction (XRD) and scanning electron microscopy (SEM). Pin on Plate abrasive machine were used to investigate of were resistance of coating. The results showed that oxide layer which formed on Aluminum surface consist of high temperature a- Al?O? and ?- Al?O? phases. The diffraction peak intensity and percentage of these phases were increased by increasing silicate sodium concentration. Microscopic studies revealed a porous surface for PEO coating. This was affected by silicate sodium concentration and oxidation time. The wear test results showed that the weight loss of PEO coating was reduced due to improvement of their wear resistance.

Oct 1, 2011

By Sadough vanini Ali

Charpy impact energy of functionally graded steels produced by electroslag remelting in crack divider configuration has been modeled in various strain rates. It has been well known that majority of materials indicate different behaviors under different strain rates and temperatures. Therefore, modifying the elastic-plastic model considering the effects of strain rates and temperature gives us an acceptable prediction of these composites behaviors in impact test. In this investigation, graded steel was divided in to several layers in which the layers have the same strains under the impact. Constitutive equation describing the flow stress variations as a function of strain rates and temperatures, have been used to express the stressstrain behavior of layers. The parameter values of constitutive equation determined for all the layers via using the boundary conditions based on composite graded behaviors which were the characterized ferrite, austenite, bainite and martensitte phases. Consequently by applying the rule of phase mixtures and ascribing the impact energy of each layer to the area of stress-strain curve of the same layer, the whole impact energy of composite is the sum of layers impact energy with considering the layers volume fraction.

Oct 1, 2011

By J. Starkey

A comminution circuit in recent history, is one of the most difficult parts of a mineral processing plant to design with confidence. It is usually the most costly part of a plant to build, and it can consume up to half or more of the energy used on a mine site. To suggest that comminution energy usage is sustainable in the long term is not possible at this time. What we have to choose from today, based on more than 50 years of experience, does include the best available technology, and the best way to design it. There is controversy in the industry as to how to properly approach the subject of comminution design, with many of the optional solutions requiring a level of training and expertise beyond the ability of a non-specialist engineer. Semi-autogenous grinding technology in particular, has not been properly appreciated because of many recent mistakes in its application and design, which have blurred the positive perception about what SAG technology is, how it can be used, and how it needs to be designed and built. In order to change this, mine owners and senior managers need to take responsibility for, and learn to understand the fundamental challenges that a comminution circuit poses to the project, to the design process, to the operators who use the equipment, and to the resulting metallurgy. This address is intended to summarize these challenges and offer fundamental engineering solutions, which are clear, specific and in a format which is directly applicable to the mining and mineral engineering community.

Jan 1, 2018

By S. A. Sadough vanini

In this paper, Stress-Strain-Temperature relations for Shape Memory Alloys are studied. Temperature effects on Shape Memory Alloys are different from those related to ordinary materials. In ordinary materials, elastic characteristics can be assumed to be constant in low temperature ranges, and only the deflection arising from temperature changes could be added to the elastic defection. As long as two phases of austenite and martensite could be present in Shape Memory Alloys simultaneously, elastic modulus follows temperature and temperature gradient. In continue a smart actuator is investigated considering a homogeneous cantilever beam. Beam bending is established by using shape memory wires. An initial strain is imposed to shape memory wires in a low temperature, and then, they are installed in the outer surface of the beam. Therefore, since the temperature is imposed in these wires and they cannot have free recovery strain, the compressive recovery stress will be produced in the outer surface. This will result in a deflection in axial direction of the beam. At first, beam deflection is calculated on the basis of theoretical relations and solving the relevant differential equations. Afterwards, experimental tests are performed on an elastomeric beam equipped with shape memory wires. When a voltage is applied, a temperature rise will occur in the wires; then, this temperature rise causes a deflection in the beam. Finally, the theoretical and experimental results? comparison indicates a good conformity. One capability of this actuator is its high flexibility, and by controlling the inlet current, the end-beam deflection can be controlled.

Oct 1, 2011

By I. B. Lambert

The guide has been developed by officials from resources and environment agencies in the Australian Government and the South Australian and Northern Territory Governments. It elaborates on the Australian Government?s policy that new uranium mines are to be approved subject to world best practice environmental and safety standards. The guide outlines the best practice principles and approaches that apply generally to mining in Australia, before giving more detailed consideration to best practice environmental protection and regulation for ISR mining.

Aug 1, 2010

By Helmer Kraemer

One of the CIM 2003 conference themes is ?Globalization and the impact on mine operations?. In this context, the first official version of the new ?International Rock Excavation Data Exchange Standard? (IREDES) is being released. This new standard is a highly flexible data interface for exchange of information between production equipment and central computer systems. The standard was defined by global players in the mining industry and will soon be used to enhance local operations of global mining companies. Beside the standard definition now other aspects are coming into focus: The question how to design and how to implement IREDES compliant data exchange in practice. Implementation of IREDES covers the following aspects: !" Implementation on in-field production systems !" Communication and networking !" Implementation on databases and commercial IT systems In-field production systems are characterized by a big variety of different automation systems. Therefor, different IREDES implementation philosophies have to apply to those systems. One philosophy uses an integrated IREDES compliant automation system on every machine. The alternative method uses one shared IREDES compliant ?Proxy server? for a number of machines connected to this server using proprietary interfaces. Communication and networking can be integrated openly and independently from hardware infrastructures. The only precondition is that communication and networking has to be Ethernet - TCP/IP protocol compatible. IREDES Implementation on the commercial IT level means to exchange IREDES data sets with databases, simulation software, office packages and special applications. Interfacing is easy as long as the software or the database system provides an interface to the Extensible Markup Language (XML).

May 1, 2003

By G. Tairova, J. Ioffe

Arsenic, selenium and mercury species are common contaminants in mining aqueous streams and present significant environmental and health problems. The objective of this project is to investigate methods to lower the concentrations of these elements in mining aqueous streams. A new composite media for removal of these elements of concern from mining effluents was developed. The results of bench scale and pilot plant experiments, using the media, indicated removal of arsenic, selenium, mercury and other elements of concern below detection limits.

Jan 1, 2014

By Adriana Ramirez, Bradford C. Wesstrom, Blanca Olave

The Freeport McMoRan El Paso Copper Refinery optimizes electrolyte quality using a number of systems. The facility controls copper, arsenic, antimony and bismuth using electro-winning cells within the Tank House and Nickel Carbonate Plant Liberator Circuit (NCP). The NCP manages sulfuric acid content utilizing recycled electrolyte in the slimes autoclave as well as operation of the Acid Purification Unit, APU. The El Paso Refinery removes common sulfates using metal hydrolysis with sodium carbonate. Finally, a Mechanical Vapor Recompression, (MVR), at the water recovery plant removes sodium sulfate generated by the NCP. This paper will provide a summary of these operations. INTRODUCTION In the mid 1920’s Nichols Copper Company, in Laurel Hill, New York, recognized the need for a modern copper refining facility in the southwest. Because of the many railroad heads, affordable power and abundant labor supply, and the close proximity to regional copper smelters in Mexico, Arizona, and New Mexico, El Paso became the ideal location. In December 1928, ground was broken for the joint venture refinery between the Nichols Copper Company, Phelps Dodge, and the Calumet and Arizona Mining Company. In September 1930, Nichols Copper Company became a part of Phelps Dodge Corporation after a stock exchange. In July 1938, Nichols Division officially became Phelps Dodge Refining Corporation. In March 2007, Freeport McMoRan Copper & Gold acquired Phelps Dodge. Water is a precious commodity in the desert southwest, making conservation of this natural resource an important goal for the El Paso Operations. In the 1980’s, work on the treatment of slimes was improved through the use of pressure leaching of the refinery slimes using an autoclave. Due to the high tellurium content in the leached slimes solution, it was crucial to implement a method for its removal before the solution returns to the tank house electrolyte. A copper telluride cementation operation was installed for tellurium recovery and the ability for the recycle of the leachate and wash water to the refinery electrolyte. In October of 1997, ground was broken for the construction of the water recovery plant using an MVR to reuse process water, reducing water consumption by 25%. In 2002, electrolyte purification was further improved with the installation of an Acid Purification Unit, (APU) (Sheedy, Pajunen, & Wesstrom, 2007). The APU recycles 90% of the acids (both sulfuric and arsenic acids) back to the tank house electrolyte. The solution that passes through the APU is treated with soda ash to precipitate metals out of solution as carbonates and generates a sodium sulfate solution. This sodium sulfate solution is easily processed in the new water recovery plant, where the majority of the water recycles back into the plant as pure condensate. In 2012, the power plant at the refinery upgraded its Reverse Osmosis System to provide RO water to the tankhouse. This insured that the refinery would not have to bleed electrolyte for metals contained in well water such as: calcium, magnesium, iron and sodium chloride.

Jan 1, 2019