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By Tedd E. Lister, Andre Anderko, Peiming Wang

Mobile electronic devices such as smart phones and tablets are a significant source of valuable metals that should be recycled. Value metals in phones are gold, palladium, silver, copper, cobalt and nickel. Devices now contain increasing amounts of rare earth elements (REE). Effective recycling schemes should include the recovery of these critical materials. Targeted recycling of items containing more of the less available critical materials could address their future criticality. This presentation will describe an electro-hydrometallurgy approach to efficient recycling of metals from scrap mobile electronics. The electrorecycling (ER) process generates oxidizing agents at an anode while reducing dissolved metals at the cathode. Development of the process involved generation of E vs pH diagrams, complemented with metals dissolution experiments used to assess the effectiveness of various solution chemistries. Although several schemes were envisioned, a two stage process has been the focus of work: 1) initial dissolution of Cu, Sn, Ag and magnet materials using Fe+3 generated in acidic sulfate and 2) final dissolution of Pd and Au using Cl2 generated in an HCl solution. Results from laboratory work will be discussed.

Jan 1, 2014

By Karol Kostúr

This paper briefly describes the current state of underground coal gasification (UCG) processes globally and in the Slovak Republic. Recent results of laboratory and technical tests are presented. In addition, on site measurements have added new knowledge of UCG technology. A series of laboratory tests based on physical models shows promise for managed UCG process control.

Aug 1, 2013

By E. Paransky, M. Rigaud, G. Paschek, S. Palco

Some of the negative impacts of carbon addition on the strength of castables are yet to be overcome in order to fulfill its potential benefits for oxidation resistance. This paper reports the results of recent studies conducted at CIREP on the effects of different types of carbon additives on the thermo-mechanical properties of magnesia-based castables. Experimental techniques included measurements of the hot modulus of rupture (HMOR), hot modulus of elasticity (HMOE), as well as the wedge-splitting test (WST). The comparison of evolving microstructures was carried out employing scanning electron microscopy with microanalysis attachment (SEM/EDS) and X-ray diffraction (XRD). HMOR values of 12 MPa at 1300°C have been reached in MgO-Si02-C castables containing up to 7% carbon.

Jan 1, 2004

By R. D. MacEchern, M. C. Rockwell

"This paper describes the research and tests carried out to recover the readily available barite from the tailings produced by the Nystone Chemical Ltd. operation at Debert, N.S. The tailings comprised 70-80% of the original feed and contained about 20-25% Baso4 .The objective of the research, undertaken during 1982, was to produce a barite concentrate which would meet the American Petroleum Institute (API) barite requirements for use in drilling mud. Samples from the tailings pond were examined and analysed to determine the tailings characteristics.Preliminary test work was performed on the tailings samples using a Haultain Superpanner, Wilfley tables and Humphrey's spirals. The grade of the barite concentrate retrieved did not satisfy the API barite requirements.The fineness of the tailings and the fact that approximately 80% of the barite was contained in the -200 mesh (0.074 mm) size fractions, indicated that flotation of barite from the tailings might be successful."

Jan 1, 1984

By Rodrigo Craig Cerello

The Brazilian economy has always presented a strong correlation with the mineral activity. Since colonization days, due to the territorial expansion caused by the explorers search for gold, mining in Brazil became a basic sector of national economy. Currently, the Brazilian mineral sector¹ estimates a 550% production increment (Figure 1A) in the last 10 years, reaching the US$ 50 billion value, reflecting the increased global demand for raw materials from mineral origin. According to the Brazilian Constitution², mineral resources belong to the Federal State and, consequently, their exploitation must be authorized, under penalty of engendering federal crime. Furthermore, activities of this nature are prone to cause environmental degradation such as, but not limited to, deforestation, pollution, soil deterioration and water contamination. The GPEMA represents the forensics group of the Brazilian Federal Police responsible for the technical analysis of traces related to crimes against the environment and consequently, illegal mining cases.

Aug 1, 2013

HIGH LAKE PROPERTY --HISTORYHISTORY -19501950??s ??Kennarctic Exploration discovers Exploration sulphides (A/B & (D Zones) at High Lake during helicopter reconnaissance exploration program.- -1991 93 Aber signs agreement to earn in to the High Lake Property from Kennecott. 63 holes drilled, primarily testing the known deposits. -2001 Wolfden purchases 100% interest in High Lake from Kennecott and Aber -2002 Wolfden performs helicopter borne TEM Survey over the High Lake Greenstone Belt. -2003 West Zone was discovered following UTEM & Gravity Surveys (performed by Teck Cominco ) over an airborne anomaly approx. 1km west of the known deposits. -2004 Wolfden awarded Bill Dennis Prospector of the Year

May 1, 2006

TIPS FOR SUCCESSFUL WASTE MANAGEMENT ? WASTE MANAGEMENT PLANS ? Define the question to be asked in waste characterization studies ? Calibrate assessments and designs with field conditions ? Ensure consistent with short, medium and long-term mine plans ? Design robust plans - goalposts and expectations will change ? Fully assess and integrate costs into economic models ? Integrate waste specialists into the feasibility and design teams ? Keep it simple and when you can?t, communicate it in simple terms ? PLAN EXECUTION ? Integrate the waste management plan into daily mine operations ? Identify the critical KPI?s , track them and set clear action triggers ? Know the difference between knowledge and data ?make sure you retain knowledge and document the important Maintain management, engineering and operational focus through the mine life

May 1, 2010

By Suzanne Paradis

Geographic distribution ? Deposit economics ? Temporal distribution ? Tectonic settings ? Basin architecture ? Morphology ? Ore-fluid chemistries Key exploration criteria

May 1, 2006

By Stephen Hardcastle

Personnel Heat Exposure Issues In Canada?s Deep Mechanized Mines ?Project developed in 2004 ?Base/precious metal industry identified heat stress/management as a major challenge affecting productivity and operating costs ?Project started in 2005 ?Current research nearing completion ?Guidelines, further data analysis and ?Communicating the Science? will continue into 2011

Oct 1, 2010

By Robert C. Lo

As tailings dams grow in physical size, their impact on public safety and the environment also increases in severity. Over the last three decades, tailings dam engineering has evolved from largely "trial-and-error" methods to a mature, multi-disciplinary engineering endeavour. This paper reviews the current practice of tailings disposal, and the evolution of tailings dam engineering. Key factors affecting dam integrity and examples of dam failures are then highlighted. Finally, the paper reviews some of the recent trends that lead to new challenges to the mining industry. These challenges include: coping with heightened public concern about dam safety; balancing potential conflict between seismic and environmental requirements; and addressing issues introduced by globalization of the mining industry. Institutional responses and technological tools available to meet these challenges are also outlined.

May 1, 2001

By W. D. Watson

"Early in mine development at Quintette Coal Limited major problems were encountered with the fleets of primary equipment which seriously hampered production. These major fleets (cable shovels, hydraulic shovels, hydraulic drills and electric trucks) have consequently been the focal point of maintenance efforts. Some were prototypes in the Canadian mining scene and brought with them new concerns to test their skills. The problems were studied and the category and areas which were having the greatest impact on the reliability of the equipment were determined. Once defined, priorities were established and a program was initiated which was designed to accomplish a resolution. Resulting from implementation of this systematic approach, over the past three and one-half years, the fleets are now giving good reliability and industry standard availabilities. Along with these significant achievements, cost per operating hour on some of the equipment fleets has decreased substantially and continue a downtrend through 1987. This paper identifies the problems and describes the resolutions. IntroductionIn the early years of the mine development, Quintette Coal Limited (QCL) experienced production shortfalls due to problems with the major excavator and haulage fleets. A large fleet of hydraulic excavators had been purchased, and QCL was among the first northern users of all hydraulic blasthole drills. They were also using some prototype equipment and encountered problems which were not common on other types of equipment or were unknown.Because of these unique problems and lack of experience from other mines to draw on, an analytical approach was taken to areas and associated causes of the delays affecting the availability and reliability of equipment. This was done by dividing the equipment downtime into seven classifications of delays, i.e. maintenance, electrical, hydraulic, mechanical, damage, service and preventative maintenance, and tires; and then each was expressed as a percentage of total downtime. Subsequently each of the delay classification was divided into categories e.g. electrical to six categories - wheel motors, main alternator, relays, cards, no propel, lighting and 24 V system. Then, the basis for further study had been established.From this preliminary analysis of historic records, it was possible to determine the areas which were causing the majority of the downtime. These areas were then analyzed to evaluate causes and to determine possible solutions to the problem s. This paper addresses the major fleets, their problems and eventual solutions. Plea se bear in mind that the over-all objectives were to increase physical availability and reliability."

Jan 1, 1988

By Felix D. Klebe

Efficient, high volume, mine load out operations have evolved in recent years to include more sophisticated control systems that integrate with mission critical equipment such as weighing systems. Traditional weighing systems often involve static weighment of individual railcars and either manual or serial transmission of scale data to a database application. In recent years integration of railcar or truck weight data into a loadout operation via direct PLC or Ethernet communication between the weighing terminal and the loadout control system has been realized. Furthermore, use of dynamic railcar weighing where railcars are automatically weighed while moving has increased productivity in a variety of mining applications.

May 1, 2008

By Y. Mitsuda, Y. Kayanuma, T. H. Okabe, M. Miyake

A new process to recover platinum group metals (PGMs) from automotive catalyst scrap using metal vapor was developed. To improve the efficiency of the acid dissolution process of PGMs, metal vapor of reactive elements such as magnesium or calcium were contacted with spent automotive catalyst. It was expected that metal vapor would react with metal selectively and form intermetallic compounds. The specimen of the spent catalyst was treated at 1173 K for 3 h, and it was then dissolved in aqua regia for 1 h to recover PGMs. After the reactive metal treatment, 88% of Pt, 81% of Pd, and 72% of Rh in the catalyst scrap was dissolved, while only 77% of Pt, 69% of Pd, and 38% of Rh was dissolved from untreated scraps.

Jan 1, 2004

By E. V. Manlapig, U. Erol, V. Ross, K. Tshimanga

Lonmin RoM ball mills are treating two types of feed ore produced by conventional mining and mechanised mining methods. It was reported that reduction in mill throughput was observed when treating the mechanised mining ore. Detailed grinding surveys were conducted for troubleshooting. Ore samples were collected for breakage characterisation using a JKRBT based on different particle density components. XRD analysis was conducted to investigate the association of minerals with density components. The plant surveys and the breakage characterisation tests all suggested that the two mining methods did not significantly affect either the ore breakage properties or the RoM mill performance. Instead, the mill discharge open area exerted a remarkable influence on mill throughput. The RoM ball mill operated at Lonmin K4 Concentrator has been proven to be a versatile mill that performed stably with variations in feed size distribution and feed ore changes by different mining techniques. The reasons are elucidated by the multi-component breakage characterisation and the plant surveys data.

Jan 1, 2012

By D. M. Bastidas

The reduction of copper sulfide and copper oxides originated during artificial tarnishing of copper was studied using potentiodynamic potential/current density experiments. Six copper surface treatments were considered: mechanical polishing; indoor exposure for 7 days; chemical etching in 1.6 M nitric acid; chemical etching and heating at 160°C; and chemical etching and dipping in a 9x10-4 M or 0.9 M potassium sulfide (1(25) solution at 70°C. Cuprite (Cu20) and chalcocite (Cu2S) were the main compounds formed. A linear relationship with the square root of the scan rate (v) was obtained by plotting the potentiodynamic potential/current density for the tarnish dissolution processes. A relationship between potential and current density cathodic peaks was not obtained, according to Müller's model, showing a proportionality factor with the dimensions of a resistance.

Jan 1, 2007

By P. D. Soares, H. R. Bullis, R. A. Hureau

"Echo Bay's Lupin Operation has produced more than 2.15 million ounces of gold since start-up in 1982. The mining method used to the£ present time has been longhole open stoping using trackless equipment. Because direct measurement of the open stopes has not been possible until recently determining the exact quantity of unplanned dilution in previously mined stopes has not been possible. Estimates of dilution hove been mode using comparisons between production tons and grades against ore reserve tons and grades.This paper discusses tracking of grade and tonnage measurements from reserve estimation through production. Comparisons between estimated and actual tons and grade are presented~ along with a brief description of methods used at the Lupin operation to control dilution."

Jan 1, 1994

By C. Y. Lim, H. W. Kim, M. S. Kim, J. H. Cho, Y. S. Lee

Al - 5.5 wt% Mg - 0.3 wt% Cu alloy strip was successfully fabricated by horizontal-type twinroll casting (TRC). For producing sound strips with no surface defect, the casting was conducted at various roll rotation speed, and the sound strip could be obtained at relatively low casting speed (3 rpm). The cast strip was homogenized at 450 °C for 10 hours, and then cold rolled with a reduction rate of 78%, followed by a final annealing at 450 °C for 1 hour. The annealed sheets showed good mechanical properties with approximately 330 MPa in tensile strength and 27 % in elongation, but exhibited strong anisotropy depending on the tensile directions. For the homogenized sheets, warm rolling was also conducted at 200, 300, and 400 °C. The tensile test results of the warm-rolled sheets showed that the rolling at medium temperature (300 °C) was proper to fabricate the sheets with relatively good mechanical properties and low anisotropy.

Jan 1, 2014

By P. R. Warner

This paper reviews the development of certain aspects of the electrical specifications of Anglo American?s suite of specifications for gearless mill drives (?GMDs?). These specifications are based on experiences in both Anglo American?s and others? operations, benchmarking against large hydro generators, the advice of industry and university experts, and continuous close co-operation with OEMs. To achieve a step change in availability additional final testing and electrical protection have been implemented, insulation requirements have been specified for machines to be operated at high altitude and clean area and access control systems have been developed.

Nov 1, 2011

By P. R. Warner

This paper reviews the development of certain aspects of the electrical specifications of Anglo American’s suite of specifications for gearless mill drives (“GMDs”). These specifications are based on experiences in both Anglo American’s and others’ operations, benchmarking against large hydro generators, the advice of industry and university experts, and continuous close co-operation with OEMs. To achieve a step change in availability additional final testing and electrical protection have been implemented, insulation requirements have been specified for machines to be operated at high altitude and clean area and access control systems have been developed.

Jan 1, 2012

By Maria Agostina Cinellu

Some aspects of the reactivity of the two different kinds of gold(III) oxo complexes [Au2(N,N)2(?-O)2][X]2 [N,N = 2,2'-bipyridine (bipy) (1), 6-alkyl-2,2'-bipyridine (bipyR) (2), R = Me a, CH2Me b, CHMe2 c, CMe3 d, CH2CMe3 e] and [Au2(C,N,N)2(?-O)][X]2 [HC,N,N = 6-benzyl-2,2'-bipyridine (bipyR') (3), R' = CHMeC6H5 a, CMe2C6H5 b] (X = BF4, PF6) have been studied. Treatment with water converts the unsubstituted bipyridine complex [Au2(bipy)2(?-O)2][PF6]2 (1) and the cyclometallated derivatives [Au2(C,N,N)2(?-O)][PF6]2 (3) into the water soluble monomeric hydroxo species [Au(bipy)(OH)2][PF6] (4) and [Au(C,N,N)(OH)][PF6] (5), respectively. These hydroxo species, likely the intermediates in the formation of the oxo complexes, are quantitatively reverted to the latter ones by reflux in anhydrous solvents. Both kinds of oxo complexes react with PPh3 to give OPPh3, the gold(I) complex [Au(PPh3)2][PF6] and the free bipyridine ligands. The reaction of the dioxo complexes [Au2(bipyR)2(?-O)2][PF6]2 (2a, 2b, 2c, 2e) with different alkenes gives the unprecedented alkene complexes [Au(bipyR)(?2-alkene)][PF6]. The styrene adduct [Au(bipyip)(?2- CH2=CHPh)][PF6] (7) (bipyip = 6-iso-propyl-2,2?-bipyridine c) has been characterized, inter alia, by X-ray diffraction analysis. Organic products arising from olefin oxidation are also found in the reaction mixture.

Oct 1, 2003