Search Documents

This work illustrates the potential of two welding processes for joining AA1100-16 vol.% B4C metal matrix composite: laser welding process using a 4 kW Nd:YAG laser and Friction Stir Welding. A comparison is made between these two welding techniques in terms of microstructure and mechanical properties of welded joints. A large amount of brittle needle-like phases, together with some residues of B4C particles were observed in the fusion zone of laser welded joints. The use of Ti filler can improve the microstructure and increase the joint efficiency from 63% to 75%. On the other hand, the friction stir welding process being a solid state welding technique is interesting as it avoids the formation of brittle intermetallic phases. In addition, the breakage of B4C particles and the grain refinement of the matrix were observed in the weld zone. Consequently, FSW joints show much better mechanical properties than laser welded joints. Up to 100% joint efficiency can be achieved by FSW for annealed AA1100-16 vol.% B4C materials.

Jan 1, 2011

By O. Hall

STOPING at Noranda" is a sequel to "Mining at Noranda". "Mining at Noranda", presented in 1937 (1), sketches Noranda's history, metallurgical problems, exploration, mining methods, mining details, pillar extraction, and costs. "Stoping at Noranda" deals in greater detail with our stoping, the use of sub-level drifts instead of benches, and the drilling out of the stopes with jointed rock drill steel and diamond drills. Sun-LEVEL DRIFT STOPING: Sub-level drift stoping is almost universal throughout the mine and is the standard sroping method in both sulphide ore and rhyolite flux ore. The features that have led to the adoption of this standard are: (1) Continuous symmetrical drilling in sub-level drifts with no delay for blasting. (2) Large-tonnage blasts Saturday night after the drillers have left. (3) Comparative freedom from gas and smoke during the working days. ( 4) The daily safety achieved by having all stope drilling done in drifts. (5) The safety and security achieved by drilling out stopes, floors, and pillars before there is any weighting or cracking.

Jan 1, 1939

By Michel Épiney, COREM, Mario Drapeau, Caroline Olsen, Claude Bolduc, Benoit Levasseur

"Several metal sulfide minerals (such as copper, zinc and iron), generally abundant in precious metal-containing ores, are known to dissolve during the cyanidation process. These unwanted reactions consume a significant amount of cyanide and oxygen, which is required for the extraction of gold and silver. Leaching kinetics of sulfide minerals are very fast in contact with oxygenated cyanide solutions. Therefore, the solution quickly becomes charged with oxidation products that are mostly metal ions, metallo-cyanide complexes, metal oxides and other sulfur species including thiocyanate, sulfides, polysulfides, thiosulfate, sulfites, sulfates, etc. COREM’s Extractive Metallurgy team has been conducting a research program on the improvement of the gold cyanidation process. As a part of this program, the current study aims to investigate the effect of certain operating parameters on the reactions involved during pre-oxidation and cyanidation. The effect of pre-treatment under ozone was investigated using an industrial pulp recreated from process water (charged with thiocyanates) and homogenized flotation tailings material from Agnico Eagle's LaRonde mine. In terms of mechanisms, the ozone treatment provides a complete deactivation of the material surface (characterized by EDTA extraction) and the solution (characterized by Ionic chromatography). This resulted in a lower reactivity of sulfide minerals that led to substantial gains in terms of consumption of cyanide and thiocyanate formation during the cyanidation process. The ozone-pre-treatment edges the classical pre-oxidation treatment (such as oxygen, hydrogen peroxides, etc) providing a quicker deactivation of the sulfide matrix and higher reagent savings in subsequent cyanidation process.INTRODUCTIONThe presence of sulfur in the process of gold leaching by cyanidation is a major drawback to optimizing the reagents consumption with suitable operating conditions. The coexistence of sulfide mineral species, such as pyrite, chalcopyrite, pyrrhotite or sphalerite along with the gold-bearing ore have, indeed, a negative impact on the extraction of precious metals by cyanidation (Bayat et al., 2003), (Azizi et al., 2010). These minerals are known to dissolve with cyanide under alkaline conditions and release in the slurry different kinds of sulfide by-products like polysulfides, thiosel, sulfite and sulfate (Seal II & Hammarstrom, 2003) (Breuer et al., 2008a), (Marsden & House, 2006) (Ghasemian Langeroudi et al., 2013). Once these sulfide by-products are released in solution they react with cyanide to form thiocyanate (Marsden & House, 2006) (Breuer et al., 2008b). The consequence of the dissolution of these cyanicides, is a significant increase in cyanide consumtpion as well as a slow-down of gold extraction."

Jan 1, 2016

By Christopher Andreae

Years before iron and steel works were established at Sydney, several thriving although short-lived iron works operated in Nova Scotia. These furnaces reflected the general nineteenth-century North American experience with iron works. At the beginning of the century, small furnaces struggled to supply local needs. Charcoal was the principal fuel and water powered most furnace equipment. By the end of the century, a few huge primary iron and steel works dominated production for Nova Scotia and the rest of Canada. Two sites achieved prominence in the nineteenthcentury Nova Scotia iron industry: Londonderry and Ferrona (Fig. 1). Londonderry, the larger and longerlasting of the two sites, is today a small village on the south flank of the Cobequid Mountains, about 30 km west of Truro. Prior to the establishment of an iron works in 1849, no community existed. At the peak of operation in the 1880s, however, over 2600 people were located there. The second site, Ferrona, today is a mere crossroads on the map, about 10 km south of New Glasgow. Following the construction of a blast furnace there in 1892, a small village grew up around the furnace. But once the furnace was blown out in 1904, the population gradually drifted away.

Jan 1, 1999

By Aidan Giblett, Michael McGlynn, Peter Radziszewski

"On the basis that 99% of the energy input into a mill is converted into heat, it is possible to estimate the amount of energy captured in the slurry, the amount that is lost to the environment as well as the possible means to reduce such losses. As a result it becomes possible to estimate the potential amount of energy that can be captured by technologies such as thermoelectric generators or even Sterling engines. Furthermore, it has been suggested that the energy recovery potential dry grinding circuit could be as high as twice that of wet grinding circuits.In this paper, the energy recovery potential of dry grinding will be explored by examining the case of the Newmont Carlin mine dry grinding circuit. The paper will open with a review of the energy recovery potential of a few wet grinding applications followed by a description of the dry grinding circuit and a definition of the control volume around that circuit. A thermodynamic model will be used to estimate the circuit discharge temperature and an estimate of any losses as well as provide an estimate of the potential impact of different means to reduce energy losses. The paper will close with a discussion of the assumptions used in model development."

Jan 1, 2016

By I. Ciabatti

Inorganic salts of hexavalent iron (ferrate (VI)) are versatile reagents for water and industrial effluent treatment because of the strong oxidising effect of the ferrate ion (FeO42-) and the well-known coagulation properties of the resulting ferric ion. Among other applications, ferrate can effectively remove arsenic, cyanide and phenols from industrial effluents. Furthermore, ferrate salts can be prepared from ferrous sulphate, a common byproduct of the steel and titanium industries, and possibly from other iron wastes. Notwithstanding their many potential advantages, the industrial-scale application of ferrate salts, such as potassium ferrate (K2FeO4), for effluent treatment has been hindered by the difficulties inherent in their synthesis and stabilisation. Within a project co-funded by the European Commission, the large-scale synthesis of stabilised potassium ferrate was realised through a new synthesis process, and different applications of the resulting ferrate to effluent and wastewater treatment are under investigation. This paper reports the results of the application of stabilised potassium ferrate for the purification of textile effluents. Laboratory and pilot-scale tests were carried out and the performance of the ferrate was compared to that of chemicals currently used in wastewater treatment. According to these experiments, potassium ferrate is a promising reagent for an effective treatment of textile and other industrial effluents.

Jan 1, 2006

By Jon A. Carlson, W. Scott Williams

The EKATI"" Diamond Mine commenced operation in October 1998. It is operated by BHP Diamonds Inc., which is a part of the Non-Ferrous and Industrial Materials Division of BHP Minerals, a business unit of BHP Company Ltd. of Melbourne, Australia. The EKATI"" Diamond Mine is a joint venture of BHP Diamonds Inc. (51%), Dia Met Minerals Ltd. (29%), Charles E. Fipke (10%) and Dr. Stewart L. Blusson (10%). In December 1993, an office was opened in Yellowknife, Northwest Territories specifically for the then Northwest Territories Diamonds Project (EKATI"" Diamond Mine) development. EKATI"" Diamond Mine is located 300 kilometres northeast of Yellowknife and 200 kilometres south of the Arctic Circle in the Northwest Territories of Canada (Figure 1 ). The site is located in a remote tundra area of continuous permafrost, north of the tree line, which is part of the Canadian Shield. Wekweti (Snare Lake), a Dogrib community approximately 180 kilometres southwest of the project, is the closest neighbour. The mining area and facilities lie within the 10 960 hectares land leases held by the joint venture. The total claim block (core zone and buffer zone joint ventures) covers 344 000 hectares. To date, more than one hundred kimberlite pipes have been identified within the claims. Five of these provide the basis for the present mine plan. Total capital investment in the project is over C$700 million. At full production employment will be about 600, including employees and long-term contractors, with over 33% being Aboriginal from the Northwest Territories.

Jan 1, 2001

By G. McIsaac

"This paper discusses the formulation of a linear program with the objective of maximizing the cash flow of the long-term plan of an underground operation. A mine is split into eleven independent ore zones, each characterized by its reserves, required development, and mining method. Based on practical considerations, maximum rates are set for each zone’s development and production capacity. For the total mine plan, a minimum daily production rate is set along with a minimum feed grade to the mill. A maximum daily development capacity is set based on the equipment and labour available. Proven and probable ore is mined preferentially over possible ore in the early years of the plan. Also, the fixed cost of operating the mine is taken into consideration whenever mining activities take place.Once the linear program is solved, it can be critically reviewed, and unrealistic results can be identified. Some resource allocations constraints can then be changed in certain sectors, and new results can be analyzed. “Whatif” scenarios can also be examined, such as determining the impact of hiring a contractor to develop a given sector, or dropping an ore zone completely from the plan."

Jan 1, 2005

By G. McIsaac

This paper discusses the formulation of a linear program with the objective of maximizing the cash flow of the long-term plan of an underground operation. A mine is split into eleven independent ore zones, each characterized by its reserves, required development, and mining method. Based on practical considerations, maximum rates are set for each zone?s development and production capacity. For the total mine plan, a minimum daily production rate is set along with a minimum feed grade to the mill. A maximum daily development capacity is set based on the equipment and labour available. Proven and probable ore is mined preferentially over possible ore in the early years of the plan. Also, the fixed cost of operating the mine is taken into consideration whenever mining activities take place. Once the linear program is solved, it can be critically reviewed, and unrealistic results can be identified. Some resource allocations constraints can then be changed in certain sectors, and new results can be analyzed. ?Whatif? scenarios can also be examined, such as determining the impact of hiring a contractor to develop a given sector, or dropping an ore zone completely from the plan.

Sep 1, 2005

By J. R. Foster

Investigations into the effect of a variety of acid digestions on common rock-forming minerals demonstrated a considerable variation in the proportion of the total metal extracted. A similar situation applies to the analysis of a number of common rock types. In addition, grain-size variation has an effect on the amount extracted by certain digestions. This work indicates that considerable care needs to be given to selecting an appropriate acid digestion capable of determining metal held in particular components of a sample. By using partial extraction techniques, the identification of certain patterns of metal distribution, undetectable by normal methods involving total metal analysis, may be achieved.

Jan 1, 1973

By Christina Graf

A synthesis of colloidal gold shell particles with a silica core is described. Small gold nanoclusters were attached to the functionalized surface of colloidal silica particles. Reductive growth and coalescence of these clusters lead to the formation of a closed gold layer. By variation of the thickness of this gold layer and the radius of the shell it is possible to adjust the plasmon resonance of the gold shell particles over the whole visible and infrared region of the spectrum. The optical properties of the particles made are in good agreement with theoretical calculations for coreshell particles. Due to their low polydispersity these gold shell particles form in solution large crystals with submicron lattice constants. It is also possible to produce hollow gold shells by dissolution of the silica core. A new method to coat the silica core gold shell particles with an additional outer silica shell is also presented. This allows due to a reduction in the Van-der-Waals forces to make more permanent dried crystals and facilitates functionalization of the particles for use in various photonic applications.

Oct 1, 2003

By J. C. Bothan

A program to provide technical in-formation on the use of fuels in pyro-metallurgical processes, from the Canadian fuel viewpoint, was initiated about five years ago by a Canadian Institute of Mining and Metallurgy liaison grou1> composed of members from the Coal Research Committee of the Coal Division and the Iron and Steel Committee of the Metallurgy Division. This paper is another of a series prepared for this program. Previous papers included a review of pyrometallurgical processes of Canadian interest, a survey of ferrous processes relevant to the development of an integrated steel industry in western Canada and a survey of the fuel requirements of the non-ferrous metals industry in Canada. It is widely recognized among per-sons familiar with the Canadian coal industry that, because of the large resources of coking coal in western Canada, the

Jan 1, 1963

By M. Grenon

OBJECTIVE ?To link slope stability and financial assessment algorithms into a commercially available mine design software packages to provide integrated global pit optimization.

May 1, 2013

By P. R. A. Andrews

"Garnet occurs in schists and gneisses in all provinces of Canada, all mainly in Quebec and Ontario. There is currently a renewed interest in exploration for economic sources of garnet for abrasive applications because of the inherent dangers from exposure to ground silica from sandblasting operations.High-quality garnet is used for lapping and grinding of glass and ceramics; for coated and bonded products such as sandpaper and cloth; and abrasive wheels for grinding and finishing various metals, woods, rubber and plastics. Low-quality garnet is used for cleaning and conditioning aluminum and other soft mewls, particularly by aircraft manufactures. Garnet may be added to grouting cements for oil-well drilling applications, and it has also been used for low- to medium-level radiation shielding. Garnet has been studied extensively by CANMET and its predecessor, Mines Branch, between 1917 and 1990. Twenty-nine studies relating 10 various aspects of beneficiation are presented and a review of the more important studies is presented. The information includes mineralogy, beneficiation methods, product sizes and analyses."

Jan 1, 1995

By P. R. A. Andrews

"The sillimanite group minerals, kyanite, sillimanite and andalusite are identified as alumino-silicate minerals with the common chemical composition AIP3.Si02' so that each possesses similar physical properties. Kyanite is the most abundant mineral and mainly occurs in Quebec, Ontario and British Columbia; sillimanite occurs in Ontario and Manitoba; and andalusite in Nova Scotia. The main use for the sillimanite-group minerals is in refractory applications for the production of refractory bricks and shapes. In refractory applications, the main performance criterion is the relative percentage of mullite formed within the material during firing. This phase gives a greater degree of resistance to creep deformation and slag attack, and improves the ability of the refractory to withstand high temperatures under load. The beneficiation of refractory silicate minerals has been the subject of many investigations at CANMET, and the former Mines Branch. Eighteen kyanite, two sillimanite, and three andalusite evaluation studies were conducted between 1933 and 1987. A review of some of the more important studies is presented, which includes information concerning mineralogy, beneficiation methods and flotation data."

Jan 1, 1995

By Michel Ruel, Ali Soltanzadeh

This paper describes how to make advanced control choices when difficult processes need improvement. The decision-making process involves choosing between a rules-based approach and a model-based approach as well as weighing benefits and drawbacks, complexity and simplicity, investment and results. This paper will present briefly each solution: basic control, advanced regulatory control, model predictive control and expert systems such as fuzzy logic controllers and neural networks. Three examples are presented: ARC (Advanced Regulatory Control) on pH in a comminution circuit, MPC (Model Predictive Control) for combustible management and FLC (Fuzzy Logic Control) on a Semi Autogenous Mill. The article then proposes a decision tree for selecting the most appropriate approach. A table will compare usage, development, commissioning, maintenance and lifecycle costs for each approach. Finally, conclusions and suggestions will summarize the methodology.

Jan 1, 2014

By H. R. Oliveira, C. R. Aragonez de Vasconcellos

Pipeline operation and maintenance necessarily involves geotechnical studies at points and areas with deflagrated instabilities or still to map and monitor areas prone to geotechnical problems. Landslides, erosions and debris flows are some examples of natural hazards, that not rarely, can bring high consequences to pipelines, sometimes leading them to high stresses levels and ruptures. Bolivia-Brazil Natural Gas Pipeline has 2.593 kilometers since Rio Grande City in Bolivia until Canoas City, in south Brazil. The pipeline crosses a lot of types of geological fields and difficult topography. The south spread of the pipeline has the most prone areas to geotechnical hazards because of its hard topography combined with the variety of geological materials, such as, colluvium deposits and debris flow areas. The aim of this paper is to present the right-of-way geotechnical risks that affect pipelines, presenting some practical remedial works done by TBG at Bolivia-Brazil Natural Gas Pipeline as well as the integrity plan and the adopted actions in way to prevent geotechnical accidents.

Jan 1, 2005

By Humphrey Dean

"Canadian mining companies now operate numerous Koepe-type friction hoists in a variety of different shafts, most of which have a depth in excess of 3,000 feet. Rope performance reliability is an absolutely essential ingredient of most installations and, for this to be provided, a more comprehensive understanding of rope reactions to applied stresses is required.It is the intent of this paper to illustrate for the operators the importance of the critical stresses encountered and to provide a maintenance program designed to circumvent potential difficulties."

Jan 1, 1970

By Ferri Hassani

Some future challenges ? People ? Shortages of HQP (e.g. engineers, scientists, geologists) ? Environment ? Regulatory standards - GHGs and air pollutants ? Mine waste management and rehabilitation ? Downstream processing (e.g., alternatives to cyanide) ? Climate change adaptation ? Lowering costs and improving productivity ? Energy efficiency ? Mine automation ? Health and safety ? Deep mining

May 1, 2008

By Jessica Hurst, Mark Holdsworth, Jeff McKay

"In 2002, Kennecott Utah Copper Copperton Concentrator installed an Expert Control system for optimization of their SAG and Ball milling circuits. The advanced process control has been well received and is utilized well over 95% of the time. In the years since, many lessons have been learned and many advances have been made. Improvements have produced millions of dollars of benefits and have included directly controlling feedrate with complex logic as opposed to using a bearing pressure controller, modifications to how sound is used for control, modifying logic for maximizing asset utilization and using advanced control for automating equipment restart. INTRODUCTIONRio Tinto’s Kennecott Copperton Concentrator produces copper, molybdenum, gold and silver. The mill has 4 SAG mills (SAG 1-3, 34 foot diameter and SAG 4 36 foot diameter), 8 ball mills and copper and molybdenum flotation plants, as seen in Figure 1. The 2010 average data is shown in Table 1.In 2002, a Metso Cisa OCS Expert Control system was installed at Copperton for SAG and Ball mill advanced control. The expert control was first placed on SAG 2; data from the first few weeks compared with operator performance indicated approximately an 11 percent increase in throughput. After full commissioning, the system was gradually refined further by plant personnel to develop key performance indices based on SAG feed size, refinement of the sound setpoint for control of mill speed and throughput, specific rules to help the adjustment of speed based on loss of a feeder, etc. With the addition of the pebble crushing circuit, the expert control began utilizing a model estimation of crushed pebble bin level to help stabilize the impact of returned crushed and uncrushed pebbles on the SAG mills. As the ore and limitations change, it is necessary to evolve the SAG logic to better handle any constraints."

Jan 1, 2012