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By J. Convey, S. L. Gertsman

"THE EXPANSION of steel capacity is seldom spectacular. It may be for this reason that the remarkable progress made in Canada has not been generally recognized. In 1950, Canada's output of steel ingots amounted to 3,270,000 tons ( l ), which is a ll8 per cent increase over the tonnage produced in 1939. It can therefore be readily seen that Canada's growth curve for steel production is climbing at a rate paralleling her growth as a nation. It is by no means •an exaggeration of its importance to consider the steel industry as the cornerstone in the economic structure of Canada's manufacturing activities. From the humble diaper pin to the giant members of massive bridges, fortifications, and other steel structures, steel accompanies us as a necessary and inescapable companion in our journey through life. The Age of Steel has a literal meaning, and refinements in the manufacture of the products of steel are adapting it to more and more varied uses as time passes.The integrated iron and steel works of Canada fall into two natural geographical divisions. One has its base on the Great Lakes and draws its supply of •coal and some of its ore from the United States. In this division lie the works of the Algoma Steel Corporation, at Sault Ste. Marie, at the junction point of lakes Huron, Superior, and Michigan; and the works of The Steel Company of Canada, at Hamilton, on lake Ontario."

Jan 1, 1952

By P. Cheung, J. Gulyas, R. Clary

Over the past 50 years, the use of autoclaves in the metallurgical industry has evolved from final metal recovery (hydrogen reduction) and purification (sulphide precipitate oxidation) to treating whole ores and concentrates. Recent process developments, such as the use of autoclaves for laterite leaching, have necessitated higher temperature and pressure operations, which in turn have seen marked advancements in technology and manufacturing capabilities to keep in step with process demands. This paper will discuss the advances in technology in terms of design, materials and construction of autoclaves and liners, typical dip tube design and geometric layout. This paper will also address specific auxiliary equipment, such as acid and steam injection systems, and components, such as agitator seal systems.

Jan 1, 2004

The Autogenous milling of ores holds an increasing attraction as the focus moves towards reducing energy usage, both direct and embodied in grinding media. However, most of the early AG mills were converted to SAG for improved stability and increased throughput. This imposes a huge penalty in steel grinding media consumption. The LKAB iron ore operations in Sweden process highgrade magnetite through fully-autogenous milling lines to a final product P80 of about 45µm. The outcomes of P9O AMIRA research surveys, covering a wide range of mill fillings and throughputs and with different feed blends, are presented. Insights are provided on operational strategies, opportunities, the influence of feed size control and balancing the blend of competent gangue and softer magnetite. Areas of importance in the successful operation and control of energy-efficient autogenous circuits are highlighted.

Jan 1, 2012

By G. W. Govier

Measurements of the settling rates and the rheological behaviour of heavy media formed of fine suspensions in water of each of magnetite, ferrosilicon, and galena have been made. For media ranging from 1.6 to 2.8 specific gravity the settling measurements gave initial settling rates of from 0.5 to 0.01 ?cm. 'Per minute for magnetite; from 4.0 to 0.8 cm. per minute for galena; and from 35 to 1.6 cm. 'Per minute for ferrosilicon. These measurements indicate the ?relative stability of the suspensions and should be helpful in establishing the useful specific gravity range for each medium. Measurements of the consistency of the media were made with a Fann Model 35 rotational viscometer. Aibnormal or non-Newtonian behaviour was observed in the case of each media, the apparent viscosity being dependent upon the rate of shear or the intensity of motion. Measurements were made over the rate of shear range of 10? to 1,000 reciprocal seconds. The apparent viscosities of the magnetite media ranged from 450 down to 4?0 centipoise at 2.30 specific gravity, and from 2,450 down to 700 centipoise at 2.80 specific gravity. In the case of the galena media, the variation was from 40, through a minimum of 6, to 10 centipoise at 2.20 specific gravity, and from 950, through a minimum of 180, to 450 centipoise at 3.6 specific gravity. The ferrosilicon suspensions exhibited apparent viscosities ranging from 42, through a minimum of 5.6, to 9 centipoise at 1.9 specific gravity, and from 160, though a minimum of 35, to 85 centipoise at 2.8 specific gravity. The dependency of apparent viscosity or consistency upon intensity of motion is considered to be of particular significance in applications of heavy media where the medium is in rapid motion.

Jan 1, 1957

By R. M. Lauer

OVER THE YEARS concentration of the Sullivan ore has become progressively more difficult as the ore has become increasingly refractory. The introduction of new reagents and changes in the flow of the concentrator have been and continue to be necessary in order to maintain and improve the efficiency of metal extraction. Prior to the completion of the pilot mill in 1957 ail new ideas were developed in laboratory equipment. If these were found to be promising, there was no alternative but to introduce them directly to the main mill flow in one step. When a major change was involved there was always the possibility of serious losses while the mill was being adjusted to the changed conditions. It proved difficult to determine whether these losses were the result of the changed procedure or of failure to adjust the flow to a change in the condition of the ore during the test. The pilot mill has provided a valuable intermediate step between the laboratory and the mill. It avoids the losses which occurred when unsuccessful full-scale tests were attempted, and conversely it provides assurance that full-scale flow changes can be made without serious hazard.

Jan 1, 1960

By J. D. Bosman, L. J. Gardner

"The Bushveld Complex is a large layered igneous intrusion, located in the northern parts of the Republic of South Africa. The complex hosts the largest known reserves of Platinum Group Metals in the world. On the western limb of the complex, mining of the Merensky economic horizon and UG2 chromitite layer has been conducted for many years by several mining companies, including Impala Platinum Limited. Over the past decade, Impala has planned a new generation of greenfield vertical shafts, commencing with comprehensive geological and geotechnical studies. As part of the geotechnical studies, numerous tests have been conducted to quantify the mechanical properties of the various near-reef rock types. These tests include point load tests conducted in the field, as well as uni-axial compressive strength, triaxial compressive strength, and Brazilian disc tensile strength tests conducted in specialist laboratories. The authors have compiled an extensive database containing a large number of tests for different rock types, ranging from felsic Anorthosite to mafic Pegmatoid. The database was analysed to quantify the mechanical properties and values for Mohr Coulomb and Hoek Brown failure criteria for each rock type typically exposed by mining. The paper will provide a data set of rock mechanical properties typically used in numerical modelling and other design processes. Using the significant number of tests available, data describing the variability of the various parameters will be included."

Jan 1, 2015

By B. Voyzelle

The deterioration of highway and bridge infrastructure has received considerable attention in recent years because of the billions of dollars needed for repair and rehabilitation. A major factor contributing to this problem is the corrosion of steel reinforcement. Reinforcing steels with good corrosion resistance and relatively low price are therefore essential for maintenance, cost reduction and service-life extension of the steel-reinforced structures. This article describes the development of low-alloying steels that offers good corrosion resistance with reasonably low cost. Topics include steel microstructures, mechanical properties, corrosion performance, industrial applications and economic aspects.

Jan 1, 2005

By P. Amelunxen

It is well-known that the particle breakage mode that occurs in a semi-autogenous mill is significantly different from that which occurs in a ball mill, enough so to warrant very different lab scale breakage tests and scale-up models. This phenomenon, at the plant scale, leads to changing process constraints depending on the particular properties of the ore. For example, hard or coarse ores might bottleneck the SAG/AG mill throughput, while the ball mills might constrain throughput when milling soft or fine ores. Because the power draw of a ball mill is fairly constant compared to that of a SAG/AG mill, periods of SAG/AG mill bottlenecks lead to increased ball mill circuit specific energy consumption and a finer grinding circuit product size, which together constitute a loss of efficiency of the overall process. Because HPGR circuit throughput is less sensitive to changes in ore hardness, this situation is less common or severe in those circuits. Furthermore, the ball mills are somewhat decoupled from the upstream crushing circuits through the use of surge bins, which also helps to mitigate this effect. As a result, ore hardness variability constitutes a significant cost penalty that should be applied to SAG mill/ball mill/pebble crusher SABC circuits when evaluating the relative economics of different grinding circuit configurations. Nevertheless, the issue is by-and-large ignored, because most current HPGR trade-off studies are based on averaged ore hardness parameters. This paper provides an estimate of the magnitude of this penalty for a typical operation by using Monte Carlo simulation methods and plant data from Freeport-McMoRan?s autogenous, semi-autogenous, and HPGR-based comminution circuits. A case study from an in-house 96K t/d sulphide project is presented to illustrate the concept. It was found that by including variability effects, the trade-off NPV of the HPGR circuit over that of the SAG mill circuit increases to $84 million from negative $33 million, effectively reversing the original decision of selecting a SAG mill circuit for the fixed hardness case.

Jan 1, 2012

By Rick Coleman, Chelvan (Chevy) Veloo

"P.T. Freeport Indonesia's lrian Jaya Operation has been producing copper concentrate continuously since 1972. Numerous ore discoveries and five mill expansion programs have seen the initial milling rate of 7,200 MTPD escalate to the present rate of 125,000 MTPD, producing 2.5 million pounds of copper and 3,500 troy ounces of gold per day. The latest expansion, commissioned in February 1995, incorporates a 34 foot Semi- Autogenous Grinding (SAG) Mill, two 20'x30' Ball Mills, conventional roughing, cleaner column flotation, and attendant upgrades to the existing concentrate pumping and dewatering facilities. This paper will describe the SAG Plant flowsheet, and focus on the key training issues which contributed to a successful plant start-up.IntroductionP.T. Freeport Indonesia's operations in the Ertsberg mining district are located in the Jayawijaya Mountains of Irian Jaya, the easternmost province of the Republic of Indonesia. P.T. Freeport Indonesia (PTFI), the operator, is owned by Freeport MacMoRan Copper and Gold (81.3%), the Government of Indonesia (9.4%), and private Indonesian investors (9.4%). Geographical location, and sailing distances are provided on the attached location map.The operation stretches over 7 4 miles ( 114 km) from the dewatering and concentrate shipping facility at the Port of Amamapare on the Arafura Sea to the Grasberg open pit located at 3400m. The regional geology is covered in detail by Van Nort et al (1991 ), with current proven and probable reserves estimated at 1.13 billion metric tonnes grading 1.30% Copper, 1.42 ppm Gold, and 4.06 ppm Silver. The Grasberg open pit mining operation provides 92% of the mill feed, and is described in detail by Hickson (1991). The remainder of the mill feed is derived from several underground block caving operations. Current production rates provide a mine life in excess of 25 years. However, very favorable geology in the area leads to expectations that additional reserves will extend the life of the operation considerably."

Jan 1, 1996

By Peter M. Watt

The objective s of this paper are: (a ) to examine and discuss the burdens we place on our extractive industry; (b) to compare the levels of taxation in Canada with those in other countries; and ( c) to suggest certain broad parameters within which our taxation policies may be made more rational and stable. Among the burdens identified are taxation, the ownership and use of our resources, environmental issues and the rather emotional issue of so-called 'super profits'. Finally, the paper will address certain broad but key areas of policy which need attention and agreement if our tax system is to be made more rational. Such areas include: whether and if so why the extractive industry should be given incentives;. what circumstances, if any, justify a 'higher' than normal' level of taxation, and, ?if the concept of economic rents is a justifiable one, how might a basis for them be established which recognizes the fluctuating value of much of the industry's output. Note: The paper was written before the 1977 Federal and Provincial budgets were presented. Consequently, the paper does not reflect any changes proposed in these budgets.

Jan 1, 1977

By G. Tairova, M. Murchie, B. Esford, E. Lam

"The objective of this project is to investigate methods to lower the sulphate concentrations in the mill effluent. Currently, the concentration of sulphate in mill effluent is approximately 2 g/L. The high concentration of sulphate ion in the effluent has the potential to become a regulatory issue. The target sulphate concentration in mill effluent for this work was less than 500 mg/L. The pilot studies, using sulphate precipitation, were carried out at the mill. The results of the sulphate precipitation pilot study, using calcium hydroxide and sodium aluminate, indicated that:• The sulphate concentrations in effluent could be reduced to less than 500 mg/L.• The concentrations of most other elements of concern, such as selenium, arsenic, cobalt, nickel and vanadium, were also reduced.INTRODUCTIONHistorically, the concentration of sulphate, SO4 2-, in water has not generally been subject to regulation. However, with the increasing global consumption of water, stricter regulations on sulphate quantity may be imposed. Sulphate is a concern in process waters as it forms scale on process equipment and leads to operational problems. High sulphate concentrations may result in adverse health effects. The taste theshhold for the most sulphate salts in drinking water ranges from 250 to 500 mg/L.A literature search and review to identify methods to reduce sulphate concentration in the mill effluent was carried out. A number of methods were selected and tested in the lab. The experimental results indicated that the precipitation methods, using calcium hydroxide and aluminum compounds, barium compounds, as well as the ion exchange and the membrane methods, were effective for the removal of sulphate to below the required limits. Some other elements, such as vanadium, nickel, cobalt, selenium and molybdenum, were also removed.The process, using calcium hydroxide and aluminum compound for sulphate precipitation, similar to the Cost Effective Sulphate Removal (CESR), also known as “Walhalla” process, described in the Montana Tech report (“Demonstration Of Sulfate Removal” 1999), was selected for further consideration [1]. In the CESR process, the water is treated with lime for precipitation of gypsum, followed by the reaction with a proprietary aluminum compound for removal of a residual sulphate. The final pH adjustment is carried out using carbon dioxide. Results of a preliminary cost estimate indicated that the removal of sulphate using calcium hydroxide and aluminum compound was the preferred method of treatment, considering its low cost, availability of chemicals and minimal changes to the existing plant circuit."

Jan 1, 2012

By P. Dent

"Rare earth permanent magnets (REPM) have become virtually indispensible in hundreds of applications including aerospace, automotive, electronics, energy, medical and military. An understanding of REPMs is important since they are key drivers of demand for the overall rare earth sector. Rare earth permanent magnets stand out due to their superior magnetic properties of high induction and coercive force. We will discuss the past, current and future of the permanent magnet market and supply chain. We will summarize present and potential new nanocomposite and lower content or non rare earth magnet technologies and customer options which may mitigate rare earth usage.INTRODUCTIONRare earth permanent magnets are ubiquitous and often unseen critical components in many civilian, green energy and military technologies. They have become imbedded in applications such as hybrid electric vehicles, computer hard drives, direct-drive high power wind generators, audio speakers, motors, energy conversion systems, most weapons systems and hundreds of other uses. Several rare earth elements including neodymium, samarium, dysprosium, praseodymium, terbium and gadolinium are essential ingredients in production of the highest performance magnets available in the world today. They have enabled vast miniaturization and the significant increase in power density in hundreds of applications.China has become the dominant source of rare earth elements over the last two decades. Today, nearly 100 percent of the world’s rare earth metals and more than 95 percent of the rare earth oxides come from China. China’s near worldwide monopoly on the production of downstream materials such as rare earth oxides, metals and magnets severely impacts the supply chain in this growing global market. The past decade has seen an unmistakable trend toward increased dominance in raw material production and manufacturing by China, and a steep decline in U.S. production capabilities, most notably in the neodymium iron boron (Nd-Fe-B) market where there is currently no domestic production. This Chinese dominance is further demonstrated with over 65 percent of hard ferrite and roughly half of aluminum nickel cobalt (Alnico) and samarium cobalt (Sm-Co) production in that nation (Figure 1). In addition, China has imposed export quotas and export taxes of up to 25 percent for rare earth elements, arguably in violation of their covenants made with their protocol of accession to the Word Trade Organization. These export quotas have been decreasing steadily over the last several years in spite of rising global demand and were slashed by 72 percent in July 2010 (Bradsher, 2010) causing many recent news stories."

Jan 1, 2012

By V. L. Gravitis

Radioisotope X -ray techniques of analysis for nickel have been tested in laboratory and plant trials. In the laboratory tests. a comparison was made of radioisotope and conventional analyses for nickel in solid s samples taken from streams of a nickel concentrator. Coefficients of variation of 1.7% for feed and concentrate samples , and equal to 10% for final tailing samples, were obtained. Continuous determination of nickel in final tailing slurries was demonstrated in a trial lasting 20 days at a nickel concentrator (Western Mining Corporation), nickel being determined with a standard error of 0.036% Ni in the slurry solids within the range of 0.24 to 0.68% Ni. This error, obtained by comparison of on-stream probe analyses with assays of samples taken from the stream, includes errors in sampling and assay by conventional techniques.

Jan 1, 1977

By William Petruk

Image analysis studies were performed on mill products from pilot-plant and laboratory tests that had been conducted to determine the effect of grinding media on the selective flotation of two zinc-lead-copper ores. It was found that, when the ores had been ground to the same degree of fineness with flint pebbles, ceramic pebbles or ore fragments (autogenous grinding) as with steel balls, there generally was increased sphalerite, chalcopyrite and galena liberation in the flotation feeds, depending on the textures of the minerals. The increased sphalerite liberation fully accounted for the improved zinc recoveries that were obtained when steel balls were replaced by either pebbles or ore fragments. The increased chalcopyrite and galena liberation accounted for part of the changed technical efficiency of concentration, but other factors, probably changes in oxidation and reduction of iron and in consumption of oxygen, also contributed.

Jan 1, 1977

By G. F. Flaherty

THE property of Tashota Goldfields, Limited, in the Lake Nipigon area, Ontario, is located about 4 miles west of Onaman lake and 16 miles by winter road south-southeast of Tashota station on the transcontinental line of the Canadian National railways. The mine, formerly developed to a limited extent under the name of Tashota Gold mine, has, since late in 1933, been under the management of Minefinders Limited, who, in 1935, brought it into production on a 60-ton per day basis. During the winter of 1934-35, the writer was geologist at the property. The geological structure in the immediate vicinity of the mine workings lends itself well to analysis on the basis of the mechanical principles of folding. Since structure is of prime importance in the localization of the ore-shoots and of the host shear-zones at the property, the correlation of all structural details and their mechanical interpretation forms a working hypothesis of structural control for the direction of exploration and development work. It is believed that the structural relations here set forth may be found applicable in part, or at least suggestive, in working out the relations of ore-shoots to structure in the Sturgeon River area to the south, and in the Little Long Lac area to the southeast (Figure 1).

Jan 1, 1936

By M. W. Grabinsky, B. D. Thompson

ABSTRACT: Use of cemented paste backfill (CPB) offers economic and environmental advantages over other backfill methods. However, many operations have limited knowledge of how their CPB behaves in situ. Therefore, to avoid over-pressuring containment barricades, backfilling strategies necessarily tend to be conservative. In situ monitoring at Barrick Gold Corporation’s Williams Mine and Inmet Mining Corporation’s Cayeli Mine has been conducted and factors controlling barricade pressures are demonstrated, including rise rates, binder content, stope geometry, and tailings properties. The application of barricade pressure monitoring on a stope-by-stope basis can increase backfilling efficiency and, thus, reduce stope cycle times, while maintaining optimal safety.

Jan 1, 2011

By Richard W. Hutchinson, Christopher Osterman

Abstract -The Selebi-Phikwe deposits are hosted by amphibolite to granulite facies gneisses of the Limpopo belt. The sulfide orebodies are generally stratiform and conformable to the foliation of the wallrock gneiss. Sulfide remobilization has occurred during metamorphism and has produced discordant sulfide veins, called piercement structures, which project into the hanging wall and foot­ wall gneisses. These piercement structures are compositionally similar to the stratiform sulfides, consisting mainly of pyrrhotite, pentlandite and chalcopyrite. However, texturally the piercement sulfides are coarse grained and inclusion-free, whereas the stratiform sulfides are fine grained and packed with tectonically produced wallrock inclusions. The piercement structure sulfides and adjacent stratabound sulfides were sampled and analyzed for major base metals and PGE's for comparative purposes. Most of the piercement structures were enriched in Cu, Ag and Au, whereas they were generally depleted in Ni, Co, Fe and PGE's. Changing elemental associations were observed from the stratabound sulfides and along the length of the piercement structures. This and the degree of depletion or enrichment of various major and minor elements in the sulfide piercement structures may reflect the relative mobilities of metals under metamorphic conditions. The similarities between sulfide piercement structures and the footwall Cu-POE veins in some Sudbury deposits are reviewed.

Jan 1, 1994

By W. P. Campbell

THE investigation herein described had its beginning in the chemical laboratory of the Department of the Interior, Calgary. After the transfer of the natural resources to the Province of Alberta in 1930, the laboratory was closed and the investigation discontinued, but in 1933, with the permission of the Director of the Mines Branch, the work was again taken up and brought to completion. OBJECT OF THE INVESTIGATION The object of the investigation as originally planned may be stated as follows : (1) To determine the chemical composition of the limestone formation underlying Turner Valley gas field. (2) To identify 'beds' in the limestone, if such existed, with definitecharacteristics which would mark them from immediately overlying and underlying measures. (3) To relate information acquired on the composition of the limestone to the occurrence of oil and gas in the particular section examined. Definite information was lacking as to the exact chemical composition of the limestone and of its variations in composition at various depths. The formation was generally referred to in the field as the 'dolomitic' limestone, but the depth to which the dolomitized zone extended and the degree to which the limestone generally had become dolomitized were not known. Jn the drilling and logging of wells, the recognition of suitable 'markers' in the various formations is a matter of some importance. Markers are generally relatively small but widespread members of a formation, which have some characteristic property, of colour, composition, or form, by which they may be identified, and with them, consequently, the formation of which they form a part. In the formations above the limestone in Turner Valley, a number of well defined and easily recognized markers are known to geologists, drillers, and others interested in the field. Many of these markers Hand out in sharp contrast to adjoining measures and are therefore easily recognized; in others, the contrast is less sharp, with consequent difficulty in identification.

Jan 1, 1937

By G. M. Ross, J. A. Scott, C. A. Laamanen, H. Shang

"Indirect recovery and use of waste heat contained in smelter off-gas is proposed to expand regions available for year-round, on-site production of micro-algae–sourced biodiesel, a fuel that could be used in underground machinery. A dynamic model of an off-gas heat exchanger describes capture and distribution of heat into open, external, rectangular micro-algae ponds. Smelter off-gas contains sufficient energy to maintain large-scale micro-algae cultivation pond temperatures above 15°C, even with winter ambient temperatures below –15°C. Results highlight opportunities that could lie in tapping these heat resources to produce renewable biofuels on-site and sequester CO2 while leaving the industrial process unaffected.RÉSUMÉ On propose la récupération et l’utilisation indirectes de la chaleur résiduelle contenue dans les dégagements gazeux des fonderies pour développer les régions se prêtant à une production toute l’année durant et sur place de biodiesel à partir de micro-algues, carburant dont on pourrait se servir pour le matériel d’exploitation souterraine. Un modèle dynamique d’échangeur de chaleur contenue dans les dégagements gazeux décrit le captage et la distribution de la chaleur dans des bassins rectangulaires ouverts de micro-algues en extérieur. Les dégagements gazeux des fonderies contiennent suffisamment d’énergie pour maintenir les températures des grands bassins de culture de micro-algues au-delà de 15°C, même avec des températures ambiantes en hiver inférieures à –15°C. Ces résultats soulignent les possibilités que pourrait offrir l’exploitation de ces sources de chaleur pour la production de biocarburants renouvelables sur place et pour la séquestration de CO2 sans que cela n’ait d’incidence sur le procédé industriel.INTRODUCTIONMicro-algae that grow in water can efficiently convertsolar energy and carbon dioxide into biomass. This biomass can be up to 50% oils (lipids), which can be extracted and converted into biodiesel through transesterification (Demirbas, 2008). Compared to terrestrial plants that produce similar oils (e.g., jatropha, soybean, and rapeseed), micro-algae represent an order of magnitude increase in areal productivity, do not require arable land, and can be continuously harvested (Rawat, Ranjith Kumar, Mutanda, & Bux, 2013). The potential advantages through the production of biodiesel from micro-algae also include sequestration of carbon dioxide, reduced reliance on fossil fuels, and the co-production of other value-added bioproducts."

Jan 1, 2017

By Martin Grenon

This paper presents two case studies where fracture set orientation was quantified using three methods: a simple fracture pole grouping, a Fisher distribution and a Kent distribution. The three fracture orientation representations were then used as inputs for kinematic slope stability analysis. Differences showed up in the probability of sliding for all instability modes considered.

Aug 1, 2013