Search Documents

By B. S. W. Buffam

"The property of Moneta Porcupine Mines, Limited, consists of a group of eight claims in Tisdale township, Ontario. It includes part of the townsite of the town of Timmins, and adjoins the west boundaries of the Hollin_ger Consolidated and Mace properties. The Moneta property was first staked in 1909, about a year after the first discovery of gold in the Porcupine camp. In 1910 the Moneta Company was incorporated and some preliminary exploratory work performed by Nova Scotia Mines of Cobalt. In 1912 English interests advanced $90,000 for diamond drilling and underground work. One drill hole gave high assays, but apparently the records were poorly kept or the cores were interchanged. As a consequence, when underground exploration was undertaken in 1923 it was directed south rather than west and no ore was found . In 1924 about 5,000 feet of diamond drilling was done in the southern part of the property, but without intersecting ore.In 1931 W. E. Segsworth assumed the direction of the property. Diamond drilling commenced on August 18, 1936. The first hole intersected 9.9 feet of ore averaging 1.23 oz. gold a ton. Underground work was started early in 1937. A mill was erected in the autumn and the first gold brick was poured January 29, 1938.The Moneta mill began operation on January 2, 1938, and the following table gives a summary of the production to June 30, 1943, when the mill was closed."

Jan 1, 1954

By S. Komar Kawatra, Youlian Zhou, Joseph A. Halt

"Bentonite clay has been the most common binder for iron ore pellets. Although bentonite increases pellet strength and durability, it has several disadvantages. For example, its use increases the cost of pellets and decreases pellet purity due to its composition and the higher levels of flux required to meet basicity limits. Several new types of binders have been proposed to replace clay. The binders include starch, modified humic acid (MHA), and dispersants. These binders were used to pelletize a magnetite concentrate from the United States. Typical doses of each binder type were 0.05-0.1 % starch, 0.5-0.75 % MHA, and 0.05 % dispersant. At these doses, the pellets exceeded the minimum recommended values for wet drop, dry compression strength, and fired compression strength. Pellets made with the MHA and dispersants had the lowest abrasion rates of the new binders, and were comparable to pellets made with bentonite clay. In this paper, we compare the new binders, considering pellet quality and the advantages and disadvantages of each binder type.INTRODUCTIONIron ore pelletizers need binders in order to make good quality iron ore pellets. The typical binder is bentonite clay, an alumino-silicate material. Bentonite increases the ballability and strength of iron ore concentrates, but reduces pellet iron grade and reducibility. As high quality bentonites can be expensive to ship, low quality bentonites are often used at significantly higher doses – this reduces iron grade and reducibility even further. Thus, several new types of binders have been proposed to replace bentonite clay.In this paper, we present several new binders for iron ore pellets: starch and modified humic acid (MHA). These have been tested alone and in mixtures with dispersants, or else with bentonite clay. Starch, MHA and their mixtures are briefly described below."

Jan 1, 2016

By Ahmad Abdollahi

Many factors affect mechanical properties of hypoeutectic Al-Si alloys. As examples the presence of impurities such as Mn and Fe due to the formation of intermetallic phases, additions of small amounts of alkaline earth metals and cooling rate in consideration of Si formation, they all have an impact on mechanical properties of hypoeutectic Al-Si alloys. In this investigation, the effect of Fe content into the specification range of A357 alloy, the addition of different modifiers consisting of Na, Sr and Ca for the alloy of A356 and different mounting techniques for separately cast test coupons of hypoeutectic Al-Si alloys using the lost wax method were studied. The results showed that using material with lower Fe content and addition of modifiers improve mechanical properties. Also different mounting techniques resulted in different mechanical properties.

Jan 1, 2004

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 E. Demedde

Carbon anodes in aluminium reduction cells are continuously consumed during electrolysis. In prebake cells the anodes are replaced at regular intervals. The spent anodes, called butts, are often allowed to cool in air while emitting fluorides into the building from the hot alumina cover and the adhering bath. In modem smelters spent anodes are placed inside enclosures and fluoride emissions during cooling are effectively reduced. Fluoride emissions from spent anodes were estimated by considering the kinetics of fluoride formation, a heat transfer analysis of the cooling anode butt and the ventilation flow from a cavity. Fluoride emissions from large anode butts cooling inside enclosures were compared with those cooling in air. Good agreement with published experimental values was obtained for enclosures having different leakage opemngs, when a hydrofluorination reaction of the spent anodes was included.

Jan 1, 2006

By S. Mamonov, V. ?shikhin

"The purpose of work was the significant increase of copper recovery from slag at a concentrating plant. Analysis of study of slag phase composition showed the perspective of a slow slag cooling method due to its recrystallization and transition of primary copper minerals to secondary.Copper content in base slag varied between 0.71 and 0.96%. The study of a degree of copper minerals release of the slowly cooled slag in comparison with a yielding slag showed that in a flotation size grade –0.071 mm of yielding slag the weight ratio of released copper minerals grains is 58.95% against 86.73% in samples of slowly cooled slag. The process flotation sheet consists of three main, one control and two cleaner flotation operations with aftergrinding of middling products. A reagent mode was differed from a factory one by decreasing the slurry pH from 11–12 to 8–9. This paper shows research results of the slurry alkalinity impact on technological indexes of beneficiation (flotation).Industrial testing of a resulted batch of slowly cooled slag at “SUMZ” concentrating plant showed the efficiency of such processing: copper recovery to a copper concentrate increased by 15–19%.INTRODUCTIONIntensive development of mining and metallurgy industries within a 250-year period in the Ural region led to forming of approximately 315 man-made mineral formations at the territory of the Sverdlovsk region. The region contain over 32.5 billion tons of barren rocks and out of balance ores, over 1.5 billion tons of tailings, over 115 million tons of slimes, and over 100 million tons of metallurgical slag (Demin et al., 2000). Latters, at average, contain 407 thousand tons of copper, 2519 thousand tons of zinc, 7 tons of gold, and 150 tons of silver (Rudoy et al., 2011). Wastes generated in mining processing and metallurgical sector of economy contain not only thousands tons of copper and zinc, but cause significant damage to the environment where they are located. The reduction of negative impact of anthropogenic wastes on the environment as well as the storage volume reduction of valuable metals from dump slags is possible by improving the efficiency of the melting and further flotation of slags formed during this process."

Jan 1, 2016

By J. Ellis Thomson

For many years the value of qualitative microscopic investigation has been recognized in both of the fields of pure and applied science. In particular, its aid has been invoked in the determination of rock specimens in thin section, and some at least of the interrelations of minerals present in any one section have been observed and, to a limited extent, applied for the solution of different problems. During the past decade this form of research has also been diverted to the determination of ore minerals in polished section, with some observation of their structural relations. Microscopic research of a quantitative character, on the other hand, while started nearly one hundred years ago, has found but a limited application in petrography and has scarcely been used at all in the more modern science of mineragraphy. This is very largely due to the methods employed, since most of them consumed too much time and were, in addition, too laborious to encourage many workers in their use. The details of procedure for these earlier methods will be found in another paper by the writer, and will be omitted from this discussion as being of small interest to practical mining men.

Jan 1, 1930

By Yusuke Yamamoto, Mineo Asano

"The present study investigated the texture transition during secondary recrystallization in the AA5182 sheet. During the initial stage of annealing, the texture showed a weak Cube orientation as the primary recrystallization texture. During the secondary recrystallization with abnormal grain growth, the area ratio of the {hkl} <011> orientations increased by consuming the other orientations. The texture transition was calculated by the 2-D Monte Carlo simulation with the misorientation dependency. When the higher grain boundary mobility was set in the specific range of the high angle misorientation, the orientation preferential growth of the RW {100} <011> orientation was reproduced. However, other {hkl} <110> orientations could not be well reproduced by the misorientation dependency.INTRODUCTION Crystal orientation and texture are important factors for aluminum sheet products from the standpoint of mechanical property, formability and isotropy. The recrystallization texture results from the orientation preferential growth from the rolling deformation microstructure and the texture (Alvi, Cheong, Suni, Weiland, & Rollett, 2008). Texture development has been a topic of intense research for decades with advances in analysis methods, e.g., orientation mapping (OIM) and computer simulations (Fjeldberg & Marthinsen, 2010; Ivasishin, Shevchenko, Vasiliev, & Semiatin, 2006). The grain boundary characteristic is considered to be a key for the orientation preferential growth. In the case of the recrystallization from the deformed microstructure, not only the grain boundary characteristic, but also the dislocation density and the subgrain size affect the nucleation and the grain growth (Engler, Löchte, & Hirsch, 2007). On the other hand, in the case of secondary recrystallization, the dislocation density and the subgrain size can be ignored and the effect of the grain boundary characteristic can play a significant role in the grain growth. There is intense research about the texture development during secondary recrystallization in aluminum alloys and it was reported that coarse {hkl} <011> grains were formed during the secondary recrystallization (Suk, Shin, & Huh, 2006; Rios, & Gottstein, 2001). However, the mechanism of forming the {hkl} <011> grains has not been fully clarified. In the present study, the effect of the grain boundary characteristic on the orientation preferential growth was investigated by EBSD analysis and Monte-Carlo (MC) simulation."

Jan 1, 2018

By D. Adiguzel

In this research, providing the sustainability of production quality was aimed for a quarry which is located in Istanbul western part of Turkey and producing concrete aggregates with different types of rock. First, research field was divided in 3 different areas in accordance with the geological differences and parameters that control their product quality, limit values of standards and effect levels were determined. Concrete aggregate conformity tests which are stated in international standards were applied on samples which were taken from these 3 different areas and physical, geometric and chemical properties of each rock type were revealed. The properties of the 3 different types of rock which were produced in the quary were determined and the binary blends were composed. Blending studies were conducted with linear programming technique. In the linear programming model, the cost of aggregate production was aimed to be minimal. The limit values that meet literature and national standards for usability of aggregates in concrete were defined as constraints in the linear programming model and evaluated with objective functions, thus the most suitable aggregate blends were composed. In conclusion, to provide the sustainability of product quality, the most appropriate product blends were composed for the research field and the usability of this model for those quarries were revealed.

Aug 1, 2013

By S. Shairp

Copper is an impurity as well as a necessary reagent in the processing of zinc sulfide concentrate at Hudson Bay Mining & Smelting Co., Limited&apos;s (HBMS) zinc pressure leach plant. Copper is present in the zinc concentrate as chalcopyrite, which consumes reagents necessary for zinc leaching. A small percentage of copper precipitates in the autoclaves, discharge lines, and flash tanks, requiring maintenance of the equipment and disposal of the solids. Copper also precipitates in the neutralization stages and is removed to low levels in a specific copper removal stage of purification. Yet some copper, as copper sulfate, is required, along with potassium antimony tartrate, in the final purification stage to improve cobalt removal from the zinc sulfate solution prior to electrowinning. The behaviour of copper experienced at HBMS&apos;s zinc pressure leach plant is discussed.

Jan 1, 2008

By Bergh. L. C.

On line monitoring and diagnosis systems of process operating performance are becoming an important part of industrial programs, leading to improve process operation and therefore product quality over time. In processes, such as the contact section of a sulphuric acid plant, a large number of input variables, highly correlated, are presented. These characteristics usually pose more difficulties in modelling the process for monitoring and diagnosis purposes. Multivariate statistical projection methods, such as Main Component Analysis, have been proposed to effectively deal with these situations. The application of these ideas to a section of a 2350 MTD sulphuric acid plant, located at the Caletones Smelter, including dry tower, gas blowers, catalytic reactor and S03 absorber processes, is discussed here. A PCA model with eight main components is used for monitoring and diagnosis of more than seventy operating variables. Hottelling&apos;s T2 and Q residuals test were used for detecting measurement problems in relevant variables, and for identifying which set of variables were responsible for driving the process outside its normal operating region. Furthermore, considerable information for the correction of the tested operating problems was given by the use of these techniques.

Jan 1, 2007

By Bruce Regensburg

As trucks become larger and larger, haul roads take on a more significant role in mining costs and economics. The School of Mining at the University of Alberta has compiled a design manual for haul roads using both empirical and theoretical information. One section of this manual deals with the economics of haul road construction. While many mines look only at the construction costs of haul roads, this paper looks at all associated parameters including construction costs, removal costs, timing, truck productivity and width implications. The authors demonstrate the method to determine the most appropriate quality of road for different road conditions and life spans.

May 1, 2001

By Chuanhui Cao, Shimei Liu, Xiaojing Li, Yueyuan Zhou

"Force analysis on weakly-magnetic particles and non-magnetic particles in magnetic field are presented, using a kind of permanent magnetic drum magnetic separator, which is designed with strong specific magnetic force and open magnetic system. Its surface peak intensity reaches to 1.0T, and the distribution density of capture line is 1.25×103/dm2. Qualitative analysis on the particles including its magnetic property, particle size, motion speed, magnetic field intensity, etc. is also presented to calculate the separating parameters for the drum separator. Experiment was conducted for the separation of fine weakly magnetic minerals for example ilmenite. The practicability to separate the minerals using separator designed with open magnetic system has been proved, providing an economic way for efficient separation of micro-fine weakly magnetic minerals and upgrading of non-metallic minerals. INTRODUCTIONMagnetic separation is a mineral processing method based on the differences of magnetic properties between minerals in inhomogeneous magnetic field (Sun, 2007). Currently for separation of micro-disseminated weakly magnetic iron ore, electromagnetic high intensity magnetic separators with closed structure of magnet system are often used. And for the separation of strongly magnetic minerals such as magnetite, low intensity drum magnetic separators with open magnet system are often used. In order to lower the operation costs and improve energy efficiency, it is important to develop efficient high intensity permanent magnetic separator with open magnet system, to some extent replacing high intensity electromagnetic separator.Oberteuffer (1974) discussed the magnetic force and competing forces in magnetic separators which compete with the magnetic forces and act on all of the particles which travel through the separator are those of gravity, hydrodynamic drag, fraction, and inertia in magnetic separation."

Jan 1, 2016

By R. Lepsoe

THE basic products of the Company are lead and zinc. Around 950 tons of these metals are produced each day. In the last decade, the production of by-products has increased to such an extent that they are now nearly as large an operation as that of the base-metals. Of the many by-products, the most objectionable, and up to a few years ago the most useless, was the sulphur. The sulphur comes in the ore from the Sullivan mine. It is in the ore chiefly as lead, zinc, and iron sulphide. By selective flotation, these three sulphides are separated into the lead concentrates, the zinc concentrates, and the mill tailings. These mill tailings contain the bulk of the iron and the sulphur. Of the 6,5CO tons of ore treated per day, about 5,000 tons are wasted to the mill tailings dump, and, while now valueless, will in future years undoubtedly be used as a source of iron and sulphur. There are about 1,500 tons of sulphur and 2,200 tons of iron per day in the tailings, and about 400 tons of sulphur left in the total concentrates. In the recovery of lead and zinc in the pure form, the first step is the roasting operation. Here, most of the sulphur is driven off as sulphur dioxide in the gases. It has always been apparent that this sulphur should be. recovered and utilized if possible. At the same time, this would cure the smoke nuisance. Because, in spite of the low concentration of sulphur dioxide and the fact that it was discharged from stacks at an elevation of 400 feet above the plant, some damage to vegetation close to the plant had been experienced.

Jan 1, 1937

By P. Molera

"In Catalonia, between the 10th century and 1878, some installations were developed which at first were called ""factories"" and later ""fargas"", since they manufactured iron and steel of low carbon content. Because of its excellent quality, the fame of this metal spread from Catalonia to many countries. Fargas were started in Corsica, the Low Countries, Germany, Oriental India, Madagascar, Finland and along the rivers Orinoco and Mississippi among others. The extractive process used in these fargas has passed into history as the ""Catalan Farga Process"", ""Catalan Process"", or just ""Farga Catalana"". With this technology, raw material was obtained for the fabrication of tools, nails, weapons, grilles, etc. to supply the national and export markets. Aside from meteorites and native iron, found as metallic nodules in basalts in Greenland and Palestine, the ancient civilizations, which had no means to reach the fusion temperature of iron (1535°C), obtained iron by a direct process. Similar processes were used until quite recently (1930s) by certain tribes in Central Africa; holes in the ground were filled with iron ore and coal, and combustion encouraged by blowing air by mouth or with bellows made of animal skins. Thus without melting the iron it is possible to reduce the mineral and obtain a porous and impure metallic mass, which is purified on forging by mechanical squeezing. With a process very likely similar, the famous column at Dehli weighing 6.4 m.t. was built about 300 B.C."

Jan 1, 1999

By K. Halada

Current trend of the global flow of strategic metals are analyzed to discuss the strategy of the development of recycling technology and alternative technology. In many cases, each global flow of metal is changing from the trilateral structure of U.S., EU and Japan in the later 20th century into the convergence to China as the factory of the world. Scrap flows are also changing dynamically. A long term change of prices of metal has gotten changed since the entrance of this century. The estimation of metal consumption up to 2050, in which the author estimated that many kinds of metal will overshoot the reserve base line, is revised considering these change of current trends.

Jan 1, 2014

By G. J. Kipouros, N. Dadvand

"In recent years coatings of alloys have been produced for a wide range of applications including many for wire bonding application. The main characteristic of the baths of electroless plating is the presence of sodium hypophosphite as a reducing agent and also as the supplier of phosphorus. In the electroplating of alloys the Watts bath is predominantly used. This presentation compares the two techniques, electroless plating and electroplating, and discusses the possibilities of cross utilization of sodium hypophosphite in an attempt to formulate baths that eliminate the waste disposal issue related to some components.INTRODUCTIONThe importance of surface characteristics and the linkage of surface coating process to surface characterization has given rise to the evolution of surface engineering. Not only the surface preparation and morphology has become very important to the coating technology but also the knowledge of surface area exposed to the process of coating or corrosion is absolutely essential in ascertaining the behaviour of coatings and their adherence to the substrate. The above concepts are not unknown to researchers involved in the protection of surfaces, particularly metallic, from corrosion and/or erosion corrosion. However, the complexity of the surface defects, roughness, porosity, interconnected porosity and other related factors have contributed to the uncertainty of the true surface area versus the nominal surface area. Therefore critical parameters such as current density and chemical surface intensity although have been studied extensively at the atomistic level by carefully prepared surfaces are very difficult to be determined at the practical scale required during the coating processes.The most pronounced case calling for an understanding the relationship between the surface area and the effective protection is the coating of surfaces of items produced by compression or consolidation of powdery materials. With the advent of nanomaterials and the additive manufacturing through 3D metal printing this issue is becoming more important. Certain experience in this field come from the accumulated knowledge resulted from the attempts to characterize the electrochemical behaviour of powder metallurgy metals and alloys. Powder metallurgy has been a well-established process for half a century on basic metals such as iron, copper and their alloys. Recently the development of powder metallurgy process for aluminum, titanium and attempts to develop powder metallurgy processes for magnesium and its alloys has brought to light another important issue that of the development of coatings on difficult to plate reactive metals such as aluminum and magnesium. Despite of many successes in the development of powder metallurgy alloys the exact characterization of the corrosion behaviour of the coatings and the substrates is difficult to determine because of the unknown morphology of the exposed area i.e. the exact morphology and area of the exposed surface (Samal, 2007)."

Jan 1, 2016

By N. Saracoglu, R. H. Wallis, J. E. Betz, F. L. Jagodits, B. R. Krause

"Geophysical test surveys were conducted with various methods (EM, lP, gravity and magnetic) over the McClean uranium deposits of the Canadian Oxy- lnco Joint Venture. The result s were assessed to judge the contribution each method might make toward further discoveries of graphite-associated uranium occurrences.The best drill targets have proven to be discontinuities in graphitic conductors and locations where the tatter are intersected by fracture zones in the Athabasca. The tests demonstrated that the preferred combination of geophysical survey s is horizontal loop EM to locate graphitic conductors in the basement and VLF-EM to locate the fractures.IntroductionThe discoveries of the McClean North and South uranium deposit s (Fig. 1) are essentially geophysical successes resulting from drilling MaxMin delineations of INPUT airborne electromagnetic responses (Saracoglu et al., 1983). After the initial discovery in 1979, various geophysical methods, techniques and instruments were employed to test their effectiveness in this environment and to guide exploration for other deposit s of a similar nature in the remainder of the 260 km2 property.The McClean uranium deposits lie below 150 m to 180 m of overburden and Athabasca Group. Radioactive signatures might be expected; however, the Athabasca Group acts as a barrier to radioactive emanations. Fortunately, the uranium mineralization is associated with graphite in the crystalline basement. Prior drilling of ground electromagnetic anomalies confirmed that EM surveys could locate and out line basement graphitic conductors. However, as there were many anomalies, most of which could not reasonably be expected to be associated with uranium , there was need to identify additional parameters, related to mineralization, which could be detected geophysically and used to narrow the search."

Jan 1, 1986

"HPGRs operate in a wide array of applications in mining and minerals. These range from relatively coarse crushing of copper and gold ores at one end of the spectrum to the processing of fine iron ore pellet feed and fine industrial mineral products at the other. Traditionally these circuits involve the treatment of relatively moist materials in pre-grinding circuits; using single stage HPGRs in open circuit or as a closed circuit operation with screening or partial product recycle. More recently, HPGR is increasingly deployed in dry grinding in combination with air classification. The high throughput demonstrated by larger HPGRs has stretched the application towards coarser size reduction duties for a number of new projects. At the same time, the basic principle of inter-particle crushing for generating a product with a high fines proportion gives ground to investigate applying the technology further towards finished product duties. The advantages that HPGR brings are clear. Multi Stage grinding enables energy efficient size reduction across more of the comminution circuit. Primary HPGR serves for a coarse grinding duty, whereas a secondary HPGR is geared towards generating a fine product for downstream processing or even a finished product. This publication summarizes some of the features of staged HPGR circuits and discusses some examples of operating and projected applications.INTRODUCTION In most HPGR applications, the grinding units are used as a single process stage, either in open circuit, such as for pebble crushing [Rose 2002, Westermeyer 2000, Van der Meer 2015] or in closed circuit with classification [Van der Meer 2009, 2012] or product recycling [Van der Meer 2010]. Where a higher plant capacity is required, the HPGRs are commonly installed in multiple lines in a parallel arrangement [Parker 2005, Koski 201, Vanderbeek 2006]. HPGRs can take a wide range of feed size distributions, and grind this down to a product with a high fines content. In general view, there is a limit on the size reduction range that even an HPGR can provide. Grinding down from a very coarse ore (e.g. 70-100 mm) to a very fine product (e.g. 100 microns range) is stretching the ability of a single stage HPGR circuit. Fine grinding generally requires a classification stage that returns the classifier oversize to the head of the HPGR circuit. From one point of view, it can be demonstrated that when recycling a large proportion of fines and middlings back to the HPGR feed results in an effective feed with an overrepresentation of middlings and fines, which will eventually reduce the grinding efficiency and consequently result in an increased recirculation mass flow [Van der Meer 2014]. From another point of view the large recycling mass puts a strain or even a limit on the capacity of present-day conveyor capacity."

Jan 1, 2018

By J. A. MacLellan

"CONSTRUCI'ION OF SHERRITT'S CONCENTRATORSSherritt Gordon is operating two mills north of the 56th parallel, and is presently engaged in building a third. The author was closely involved in the design and construction of all three of these concentrators.The Lynn mill is the oldest of these three concentrators-it is a 4,000 ton per day nickel-copper plant built in 1953. The Fox mill is a 3,000 ton per day copper-zinc concentrator built in 1970. The Ruttan mill will be a 10,000 ton per day copper-zinc plant scheduled to go on line in July 1973.LYNN MILL The Lynn mill including the crushing, concentrating, drying and load out plant is about 69,700 square feet or 17.4 square feet per ton per day. '!his plant was originally built in 1927 at Sherridon, 150 miles south of Lynn Lake, as a 2,000 ton per day copper-zinc plant. In 1952 the plant was moved by tractor train to Lynn Lake. The whole plant was re-oriented within the original perimeter walls as a 2,000 ton per day nickel-copper plant. This plant was expanded to 4,000 tons per day by the addition of t1-Jo rod mills and a 5-1/2 short head crusher in 1959.The Sherridon mill processed its last ore in Sherridon in September 1951 and the first load of nickel concentrate was loaded at Lynn Lake on November 9, 1953 when the railroad arrived at Lynn Lake.The site for the Lynn Lake mill was cleared of overburden in the summer of 1952 and foundations for structural steel and SO!l8 equipment foundations were poured the late summer and fall of 1952 • Steel was erected from January to June 1953. Most of the equipment came in from January to March of 1953 by tractor sleighs. Sane sleighs upset but no equipment was lest through the ice."

Jan 1, 1972