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By V. Shumila, T. Butler

Microseismic monitoring systems listen to a rockmass and record ground vibrations associated with brittle rock fracture. Modern systems record continuously and can identify as many as one thousand small and possibly larger magnitude events occurring each day from induced stress change and redistribution. This paper presents examples of the real time use of microseismic information in mining applications. It shows how alerts can quickly identify large magnitude events or unexpected clusters of seismicity and how seismic re-entry protocol can help to improve safety decisions. Additionally, newly developed advanced analysis techniques applied to mine seismic data sets are shown including the use of clustering methods to see into a cloud of seismic data to identify significant activity and quantify possible planar features. The use of source parameter trend analysis is shown to be a beneficial method for interpreting changes in relative stress levels. Seismic moment magnitude distributions are analyzed using the TGR (Truncated Gutenberg Richter) and TMD (Tapered Moment Distribution) methods to estimate bvalue and expected maximum magnitude. Seismic hazard analysis is shown as a useful way to simplify a dataset and highlight seismic hot spots. The rockmass response to excavation is a complicated spatial and temporal process and microseismic monitoring is a method that can be used to help understand the location and mechanics of failure occurring in the rock ultimately helping to improve safety and productivity at a mine site.

Jan 1, 2015

By R. J. Mitchell

"The use of hydraulically delivered classified tailings sands to provide ground support in large mining operations is still widespread despite recent developments of alternate backfilling methods and materials. The major disadvantages of the use of hydraulic fill are the costs and risks associated with slurry delivery. The main risk is that of bulkhead failure resulting from sand liquefaction due to insufficient operational control or due to dynamic loading from earthquake or rockburst. That risk may be eliminated by the pouring of a stiff cemented sand plug in the base of each stope prior to continuous fill pouring in that stope. An additional advantage of cemented plugs is that massive bulkheads are not needed. Instead, a temporary (removable and reusable) bulkhead can be used for plug forming.Physical model studies of fill pressures on a temporary bulkhead were carried out in a 3 m radius centrifuge facility. Fill pouring in-flight was carried out in order to model prototype stress paths. The results indicate that the average bulkhead pressure is likely to be less than 10 kPa under normal operating conditions and less than 20 kPa under the poorest anticipated operating conditions which include smooth walls, high slimes content and high water-content slurries. A portable bulkhead consisting of a central core and a surrounding sealing bladder was modelled and found to be effective. The use of different sizes of cores allowed the stress distribution adjacent to these bulkheads to be evaluated."

Jan 1, 1992

By A. Cabañas

"In this paper, geostatistical techniques are applied to forecast the annual copper price in the short and medium terms (from one to five years ahead). These techniques allow the incorporation of monthly and multivariate information in the analysis and provide more accurate results than traditional approaches, especially as far as the one-year forecast is concerned.A second advantage of geostatistics stems from its ability to assess the uncertainty associated with the unknown future prices, thanks to estimation variances or confidence intervals, depending on the technique used. Such an assessment has a crucial importance in decision-making, from both macroeconomic and microeconomic points of view. IntroductionThe copper price traded in the London Metal Exchange is a relevant parameter for defining macroeconomic policies of producing countries like Chile. It is also a key factor for the mining companies, since fluctuations in the sell price affect the expected financial flows. Due to the amount of money involved in decision-making, it is necessary to have accurate forecasts of the future copper prices and to quantify the uncertainty associated with such prices.This paper focuses on the annual copper price estimation in the short and medium terms, i.e., from one to five years into the future. Henceforth, the word “estimation” will be used as a synonym of “forecast,” according to the geostatistical jargon (Matheron, 1989).Two main approaches, based either on statistics or econometrics, are currently used to forecast commodity prices, but both of them are not very accurate when applied to copper. First, the main methods are briefly reviewed, then the geostatistical formalism will be presented. So far, the latter approach hardly has been used to estimate commodity prices, although it may reconcile both statistics and econometrics via (1) the use of a stochastic approach and (2) the handling of ancillary variables related to the copper market. Another advantage of geostatistical techniques is the ability not only to forecast the copper price, but also to measure the uncertainty associated with it."

Jan 1, 2004

By J. Coffin, R. Multani, C. Deredin

Glencore’s Strathcona Mill has recently evaluated a pyrrhotite depressant combination of diethylenetriamine (DETA) and sodium metabisulfite (SMBS) to improve its overall plant pyrrhotite- pentlandite (Po-Pn) selectivity, with the aim of producing a higher quality nickel concentrate. In a previous paper, key findings from a comprehensive lab-scale program (completed at the XPS Centre) were summarized where, of the depressants tested, DETA/SMBS combination was found to be the most effective in improving the Po-Pn selectivity. The present paper describes the metallurgical program recently completed at Strathcona Mill; DETA/SMBS evaluation on select plant “grab” samples as well as the major results of three DETA/SMBS plant trials conducted on several plant ore feeds (long-term testing). Interestingly, it was found that there was variable success in using DETA/SMBS depressants on the different plant ore feeds; DETA/SMBS (dosage: 25/50 g/t milled feed) on lower Cu feeds demonstrated a ~2% Ni recovery increase at the same Ni grade. On the other hand, higher Cu feeds demonstrated virtually no benefit from DETA/SMBS at the same plant dosage, suggesting that higher DETA/SMBS dosage (at specific locations) than that tested is required to overcome the increased Cu-DETA complexation for these particular feeds. Glencore Nickel – Sudbury Integrated Nickel Operations owns and operates Strathcona Mill which has been processing Ni-Cu ores from the Sudbury Basin since 1968. The valuable sulfides are pentlandite (Pn) – (Ni,Fe)9S8 and chalcopyrite (Cp) – CuFeS2, majority of the sulfide gangue is pyrrhotite (Po) – Fe(1-x)S [0 < x ≤ 0.125] which is present in two forms: hexagonal Po (Fe9S10) and monoclinic Po (Fe7S8) (Multani & Waters, 2017; Lawson et al., 2014). Currently Strathcona Mill processes ore mined from two primary sources from the Sudbury area and produces two concentrate streams: (1) nickel-copper concentrate that is sent to the Sudbury Smelter; and (2) copper concentrate that is shipped to the Fonderie Horne (Glencore Copper, Rouyn-Noranda).

Jan 1, 2019

By Earl M. Frizzell, Joseph A. Dos Santos

"Conventional belt conveyors offer an economical method for transporting materials at inclines approaching 18 degrees. Sandwich belt conveyors may be used to transport materials at high angles, to 90 degrees, while maintaining the most positive features of conventional conveyors, that is, (1) proven conventional conveyor components. (2) high-speed operation, (3) high-single lifts, (4) continuous cleaning of the smooth surf aced belts, and (5) easy, quick repair by hot or cold vulcanizing. The present discussion deals with the evolution and development of sandwich belt conveyors to satisfy the operational requirements of the open-pit mining and materials-handling industries.A look at the limitation s of conventional shallow angle conveyors reveals the conveying angle at which a cover belt is needed. The relationship between conveying angle and hugging pressure by the cover belt is developed mathematically. A study of past and current developments reveals that the Loop Belt and Beltavator are significant advances in the state-of -the- art. The vertical radius of curvature constraints are discussed in detail and the constraint equations are developed. Criteria for future development is established as a basis for evolutionary developments in sandwich belt high-angle conveyors. The use of intermediate drives in sandwich belt high-angle conveyors is investigated.IntroductionIn connection with U.S. Bureau of Mines funded–study relating to continuous haulage from deep open-pit mines, the authors had occasion to study extensively, the use of high-angle conveyors as a means of hauling mine products continuously from the pit while maintaining optimum mine slopes to minimize total excavation. The many possible high-angle conveying methods investigated included skip hoists, bucket ladders, pocket belts, fin belts, cleated belts, sandwich belts, pipe belts, screw conveyors, slurry pipe lines, and others. The sandwich belt high-angle conveyor appeared to be the most operationally-appropriate and economical solution for the mining industry. The present paper presents the theory, historical development, state-of-the-art, and evolutionary developments in sandwich belt high-angle conveyors."

Jan 1, 1983

By Lloyd A. Clark

"The kuroko deposits, which are extremely variable in size, comprise both stratiform layers of clastic sulphide particles and cross-cutting vein and disseminated components. The ores lie on the flanks of rhyolitic lava domes which have risen from a postulated subvolcanic magma chamber that provided cupriferous hydrothermal solutions and also acted as a heat source driving ground-water convecting cells. The polymetallic sulphides precipitated initially in explosion craters, pipe fillings and feeder veins as rising hydrothermal solutions mixed with sea water. As sulphides clogged the plumbing system, minor phreatomagmatic explosions produced layers of sulphide fragments on the adjacent sea floor. One to ten repetitions of this process produced multiple fragmental sulphide beds. Each deposit formed in a relatively short space of time, because only minor tuff beds are intercalated in spite of active volcanicity in the region. In this model, the heated ground waters convecting through thick piles of acidic pyroclastic rocks leach the zinc, lead and barium later deposited as kuroko ores. As the subvolcanic pluton cools, the supply of silica and copper wanes and the minor counter-circulation cells above the pluton are replaced by main cell fluids bearing zinc, etc. This change in solution flow is abrupt rather than gradual, as the plumbing system is somewhat disrupted by the magmatophreatic explosions that create each ore layer.IntroductionKnowledge of the kuroko deposits ha s greatly expanded during the 25 years since modern recognition of their volcanogenic origin. However, one aspect of the ore s, which may be of unique importance in their genesis, has received little attention. That is the fragmental character of much o f the sulphide ore, which was briefly referred to in a previous publication (Clark, 1971) and is examined in more detail by Barton (1978). Most researcher s have concentrated their attention on or e deposition above and beyond the vent, which is inconsistent with the geology."

Jan 1, 1983

By Thorndycraftm R. B.

"PURPOSEThe purpose of this presentation to the Canadian Mineral Processors is to review gold heap leaching systems currently in use and discuss their applicability to Canadian ores. The author's experience with the development and operation of heap leaching spans the past four years at. Pinson, and visits to many ether heap leaches in the western United States.INTRODUCTIONBy way of introduction to the heap leaching system, I will describe in slight detail the method used at Pinson Mining in northern Nevada. This will be followed by a discussion of optional methods in use at other operations visited.The Pinson orebody is a finely disseminated, well-oxidized hydrothermal deposit. Gold particles are finer than 20- microns. The orezone hostrocks are metamorphosed and silici¬fied limestone and shale. Sulfides and carbonaceous materials are negligible.The Pinson open-pit mine has operated since June 1980. It produces 1500 tpd of C.I.P. mill feed averaging .10 oz gold per ton, and 1500 tpd of heap leach material averaging .025 oz gold per ton. Cutoff grades are 0.04 for mill feed, and 0.01 for heap leaching. Stripping ratio is 9 tons of waste and leach grade to 1 ton of mill feed.The project is located in northern Nevada at 4900 feet above sea level.,Winters are fairly severe, with freezing conditions affecting operations from early December through April. Although officially designated as ""high-mountain desert"" country, snow and/or freezing rain occur almost every week of the winter.To date, all Pinson production-scale heap leaching has treated run-90,000 tons of ore are stacked on 300 foot square clay leach pads. Cyanide leach solution is applied through ""wobbler"" sprinklers at .0025 gpm/sq ft for 60 to 90 days. The pregnant solution flows from the heap by gravity to plastic-lined ditches, into a collection sump and then through buried piping to the 2.2 million gallon pregnant solution pond."

Jan 1, 1984

By E. H. Smith

"The El Indio mine treats a complex mixture of copper and gold/silver ores at its plant located in the high Andes in Chile. The plant utilizes conventional crushing, grinding and flotation to produce a copper/gold/silver concentrate. Due to high levels of arsenic and antimony, the flotation concentrate must be roasted prior to custom smelting. The flotation tailings is leached and additional gold recovered from a CIP circuit. Present and future metallurgical developments are discussed in this paper. INTRODUCTIONIn late 1989, LAC Minerals purchased 65 % of Bond International Gold and as a result became controlling shareholder of the El Indio Mine through Bond and San Jose.El Indio is a world class, complex sulphide gold deposit located in the hydrothermal alteration belt of the Andes mountains in the 4th Region of Chile. The mine is located in the high Andes about 185 km east of La Serena at an elevation of 4000 meters. The 1450 workers at El Indio live in the mine camp at 3200 m and on days off are bussed to La Serena.The El Indio mine was started in 1979 by St. Joe Minerals Corp., bought by Bond in 1987 and subsequently by LAC in 1989. The mine has produced 2.7 million oz. of gold, 9.5 million oz. of silver and 170,000 t of copper since start of operation. The mill is currently operating at a rate of 2850 t/d and producing a copper/gold concentrate which is roasted to produce a copper/gold calcine and high quality, saleable crude AS2O3 . A small proportion of the precious metals are also produced as bullion from the leach circuit.Total production during 1989 was 224,197 ounces of gold, 1,309,342 ounces of silver and 26,968 tonnes of copper. The average cash cost of production for the period was U.S. $96 per ounce of gold, net of by-product credits. The average realized price was $5. 30 per ounce of silver and $1.14 per pound of copper."

Jan 1, 1991

By Lloyd H. Yeomans

"This paper will cover recent developments in conveyor applications with specific reference to capacities, bell speeds and distances. It will also discuss certain unique arrangements of horizontal, curved and loop belt systems. In addition, the recent changes in safety factors resulting from new conveyor construction methods will be reviewed.IntroductionConveyor belt systems are currently undergoing dramatic changes. Their use is being extended to providing a viable means for the transportation of bulk material over longer and longer distances.In this paper, a brief account of the historical development&apos; of the belt is outlined, demonstrating how conveyor technology has adapted to changing market demands.Today, energy and environmental requirements are providing what may even be greater challenges. The ability of the belt conveyor to transport material and meet those requirements, places it in the position of replacing many conventional means of bulk material transportation.The paper also outlines some of the progress which has been recently made in this regard and includes a broad approach to the subject of belt design and application.Recent design developments have greatly extended the potential of conveyor belt systems to include applications thought impossible just a few years ago.Graphically illustrating the potential of this new technology IS a belting system currently operating in New Caledonia. Built in 1970, the system has an incredible centre distance of 43,000 ft, or about eight miles.Not to be outdone, the British Coal Board is currently constructing a belt system with a centre distance of 49,000 ft and a speed of 1,650 feet-per-minute. This system is expected to be completed in 1986.These innovative advances contrast dramatically to the conveyor belt&apos;s beginnings in the early industrial revolution. Oliver Evans, writing in the 1795 edition of &apos;Miller&apos;s Guide&apos; defined the conveyor belt as a ""broad endless strap of thin pliant leather or canvas, revolving on two pulleys in a case or trough.""Obviously, the conveyor belt has come a long way since those early days."

Jan 1, 1983

By W. R. Hargrave

"Mining OperationsOre will be mined by open pit techniques. Because of the high grade of the deposit and the low strip ratio, mining rates are small relative to most other open pit operations.The ore deposit is located in the valley of the main fork of Red Dog Creek. The bulk of the deposit is located on the southwestern flank of the creek, but mineralization does traverse the creek in both the north and east directions.Erosion has exposed the orebody in a number of locations, and has resulted in oxidation of the mineralization closer to the surface. Although much of this oxide material is very high grade, it leaches readily and, at least in the initial phases of the operation, will be stockpiled and not treated in the concentrator.During construction, 2.3 million mt. (2.5 million st.) of overburden and waste will be stripped from the orebody to expose ore for initial operations. Competent non-mineralized waste will be used to build roads and waste dumps, but the bulk of material removed consists of oxide or ice-rich soils and weathered rock which is not suitable for construction.The annual ore mining rate will be 1.9 million mt. (21. million st.). The strip ratio will start off at 1.2 to 1, falling to 1.0 to 1 by year 5 and ultimately to 0.8 to 1.Bench heights are set at 7.6 m (25 ft). Pit slopes will vary depending on the material present in the wall. The slope, through competent waste and the sulphide package, was set at 45 degrees. This is flattened to 26 degrees (i.e. 2: 1) through overburden and Upper Kivalina shales. The Kivalina Shales are an ice-rich shale whose carbonate matrix has been leached out and which exhibits little or no strength as it thaws. In addition, a 100 ft containment berm will be left in the wall below overburden and Kivalina."

Jan 1, 1989

By Neil Schofield

"The estimation of recoverable ore reserves for feasibility in precious metal deposits such as Pine Creek must account not only f or the extreme variability of the ore grade but also for the complexity of the geology. Compatible models f or both must be adopted. Further, very selective mining demands reserve estimates be based on small selection units whose individual grades cannot be estimated reliably from the exploration drilling data.Multigaussian kriging is one method based on a multivariate normal model for estimating recoverable reserves under such conditions. In this paper, a non-mathematical description of the multigaussian model is presented together with its application to the Pine Creek Gold Deposit. The results, when compared to the first year of production, are encouraging for the model but not without surprises.Together, Part 1 and Part 2 of this study combine a detailed and geologically conditioned variogram analysis with an appropriate estimation method for a highly variable low-grade gold deposit. This and other studies of gold deposits familiar to the author show convincingly both that while the appropriate geostatistical skills and techniques are necessary to tackle the question of reserves, equally important but often discounted is the need for an appropriate and compatible geological model. IntroductionThe Pine Creek gold mineralization is associated with saddle reefs, and quartz and quartz- sulphide veining within the Enterprise Anti cline. The anticlinal structure is complex and, prior to mining, the mineralization was considered to be mainly strata controlled. Grades vary up to 160 grams in l .5rn core samples with coefficients of variation in excess of three.The estimation of the recoverable reserves for such a depo sit must account for both the geological complexity and the extreme variability of the gold grade.Part 1 of this work presented the geological model for the deposit and summary statistics 0 f the gold data. A detailed structural and variogram analysis considered both gold grades and the normal score (or gaussian transform) of these gold grades for different composite sizes."

Jan 1, 1988

By R. L. Guerguerian, Eugene Bercel

"Grinding mill hydrostatic trunnion bearings require an external pumping source to provide and maintain the oil film between the bearing members. In order to guarantee a predetermined minimum film thickness, the lubrication system tends to be oversized. The oil film is ""indirectly"" controlled by flow, pressure and temperature monitors with fixed settings on the conservative side. This can lead to excessive maintenance and abbreviated life for the lubrication system components. A reliable method of monitoring actual film thickness would not only provide greater mill availability, but also minimize maintenance costs.This paper describes the instrumentation installed in Dominion hydrostatic bearings, and presents results of field tests where the output of that instrumentation was recorded under various operating conditions.IntroductionThe trend toward larger and more sophisticated grinding mills has made the operators of these machines increasingly vulnerable to financial loss, as the cost of downtime and repairs has increased directly with machine size. In order to guard against such losses, it is becoming imperative that large, sophisticated grinding mills be equipped with protective instrumentation to monitor some of the critical operating parameters and to identify events and trends which, if they go unnoticed, can lead to excessive maintenance costs and machine downtime. The idea of protective monitoring systems is not new. The operators of certain types of machinery where a high degree of safety is required or where machinery health can deteriorate very rapidly, as in the case of high-speed turbo-machinery, have long been using protective instrumentation on their machines. The increased awareness of the benefits of monitoring machinery conditions and the availability of reliable and relatively low-cost instrumentation of a large range of sophistication is making the practice now widespread. Traditionally, grinding mills have not been considered as high-risk machinery requiring instrumented protection. However, the trend, mentioned earlier, toward employing fewer, but larger capacity, mills increases the risk of significant disruption of production, and therefore measures to minimize the risks are desirable."

Jan 1, 1981

By Hoeve. J.

"In the unconformity-type uranium deposit at Midwest Lake, mineralization is associated with extensive host rock alteration, which affects the metamorphic basement as well as the overlying Athabasca Group sandstones. Host rock alteration is manifested by (I) transformation of clay minerals [kaolinite into illite and chlorite (sudoile)]; (2) bleaching due to removal of hematite from the lateritic paleoweathering profile and the overlying red bed, Athabasca Group sandstones; (3) loss of coherence of the sandstone resulting from corrosion of quartz cement; and (4) in the immediate vicinity of high-grade ore, development of a clay envelope due to residual enrichment of clay minerals caused by massive dissolution of quartz. Clay mineral transformation and bleaching are the most prominent and the most widespread alteration effects, forming haloes that extend for several kilometres along the strike of the mineralized structure and also constitute distinct alteration pipes that rise f or several hundred metres above the unconformity to be truncated at the present top of the bedrock.Although the two haloes are largely congruent features, cross-culling relationship s indicate that clay mineral alteration represents an earlier phase in the history of the deposit than the large-scale bleaching that gave rise to the superimposed bleaching halo.Because clay mineral alteration and bleaching are intimately tied to the mineralization and extend well beyond the limits of the actual orebodies, host rock alteration may be used as an ore guide in exploration and drill-hole evaluation. In this application a third hydrothermal discharge centre was identified, as yet untested for are, which is located between the hydrothermal centres associated with the two known orebodies of the deposit.It is estimated that host rock alteration may enlarge a potential drill-target by a factor 10 - 20X. Information on the configuration of bleaching haloes can be obtained from systematic core logging, whereas diagnostic clay mineral alteration is readily identified by means of automated, quantitative XRD techniques."

Jan 1, 1984

By D. Houghton

"I am very pleased to be a member on this panel today because abrasion and wear in mills has been part of my life over the past forty years. My presentation will deal with the role Ni-Hard has played in combating wear and abrasion in mills. Before Ni-Hard came along, unalloyed white iron was used in ball mills and one of the most popular types of white iron liners was the pocket liner. Slide #1 illustrates the design of the pocket liner used at Dome Mines in their 5' x 22' pebble mills. The pockets filled with grinding media and it was on this that the wear took place. The concept is not unlike the new magnetic liner which utilizes the ore and grinding media to form the wearing surface. In this slide please note the tapered pocket type of cored bolt holes. If cored bolt holes do not fill with grinding media there could be excessive grooving or wear at that area. Therefore all cored bolt holes should be tapered in this manner.Before Inco patented the name Ni-Hard several foundries were making the alloy iron under different brand names such as Diamond Alloy, Mitchelloy and Specialloy. In the early days some of the Ni-Hard was poor quality. Inco provided foundries with technical knowhow and provided assistance to licence them to sell under the name of Ni-Hard. This was in the late 1920's. The material we are discussing is Ni-Hard type I with the following analysis (slide #2). It is a martensitic white iron with BHN of 550 - 600 and is a relatively easy alloy to produce in either a cupola or electric furnace. The annual average production of Ni-Hard in North America is 90,000 tons with mill liners making up 25,000 tons and grinding media 30,000 tons, according to Warren Spear of Inco."

Jan 1, 1983

By Franco Oboni

Numerous voices are raising around the world to show how misleading and fuzzy commonly used risk assessments methods are. These criticisms come at a time when public trust in ?proponents of new projects?, operators, private or governmental, seems to have hit a low and the legal system ?targets? public officers. It is common that technical experts and the public strongly disagree in their analysis of risks. Risk definition requires the evaluation of probability and consequences and those words are oftentimes enough to stir great worry to the public. Thus it is nowadays commonly understood that ?reality? is not scientific, but resides in public opinion, hence urging technical people to communicate better, more transparently. Blatant failures on both counts have lead to the emergence of ?new myths? used to justify complacency using ?complexity? and other buzz words as an alibi. This paper (together with its companion presented elsewhere) explores how poor ?common practices? in Risk Assessment contribute to biasing project team, design teams opinions, skew decision-making process and finally misrepresent reality to the public resulting precisely in the raise of public distrust, legal implication witnessed around the world. The discussion first reviews the pitfalls of common approaches (FMEA, Probability Impact Graphs) pinpointing them as possible causes of future legal liabilities. An alarming disconnect also comes from various codes, ISO 31000 itself has this flaw, invoking the term ?acceptable?/?tolerable? without defining it or giving any guidance for its determination. Wide-spectrum public consultation could be developed to define a ?modern? social acceptability criteria helping all the stakeholders making/understanding decisions. Another alarming disconnect comes from the poor definition of consequences of mishaps and their societal ripple effects. This aspect is indeed mostly ignored in codes, leaving ample room to biases and censoring applied to potential losses. In our society no one seems to have anymore the possibility of hiding behind a shroud of ?carefully maintained? misrepresentation. It is time to act and ?write the book? for proper risk assessments avoiding misrepresentations.

May 1, 2013

By Haibin Wang, Zhiwei Huang, Zhixiang Cui, Wenzhao Cui, Zhi Wang

Fangyuan Two-Step copper smelting process was commercialized in October, 2015 and has been operating for 3 years and 5 months. As the unique continuous copper smelting process with simplified flow in the world, production parameters have been significantly improved after three years. In the first half of 2018, the feed rate was above 200t/h, availability reached 97.5%, operation cost was about 20% lower than the conventional three-step processes showing obvious economic advantages. The Two-Step process in Fangyuan is composed of 1 Submerged Lance Smelting furnace (SLS) and 2 Submerged Lance Converting& Refining furnaces (SLCR). Two SLCRs work alternatively to ensure continuous production. High grade and liquid matte from the SLS is introduced to the SLCR by sealed launder to complete converting and refining. The SLCR is an original and independent innovation of Fangyuan, for which Fangyuan completed lots of development and improvement. This paper will introduce the process and experience. INTRODUCTION China is the largest producer and consumer of refined copper. Most of the processes adopted in China are conventional "Three-Step" copper smelting processes, which are comprised of smelting, converting and refining. There exists some problems in the conventional processes, such as high energy consumption, large heat loss, low altitude emission of SO2, etc. To deal with these problems, Fangyuan developed the new copper smelting process with simplified flow, low cost, clean and high efficiency. The SLCR that combines converting and the refining process was also developed, which shortens the process flow from conventional three steps to two steps. The SLCR is of great significance in promoting the development of the copper industry. Development and industrialization of SLCR At present, copper concentrates are treated in three steps: smelting, converting and refining. Anodes are also produced by continuous converting processes such as the Mitsubishi process and the Double Flash process. Problems like matte transportation by ladle, capacity limitation, and low altitude pollution exist.

Jan 1, 2019

By Rick Steen, Weldon Read, Morrism Tracy T.

Edging for starter sheet blanks used in conventional copper refineries has always been problematic for getting the edging to seal and adhere to the titanium material used for the blank so that copper is prevented from plating under the edging and cause undo problems in getting the copper sheets to separate from the blanks. A method was developed at the Amarillo Copper Refinery utilizing an injection molding process that better adheres the edging material to the titanium that makes the harvesting of starter sheets much easier to the point that robots are now used to strip with and which holds up very well to the unforgiving physical nature of the electroplating process. It is believed that this technology could be successfully utilized for permanent cathodes as well. INTRODUCTION ASARCO LLC (Asarco) was organized in 1899 as the American Smelting and Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co- products (Marcosson, 1949). Grupo México, S.A.B. de C.V acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, molybdenum, selenium and tellurium. Asarco operates three open-pit mines and mills and two solvent extraction-electrowinning (SX-EW) plants all in Arizona plus a copper smelter in Arizona and a copper refinery in Texas. Figure 1 illustrates how the copper metal comes out of the ground at the mine and ends up as a refined product at the refinery. The copper refinery in Texas is known as the Amarillo Copper Refinery (ACR) and is located in Amarillo, Texas. It was built in 1975 to replace 3 other aging refineries and was designed to produce 550,000 tons (500,000 MT) of refined copper per year using conventional starter sheet technology. At the time it was commissioned it was the largest tankhouse in the world at just under 1/2 miles long under one roof.

Jan 1, 2019

By H. E. (Buzz) Neal

"Abstract - The Labrador Trough contains world-class iron deposits which have been mined since 1954. The direct shipping of Knob Lake ores were mined at Schefferville from 1954 to 1982. Concentrate production began in 1961 in the southwest end of the Trough, with three mines currently producing concentrate and pellets at a rate of 35 Mt per year. West and north of Schefferville, several billion tonnes of taconite have been outlined in fine-grained, cherty magnetite iron formation. Several deposits of highly metamorphosed magnetite-specularite iron formation are located west of Ungava Bay. Numerous studies have shown that this medium- to fine-grained iron formation can be beneficated to 66% to 68% iron. In the area from Wabush Lake to Mont-Wright, a medium- to coarse-grained friable specularite-quartz iron formation is repeated by folding to form several large deposits. In this area, three mining operations are located with reserves and resources in the order of 5 billion tonnes.The iron deposits occur within iron formation in sediments in the extensive Proterozoic geosyncline called the Labrador Trough. Several facies of iron formation within the Sokoman Formation reflect variations in chemical composition and depositional conditions. The correlation between the mineralogy and textures is discussed to illustrate the development of different types of iron ores. This band extends for about 1100 km southeast of Ungava Bay through both Quebec and Labrador. Further south, it turns southwest past the Wabush and Mont-Wright areas to within 300 km of the St. Lawrence River. The iron formation is essentially folded and faulted along most of its length. The degree of metamorphism is variable, ranging from intense in the northern and southern portions to greenschist facies in the central portion.The stratigraphy, structure and mineralogy of the producing mines are described along with the history of discoveries. Geological input is required to achieve the strict specifications of the international iron ore market."

Jan 1, 2000

By M. E. Stutt, R. H. Rehder

"The mining industry is taking advantage of the increased performance resulting from the use of variable speed A C drives for large motors. This technology provides increased efficiency under the variable speed and torque requirements of such drives as mine hoists, conveyors, and air moving equipment. The technology does introduce voltage spikes on the voltage wave form that stress the insulation system to a greater degree than would occur with a constant voltage source. These voltage spikes must be considered in the design of the insulation system used for these motors.BackgroundHistorically the insulation systems for large AC motors were designed to withstand with reasonable life the voltage stresses of a 60 Hz constant sinusoidal voltage. One of the design tests is a voltage endurance test that requires the application of a 60 Hz voltage from conductor to ground equal to four to five times normal and establishing a time to failure. These higher than normal voltages accelerate the normal aging process by causing extensive partial discharge activity (corona) within the insulation system and the time to failure is a relative indication of insulation life.In addition to the voltage endurance test at 60 Hz, the individual coils are subjected to a surge voltage test to establish the withstand capability of the turn to turn insulation under switching surge conditions. The surge voltage is a fast rise time, 0.2 microsecond to crest value, voltage spike that can be caused by a circuit breaker or contactor closing operation. These voltage spikes can have a crest value of greater than 3.5 times the normal line to ground crest voltage of the normal 60 Hz power supply. The standard withstand test value is thus 3.5 times normal line to ground voltage. Because the voltage surges or spikes occur mainly during start and stop switching conditions, voltage endurance under these conditions has not been a major factor in insulation system design."

Jan 1, 1995

By C. H. Ash

"The Red Chris Cu-Au deposit (522.7 Mt at 0.35% Cu and 0.27 g/t Au), northwestern British Columbia, is one of several pre-accretionary porphyry systems in the Cordillera of westernCanada. It is hosted by an Early Jurassic hornblende monzonite to quartz monzodiorite porphyry which forms part of a suite of dikes and stocks that intrude Late Triassic volcanic strata. Major and trace element chemical data suggest that these Early Jurassic intrusions have compositions which fall on the boundary between alkalic and calc-alkalic compositions. Alteration and mineralization in the Red Chris deposit are more typical of calc-alkaline porphyry systems with abundant potassic, sericitic and argillic assemblages and quartz-rich stockworks. It lacks Na- and Ca-bearing silicate assemblages which characterize the alkalic porphyry deposits of British Columbia. One of the more unusual features of the deposit is the abundance of carbonate alteration and veins which occur throughout the hydrothermal history of the deposit. This type of alteration and veining is more typical of alkalic porphyry deposits.The composition of the carbonates vary both temporally and spatially with different alteration zones. Potassic zones, which are characterized by orthoclase±albite±quartz±chalcopyrite±bor-nite±magnetite±hematite and Au/Cu ratios of 1:1 (g/t Au:% Cu), contain minor siderite veins and alteration. Quartz-sericite-carbonate (QSC) zones overprint earlier potassic alteration and comprisequartz+ankerite+sericite+pyrite+chalcopyrite with Au/Cu ratios of 0.5:1 (g/t Au:% Cu). Ankerite isthe main carbonate in this stage but has a variable composition with a more Fe-rich variety associated with mineralized veins. Localized chlorite-carbonate alteration zones, characterized by chlorite+carbonate+quartz±kaolinite±pyrite±gypsum and high Au/Cu ratios [2 to 3.5:1; (g/t Au:% Cu)],contain predominantly calcite. Late stage carbonate-gypsum veins have an ankerite to dolomite com-position which is very similar to the regional carbonate alteration and veins."

Jan 1, 1997