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By Marianella Perez, Williams Calderón, Gonzalo Montes-Atenas

The lack of fresh water sources, particularly in the Northern part of Chile, has driven the mine sites to search for new and sustainable paths to obtain water resources to run minerals processing operations. Among them, the use of seawater in concentrators appears as an interesting solution to this problem. However, the presence of seawater will have an impact onto the operation, not only because it will enhance corrosion reactions in the equipment installed in a plant, but also because it may affect how particles will effectively be processed across the numerous unit operations existing in the mine site. Among such unit operations, the grinding stage is a highly regarded as it defines the success of the separation of valuable minerals from gangue material in the froth flotation operation. Then, one important aspect to be addressed is to understand how the presence of seawater will affect the different mechanisms acting during the operation of a ball mill. The aim of this research work is to assess the effect of changing the aqueous matrix from process water to seawater in ball mills onto the mill performance. The methodology considered the use of Fluent® software and its capabilities to run numerical simulations with heterogeneous media. On one hand, from the data analysis, it is possible to infer that breakability mechanisms should not be significantly affected. On the other hand, the high ionic strength of the matrix should impact importantly particle transport mechanisms within the mill. Particularly, when transporting finer particles. Rheology results were in agreement with previous published research studies suggesting the suspensions to behave as Newtonian, Dilatant o Pseudo-plastic fluid depending on the amount of fine particles present in the grinding media. The latter will result in changes in the residence time of particles in the mill producing overgrinding or an excess in the circulating loads.

Jan 1, 2014

By Y H. Zhu, X X. Tang, Y C. Yin, M L. Xing

Based on the stiffness theory, the stiffness difference and energy supply of surrounding rocks are important inducing factors for strain burst. However, due to the lack of multi-level low stiffness testing machine, there are few experimental studies on rock failure mechanisms under the influence of loading stiffness. This paper introduced a self-developed rock testing system with changeable stiffness. The main testing machine of this system is a combined structure of inner and outer frame. The change in the loading stiffness is achieved by using a stiffness servo control system to control the energy accumulation in the inner frame. The tests of the sandstone specimens under three different loading stiffnesses in the testing system showed that the loading stiffness did not significantly affect either the uniaxial compressive strength or the Young’s modulus of the rock. However, the post-peak stress-strain curve of the rock became smoother and steeper when the loading stiffness was decreased, and the stress drop rate increased. It is shown that the stress drop rate had a power function correlation with the loading stiffness. After the peak load, the inner frame of the testing system rebounded several times at high speeds. The magnitude of the instantaneous rebound speed and the rebound duration increased with the decrease of loading stiffness. Both the mean rebound velocity and the total rebound deformation had power function correlations with the loading stiffness. The loading stiffness has limited effect on the energy storage and energy dissipation characteristics of the specimen, while the released energy of the testing machine increases as the loading stiffness decreases, which is the key factor affecting the failure mode of the specimen. According to the test results, a rock burst mechanical model considering the stiffness is established, and the energy supply mechanism of rock burst is quantitatively explained.

Nov 29, 2022

By Malcolm Clark, Robin K. H. Falconer

There are a number of likely impacts from mining operations, but a key issue is uncertainty about the environmental effects of sediment plumes created by disturbance to the seafloor and discharge of processed waters. The New Zealand National Institute of Water and Atmospheric Research (NIWA) is undertaking a research project to improve understanding of such impacts (relevant to both mining and trawl fisheries), by examining the extent and persistence of sediment plumes, the immediate impact and subsequent recovery of seafloor exposed to these plumes, and the effect on functioning of ecologically significant species. The project will use a combination of field survey experimentation with in situ observations and controlled laboratory-based experiments. The field work begins in May 2018 when an area of up to 1km2 at depths of 400-500 m on the Chatham Rise, 450 km east the New Zealand South Island will be subjected to disturbance by an upgraded former NOAA Benthic Disturber. The suspended sediment load created by the disturbance will be tracked and monitored, with the effects on seafloor animals examined by pre-and post-disturbance sampling. A wide range of seafloor sampling, benthic landers, towed cameras, oceanographic moorings and water column monitoring will be carried out over a three week period. Monitoring surveys will be repeated in 2019 and 2020 to determine the longer-term resilience and recovery of disturbed communities. The laboratory-based side of the programme, also starting in 2018, involves holding live deep-sea corals and sponges in tanks at NIWA, and exposing them to various levels and duration of particle loads in the water in order to reveal lethal thresholds as well as sub- lethal effects of settled and suspended sediment.

Jan 1, 2018

By Henry M. Howe

A discussion of the paper published in Bi-Monthly Bulletin, No. 20, March, 1908, pp. 227 to 237, and No. 22, July, 1908, pp. 615 to 620. PROF. HENRY M. HOWE, New York, N. Y. (communication to the Secretary *) :-Mr. Hibbard's definition of steel would be the best yet offered were it not for its one defect, the vagueness or equivocalness of "fusion-process." Puddling is surely in one sense a fusion-process, and so are the charcoal-hearth or knobbling-processes. But what he says suggests the following definition, which seems to me a good one: " Steel: any variety of iron which is usefully malleable at least at some one temperature, and is either cast when molten into a malleable mass, or if not so cast can be much hardened by sudden cooling." It is not necessary in a definition that quantitative bounds should be set up, for instance, that the exact height at which dwarf apple-trees cease and standards begin, or at which hills cease and mountains begin, should be stated. These quantitative measures are proper for specifications and contracts, but are not necessary for purposes such as the present. HENRY D. HIBBARD, Plainfield, N. J. (communication to the Secretary t) :-Professor Howe's criticisms of my definition of steel are not, it seems to me, well founded, for the . following reasons: The term "fusion-process" has been used during the past quarter or half century to distinguish the crucible, Bessemer and Siemens-Martin processes from the puddling- and cementation-processes, and probably no one at all conversant with the art of iron-metallurgy would now mistake its meaning. Moreover, no steel-metallurgist is in doubt of the meaning of the term "hardened? as applied to steel. If it were really necessary to describe what is meant by the term then it would

Nov 1, 1908

By A. T. Yu

Once exploration is complete, "winning" of the ore can be viewed as fundamentally a bulk handling proposition. Whether it is to strip, break, size, extract, load, haul, or even process, the success of each of these phases will depend upon how effectively one can utilize-the methods and tools that are available in bulk handling. Since as much as 30 to 60% of the total delivered price of raw materials can be attributed to handling and shipping (ref. 1), this expenditure may spell the success or failure of an entire mining venture. In fact, it has become increasingly evident that handling and shipping are so intimately associated with mining that only when they are duly considered throughout the mine-to -smelter master plan as an integral part of a total system can an optimum operation be expected and the most economical ton of ore obtained, this total systems approach should not only take in handling and haulage in and out of the mine, but also storage and transfer at the terminals (ref. 2,3,t), including ship and barge loading and unloading which are likewise a major consideration (ref. 5). Much has been developed during the past century in bulk handling, particularly in its expanding use in the mining industry. In view of the major role bulk handling has played and will continue to play in mining, in commemorating AIME's centennial, this paper will attempt to outline the state-of-the-art at this three-quarter point of the 20th century - one that is marked by its industrial revolution and rapidly accelerating technological advances. Bulk handling systems Although many developments in bulk handling are worth noting. The most significant during the past three-quarters of a century are: the total systems approach to solving problems, automation, the increase in speed and capacity.

Jan 1, 1971

"Boston’s Central Artery passes beneath nine active railroad tracks carrying commuter and Amtrak trains into South Station, the City's busiest rail terminal. These railroad operations had to remain in service throughout the construction of the “Big Dig”. The solution was to jack the tunnel under the tracks, rather than build the tunnel by more conventional means.Jacking of utility pipes is fairly common, but jacking boxes as big as a highway had never been done in North America, until the Big Dig came along.Soil freezing was decided upon as a means of stabilizing the soil under the tracks. This allows the tunnels to be jacked into place without soil caving when the soil is excavated at the leading face of the advancing tunnel boxes. Hundreds of pipes were driven into the ground between the tracks. Inside the steel pipes were smaller plastic pipes. A freezing plant near the railroad tracks pumped refrigerated brine into the inner plastic pipes. The brine ran out the bottom of the inner pipe, flowed up to the top inside the outer pipe, and was re-circulated to the freezing plant and back again into the ground. Over several weeks the circulating brine drew the heat out of the soil little by little, and froze the ground outward from the pipes. Soil FreezingThe plan required the construction of jacking pits in which the tunnel boxes could be constructed, and from which they could be jacked forward to their final locations, as described in the accompanying article. Once the jacking pit was built and the tunnel box constructed inside the pit, crews made an opening in the headwall of the pit to allow passage of the tunnel sections, excavated about three feet of the frozen soil, pushed the tunnel box ahead, and repeated the procedure again and again."

Jan 1, 2003

A generalised mathematical model for hydrocyclone classifiers was developed by the author (Nageswararao, 1978) using dimensionless groups which include phenomenological characteristics as independent variables. This model is incorporated in JKSimMet, the steady state mineral processing simulator developed by JKTech.Recently, when this model was rewritten (Lynch and Morrell, 1992), in terms of variables other than those used by the author, a few errors have crept in. For example, while the exponent of (Du/Dc) in the equation for d50e should be negative (-0.47), it was recorded as positive (0.47). Also, the exponent of (DoIDe) in the equation for pressure drop should be 0.67 and not 0.60. In the same equation, the exponent of Dc would turn out to be -0.10 and not 0.15. These are clearly attributable to typographic and rounding off errors, while transforming the original equations.More recently, Cilliers (pers comm) has done a comprehensive evaluation of the major semi-empirical models for hydrocyclones.He observed that the major difference between the cyclone model developed by the author and other models lies in the method of quantifying the effect of spigot diameter on d50e. He noted that while all other models predict an increase in d50e with a decrease in the spigot diameter, the model as cited by Lynch and Morrell (1992) predicts just the opposite. However, he conjectured correctly that the discrepancy could be due to a typographic error. As the model is still unpublished, it is felt that the original model equations should be recorded with the correct exponents, so that errors in predictions other than those due to the limitations of the model itself could be avoided. They are given hereunder.

Jan 1, 1995

By G. Cherkashov

A new hydrothermal field with massive sulfide deposits was discovered in 2004 at 16º 38.4?N, 46º 28.5?W on the Mid-Atlantic Ridge. Hydrothermal signals had already been recorded from bottom waters and sediments in this area during cruise 19 of R/V Professor Logatchev in 2000. This site was revisited during the 24th cruise of R/V Professor Logatchev in February 2004 when samples of massive sulfides were recovered and video records of the deposits made. The basalt hosted hydrothermal field is situated at a depth of 3700-3750 m, 600 m above the inner floor on the eastern slope of the rift valley. Structurally, the new field is located at the intersection of a deep along-axis marginal fault and a transverse sub-latitudinal dislocation. Six sulfide mounds as well as associated metalliferous sediments were mapped (sampled and/or recorded by video profiling) within the hydrothermal site. The largest ore body, 500 x 225 m, in the southern part of the field consists of small blocky talus and relics of sulfide chimneys partly covered by iron oxyhydroxides. The chimneys are 1-5 m high. The southern and western boundaries of the massive sulfide deposit have not yet been delineated. More than 1,100 kg of massive sulfides and stockwork mineralization were sampled at 7 sites by dredge and TV-grab. Everywhere, iron sulfides were the principal minerals present. Pyrite in association with lesser amounts of chalcopyrite occurs in both massive sulfides and stockwork mineralization. Of particular interest is the chalcopyrite-siliceous stockwork where silicified and chalcopyritized basalts are intruded by a network of chalcopyrite veinlets. These zones could be fairly thick and enriched in base metals. Sphalerite was very rare.

Jan 1, 2004

By Siobhan Quayle

Managing sediment plumes under multiple jurisdictions Management of activities in the New Zealand EEZ can be characterized as a distributed basis of decision-making with each independent and separate decision-maker focused on specific elements of a proposal (environmental, work place safety, wildlife management, fisheries, navigation, oil spill). The New Zealand EEZ Act 2012 was intended as gap-filling legislation to address the lack of an environmental assessment lens for permissions to undertake certain activities in the New Zealand EEZ. These activities relate mostly to marine scientific research, dumping and discharges, oil and gas exploration and development, and seabed mining. The regulatory decision-maker for most EEZ Act marine consents is the New Zealand EPA. Since 2013 when this gap-filling legislation took effect, the EPA and its decision- making committees have processed three seabed mining applications. Two consents were refused, one consent was granted in 2017. A common feature of all consents has been the assessment and consideration of the scale, significance and effects of sediment plumes arising from the activity. One consent is for irons and mining in about 40m of water where the plumes reach the nearby coastal waters and shoreline, the second consent is far offshore but plumes extend far beyond the mining area (850 km2) in to rare coral habitats and in to a significant offshore fishery. A significant consideration for decision-makers is how the assessment and management of plumes under the EEZ Act interact with, and potentially overlap, management of such plumes under other legislation (Resource Management Act, Marine Mammals Protection Act, and Wildlife Act). This is in a statutory context where the EEZ Act requires explicit consideration of the nature and effect of other marine management regimes over the matter under consideration.

Jan 1, 2018

By Felix Lehnen, Peter Kukla, Mirjam Rahn

"Significant uncertainty is associated with predicting future trends in deep-sea mining projects, especially when attempting to assess markets for associated products such as ships and collectors. In order to help European Original Equipment Manufacturers (OEMs) to appraise the future market share of deep-sea mining equipment, a methodology was developed that allows to assess and predict equipment turnover. This study presents a market analysis, which evaluates the scale of the potential market for deep-sea mining equipment for seafloor manganese nodules (SMnN) and seafloor massive sulfides (SMS) based on six key drivers: (i) the worldwide deposit potential of SMnN and SMS deposits, (ii) the profitability of deep-sea mining projects, (iii) the metal market of seven associated metals (Cu, Zn, Au, Ag, Co, Ni, Mn), (iv) the current legal and environmental situation in the Area, (v) investment and maintenance costs, and (vi) a competitor analysis.Figures for the different key drivers are based on public reports and expert interviews. Large uncertainties as well as contrasting views and expectations resulted in different options (scenarios) for the future development of the deep-sea mining market. Several scenarios were developed and based on the future number of “mining projects” in the short-term (2022-2041) and the long-term (2042-2061). The number of such mining projects has been calculated based on the combined analysis of the different key drivers.In the scope of this study, the definition of a “mining project” is a deep-sea mining operation for SMnN or SMS lasting for 20 years. This operation includes the purchase of a set of deep-sea mining equipment consisting of a mining support vessel, a vertical transport system and the seafloor mining equipment, in line with other work within the EU FP7 project “Blue Mining” (GA No. 604500)."

Jan 1, 2017

By Tetsuo Yamazaki

Natural methane hydrate has been scientifically studied as a carbon reservoir globally. However, in Japan, the potential for energy resource has been industrially highlighted. There is less domestic oil and natural gas resources in Japan, but many potential deposition areas for methane hydrate in ocean around Japan are the reasons. Less CO2 discharge from methane compared with coal, oil and conventional natural gas when the same calorie value we get is considered as the advantage for energy resource. However, because methane hydrate distributes in shallower sediment layer in ocean floor, accidental leakage of methane may occur while we utilize methane hydrate. Methane itself has 21-times impact on the greenhouse effect, if it reaches the atmosphere. Therefore, it is necessary to estimate the behavior in the environment after the leakage, if we want to use methane hydrate as energy resource. The mass balance after leakage of methane on seafloor and in water column is numerically studied through the analyses of methane emissions from natural cold seepages and hydrothermal activities in this research. The outline structure of mass balance ecosystem model shown in Fig. 1 is introduced. A numerical early diagenetic model CANDI (Carbon And Nutrient Diagenesis) developed by Boudreau (1996) for simulating the biogeochemical processes such as organic matter, oxidant, nutrient, bi-product, and pH diagenesis in aquatic surface sediments and C. CANDI improved by Luff and Wallmann (2003) for describing the formation process of calcium carbonates in CANDI are used as bases of the ecosystem modeling in surface sediment layer around seafloor methane emission. Two functions such as methane bubble dissolution and bacterial methane oxidation in water column are added to an existing physical plume dispersion model by Doi et al. (1999).

Jan 1, 2005

By J Pearce, B Miles, V de San Miguel

Incorporating industry best practice waste rock management methods can be a relatively straight forward task when preparing management documentation, such as an acid and metalliferous drainage management plan (AMDMP). However, a key difficulty is the incorporation of industry best practice methods that are practical and non-compromising on their purpose from a scientific standpoint. The second key difficulty is the implementation of these practical methods as various operational groups/departments are typically relied upon to execute and take ownership of different tasks or procedures.One approach to overcoming these difficulties is to develop an AMD Operations Manual (AMDOM) that:•Incorporates, where practicable and without compromising scientific merit, existing processes that those groups/departments ultimately responsible for the execution of the management action are familiar with; and•Provides standalone, simplistic, and easy to follow procedures for site personnel. The purpose of the standalone operations manual is to ensure site personnel who are responsible for undertaking specific procedures, have clear, step-by-step instructions for an individual procedure, without requiring interpretation and understanding of the more comprehensive AMDMP.In adopting a best practice approach to waste rock management for their iron ore mine in Western Australia’s Pilbara region, Roy Hill developed an AMD Management System that is comprised of both an AMDMP and an AMDOM that are connected through adaptive management processes. The Roy Hill iron ore mine, which has a mine life of 18 years, will require the management of more than three billion tonnes of waste rock.CITATION:de San Miguel, V, Miles, B and Pearce, J, 2018. Practical waste rock management at the Roy Hill iron ore mine, Western Australia, in Proceedings Life-of-Mine 2018, pp 80–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By J. A. Hillier

"IntroductionThe purpose of sampling is to remove a portion of material from a stream which is representative of it in size, moisture and mineral content.To prevent the effects of segregation, generally caused by the way in which a conveyor, pipe or launder is loaded or directed, the sampler should cut proportionally the entire cross section of the stream.If one conveyor transfers to another at a right angle, fines may be dropped on the near side, and the coarse material thrown to the opposite side. Segregation can also occur as a result of the motion of a conveyor belt passing over the idlers causing the coarse material to roll to the sides of the belt.When slurry changes direction of flow in a launder or pipe, the heavier and coarser fraction will centrifuge to the outside of the curve and tend to remain on one side of the stream. Similarly, if two streams joining in a common launder are not mixed at the point of confluence, they will continue down the launder unmixed . This effect is particularly noticeable in a plastic lined launder.Therefore, a proportional sample is usually accomplished by a constant rate of cutter travel across the entire stream, making certain that the cutter is not full or splashing over before reaching the end of travel.The cutter should operate on a constant interval based on time, tonnage and uniformity of flow. The opening should be at least three times the width of the largest piece to be sampled. The cutter width is more critical with ore samples where particle sizes are large. With slurry samples, the opening is usually much larger than the minimum in order to obtain sufficient samples"

Jan 1, 1989

By Ed Sullivan

"Australia is one of the richest continents when it comes to mineral extraction, ranging from exotic projects like the Olympic Dam — a copper, silver and uranium mine believed to have the world’s largest uranium resource — to the extensive iron ore, nickel, coal and gemstone formations that provide many of the country’s most rewarding exports.Among the challenges to succeed in this industry is the ability to provide efficient “pitto- port” infrastructure performance, which essentially means ensuring that minerals move seamlessly from the point of extraction to the facilities that can then move them to international market destinations.To provide such efficiencies, avoid human error and facilitate automated mining functions, producers are increasingly turning to fiber optic cable suppliers for “end-to-end” communications and control solutions. Many such solutions include ruggedized cable and connectors that ensure the survival of fiber-based DCS/PLC automation/ control architectures for various types of mining operations, even in the harshest environments.Integrating the solutionAs industrial Ethernet and fiber optic cable emerges as the medium of choice in many industrial arenas, communication and control integration using the most appropriate products for a specific application is increasingly important.“This whole ‘pit-to-port’ performance concept is focused on control and process automation,” says Boyd McDonald, Founder and Managing Director at Datalek Systems & Electrical, Rockhampton Area, Australia. “It also means bringing reliability to networks and providing the needed bandwidth. An appropriate plug-and-play solution is also important because it takes human error out of the equation.”Datalek Systems & Electrical, is responsible for the design, installation and maintenance of numerous fiber optic communications systems including those that involve automation, security, access control an CCTV systems for open-pit and underground mining operations as well as LNG and coal seam gas facilities."

Jan 1, 2015

By AIME

TURMOIL has been rampant in the lead producing industry during 1946. The chronic labor shortage was aggravated by various work stoppages in mines, smelters, and refineries, while shortage of materials was widespread. Price uncertainties helped to confuse the situation in many countries and particularly in the United States until the removal of price control in the latter part of the year. At the end of the first year of peace, lead, which had been comparatively plentiful during the war years, was a scarce and high-priced metal throughout the world. It is the hope of the industry that the law of supply and demand, if allowed to operate without interference, will bring about a satisfactory balance between production and consumption. Under these circumstances it is not surprising that there have been few important developments in the metallurgy of lead, though a number of items of general interest to the industry have been reported. An ore body which may prove to be of considerable importance has been discovered at Mpanda, Tanganyika. The scarcity of lead ore is illustrated by the announced reopening of the La Manche lead mine in Newfoundland, idle for 56 years. A new lead producer came into production when Rhodesia Broken Hill started up its new smelter. Lead concentrate of 75 per cent grade is smelted in Scotch hearths and the lead is refined to market grade by the Harris process without desilverizing. Production is about 1000 tons per month. One Australian lead producer, Mount Isa, has returned to lead production after having operated its lead plant for the production of copper during the war. The East Chicago plant of the International Smelting and Refining Co. has been sold to the Eagle-Picher Co.

Jan 1, 1947

By M. S. Davis

The Tek Process can produce masonry products such as bricks, roof or wall tiles, and block from virtually any inorganic waste. In the process the aggregate raw materials, portland cement, water and common chemicals are first mixed together; then mechanically subjected to several thousand pound pressure per square inch. This causes a novel chemical reaction between the cement, chemicals and water; producing the "patented" Tek adhesive binder which holds the aggregate together in a stone-like mix. Simultaneously, the desired product shape is formed. The building modules can have strengths of 8000 p.s.i. (pounds per square inch) with completely sound aggregates utilizing air curing for a period of 28 days. With most aggregates, 3000 p.s.i. is achieved within 24 hours. Eventual strengths usually exceed 5000 p.s.i. with almost any raw material. Water absorption ranges from 5-7.5 percent. Both absorption and strength figures are superior to the most rigid of any and all A.S.T.M. specifications for the highest quality bricks. In most locations, the product (when brick shaped is called Tekbrik) can be produced significantly more economically than can comparable grades of clay or other bricks, be- cause almost any inorganic waste materials or pollutant can be used as a raw material. The process results in a lower manufacturing cost as compared to clay bricks; fuel cost to operate a clay kiln represents a substantial portion of the total cost. Capital expenditure for a Tek plant also is lower due to the large investment in clay kilns. Transportation savings also are important, clay brick factories must be very large because the kilns are uneconomical unless they are large. Most bricks are manufactured at the sites of clay deposits in relatively uninhabited areas. The cost of transportation to the job site represents a considerable percentage of the selling price.

Jan 1, 1974

By A. J. Williams

"IntroductionAN EXCELLENT paper entitled Potash Discoveries in Western Canada (l) was presented to the 1948 Annual Meeting of the C.l.M. by L. Heber Cole, of the Department of Mines and Resources, Ottawa. In the intervening three and a half years, the search for oil and gas in Saskatchewan has added considerably to the information available on the occurrence of potash. It is the purpose of this paper to summarize the additional data. For greater clarity, it may be useful, first, to recapitulate some of the highlights of Mr. Cole's paper.Underlying the western plains of Canada there is a large deposit of sodium chloride, believed to be of early Devonian age. Associated with the sodium chloride are certain potash salts, primarily 'sylvinite,' a mechanical mixture of sodium chloride (halite) and potassium chloride (sylvite) crystals. The potash salts, when present, are usually near the top of the salt formation, though in at least one well they were found near the central part of the deposit. Cole reported on some seven wells in Saskatchewan which had encountered appreciable amounts of potash; these were the Ogema, Radville, Davidson Nos. 1 and 2, Prairie Salt Nos. 1 and 2, and Verbata wells. Depth of potash from surface ranged from 7,653 feet in the Radville well to a minimum of 3,466 feet in the Verbata well. Such depths do not compare favourably with those at which the potash is found in mines in the United States, France, and Germany, where about 1,000 feet is the average. The greatest concentration of sylvite encountered was in the Verbata well, where a bed 11 feet thick carried the equivalent of 21.64 per cent K20."

Jan 1, 1952

By Fumio Hashiuchi, Yushiro Hirai, Masatoshi Maeda, Toshihiro Nagata

"Increase in the copper smelting capacity at Saganoseki Smelter & Refinery was attained through various improvements in the PSconverters and the flash furnace. Two of the major innovations in the converting process were: a new operational technology which avoids increase in the copper content in the converter slag even when higher copper grade matte (65%) are treated in the slag making stage and a technology which shortens the operational interruption time which is caused by coolant charging. The latter was realized by introducing a new automated coolant charging system with which it was made possible to charge the coolant without stopping the blowing into the converter. These improvements brought about a remarkable increase in · the production capacity per converter and an annual production of 450,000 tons of copper without adding new furnaces was made possible. In addition, good results have been obtained of the tests with modified tuyeres to further increase the production.IntroductionIn a bid to renovate its Saganoseki Smelter & Refinery and to establish a leading production unit in terms of global competitiveness, Nippon Mining & Metals undertook major restructuring efforts since 1994. One of its themes was the shift from· a two-flash furnaces operation to a single-flash furnace operation. The shift was successfully completed in 1996 while maintaining the production at the same level (330,000 tons per annum of copper). Then, the productivity was enhanced to 450,000 mtpy without adding new furnaces through technological and operational improvements. It is now planned to increase the smelting capacity further to 470,000 mtpy this year.Some technological and operational improvements in the matte converting process and the new plan resulted from the tests with modified tuyeres are presented in this paper."

Jan 1, 2000

By Srinath Viswanathan, Zhijing Zhang, Ramana G. Reddy

"The viscosity measurements were carried out on melts of 380 aluminum alloy containing 20 volume % SiC particulates under various shear rates at different temperatures using a Brookfield viscometer. Results showed that viscosities of the melts increased with decreasing temperature and decreased with increasing shear rate. These results were compared with those of 356 alloy and it was found that the temperature had a more significant effect on viscosity of 356 alloy than that of 380 alloy containing SiC particulates. Based on the present experimental data an empirical viscosity model, which considers the effects of both solid fractions in the melt and shear rate, is proposed.IntroductionDiscontinuously reinforced metal matrix composites materials (MMCs) such as aluminum alloy containing SiC particulates have considerable potential for applications in the automotive industry because of their superior stiffness, higher specific mechanical properties, better dimensional stability and strength retention at elevated temperatures when compared to their monolithic counterparts. They have a great advantage in the specificity of their properties, meaning that specific materials can be engineered for specific applications. With such freedom of design, materials engineers have to accumulate a very large database of mechanical properties. Among these properties, the viscosity of alloy slurries is very important for producing, casting and forming process of metal matrix composites materials because viscosity has a decisive influence on fluid flow. The understanding of the rheological behavior of alloy slurries is necessary for these materials to become economic reality. Therefore, a study was carried out to measure the viscosities of 380 aluminum alloy containing 20 volume % SiC particulates under various shear rates and temperatures. In addition, a viscosity model representing the primary features of the alloy slurries was developed."

Jan 1, 1999

By Hans Lundberg

An electric survey from a 'plane flown over the ground is much faster and cheaper than an electric survey carried out on the ground. The results are obtained as continuous recordings that are resolvable into both a depth expression and a conductivity effect, so that the indications are easier to evaluate, as well as to correlate from one flown line to the other. The prospecting technique adopted in our electric airborne surveys may be brie fly described as follows: A loop of many turns of insulated copper cable is fastened around the fuselage of the 'plane and connected to a generator supplying a few ampere alternating current, usually of a frequency less than 1,000 cycles per second. Just as the current in the primary coil of a common transformer will induce current in the secondary coil when shorted, the alternating magnetic field from this primary current now induces alternating current in electric conductors that happen to be located in the vicinity of the path over which the 'plane is flown. This induced secondary current in each conductive section of the ground causes, in turn, an alternating magnetic field, secondary field, which disturbs or dampens the normal alternating magnetic field from the primary loop flown by the 'plane. These secondary fields are then picked up and recorded by the help of detecting solenoids, amplifiers, and recorders carried in the 'plane. By closer study of such a secondary field it is possible to localize the secondary current causing it and, thereby, the conducting body that contains the secondary current. In the 'plane are continuously recorded, besides the amplitude or intensity of the field, also the phase, which is a measure of how much the recorded secondary field is out of step with the primary field.

Jan 1, 1950