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By CADEN VITTI, Barbara J. Arnold

Mine tailings, the byproduct of mining and mineral processing, are increasingly mass produced as a result of increased demand for metals and minerals as well as the advancement in technology that allows for the exploitation of lower-grade ores. Lower grades can increase the volume of tailings that may contain new gangue minerals that should be evaluated for the presence of critical minerals and other valuable metals. The practice of reprocessing, while relatively new, is crucial to reducing environmental damages, obtaining valuable critical minerals from waste, and contributing to more sustainable repurposing and disposal methods. With the increase in tailings dam failures in recent years, there is a large motivating factor in remining and removing the potential hazard to benefit the safety of potentially impacted communities. In analyzing the perspectives of various domestic and international studies, this literature review will determine the feasibility of reprocessing and reutilizing mine tailings waste for a more sustainable future while exploring current practices that have benefitted ecosystems and communities.

Jan 1, 2022

By A K. Ghosh

"Inrush of water is always an issue, especially for mines located in heavy rainfall areas. Nowadays, mining companies and research institutes have developed many advanced technologies for study and analysis of hydrological processes. In this paper, an advanced method is introduced, which uses the Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) data in the Geographical Information System (GIS) platform to simulate the stream distributions around two specific mines: Super Pit and Griffin coalmine in Western Australia. The impact of this approach is important because it reduces the time and economic cost by creating a high spatial resolution hydrological map in the specific areas. The study identifies the flow path of the run-off water, which helps in adopting a suitable water management plan surrounding the case study mines. The results match with the ground reality. Based on the results, the stream structure around Griffin coalmine is more complicated than that of Super Pit. The bifurcation ratio and drainage density are computed to estimate the subsoil permeability characteristics of the two mines. Recommendations have been put forward to prevent and reduce the potential risks of water accumulation around the open pit mines.Citation:Ghosh, A K, 2016. Application of Shuttle Radar Topography Mission Data in Hydrological Analyses of Super Pit and Griffin Coal Mine, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 162–169 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By Raymond A. Bradbury

Martin County Coal Corporation's operations are located on Wolf Creek in Martin County in the eastern part of Kentucky. The mining complex was started in 1971 and has grown to a 2.273 Mt/a steam coal operation. All of the production goes to Duke Power Company's Belews Creek electric generating station in North Carolina. Production comes from four seams that are mined by deep and surface mining methods. Surface mining accounts for 55% of the production and the remainder comes from 2 underground mines. Continuous miners are used exclusively underground. The preparation plant was originally designed to take coal at the rate of 907 Mt/h but that has gradually been increased to 1134 Mt/h. Other cleaning equipment includes Daniels DMS vessels, Model 77 Deister tables, 355.4-mm R. & S. Hydro- cyclones, Krebs 254-m classifying cyclones, Daniels froth cells and in 1980, 3 Krebs 508-mm heavy media cyclones were added to recover some lost and misplaced material. CMI centrifugaldryers and a Hey1 & Patterson size 100 thermal dryer are also part of the coal preparation equipment.

Jan 1, 1981

By W. J. Parton

THE efficient recovery and preparation of small sizes of anthracite called No. 4 Buckwheat (3/3 2 by 1/3 2 in.) and No. 5 Buckwheat (1/3 2 in. by 0), present a difficult problem to the anthracite operators. In many instances preparation of these sizes, particularly No. 5 anthracite, is extremely inefficient. In many of the older preparation plants, inadequate facilities, and often none at all, were provided as an integral part of the plant for cleaning this fine anthracite. Consequently, much of the material smaller than s, 32 in. was discarded. As the demand for these sizes increased, facilities for preparing the fine sizes were often crowded into existing structures with consequent sacrifices of capacities and efficiency. In addition to this condition, the methods of preparing the finest sizes are being developed in an attempt to improve their efficiencies. Because the demand for small sizes of anthracite still is increasing, many operators would benefit by investigating and improving the cleaning equipment employed on these sizes.

Jan 1, 1949

By Young C. Kim, Francis Martino, Ish Chopra

For the past two and one-half years, various emission control strategies were jointly developed by the University of Arizona and the Homer City Owners to com- ply with the clean air requirements at its Homer City Power Plant. Some of the available options for the SO2 emission control by the Homer City Owners were:l)cleaning of run-of-mine coal,2) scheduling of mining operations at its captive mines, 3) blending the captive mine coal with externally purchased low sulfur coa1,and 4) placing a partial FGD system. This paper describes two specific emission control strategies developed and implemented. These are: 1) production scheduling at the mining face to minimize sulfur variability, and 2) external purchasing of low sulfur coal for further blending. The main objective of this paper is to share our experiences on implementing the developed strategies. This paper emphasizesthe need for proper mine planning on a short-term basis, if the power plant is to meet the desired objective.

Jan 1, 1983

By E. Allen Hendt

It is a pleasure to be invited to speak before a gathering of executives representing America's leading mineral companies, I welcome this opportunity, particularly because it comes at an important period in the development of U.S. commodity policy. This morning, I discussed our general commodity policy primarily in the. Context of the north-south dialogue between developed and developing countries. This afternoon, I would like to focus more specifically on potential cartel activity and U.S. mineral import dependence.

Jan 1, 1978

By William Gleason

From Nov. 16-20, the Extraction 2025 Conference will be presented in Phoenix, AZ. The unique conference brings together the 12th International Copper Conference, the 6th International Symposium on Nickel and Cobalt as well as cross-cutting symposia. Extraction 2025 is co-organized by The Metallurgy and Materials Society (MetSoc) of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the Society for Mining, Metallurgy & Exploration (SME) and The Minerals, Metals & Materials Society (TMS). The previous, and first Extraction meeting (Extraction 2018) was held jointly by these three societies seven years ago in Ottawa and was a huge success with more than 90 percent of respondents indicating interest in attending a future event. Kimberly Mills, senior process engineer at Samuel Engineering, is the lead for SME. “This installment of Extraction is featuring Copper 2025, Nickel-Cobalt 2025 as well as crosscutting symposia,” said Mills. “All three societies participate on the International Organizing Committee for the Copper Conference Series and are well situated to host this event together. TMS is also hosting the Ni-Co conference this year and agreed to include it as part of Extraction. There are many aspects that can be shared between these commodities to share information on processing technologies and to learn from each other.” SME is the overall conference chair and running the logistical aspects of the event, which includes managing all aspects of the venue and the registration system as well as tours and short courses, Mills said. “SME has many dedicated members serving in various capacities on organizing and programming committees, including Nick Gow serving as Technical Committee Co-Chair for Copper and Adam House assisting on the Copper IOC.” When Extraction 2025 kicks off, it will be focused on the metals needed for the global energy transition with a special focus on copper and nickel-cobalt. “With as rapidly as the industry is changing and the huge demands for these metals we have some serious challenges ahead of us,” Mills explained. “These challenges require collaboration, creative solutions and engaging experts, both inside and outside of our fields, with a push for sustainable sourcing, ethical supply chains, environmental and social responsibility.” The International Copper Conference was started in 1987 as a collaboration between the Institute of Mining Engineers of Chile (IIMCH) and MetSoc of the CIM. The event is typically held every four years and has always been held as a standalone or headlining event at a society annual meeting, said Mills. “Over the years, this conference series alone has brought together members of IIMCH, MetSoc, TMS, SME, the Society for Metallurgists and Miners from Germany (GDMB), the Mining and Materials Processing Institute of Japan (MMIJ), the South African Institute of Mining and Metallurgy (SAIMM) and the Nonferrous Metals Society of China (NFSOC),” she added. “Being a part of Extraction allows for even more sharing of ideas and expansion of networking. This conference has not been held in the United

Oct 1, 2025

By B. Arvidson

Computer-controlled machine sorting may, if properly applied, have a dramatic effect on overall economics of a mine operation. Radiometric and photometric sorters have been used for many years and new developments will be reported, such as a sorter for fine particles and a conductivity/magnetic sorter. Application examples with emphasis on precious metals will be given. Economics for some of the projects will be reviewed and discussed. Sorting underground is shown to be particularly attractive, but machine sorting would be profitable in most cases based on savings in transportation and milling/beneficiation costs only.

Jan 1, 1987

By Rogerio C. Guimarães, Antonio E. C. Peres

The production of phosphate concentrates (phosphate rock) from slimes represents a challenge to the phosphate industry worldwide. In Brazil, this challenge is particularly relevant due to the consistently low P2O5 grades and the igneous origin. The Brazilian phosphate deposits are made up mainly of apatite from alkaline chimneys, representing 80% of the Brazilian reserves; phosphorite deposits contribute 18% and the other sources (guano, phosphorous bauxite, and apatite from veins) reach 2%. The Brazilian industry beneficiates phosphate ores that are mineralogically more complex than those treated elsewhere. The low apatite grade, inherent to the igneous Brazilian ores, added to the mineralogical complexity due to the weathering of the rocks, has represented a permanent challenge to the Brazilian process engineers. The total measured, indicated and inferred reserves reach 3.2 million tonnes of ore with average grade 11% P2O5. The development of local technology for phosphate beneficiation started in the 1960’s. The first industrial experiences of producing phosphate rock from slimes (-44µm or -325#) fraction started at Arafertil, currently Bunge Fertilizantes SA, in Araxá, in the 1980’s. This production corresponds, nowadays, to 35% of the total production of concentrates in the company (830,000t/year) in a circuit consisting of desliming in 40mm microcyclones and concentration in flotation columns, corn starch and fatty acids being utilised as reagents. The performance of slimes flotation and the process control, at Bunge´s concentrator, were improved after the introduction of column flotation technology, in the first half of the nineties. The column flotation technology for slimes recovery was expanded to other Brazilian concentrators still in the nineties: Ultrafértil (Catalão – GO), Bunge (Cajati – SP), Fosfértil (Tapira – MG) and Copebrás (Catalão – GO). At present the Brazilian production of phosphate rock is approximately 4.5Mt/year, with a strong trend for a market increase. Genuinely Brazilian technology is utilised for the processing of slimes, the concentrates representing 11 to 13% of the overall production. The production of apatite concentrates from slimes was relevant to increase phosphate recovery and reduce costs, contributing to the growth of the fertilisers industry.

Jan 1, 2003

High-sulphidation (HS) gold, silver and/or copper deposits are generated in both the epithermal and the upper parts of the underlying porphyry environments over vertical intervals of up to 2 km. The HS deposits are generated in advanced argillic lithocaps, which are products of the absorption of acidic magmatic volatiles by voluminous groundwater systems. Mineralisation styles in HS systems reflect depth of formation as well as the interplay between structural, lithological and hydrothermal parameters. The deep parts of HS systems, at depths of >1000 m, are typified by disseminated copper¦gold mineralisation comprising digenite, chalcocite and covellite in pervasive advanced argillic as well as underlying sericitic alteration. In highly telescoped systems, such mineralisation may overprint porphyry stocks and associated quartz-veinlet stockworks. Intermediate levels of HS systems commonly contain fault-controlled copper-gold mineralisation, typically as enargite in bodies of vuggy residual quartz, silicification and/or massive pyritic sulphide. The shallow parts of HS systems, at depths of The exploration focus is on four principal HS mineralisation styles:copper (eg Chuquicamata, Monywa) or copper-gold (Wafi) in the deep porphyry-hosted parts of systems preferably, in the case of the latter, where supergene oxidation is limited and, hence, flotation may be used for metal recovery; copper¦gold-bearing replacement mantos and pipes hosted by carbonate wallrocks in the deep parts of systems (eg Bisbee); high-grade gold in late-stage veins or hydrothermal breccias that overprint the intermediate to shallow levels of systems (eg El Indio, Goldfield); and large, bulk-mineable gold deposits in the shallow parts of systems that were subjected to supergene oxidation, thereby permitting heap-leach treatment (eg Yanacocha, Pierina). To these preferred HS styles may be added the low-sulphidation vein or disseminated gold¦silver mineralisation that is commonplace alongside many HS systems (eg Victoria at Lepanto).

Jan 1, 1999

By E. W. Pehrson, J. W. Furness

THE five charts presented here- with are part of an original group prepared by the U. S. Bureau of Mines showing the international trade in the principal metals and metallic ores. Charts 011 anti- mony, chromite, copper, lead, manganese, mercury, nickel, tin, tungsten, and zinc were published in the February, 1936, issue of the Engineering and Mining Journal. Those shown here include bauxite, aluminum, iron ore, pig iron, and the platinum-group metals.

Jan 1, 1936

By Richard Keith Corbin

INTRODUCTION With the world media full of predictions that the price of gold will quadruple in three years (Maybury, R.J., 1988), and with financial forecasters and strategists touting opportunities to make 400% in gold (Skousen, M., 1988), explorationists and entrepreneurs are scurrying to find enough gold to feed the global gold fever created. At the same time, gold deposits in the United States and other developed and intermediate countries are becoming less attractive because of environmental restrictions, radical reductions in tax incentives, and depleting reserves, causing people in the mining industry to begin looking at opportunities for foreign investment in gold mining concessions in lesser developed countries (LDCs). Meanwhile, LDCs are responding with chamber-of-commerce aplomb in marketing their opportunities. In the face of all this frenzy and hype, targeting gold mining concessions in LDCs for foreign investment may be done more objectively by employing a systematic approach. For this paper the SHOP rating system (Corbin, R.K., 1987), which considers factors of the LDC's stability, hospitability, ore occurrence, and profitability potential is used. The result is that a tiny banana-growing republic in Central America, first discovered by Columbus and named the "Rich Coast'' because of the many gold adornments worn by its Indians, has been rediscovered and emerges as a classic LDC gold target.

Jan 1, 1988

By D. A. Augenstein, L. V. Amundson

Operators of coal preparation plants use equipment such as large-capacity dump trucks and bulldozers to haul, spread, and compact refuse material to conform to federal and state regulations governing the disposal of solid waste. For example, federal regulations require that refuse be spread and compacted in layers not more than 0.6 m (2 ft) thick. If the refuse layers or piles have poor load-bearing characteristics, movement of equipment over them becomes extremely difficult. The increasing cost and limited space for the construction of settling ponds extensively used for fine refuse disposal are leading to the growing practice of dewatering the fine refuse by means of vacuum disk filters and combining the resulting filter cake with coarse refuse for waste bank disposal. However, this filter cake usually contains more than 25% moisture. Therefore, when it is combined with coarse refuse, the moisture level of the total refuse may become high enough to impair the load-bearing strength of the refuse. Precisely this problem and the attendant difficulties of moving heavy equipment arose when vacuum disk filters were installed at a preparation plant in West Virginia. Combining the moist filter cake with the coarse refuse generally results in a 12% moisture level for the total refuse at this plant. At this moisture level, the refuse can still be handled with some dif¬ficulty by the equipment. However, the problem has frequently been compounded after rains. The experimental program described in this paper tested the following methods of improving the load-bearing properties of coal refuse: moisture reduction, addition of crushed coarse refuse, addition of fly ash, addition of lime, and addition of a mixture of lime and fly ash. In terms of a balance between economic and technical considerations, the most effective method was demonstrated by laboratory and plant tests to be a 2% to 5% addition of lime. Test Program During formulation of a test program aimed at improving coal refuse stability, a number of treatment techniques were selected for evaluation of their effect on refuse load-bearing characteristics. The reduction of refuse moisture was the first technique considered, since moisture content plays a key role in the bearing strength of a bulk solid. The reasoning was that a very small reduction in refuse moisture, provided it could be accomplished with minimal effort and cost, would be sufficient for eliminating refuse disposal problems most of the time. At the same time, it was recognized that periods of rainy weather would offset moisture-reduction measures. Other techniques selected for evaluation because of their potential for improving refuse-bearing strength at reasonable cost were: addition of crushed coarse refuse, the addition of fly ash, and the addition of lime. A simple one-dimensional laboratory compaction test was designed for evaluating the effect of each of these techniques on refuse-bearing strength. Those techniques that gave best results in the laboratory would then be tested in the preparation plant in West Virginia. Laboratory Tests The laboratory test for evaluating each of the techniques involved the application of weight to a load module placed on a refuse sample in a container. The distance the load module sank with an increasing amount of applied weight was measured, and the relationship between module displacement and loading was obtained. The refuse container was large enough to minimize the influence of wall effects, and to decrease the effect of the container bottom, a test was terminated when the load module sank to about three fourths the depth of the container. Initially, an attempt was made to conduct compaction experiments with samples of total plant refuse. However, the presence of + 0.13 m (+ 5 in.) material in the refuse interfered with the mechanics of the test, and the large amount of material required for a representative sample made testing extremely tedious and time-consuming. To avoid this problem and because it was believed that only the fine components of the refuse were the major cause of the stability problem, tests were conducted with 13 mm X 0 (1/2 in. X 0) material from the total plant refuse. The equipment consisted of a 0.46 m (18 in.) cubic container, a loading module with 62 cm2 loading area, weights totaling 450 kg, and a portable concrete mixer for combining water and additives with the refuse. Refuse samples of about 110 kg dry weight were used for each test. Experimental compaction test data were evaluated by plotting the linear displacement of the load module vs. loading. During compaction tests, the vertical displacement of the load module was measured at each loading value. The plot of

Jan 1, 1980

By Y. M. Zhu

Lead in environment often causes a serious health hazard. The removal of Pb2+ from aqueous phase is a beneficial project. In this paper, deposited Saccharomyces cerevisiae (S.c.) was chosen as adsorbent, Pb2+ ions as adsorbate, and the process of biosorption was studied. The dynamics of the adsorption was investigated. The adsorption mechanism of Pb2+ by S.c. cells was also investigated by detecting microstructure, zeta potential under different pH value, FT-IR spectra of the S.c. particles before and after biosorption. It was shown that the biosorption of Pb2+ by deposited S. c. is a rapid process, and the adsorbing equilibrium is reached within 10 minutes. The Zero point of zeta potential of S.c. cells is pH=3.3. When 2.0<pH<3.3, there exists biosorption (biosorption rate 76%~88%), which means static bio-sorption been not the only kind of biosorption. FT-IR spectrum analysis showed that groups on bacteria surface were mainly characteristic groups of protein and amylase; oxo-groups and nitric-groups on S.c. cell surface could chelate with heavy metal ions. Chemical adsorption might exist in the process.

Jan 1, 2014

By T. S. Golosinski

This paper identifies the components of belt conveyor shifting force as a vertical force. Pv, horizontal force, Ph, and longitudinal force, P1. A method for estimation of these forces is proposed, which relates their value to the properties of the conveyor structure and rails, shifting operation parameters, and other site-specific conditions. The effect of this force on shifter behaviour is analysed and guidelines are developed for selection of a suitable shifter. Also discussed are the requirements of the shifting operation for other equipment.

Jan 1, 1986

By Desmond Cook, Cynthia P. Dogan, Dale Govier, Gary Korth, James C. Rawers

"The microstructural and mechanical properties of iron powders processed in an attrition mill are highly dependent upon the processing environment. Extended high-energy ball milling in argon resulted in nanocrystalline bcc-Fe microstructure, while processing in nitrogen or alloying with carbon resulted in both nanocrystalline bcc-Fe and bct-Fe microstructures. In this U.S. Bureau of Mines study, both X-ray diffraction and Mössbauer analysis were used to show that the infused carbon and nitrogen concentrations were predominantly on the grain boundaries. Explosive consolidation resulted in a fully dense product with microstructure similar to the microstructure of the mechanically processed powder. Hardness values of the compacts correlated highly with grain size, independent of the processing conditions.IntroductionNanocrystalline materials have been theorized and shown to have unique properties that make them interesting for material scientists and promising for material engineering applications. Several conferences have been devoted solely to the techniques of preparing nanostructured materials have been held(l,2,3.). To date, most techniques used to generate nanocrystalline materials produce only a few grams of particles(1). High-energy ball-milling, however, is an efficient and effective technique that can produce substantial quantities of nanocrystalline materials with homogenous chemical composition that cannot be produced by conventional processing techniques(3).Applications and material evaluations of nanocrystalline materials require several grams of solid samples. Because nanocrystalline microstructures' are thermodynamically unstable, producing consolidated macro structures of nanocrystalline material has proved to be very difficult(2,3). In particular, retention of the nanocrystalline microstructure during consolidation of nanocrystalline particles has proven to be a problem. In contrast to many consolidation techniques that require elevated temperatures, explosive compaction uses a shock wave for consolidation( 4,5)."

Jan 1, 1994

By Stênio Cavalier Cabral

O diboreto de titânio (TiB2) é um material cerâmico de alta dureza com uma grande potencialidade de aplicação tecnológica. Neste trabalho, foi empregada uma técnica de processamento em altas pressões e altas temperaturas para produzir compactos de TiB2 com AlN. Os pós utilizados foram misturados manualmente em quantidades de 70%p TiB2 + 30%p AlN. Amostras cilíndricas, com 5 mm de diâmetro e 7 mm de altura, foram processadas durante diferentes intervalos de tempo compreendendo os ciclos de sinterização, cada ciclo de sinterização consistiu em aumento de pressão a aproximadamente 7 GPa a uma temperatura aproximada de 1500°C por um tempo de 180 segundos, para cada ciclo. O número de ciclos variou de 1 a 5. O objetivo do trabalho foi a identificação do efeito da quantidade de ciclos sobre a microestrutura e sobre as propriedades mecânicas dos compactos. Para estas observações foram realizadas analises de Difração de Raios X, Microscopia Confocal a Laser, Microdureza Vickers e ensaio de flexão. Os resultados obtidos apresentam perspectiva de utilização do processamento em alta pressão e alta temperatura para produção de compactos de alta qualidade como o TiB2- AlN.

Aug 16, 2017

By Thomas B. Douglas

INSTRUMENTATION in the process industries can no longer be regarded as a convenience, but rather an absolute necessity. Although many chemical processes must already be conducted with instruments, every properly designed application of automatic process control will improve operation: 1) the product will be more uniform and of higher quality; 2) the manual labor saved will reduce cost; 3) uniformity of flow and uniform control of process will increase production; and 4) surges will be eliminated, making it possible to operate equipment near ultimate capacity at all times. Industrial instruments fall into two general classifications-those that measure and those that measure and control. The cement industry has been using instruments for a number of years, particularly in the burning process, primarily for indicating and recording. Automatic process control makes additional use of these instruments, and others, to control variables. Assisted by the instrument manufacturers, engineers at Ideal Cement CO. achieved considerable progress in determining how well the usual recording instruments could be made to control various phases of cement-making. The results of these experiments were used to make the new plant at Houston as wholly automatic as possible.

Jan 2, 1958

By N. Santa, V. Salinas

"Printed circuit boards are potentially recyclable materials. Developing suitable methodologies for proper disposal and better utilization, brings major environmental and economic benefits. A methodology for copper recovery using heat treatment before conventional leaching is carried out. A comparison between conventional methodology and the one that includes incineration treatment is presented. It concludes about results and differences in terms of the percentage of copper leached over time. INTRODUCTION The rapid proliferation of electronic devices in the past two decades, has forced researchers to find a solution for one of the most toxic and hazardous materials, the printed circuit boards (Ghosh et al, 2015). For this, countless techniques have been developed, the methodologies includes hydrometallurgy, pirometallurgy, electrometallurgy or a combination between all of them. The amount of precious and base metals in its composition are very attractive and usable to implement methodologies that allow maximum recovery and recycling. This subject has been extensively studied and researched in order to provide solutions to the great problems generated by incorrect final disposal of this waste. Over 150 articles have been widely published in the last 15 years, covering large areas such as characterization of discarded printed circuit boards, health risks associated with processing and different routes of recycling have been analyzed to provide an overview understanding this issue (Ghosh et al, 2015). (Oh et al, 2003) performed a selective leaching of valuable metals from waste printed circuit boards by size reduction, magnetic and electrostatic separation, also leaching with sulfuric acid and hydrogen peroxide, achieving 95 \% of copper extraction. (Chaverra Arias, 2014) proposed a similar methodology to extract copper from electrical and electronic waste, performing similar processes and applying metallic copper electrowining as well as copper oxychloride precipitation. (Silvas et al, 2015) used hydrometallurgical processes for recycling printed circuit boards applying physical processing and copper extraction by selective leaching. (Kumar et al. 2014) conducted a leaching of metals from waste printed circuit boards using sulfuric and nitric acids. Also there have been proposed various methods for recovery of different metals including applying multiple metallurgical techniques that involve both living organisms and high temperature processes such as pyrometallurgical. The printed circuit boards are a very important source of copper, according to several authors mentioned above, the amount of copper on a printed circuit board can reach about 20 \%, because copper is responsible of establishing a conductive layer that will enable the connection between electrical and electronic components. This document proposes a methodology for recycling printed circuit boards and extract copper by selective leaching. The process that is carried out consist in a preliminary characterization and mechanical separation which will condition the material for further hydrometallurgical treatment that includes leaching in nitric acid media 3M."

Jan 1, 2017

The writers of these notes, having conducted some tests on the steam consumption of air compressors under varying conditions, believe that the detailed results of such tests will be of interest to the members of the Institute, and may lead to the contribution of further and more valuable information, of benefit both to manufacturers and users of this class of machinery-to the manufacturer in that he frequently has the opportunity of giving a very thorough test to the machine in the shop, and-tothe user or purchaser by making clear to him what may be reasonably demanded of a high-class machine. It must be remembered that, though of the highest importance, a low steam consumption is but one of the many features of a high-classmachine; for the present, however, it has been considered advisable to confine the paper chiefly to the first-mentioned aspect, with such information concerning the air ends as is obtained along with the steam consumption tests. Unfortunately, too few of these tests are conducted, and but few results are published, therefore the writers feel that no apology is needed in bringing their results before the members.Some nine months ago the Brilliant Extended G. M. Co. was supplied with a compressor by Messrs. Thompson and Co., of Castlemaine, and with the object of testing its actual performance.

Jan 1, 1907