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By S. Mao

Total station has been predominantly applied in stationary survey scenarios in construction. With the moving target tracking and point survey automation functions, a robotic total station (RTS) lends itself well to more dynamic applications. Nevertheless, a RTS unit is still unable to track multiple targets simultaneously or to survey a target point when the line-of-sight is temporarily unavailable. In this paper, we propose a methodology to synchronize and automate multiple RTS units intended to address dynamic tracking and surveying applications in the construction field. By using the application programming interface (API) from the manufacturer, we implement the proposed methodology and the prototype system integrates two RTS units in regard to space and time and communicates survey command instructions among RTS units through wireless networks. The two RTS units can be operated to survey the two ends of one swinging sling concurrently in order to retrieve the actual length of the sling within several millimeters accuracy. Besides, in applications where line-of-sight between a target object and one RTS unit cannot be guaranteed all the time, continuous surveying can be materialized by automatically delegating the task to another synchronized RTS unit with clear view of the target object. A field test was conducted to demonstrate the application of the proposed automation approach in which sling length was measured of a rigging framework used for lifting industrial modules. The testing results are presented and achievable accuracy and reliability are discussed. The proposed solution overcomes the limitations of global positioning system (GPS) and laser scanning and holds high potential to provide cost effective solutions to many dynamic field applications.

Aug 1, 2013

By E. L. Bruce

Introduction The Outokumpu copper mine is situated in eastern Finland, 50 kilometers west of the city of Joensuu or 225 kilometers directly north of the city of Viborg (Viipuri), which is situated at the eastern end of the gulf of Finland (Figure 1). The ore-body was discovered in 1910 by Dr. Otto Trüstedt after two years of careful, scientifically-directed, search. During the early period of development of the mine, the ore was treated locally and the copper re-covered by an electrolytic process. Now the ore is concentrated by tables and by flotation. The concentrates are shipped to Germany for refining. In 1929 the mine produced 150,000 tons of ore from which between 20,000 and 25,000 tons of flotation concentrates containing 20 per cent copper were produced. Profits in 1929 were approximately half a million dollars, but the present price of copper will affect very seriously the profits for 1930. The ore reserves are given as between 7 and 8 million tons (1). The grade of ore is stated to be 4 percent to 6 percent copper, with a little zinc.

Jan 1, 1931

By William B. Coker, Vladimir J. Sopuck, J. S. Fox

"Preliminary investigations indicate that organic lake sediments offer some potential for gold exploration within the Canadian Shield of northwestern Saskatchewan. It is also apparent that certain precautions must be taken.Gold is primarily related to the organic fraction of the lake sediments, which, although giving consistant Au contents to those sediments, may restrict the dispersion of Au within the lake itself. It may be necessary to carry out selective extractions on the lake sediments to differentiate between Au related to organic sequestration, indicative of hydromorphic and/ or chemical dispersion, and Au related to inorganics, indicative of mechanical dispersion.Lake sediments are probably only of use for very detailed exploration (i.e. every lake). One to three samples per lake should be appropriate, although a single centre-lake organic-rich sediment sample may be adequate in very small lakes. Each lake sediment sample should be analyzed at least twice and the analytical data carefully monitored and evaluated.The use of As in lake sediments as a pathfinder element for gold is applicable in the search for certain types of gold occurrences.Following detailed lake sediment sampling, basal till sampling can possibly be used to localize areas of potential gold with or without base metal mineralization."

Jan 1, 1982

By R. V. Kumar, C. Schwandt, S. Subramanian, S. Sampath, S. Vimalnath

Waste waters and industrial effluents containing toxic heavy metals such as Pb, Hg, As and Cr, beyond permissible limits (0.1 ppm, 0.01 ppm, 0.02 ppm and 0.05 ppm, respectively) (WHO, 2011), pose serious threats to the ecosystem, when discharged into the environment. It thus becomes imperative to monitor the concentration of the toxic heavy metals and treat them before discharging. In this study with the above objective in mind, a microbial sensor has been developed using P. aeruginosa cells drop coated onto a carbon paste electrode (CPE) for the detection of Pb(II) ions in aqueous solutions. Detailed biosorption experiments confirmed that complete bioremoval of lead could be achieved using P. aeruginosa cells under optimum conditions of pH and biomass loading. For the electro-analytical determination, the Pb(II) ions were initially preconcentrated on the P. aeruginosa modified CPE, reduced and then anodically detected with oxidation of Pb0 using differential pulse anodic stripping voltammetry (DPASV) technique. All the experiments were carried out in the presence of 0.1 M sodium acetate buffer and KNO3 as background electrolyte. The parameters namely pH, scan rate, biomass loading, deposition potential, deposition time and concentration of Pb(II) ions were optimized for the biomass modified CPE, to obtain maximum voltammetric response. Under the optimized conditions of pH 5.6, scan rate of 0.008 V/s, biomass content of 1.7–1.8×109 cells/mL, deposition potential of –1.2 V, and deposition time of 500 s, the developed microbial sensor showed a linear response for the peak current between 0.5×10-5 M and 1×10-8 M of Pb(II) ions with the R2 value of 0.9979. The lowest limit of detection (LLOD) was determined as 2.4×10-7M of Pb(II) ions (0.05 ppm). The redox mechanisms of Pb(II) ions on the P. aeruginosa modified CPE surface are discussed.

Jan 1, 2016

By K. B. Culver

"This paper provides background information on the expansion programs of Rio Algom Limited at Elliot Lake. Included are details on the Quirke expansion program, the Panel mine rehabilitation program, including the selection procedure for the tailings containment area, the Stanleigh mine rehabilitation program, housing, government regulations and the Environmental Assessment Board hearings. Introduction After 2Y2 years of public hearings, 4 years of arbritrating differences of opinion between our engineers and government licencing authorities, interspersed with research into radium removal and development of the LAMIX process and carrying out the work associated with some 24 control orders issued to us by the MOE, it is very difficult to compress all of the experiences and frustrations into a single paper. The highlights, as they relate to the expansion programs of Rio Algorn Limited and its affiliate, Preston Mines Limited, will be covered. Denison Mines Limited, of course, is the other uranium producer in Elliot Lake. They are currently in the process of expanding from 7,000 to 11,000 TPD by the second half of 1980 and then to 15,000 TPD by the mid 1980's. In giving this overview, the following seven items will be discussed: • The basis for Rio Algom's and Preston's expansion plans. • The Quirke Expansion. • The Panel Rehabilitation. • The Stanleigh Rehabilitation. • Housing Programs. • Government Licencing Requirements. • Environmental Assessment Board Hearings."

Jan 1, 1980

By George C. Bateman

WHAT I would like to do is to talk for a while tonight about the Canadian mining industry in wartime-at least, the Canadian mining industry as viewed through the eyes of the Metals Controller. There is nothing quite like the Canadian system in the system of controls in the United States, because the Canadian Controller combines the functions of a good many of the organizations here. I think the nearest counterpart would be the Divisional Chiefs of the WPB-although they have perhaps less authority and operate in a somewhat narrower field. My own field, as you know, is the metals and minerals-all of them, as a matter of fact, with the exception of steel and iron and coal and oil. And as I am responsible for supplies not only from domestic sources but also from foreign sources, I exercise most of the functions of the WPB and some of the functions of the Board of Economic Warfare. As my department is also responsible for stock-piling and for the financing of new operations, I therefore exercise some of the functions of the Metals Reserve and also of the Defense Plants Corporation. Being an administrator under the Wartime Prices and Trade Board, I also have the same function in relation w the price of metals as the OP A. The Canadian system of controls is compact, relatively simple, and I believe reasonably efficient. I think two of the reasons for that are that both the Controllers and the Directors of production are clothed with very wide authority, and also the fact that all the buying for the three arms of the service is done through the Department of Munitions and Supply, of which we are a part.

Jan 1, 1943

By L. J. Bryson, C. A. Biley

"Anglo American Platinum’s Rustenburg Base Metals Refiners (RBMR) produces Ni and Cu cathode from slow cooled converter matte after Platinum Group Metals (PGMs) are magnetically separated for further processing. In 2010, execution of the RBMR expansion project was commenced to increase the production capacity to 33 ktpa Ni. The expansion, which is currently still in a ramp-up stage, brought about several fundamental changes to the circuit chemistry, including the installation of a dedicated Pressure Iron Removal (PIR) autoclave. This provided an independent outlet for iron from the refinery, which previously deported to the residue from the leach circuit and was toll refined. At the same time as changes in the circuit associated with the RBMR expansion were being made, the plant experienced a significant increase in iron and copper units per nickel unit in the feed. The decoupling of the leaching and iron removal process steps has had significant advantages for the robustness and control of the overall circuit, in particular pertaining to the preparation of a nickel electrolyte of sufficient purity to produce LME grade nickel. This paper details the primary changes to the RBMR circuit chemistry with a particular focus on iron deportment and the benefits derived from the installation of the PIR autoclave.INTRODUCTIONAnglo American Platinum mines and refines Platinum Group Metals (PGMs) through a complex processing pipeline in its South African operations. Mined ore is first treated through several mineral processing stages, geared to the recovery of base metals and associated PGMs, followed by smelting and refining operations that aim to separate base metals from PGMs and recover the value components to purified, saleable products. The focus of this paper is the Rustenburg Base Metals Refiners (RBMR) complex which receives a PGM-containing converter matte, then physically separates PGMs and base metals, and recovers nickel and copper to cathode by utilising leaching, precipitation and electrowinning processes.With new mining operations coming online and the continued increase in PGM ore arisings, it was necessary to undertake an expansion project at the Base Metal Refinery (BMR) to increase production capacity from 21 ktpa to 33 ktpa Ni. Complicating the expansion project was the requirement of continued production through all stages of design, construction and implementation and, due to stringent capital constraints, the utilisation of all existing equipment installed during a previous expansion in 1981. Against this backdrop, the expanded BMR flow sheet involved significant changes to the chemistry, especially iron management. These changes in iron management allowed for the separation of iron and copper residues and significantly increased the robustness of the plant to changes in feed mineralogy as well as the potential to increase production duties of the existing equipment."

Jan 1, 2016

By J. T. Sims, C. E. Karayannopoulos

Today's rare earth industry is undergoing significant and rapid evolutionary change toward greater reliability and diversity of supply, increased security of supply chains, and better price forecasting. Technology innovation is reducing rare earth production costs while decreasing the impact of producers on the environment. Advances in rare earth material science are reducing the need for relatively scarce heavy rare earths (HREEs) in high-performance neodymium-iron-boron (NdFeB) permanent rare earth magnets and opening the NdFeB magnetic market space for a broader range of downstream applications. Rare earth producers such as Molycorp are increasingly able to offer long-term supply agreements with forward price predictability, something that has not been the case for many years. All of these trends are helping to restore the confidence of customers and other stakeholders in the rare earth space. That increased confidence is likely to bolster global demand for rare earth materials and expand innovative utilization of these remarkable materials.

Jan 1, 2014

By Julien Rivard

Au printemps 2011, la Corporation minière Osisko met en production le gisement Canadian Malartic, qui devient la plus importante mine d?or à ciel ouvert au Canada. Pour lui faire place, elle a déménagé un quartier de 205 maisons et construit 6 nouveaux bâtiments institutionnels. Les démarches ont commencé en 2006. La compagnie a d?abord établi l?emplacement du nouveau quartier résidentiel, en collaboration avec la Ville de Malartic, puis fait la conception de ce quartier de manière à refléter au mieux les caractéristiques du quartier à déménager. Elle a ensuite effectué une opération d?assignation consistant à proposer à chaque propriétaire intéressé un lot dans le nouveau quartier. Au total, 140 résidences ont été déménagées en 2008 et 2009 et 65 été rachetées par la compagnie, le tout par des ententes de gré à gré sauf pour un seul cas. La réussite d?une opération d?une telle importance sociale n?a été possible que parce que la compagnie s?est assurée d?un soutien massif de la population et des autorités pendant tout le processus. Cette expérience peut être fort utile pour les nombreux projets miniers dont l?insertion dans la communauté est un enjeu important.

May 1, 2011

By Charles Camsell

Few persons ever stop to consider how vital an influence minerals, and especially metals, have had upon human history, how they have affected the every-day life of the individual or how at different periods they have altered the course of nations and determined their progress. Students and writers of history have dealt very fully with political history and have given us a great deal of detail about the careers and policies of kings, parliaments and nations, but frequently have not touched the economic causes that have been the real forces influencing the development and carrying out of these policies. So far as minerals are concerned there is no single work from which one can get a concise and consecutive account of the growth in the use of minerals, nor of the diverse ways in which the. geographical distribution, the .search for, the development and the use of mineral resources have affected human progress from the beginning of man's history. The reason for this is quite plain, and when one takes a little time to think of it he begins to appreciate the magnitude of the job and he will realize that the story of minerals and mineral resources touches a tremendous range of human activity, not only of mining .and metallurgy, but the whole field of agricultural and industrial growth, of exploration and colonization, transportation and commerce, monetary system, commercial policy, in short, almost every phase of economic life.

Jan 1, 1926

By C. O. Campbell

THE recognition by C. W. McKee, field engineer for Springer Sturgeon Gold Mines, Limited, in the fall of 1940, of the economic possibilities of a small outcrop of baryres near Pembroke, in Hants county, Nova Scotia, followed by aggressive exploration and development by the Company, has placed Canada for the first time in its history in the position of becoming a major producer of barytes and its products. In past years, production of this mineral in Canada has been unimportant. Thus the coral output from 1885 ro 1933, inclusive, amounted to only 41,027 short tons, following which there was no production until 1939. Deposits in Nova Scotia, and particularly in the Lake Ainslie district, Cape Breton, have been the main source of supply, with a production between 1866 and 1925 of 31,689 tons. Following the examination of the outcrop of baryres near Pembroke by Mr. C. W. McKee in October, 1940, the area surrounding it was trenched, and, as this work gave encouraging results, a diamond drilling programme was commenced. A grid system was laid our and sixteen holes aggregating 2809.3 feet were put down, spaced at 100-foot intervals, the deepest hole being 300 feet. This drilling outlined a body of high-grade baryres over 600 feet long and 200 to 250 feet wide, with an average depth of 120 feet and estimated to contain well over one million tons of ore. The limits of the body were reached on the west, north, and southwest, but the drilling was suspended before the eastern limit was determined. Quarrying operations, and construction of a 100-ton mill, were commenced in February, 1941. The mill was placed in operation on May 29th, and on June 15th, eight months after the initial discovery, the first shipment of 2,500 long rons of milled baryres was made to Trinidad, British West Indies.

Jan 1, 1942

By F J. Kelly

A chemical process, based on laboratory investigations, is proposed for the production of high-purity niobium oxide from a pyrochlore-perovsk1te flotation concentrate produced from ore obtained at the Oka, Quebec property of Columbium Mining Products Limited. The method developed included the decomposition and dissolution of the flotation concentrate with hot, concentrated sulphuric acid. The dissolved niobium was purified and concentrated by a solvent extraction step, using methyl isobutyl ketone as the extractant. The niobium was recovered from the extractant with ammonium fluoride solution from which niobium oxide was precipitated with ammonia. Finally, the filtered and washed precipitate was calcined. Ninety-six per cent of the niobium was recovered in a product analysing 99.9 per cent Nzo.. The reagent cost was in the range of $1.00 to $1.25 per pound of niobium recovered. Introduction OVER the past few years, Columbium Mining Products Limited has been engaged in the development of a niobium-bearing mineral deposit in the vicinity of Oka, Quebec. One phase of this program resulted in a flotation process capable of producing concentrates containing up to 50 per cent Nb205? Flotation pilot-plant

Jan 1, 1965

By T. Hidayat, D. Shishin, V. Prostakova, M. Shevchenko

The chemical compositions of copper feed streams are becoming increasingly complex following the growing demand for metals and corresponding shortages of primary sources. The optimisation of process conditions requires an accurate description of phase equilibria and thermodynamics. Integrated experimental and thermodynamic modelling research program on the characterisation of the complex, multi-component, multi-phase gas-slag-matte-speiss-metal-solids Cu2O-PbO-ZnO-Al2O3- CaO-MgO-FeO-Fe2O3-SiO2-S-(As-Bi-Ni-Sb-Sn-Ag-Au) system is being carried out to support companies undertaking the pyrometallurgical primary production and recycling of copper. The experiments involve high temperature equilibration in controlled gas atmospheres, rapid quenching and direct measurement of equilibrium phase compositions with quantitative microanalytical techniques, including electron probe X- ray microanalysis and Laser Ablation ICP-MS. The thermodynamic modelling is undertaken using FactSage computer package with advanced thermodynamic solution models. The continuing development of research methodologies has resulted in significant advances in research outcomes. Implementation of the results of these fundamental studies involves an ongoing collaboration of researchers and industry technologists. An overview of recent progress in research, implementation and applications in industrial practice are given in the paper. INTRODUCTION Rapidly developing technologies increase the demand for various metals in number and volumes. Modern technological devices such as mobile phones, computers, other electronic devices, have dozens of metals—all those metals have to be a) produced and b) recycled. The fast transition in mobility from fossil energy delivered through combustion to renewable energy first stored in bakeries and delivered through electric engines introduce a significant change in the metal demand in terms of both type and volume of metals. Pyrometallurgy is playing a key role in supporting these changes in our industrialised society.

Jan 1, 2019

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By F. J. A. van Ruitenbeek, M. Dalm

In the presented study test work was performed with near-infrared hyperspectral imagery (NIR-HI) on 36 ore samples from a South-American epithermal Au-Ag mine. The aim of the test work was to investigate if NIR-HI provides information about the alteration mineralogy of samples that can be used to predict their economic value. Mineral distribution maps were produced from the hyperspectral images by using correlation coefficients between the image pixels and a set of reference spectra. These maps showed that detection of mineralogy with NIR-HI can be used to distinguish; i) ore particles with low Au and Ag grades, ii) ore particles with high carbon contents, iii) ore particles with high sulphur contents.

Jan 1, 2015

By B. Jin

Removal of fluoride and chloride by alkaline washing from direct lead smelting dust which originated from an Ausmelt furnace is reported. The results show that the fluoride removal efficiency increases with an increase of alkaline concentration, alkaline washing temperature and time. The L/S ratio has little effect on fluoride and chloride removal efficiency. A new flow sheet for removal of fluoride and chloride from the dust was successfully proposed according to the results. Fluoride and chloride removal efficiencies are more than 53.68% and 63.18% respectively using the flow sheet under the optimum parameters of temperature 338 K, L/S ratio 3:1 and alkaline washing time of 1.5 h. The contents of fluoride and chloride in the alkaline washing residues can meet the standard of zinc purity as hydrometallurgical materials for zinc processing.

Jan 1, 2014

By J. B. Hadaway

The operation at Phu Kham commenced design and construction in early 2006 and was commissioned in May 2008. This paper will examine and discuss the project from the inception of flow sheet development and equipment selection, equipment design and manufacture, construction, commissioning and ramp up to full production. The paper will touch on the strategies employed to achieve a short schedule and the efficient use of capital, but with the main emphasis on the grinding circuit. Various challenges during the early years of operation will be discussed including the effect of ore characteristics, including competency, on the performance of the grinding circuit. Actions to overcome these challenges and to enhance performance will also be discussed. Finally, current and future plans to improve the performance of the grinding circuit and the overall plant will be summarised.

Jan 1, 2012

By J. Shanks

A S far back as 1925, Brazeau Collieries, Limited, became interested in .briquetting. This was brought about by complaints from their principal customer that stack losses, due to a high percentage of fine coal in their mine run, were excessive. The Company considered oil spraying of the fines. This, after some experiments and tests had been made, was ruled out as uneconomical and impracticable. When sufficient oil to be effective was put into the fines, it caused the coal in the tender of stoker-fired engines t0 arch over the screw feeder. The Company ultimately placed their problem in the hands of the Re-search Department of the University of Alberta. Experimental work was carried on by this department over a period of more than a year. The results obtained and the experience gained in this research work were conveyed to Brazeau Collieries in a report dated October 31st, 1929, and in a supplementary report dated February 2nd, 1935. Most of the results obtained in experimenting with Brazeau coal are embodied in a brochure, reprinted from the proceedings of the Second International Conference on Bituminous Coal, Vol. 19-24-28, entitled Principles in the Briquetting of Coking and Non-Coking Bituminous Coals, by E. Stansfield and W. A. Lang. All who are interested in briquetting should read this brochure. In the writer's opinion, iris the most important treatise on the subject printed in recent years. The results given in the paper are, of course, those obtained in laboratory investigation. It was pointed out to the writer that it would be most interesting to have such results correlated with those obtained in commercial practice. In this short paper, an attempt is made to do so.

Jan 1, 1942

By R. Wang

"Under high stress conditions, rock bursts, borehole breakouts, and spalling events are common phenomena that occur around underground openings. In general, together these three phenomena represent brittle failures of an intact rock mass; however, individually they reflect different failure modes under high stresses. After analyzing and comparing the stress-to-strength criteria for rock bursts, borehole breakouts, and spalling events, proposed by previous researchers, it is found that these brittle failure phenomena share common stress-to-strength prerequisite. The stress-to-strength preconditions for brittle failures can be defined by the ratio of the maximum tangential stress around an underground opening to the uniaxial compressive strength (UCS) (s?max/sci) or by the ratio of the maximum far-field principal stress to the UCS (s1/sci). Both these indicators can be used to reflect the same stress preconditions. For s?max/sci, a ratio of 0.4±0.1 represents the critical stress requirement for brittle fracture. However, for s1/sci, a ratio of 0.15±0.05 should be considered as the critical stress requirement. Numerous engineering case studies and analysis of rock mechanics based on the Hoek-Brown criterion also verify these two stress-to-strength preconditions. Here, these two indicators are presented with an error range because complex rock mass quality ratings, lithology, and geotechnical conditions have profound impacts on the stress-to-strength preconditions for brittle failures. INTRODUCTIONHigh stresses are one of the most important factors that must be considered when undertaking underground rock mass projects (Kaiser et al., 1998). Wang et al. (2009) reviewed current progress in the evaluation of high stresses and their corresponding criteria. However, after clarifying the definition of high stress, civil engineers need to understand the deformation and failure behaviors of rock mass around an opening under high stresses. Under high stress conditions, the deformation of rock masses around an opening can be categorized into two groups, i.e., severe brittle failures (or rock bursts) and compressional plastic deformation of the surrounding rock mass, as indicated in Figure 1."

Jan 1, 2015

By W. G. Hubler

It has been within only the last two or three years that enough progress has been made in preferential flotation to warrant metallurgists in recommending the installation of commercial-sized plants for the treatment of copper-zinc-iron ores. Until the new processes had been worked out successfully, the treatment of this type of ore had proved a stumbling block in the path of metallurgical progress. Separation of lead-zinc ore is comparatively simple. A lead-zinc ore low in iron may be separated and concentrated by gravity con-centration, provided it is not necessary to grind too fine. Owing to the specific gravity of chalcopyrite and sphalerite being so nearly the same, however, their separation by gravity concentration is out of the question. Complex lead-zinc-iron ores in which the several minerals are intimately associated, requiring fine grinding to free them, have been successfully treated by flotation for the past fifteen years. Galena is easily floated, and its flotation, unlike that of chal¬copyrite, is not affected by the reagents used to inhibit the flotation of sphalerite and iron sulphides. When an attempt was made to use the methods of lead-zinc se-paration on copper-zinc ores, it was found that the depressant re-agents added to inhibit the flotation of the iron and zinc minerals would, under certain conditions, depress a large part of the copper. It was also recognized that, in the grinding of copper-zinc ore, soluble salts were generated which were detrimental to flotation unless properly controlled. The main part of this paper will be a discussion of solutions in the grinding circuit in relation to the pro¬duction of soluble salts and their effect on flotation.

Jan 1, 1931