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By G. Van Weert, O. Wang

"As part of a general review of processing double refractory ores through Barrick Gold’s autoclaves / CIL facility at Goldstrike, blanking the preg robbing native carbon in the process solids with hard (m.p. 55 - 60 º C) paraffin wax was studied, specifically in relation to pressure oxidation. The improvement in CIL gold extraction was found to depend on the wax addition point, with hot, dry contacting of the ore in the presence of wax - prior to POX - yielding the largest, most consistent improvement in gold extraction.INTRODUCTIONDouble refractory gold ores present two barriers to gold extraction. The first is generally a physical barrier: the gold is encapsulated or dispersed in a matrix which is impervious to the gold lixiviant. In most cases, including Carlin Trend, NV, deposits, this involves a pyrite or arsenopyrite matrix, although minor gold may also be dispersed in competent silica (quartz) or iron oxides. Gold can be rendered accessible by oxidative destruction of such sulphide matrices. At Goldstrike this is practised by roasting and autoclave oxidation (Thomas, 1994). It is the latter route to which this paper refers.The second barrier refers to the actual gold recovery. Gold may be extracted from the pressure oxidized solids with cyanide, forming a gold cyanide complex. One characteristic of this complex is that it adsorbs on graphitic surfaces. This is taken advantage of on a large scale by gold millers, who use manmade activated, i.e., graphitized carbon particles to remove the gold from solution during leaching: the Carbon-In-Leach, or CIL process. The gold cyanide bearing carbon particles are larger than the ore solids and can be separately recovered by screening. Goldstrike uses the CIL technology to recover gold. The second barrier becomes problematic when the ore naturally contains graphitic orcarbonaceous material, hereafter referred to as native carbon (versus the man-made activated carbon). This material may also adsorb gold cyanide in competition with the activated carbon. Since the native carbon is ground with the ore it is much smaller than the activated carbon. Any competition between the two carbons may produce a loss of gold from the pregnant leach liquor to the process tailings. This phenomenon is called “preg robbing”. Goldstrike ores come from the Carlin trend, which is known for the occurrence of native carbon (Adams & Burger, 1998; Schmitz, Duyvesteyn, Johnson, Enloe & McMullen, 2001; Tretbar, 2004)."

Jan 1, 2012

By J. Ji

Oxygen requirement during acidic pressure oxidation of sulphide concentrates can he as high as 800 kg/(m3.h) in the first compartment of an autoclave when the total oxidation residence time is shortened to 30 minutes. To achieve such a high oxygen transfer rate while maintaining satisfactory oxygen utilization, a pilot plant campaign was launched at the Placer Dome Research Centre in 1998 to measure the oxygen mass transfer coefficient in a 5 m3 pressure vessel at a total pressure close to 500 psig with a 30 HP gassing agitator. Maximum oxygen flowrate to the pressure vessel was designed at 3 600 kg/h. In this paper, a great deal of information is provided on the gassing agitator, pressure vessel. measurement procedure and results. Without oxygen sparging, the oxygen mass transfer coefficient is 2 600 h-1 with a mixing power input of 5.0 kW/m3 in solution. With oxygen sparging, the oxygen mass transfer coefficient increases to 3 500 h-1 with a mixing power input of 4.0 kW/m3 in solution.

Jan 1, 2004

By Xuanxue Mo, Kaihui Yang

"Abstract- The Laochang mine, located in the Sanjiang area of southwestern Yunnan Province of China, is a volcanogenic massive Pb-Zn-Cu sulfide deposit. It is hosted by a pyroclastic sequence of Barly Carboniferous age, namely the lower member of the Yiliu Group, which was intruded by syenite and rhyolite porphyry . The volcanic suite is basaltic or basaltic-andesitic in composition, has alkaline affinities, and is associated with the initial rifting along the margin of the Baoshan-Shanstate continental rnicroplate (Yang, 1989). The ores are typically Pb>Zn>Cu in composition, averaging 3.820Jo Pb, 3.51% Zn, from 0.01% to 1.85% Cu (0.107% av.), a high average content of Ag (113 g/t) and recoverable amounts of Au, Tl, Gd, Ga, Ge, In. A massive sulflde zone, in which lenticular and stratiform orebodies are localized in a sulflde-carbonate-silica shale unit or sulfldic tufflte horizon that usually overlies coarse-grained pyroclastic rocks, is underlain by a stringer sulflde zone developed in a subvolcanic intrusion or volcanic sequence. The sulfide mineral assemblages, from the top to the bottom of the deposit, are: realgar + orpiment - galena + sphalerite + pyrite- chalcopyrite + pyrite + pyrrhotite + arsenopyrite. Oxide and sulfate minerais occur rarely in the massive ores. The massive ores are generally fine-grained and banded, but coarse-grained ore, colloform and framboidal texture, and growth-zoned pyrite and sphalerite are common. Sedimentary features such as graded bedding, brecciated and deformed ore clasts, and chaotically emplaced blocks, are well preserved, indicating that the massive orebodies have undergone slumping and dis­ placement. Alteration is weak in the hanging-wall rocks, but strong in the stringer zone. Two dis­ tinctive alteration zones have been identified: the upper zone, characterized by an assemblage of quartz, carbonates, chlorite, albite, zeolite and sericite, and the lower zone containing diopside, trema­ lite, actinolite, gamet, clinozoisite, and epidote.The general features of the Laochang deposit are in accord with the descriptive mode! of VMS deposits (Lydon, 1984). However, it falls into neither the Zn-Cu group nor the Zn-Pb-Cu group chemically (Franklin et al., 1981). The depositional setting of the Laochang deposit is quite different from Cyprus or Besshi-type massive sulfide deposits. Laochang is hosted by alkaline lavas that were erupted in a submarine continental rift. Although some features of the Laochang deposit are similar to those of Kuroko-type deposits, there are remarkable differences in the alteration mineral assemblage, the proportion of ore-forming elements (lead enriched) and the amounts of oxides and sulfates. These suggest corresponding differences in ore fluid composition and the associated ore-forming environment. Thus, the authors suggest that the Laochang deposit may be a distinct type of VMS deposit."

Jan 1, 1993

"These guidelines set out information on timely disclosure of news releases which are intended to provide, existing shareholders and potential investors, factual information on which a reasoned investment decision can be made.Consider the problems and concerns raised by the following hypothetical news releases:Natural Resource Company""The Company has recently optioned a large and exciting gold property near the ""XXX"" gold discovery area. In describing the property, the Company's independent consultant has said: ""The favourable location of, and some of the results of prior work done on the property give the Company a worthwhile mineral exploration opportunity .... "". The Company proposes to expeditiously conduct a sizeable exploration program on the property as soon as the appropriate financing has been arranged.""Non-Resource Company""Based on discussions with several European countries, the Company anticipates that it will have orders to ship over 200,000 crates of widgets to those European countries over the next two years. These orders, which considerably exceed the Company's forecasts for the first year, represent a projected profit to the Company in excess of $1,000,000 over the next five year period.""GuidelinesTimely disclosure news releases are intended to provide, to both existing shareholders and potential investors, factual information on which a reasoned investment decision can be made. National Instrument 43-101 Standards of Disclosure for Mineral Projects provides requirements for disclosure of a scientific or technical nature for a mineral resource company.The examples do not provide sufficient detail and are misleading because material information is omitted. The following guidelines should be observed when preparing a news release:"

Jan 1, 2003

The Autogenous milling of ores holds an increasing attraction as the focus moves towards reducing energy usage, both direct and embodied in grinding media. However, most of the early AG mills were converted to SAG for improved stability and increased throughput. This imposes a huge penalty in steel grinding media consumption. The LKAB iron ore operations in Sweden process highgrade magnetite through fully-autogenous milling lines to a final product P80 of about 45µm. The outcomes of P9O AMIRA research surveys, covering a wide range of mill fillings and throughputs and with different feed blends, are presented. Insights are provided on operational strategies, opportunities, the influence of feed size control and balancing the blend of competent gangue and softer magnetite. Areas of importance in the successful operation and control of energy-efficient autogenous circuits are highlighted.

Jan 1, 2012

By K. Lambrych

Hydrometallurgical equipment used to extract and refine copper and other metals is exposed to extremely corrosive chemical environments. These systems must be fabricated from materials that are durable against corrosion, meet exacting mechanical requirements, and perform economically over the life of the mineral processing plant. In several recent large hydromet projects, fiber reinforced plastic (FRP) has been shown to provide equal if not superior durability relative to alternative materials of construction. This paper will compare corrosion performance and cost of plant equipment fabricated with corrosion resistant alloys, rubber lined steel, and FRP made with Epoxy Vinyl Ester thermoset resins. Case histories for FRP piping, storage tanks, extraction vessels, and electrowinning cells combined with laboratory-based corrosion studies will be reviewed to demonstrate how FRP materials are selected for hydrometallurgical equipment. Specific examples from projects such as El Boleo, Long Harbour and others will be used to demonstrate how the versatility of FRP allows for remote fabrication of durable corrosion-resistant large-scale equipment for hydrometallurgical refinement of copper and other metals. INTRODUCTION Fiber reinforced plastic (FRP) began to emerge as a material of construction for corrosion service in many industrial processes in the late 1950s because of its ease of use and overall performance. Corrosion resistant (CR) FRP, as an alternative construction material to alloys, rubber and tile linings, grew steadily in following decades. The aggressive operating conditions associated with hydrometallurgical processes typically require materials of construction that can withstand acids and acid chlorides at temperatures up to 90°C, sometimes higher. Common metallic materials of construction, such as carbon steel, are not compatible with these conditions. High nickel alloys are capable of meeting performance requirements, but often at a high cost. In many cases FRP mining equipment based on epoxy vinyl ester resin (EVER) offers durability, long service life and lower maintenance costs. Through demonstrated performance and decades of case histories, more and more design engineers are confidently specifying FRP as the material of construction for new mineral processing equipment.

Jan 1, 2019

By E. Asselin, G. K. Yue

"In the present study, electrochemical measurements, especially cathodic potentiodynamic polarization (CPC) and cyclic potentiodynamic polarization (CPP), have been employed to study the kinetics of ferric reduction on chalcopyrite in aqueous Fe(II)Fe( III)H2SO4 solution at 90 °C and 110 °C. Results from the calculation of speciation in the above solution reveal that, at both 90 °C and 110 °C, the real Fe3+/Fe2+ ratio is much lower than the nominal ratio, which leads to smaller VALUES (for the reversible potential of the ferric/ferrous couple. Exchange current densities of the ferric/ferrous couple were obtained and are on the order of 106 10 5 A/cm2 a t 9 0 °C and 1 07 10 6 A/cm2 at 110 °C, respectively. The Tafel slopes from the CPP method are higher than those from the CPC method at both 90 °C and 110 °C. The transfer coefficients were about 0.360.59 at 90 °C and 0.370.65 at 110 °C. Based on the exchange current densities obtained, the rate constant kc was calculated. It was found that kc at 90 °C was slightly larger than at 110 °C, especially for the results obtained by the CPC method. The average rate constants are 862.17 cm/s for CPC and 65.30 cm/s for CPP at 90 °C, and 477.69 cm/s for CPC and 63.53 cm/s for CPP at 110 °C for nominal Fe3+/Fe2+ ratios ranging from 1:1 to 1000:1. INTRODUCTIONChalcopyrite is one of the most abundant copper-bearing minerals, accounting for approximately 70% of the world’s known copper reserves (Wang, 2005). Most of the currently proposed leaching processes are based on sulfuric acid with ferric ions and/or dissolved oxygen as oxidants. Some of these processes have been piloted in attempts to implement these technologies on an industrial scale, such as Activox (U.S. 5,232,491, 1993), Nenatech (U.S. 5,993,635, 1999), Dynatec (U.S. 5,730,776, 1998), AAC/UBC (U.S. 6,503,293, 2003), Total Pressure Oxidation (U.S. 5,698,170, 1997), CESL (U.S. 5,874,055, 1999) and Galvanox (U.S. 7,846,233, 2010).To date, much effort has been devoted to understanding the kinetics and mechanisms of the oxidative processes (Biegler & Horne, 1985; Córdoba, Muñoz, Blázquez, González, & Ballester, 2008, 2009; Ghahremaninezhad, Asselin, & Dixon, 2010; Hirato, Majima, & Awakura, 1987; Hiroyoshi, Kuroiwa, Miki, Tsunekawa, & Hirajima, 2004; Warren, Wadsworth, & El-raghy, 1982) or the cathode reduction reactions of chalcopyrite itself (Arce & González, 2002; Biegler & Swift, 1976; Biegler, 1977; Nava, González, Leinen, & Ramos-Barrado, 2008), by chemical or electrochemical methods. However, as the most important cathodic processes in chalcopyrite leaching systems, the cathodic reductions of ferric ions or dissolved oxygen are worth measuring due to their effects on the overall leaching rate, as predicted by mixed potential theory."

Jan 1, 2012

Mine Safety in Chile ?Since the year 2000 fatality rate averages 34 per year ?1% of world mining labour force but 8% of world?s mining fatalities San Jose Mine Safety ?From 1998 to 2010 eight fatalities ?In 2003 mine inspectors recognized no second means of egress and a raise system was developed ?In 2006 182 workers were injured, 56 of them seriously ?In January 2007, there was a fatality after a rock burst, and the government ordered the mine closed ?Less than a year later the mine was back in operations. It had not complied with some of the basic safety measures ordered. One of those measures was to complete the escape way ladder.

May 1, 2011

By J. A. Drozdiak, W. Tse, P. P. Rosario

"In a recent publication (SAG 2015), we presented a non-conventional high pressure grinding roll (HPGR)-ball mill circuit as a lower capital cost alternative to the “standard” HPGR circuit. The circuit was designed for the treatment of a hard ore and relatively high tonnage (50,000 t/d). That paper provided details such as flowsheets, layouts, and equipment lists for the two options and compared their calculated capital costs demonstrating significant savings for the proposed circuit. This paper extends the analysis to a third option, a traditional semi-autogenous ball crushing circuit, giving the same level of details and now including the operating cost estimates for all three options for a more comprehensive analysis. Moreover, this work also provides information about the strengths and weaknesses of the non-conventional HPGR circuit when compared to the “standard” HPGR option.This study demonstrates that the proposed non-conventional HPGR-based circuit not only provides a lower overall capital costs for the project if compared to a “standard” HPGR circuit but also brings the capital cost to the level of the traditional semi-autogenous grinding (SAG)-ball mill circuits. In addition, the innovative HPGR circuit provides similar operational cost savings of the “standard” HPGR and thus a significant advantage when compared to the SAG option. With the current capital cost sensitivity for most greenfield projects, the proposed alternative circuit should help make HPGR-based circuits more competitive and thus promote the utilization of a technology that enables higher energy efficiency and reduced greenhouse gas emissions. INTRODUCTIONThe application of high pressure grinding roll (HPGR) technology in comminution circuits is well established for the processing of cement, diamonds and iron ore (Broeckmann & Gardula, 2005), and over the past 10–15 years, this technology has slowly been applied to hard ores in high-tonnage precious and base metal operations. Unfortunately, under the current economic climate, the ability to finance large capital projects has become very difficult and companies tend to have an easier time securing funding if the capital expenditures (CAPEX) are low with a proven process method. The traditional semi-autogenous grinding (SAG) mill / ball mill circuits easily fit into this mould, having been installed in countless plants around the world over the past 30 years with relatively low capital requirements. In contrast, it has been well-documented that HPGR-based circuits are capital intensive with complex material handling systems (Seidel, Logan, LeVier, & Veillette, 2006). Although these circuits benefit from reduced operating costs with the increase in energy efficiency and the elimination of steel grinding media (Rosario, Boyd, & Grundy, 2009), if the company is unable to secure financing to build the plant, these advantages remain out of reach. With the current trend to retrofit existing SAG circuits with a secondary crushing circuit to achieve design throughput, the opportunity to circumvent this gross inefficiency by making HPGR-based circuits more capital friendly would greatly benefit the industry."

Jan 1, 2016

By John Blackshaw

NEW sources of supply of tungsten concentrates became necessary when the flow from the Far East was blocked in 1942. In Canada, one source has been noted in the workings of the Hollinger mine at Timmins, Ontario. For many years, a small amount of scheelite had been removed with the gold ore, and an appreciable tonnage of scheelite still remained in the mine. At the request of the Dominion Government, a plant was built to recover this scheelite in the form of a concentrate that could be used by the alloy-steel industry without further preparation. The plant began operating early in March, 1942, and a small tonnage of ore, carrying scheelite and gold values, has been treated daily since then. The possibility of recovering the scheelite had been considered on several previous occasions. Each time the proposal had been given up because the total profits from the enterprise were estimated to be insufficient to repay the capital cost of building the recovery plant. At the time the plant was built, additional information had been gathered about the tonnage and grade of the scheelite ore in the mine, and several thousand tons of ore grading higher than 0. 25 per cent WO3 (tungstic trioxide) were known to be available.

Jan 1, 1943

By James F. Archibald

A research effort has been undertaken, under WSIB sponsorship, to characterize the support capabilities of conventional and innovative spray-on lining materials for mitigating dynamic failure effects created by simulated rockbursts. Conventional spray support media, such as shotcrete and fibrecrete linings, and a variety of new spray-on lining materials (TSL?s), typically polymer-type thin coatings, were subjected to simulated rockburst influence. For baseline comparison, conventional rockbolt and boltand- mesh support products were also evaluated. Observation of lining performance was undertaken through completion of field scale support and rock detonation trials. Controlled blasting tests were conducted at the Queen?s University Explosives Laboratory to examine the effectiveness of the variety of surface coating agents for modifying dynamic rock spalling processes. All tests were performed upon largely undisturbed and homogeneous rock materials in highly repeatable fashion. Both conventional and innovative TSL-type surface lining materials were subjected to ?rockburst? exposure in rigorously-controlled blast trials. All blasts were observed seismically and photographically to provide detailed information concerning rock motion, surface fracturing, ejected fragment motion and support liner survivability characteristics. These material comparison trials were performed to assess the relative effectiveness of a wide range of currently-available area support techniques for suppressing hazards associated with dynamic rock ejection. The results of this study validates that thin, sprayon linings may be equally as effective, and often better, than conventional support materials at mitigating rockburst or like damage in highly stressed mine environments.

May 1, 2003

By L. Yaun

In underground coal mining operations, gas content in a coal seam is used to assess the risk of coal and gas outbursts. To estimate the gas content, a number of systems have been developed, however issues remain about the rapidness and accuracy of these systems. To address these issues, a new and improved system has been developed that includes a sampling-while-drilling unit for coal sampling, a coal canister, an underground-based portable measurement unit, a surface-based measurement apparatus, and gas content calculation software. The system has been successfully applied in underground coal mines at Huainan, China. This new, rapid and accurate system, its main components and field trials are described in this paper.

Aug 1, 2013

By J. P. Caulfield

THE Hudson Bay Mining and Smelting Company's underground mine at Flin Flon, Manitoba, has in the past been serviced by two working shafts-the North Main shaft, and the No. 3 shaft. The North Main shaft is used to hoist the total production from under-ground, and handles the greater part of the mine supplies and crews. The shaft is five-compartment design, rectangular in cross-section, and is equipped entirely with steel shaft sets from the surface to the finished depth of 2,210 feet. Hoisting equipment in the surface plant will not permit the North Main shaft to be extended below its present finished depth. The No. 3 shaft, located approximately 2,300 feet from the North Main shaft, is used primarily as a ventilation shaft, and for hoisting lower-level development waste to the 390 level, where this material is used as mine fill. The No. 3 shaft is of standard rectangular design, timbered with 8-in. by 8-in. creosoted fir sets, hung on 6-foot centres. From the surface to the 1,430 level, the No. 3 shaft consists of three 5 ft. by 5 ft. compartments, and below this level to the completed depth of 2,300 feet, the shaft is increased to four compartments. To service the mine and to expedite development below the 2,210 level, a one and one-half compartment winze was sunk from the 2,210 level to a depth of 766 feet, or approxima tel y the 3,000 level.

Jan 1, 1941

By Jun Deng

The aim of this paper is to study the scientificity and reliability of three coal gas indices used to predict coal fire disasters, namely Graham?s ratio, CO/CO2 ratio, Litton ratio and their different characteristics and service conditions. Data from a programmed temperature experiment were applied to check their veracity and accuracy. Each index performed well in detecting the level of a fire. We conclude that it is better to redefine the definition through experimentation before applying a given index. Integrated analysis of the results can provide reliable reference data for predicting spontaneous combustion of coal.

Aug 1, 2013

By A. G. Lylie

Introduction At the Britannia Mining and Smelting Company's mill, the equivalent of 2,500 to 2,800 pounds of copper sulphate crystals per day is made from copper which is precipitated from the mine-water. This copper sulphate is used in the mill for the recovery of sphalerite by2 flotation. From 1932 until 1936 it was produced by exposing the precipitate to air for thirty days and then dissolving the oxidized copper with dilute sulphuric acid. In 1936, the flotation of sphalerite was discontinued and, when it was resumed in 1947, steps were taken to try to improve the former method. The present paper outlines the way in which this was done, and describes the plant and procedure by which copper sulphate is now being made, and by means of which an appreciable saving is being effected. Aboratory Tests The previous work had established that the precipitate, which consists mainly of metallic copper, must be oxidized before the copper would dissolve in dilute sulphuric acid. Various methods for oxidizing it were tried but in the early laboratory work the only suitable one found was to heat the precipitate to 600°C. and hold it at this temperature for two hours. When this was done, approximately 90 per cent of the copper became soluble in .acid. This percentage was considered satisfactory for practical purposes, but the cost of roasting was prohibitive because only a small amount of roasted precipitate was required each day.

Jan 1, 1951

By Zygmunt Kowalczyk

"A theory permitting the determination of expected surface deformations for planned underground exploitation is proposed and discussed in this paper. The relations between surface subsidence and various methods of mining are analyzed, and allowable horizontal .deformations for protected objects, according to the degree of their significance, are reviewed."

Jan 1, 1966

By W. M. Williams

"Although manganese is a metal virtually unknown to the layman, it is hardly necessary to point out to the engineer the importance of manganese in modern metallurgy, an importance intimately linked with iron (and steel), the basic materials of engineering construction for hundreds of years and certain to remain so for long into the future. World steel production will approach and perhaps reach 1 billion tons/year in the 1980s; with a manganese content between 0.5% and 1 % in ordinary steels, and more in specialty steels, manganese use worldwide will soon approach 15 million tons annually. Manganese was discovered and isolated in Sweden in 1774 by Karl Wilhelm Scheele (who also discovered molybdenum), but the element was only of scientific interest for several decades. By the early part of the nineteenth century, however, manganese oxide had become commercially available and was in use for colouring glass and for the production of chlorine. Commercial application in metallurgy appears to have been limited to the manufacture of crucible (or ""cast"") steel, a highquality product made by carburizing wrought iron, and melting it in small batches to make ingots which could be rolled and used for special applications, e.g. for the manufacture of fine tools or for ""steeling"" the cutting edges of implements such as wrought iron axes and chisels.* However, it was not until Bessemer's epoch-making invention of cheap steel in 1856, and the dramatic expansion of the steel industry thereafter, that manganese assumed the importance that it holds in modern steelmaking."

Jan 1, 1999

By J. P. Jylhä, A. Jokilaakso

The Outotec Flash Smelting process is widely used in primary copper production. A layer of slag on top of matte (copper–iron sulphide melt) creates a barrier through which matte droplets descend. Droplets of different sizes settle through the layer at different rates, which increases possibility of copper losses as smaller matte droplets may be removed with the slag. In this work CFD-DEM (computational fluid dynamics – discrete element method) coupling was used to simulate matte droplets settling through the slag during slag tapping. Discrete droplets and slag flow were simulated with DEM and CFD, respectively. This new approach enables tracking and solving movement and interactions of individual droplets. User-defined models were created to take coalescence and reaction kinetics into account. Coalescence created larger droplets, while the reactions decreased droplet size and increased its density. Drag caused funnelling effect, which pulled droplets towards the centre line of the descending cluster. This research is the only study known by the present authors in modelling liquid-liquid systems with the CFD-DEM coupling. Simulating coalescence and chemical reactions for discrete droplets enables more realistic simulations. However, CFD- DEM simulations are computationally resource intensive already without additional models, so a full scale industrial settler modelling still waits for further increase in computer performance. INTRODUCTION Flash smelting is a method used in copper and nickel production. In the flash smelting process, oxidation of sulphides in a concentrate is used to release energy needed to smelt the feed. In the process, copper matte is formed. Matte has copper content in the range of 55 – 70% (Sridhar, Toguri, & Simeonov, 1997), the rest is mainly sulphur and iron but has still many other impurities (Taskinen, Seppälä, Laulumaa, & Poijärvi, 2001). Oxidized iron forms iron-silicate slag while SO2 is collected for acid production (Davenport & Partelpoeg, 2015). The Outotec flash smelting furnace (FSF) can be divided in four major component: concentrate burner, reaction shaft, settler and uptake. Concentrate, flux and oxygen enriched air are injected into the reactor through the concentrate burner. The mixture then reacts in the reaction shaft forming matte and slag, which are collected in the settler, while off-gases flow out of the reactor through uptake for heat and dust recovery, and SO2 collection for H2SO4 production. The matte and slag form separate layers due to immiscibility and density difference. Raw material feed is continuous, but the matte and the slag are tapped periodically. A flash smelting furnace is depicted in Figure 1.

Jan 1, 2019

By Leroy C. Stewart

Owing mainly to the use of ethylene dibromide in the production of tetraethyl lead for gasoline treatment, there has been a tremendous increase during the past decade in the demand for bromine. In the United States, production, derived mainly as a by-product from the treatment of brines from salt wells, rose steadily from about two million pounds in 1924 to nine million pounds in 1931. In 1936, production amounted to between 20 and 21 million pounds. Much of the increase during the past four or five years has been due to the operation of the Ethyl-Dow Chemical Company's plant, which extracts bromine directly from sea water. The process employed by the Ethyl-Dow Company is somewhat similar to that in use on salt-well brines at their plant at Midland, Michigan, but whereas these brines contain around 1,300 parts per million bromine, sea water contains only 65 to 70 p.p.m.-about as much as the waste effluent in the brine process. By intensive research, however, a process was developed whereby a very considerable percentage of the bromine content of sea water could be recovered, and at a satisfactory operating cost. In its essentials, the process consists in liberating the bromine from the sea water by treat-ment with chlorine, blowing the bromine out of the water by a current of air, and finally absorbing it in a solution of soda-ash.

Jan 1, 1938

By Ryan W. Siggelkow

Mines today use various methods of mining to extract ore. Because of the dangerous nature of many of these processes, remotely controlled LHD machines are being used to extract the ore from the draw point. The remote control system, although being made safer all the time, has remained virtually unchanged for many years. The basic functionality is an operator switching the machine to remote control, getting out of the cab, walking up a stand, operating remotely, returning to the cab, switching to manual, driving manually, switching to remote, and switching to manual. It seems repetitive, and time consuming, does it not? Networking, convergence, video, voice, and data infrastructures, and other technologies are growing by leaps and bounds in virtually every industry and region, except for mining. From the comfort of the living room couch, a Canadian can play hockey online with full voice conversations over the Internet with someone in Russia in real time. Yet, a mine superintendent must jump through hoops to have a private conversation with the front line supervisor underground. "Is Joe around anywhere?" If Joe hears the message, he will respond. If not, who knows? Maybe he's hurt. Maybe he's not. Where is Joe? Nobody really knows, and that is scary. Today, surface knows that the workers disappeared into the cage at 7:00 a.m. They also know that the workers will probably and hopefully return at 3:00 p.m. Is there not a better way to handle this? With such a complex industry, it seems as if, for the most part, the introduction of new technology into mining has either been overlooked or has been met with some resistance. It is time to step back, look at the process, and see how it can be improved. Key areas of focus will be safety, productivity, dependability, and cost-effectiveness.

Oct 1, 2010