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By A. Lee Barrett

"THE COAL INDUSTRY of the United States• and Canada has made great progress in recent years. Coal mining in •the old days represented one of the most arduous tasks for labour and industry, but over the years great progress has been made in reducing the effort required from labour. Also, the tonnage produced per man, the cost of the coal per ton, and the overall safety of the operation, have been greatly improved.Looking back over the past fifty years:, the era can be divided into four principal parts: (a) hand-loading, (b) track mining methods, (c) off-track mining methods, and (d) continuous mining. For many years, all of the coal was won by hand-mining methods. The first forms of mechanization •resembled the move from the horse •and buggy to the automobile. Early track mechanical mining methods were usually adaptations of the direct methods involved in hand-mining, with each improvement directed toward some specific process. A revolutionary development came about with off-track mining methods. The first efforts in this direction were provided by off-track mechanical loading machines, which loaded the cars •on track and differed from conventional track mining methods only in that the loading machines themselves operated on the mine floor. With the advent -of the shuttle car about ten years ago, true off-track mining came into being, and real progress in this direction began to be made.At the present time we •are at the beginning of a new era -.the era of continuous mining. There will be a period of development with some time needed before the system is generally applied throughout the industry, but -already enough •has been done to indicate rather dearly what the future holds in this direction."

Jan 1, 1953

By J. Kramer, T. Hartmann

In the Hydrometallurgical processes, the presence of the so-called “crud” is a constant challenge in solvent extraction. Crud is a stable emulsion which forms along the interface between the aqueous and organic phase. The spread is influenced by the following parameters: first, wind blows the dust and impurities into the open sedimentation tanks. Second, the undissolved solids such as sand transported in the PLS causing problems in conjunction with incorrect agitator design. The crud fraction can decisively impact the efficiency of the hydrometallurgical extraction because the phase interface can constitute a large fraction and the sedimentation tanks cannot react flexibly to it. In the downstream process of the seriesconnected sedimentation tanks, they are thus all contaminated with crud. At the same time, the necessary mass transport is significantly impeded at the phase boundary between organic phase and aqueous phase due to the crud formation. The transfer of the organic phase into the electrolysis cell can result in a “burnout” of the cathode. The carry-over of this electrolyte into the extraction can cause problems with the pH regulation. The carry-over of the organic components into the raffinate also leads to contamination of the leaching circuit. The continuous treatment of the crud with a 3-phase decanter centrifuge is extremely effective in combating this problem. This technology splits all three phases from each other and they are consequently continuously separated. All subsequent process steps exhibit a stable, uniform effectiveness. The main advantage for the customer is that fluctuations in the process are eliminated and the organic phase can be recirculated back to the extraction. The recycling of the solvent alone justifies the investment in less than 6 months as examples from South Africa and Chile show. To operate solvent recovery in daily operation fully automated online at the optimum limit, the decanter centrifuge is equipped with a concentration-dependent pond adjustment called DControl®. By this means, we can guarantee our customers the maximum possible solvent recovery and minimise the solvent costs in this process step. This system is presented in detail in this paper.

Jan 1, 2012

By Horace Freeman

The sulphur consumed in Canadian pulp mills and acid plants is worth approximately three million dollars annually and amounts to one hundred and fifty thousand long tons, all of which is imported from the United States. Concurrently with a decline in the value of newsprint there has been a gradual increase in the price of this raw material. Most pulp mills in Canada are situated within reasonable distance of domestic pyrite deposits; nevertheless it has not yet been found possible to mine these deposits and utilize the contained sulphur in competition with the imported material. It is the purpose of this paper to elucidate the reasons therefor, and to describe? a commercial-scale experiment undertaken with the object of introducing a native raw material into the Canadian pulp industry on the purely economic basis. Reasons for the Preferred use of Sulphur The known sulphur deposits in the United States are very large, so that at least a twenty-year supply of this material is assured. It is recovered cheaply and in pure condition. Although large deposits of pyrite are known in Canada, nothing has yet been developed to compare in size, cost of mining, or purity with the United States material. It has been necessary to handle and transport more than two tons of pyrite to equal a ton of sulphur.

Jan 1, 1930

By F. T. M. White, W. A. Bardswick

"The parameters of airborne minerallic particulates which create industrial dustiness, together with the physiological hazards caused by their inhalation, are reviewed. Various techniques of dust sampling are discussed and analysed, and the parameters referred to above are classified as the basis for methods of assessing the physical, chemical and mineralogical characteristics of dust-particle suspensions. The paper surveys those methods of assessment currently accepted by various statutory authorities, and reviews other methods that warrant attention and newer techniques that are being developed."

Jan 1, 1969

By A. C. Halferdahl

The Granby ores may be divided into three groups or classes. The No. I ore is a heavy pyrite, chalcopyrite, pyrrhotite, sulphide carrying some free silica, and calcite. No. 2 ore carries the same general group of sulphides as does No. 1, but in a lesser amount. The gangue is an altered greenstone. No. 3 ore has a smaller amount of sulphides than either of the others. Analyses of these ores is as follows: Cu. Si02 Fe. CaO S. Al 203 MgO No. I. Per Cent. 1.8 17.5 33.0 5.7 34.5 2.3 1.3 No. 2 Per cent. 2. 0 35. 6 23. 9 4. 3 I .5. 0 9. 2 6 .. 0 No. 3, Per cent. 1 . 5 40. 9 21 . 7 3. 0 I 1 . 3 11 . 0 5 . 4 The sulphide minerals in No. 2 and No. 3 ores occur largely in bands in the gangue, and for these portions comparatively coarse grinding serves to release the gangue. Drill cores show a certain dissemination of sulphides in portions of the rock, so that grinding to 5 per cent. + 65 mesh with 65 per cent.-200 mesh liberates the sulphide minerals very completely. The association of the sulphides is fundamental. The pyrite was probably deposited first and was followed by a portion of the chalcopyrite, or these two portions of the sulphide minerals were deposited together.

Jan 1, 1924

By Michael R. McPhie

Topics of Discussion 1. The Global Mining Initiative (GMI) and MMSD North America (Brief) 2. Task 2 of MMSD North America ? A Test for Sustainability 3. The Seven Questions and their Application 4. Key Recommendations and Next Steps GMI = Global Mining Initiative Significant international collaborative effort supported by more than 30 of the world?s largest mining/minerals firms which sought to involve all communities of interest. Three major streams of activities: 1. Mining, Minerals and Sustainable Development Project (MMSD) ? 4 regional Process (North America, Southern Africa, South America, Australia) 2. Creation of ICMM (formerly ICME) 3. Major conference in Toronto in May, 2002

May 1, 2002

By Jeremy Breker

Cameco aligns its social and environmental responsibilities with its vision, mission and values. Environmental Leadership is established as a corporate objective that emphasizes the triple-bottom-line and a systematic approach to understanding environmental, social and economic issues, risks and opportunities. These are ingrained in the project culture, systems and processes and used to influence solutions derived by the project teams to achieve Cameco's objectives. This paper traces the organizational objectives from the early stages of a project through to implementation and turn over to Operations. A case study is used to demonstrate how an asset is influenced by Cameco?s strategy.

Aug 1, 2010

By J. B. Kitchin

"The design of conveyor belting for use in mines poses problems to the manufacturer that are unique. The challenge to be met is that of the production of a conveyor belt which can withstand use and misuse in an environment that may differ vastly from one country to another, and even between one mine and its neighbour.The development of a product to meet such varying requirements necessitates a protracted program of trials, both in the laboratory and in the field; a new successful development, the only criterion, can be said to have been achieved only after very long-term usage under actual, deliberately chosen, arduous mining conditions.New developments in conveyor belt construction can never stop, no more than can developments in new and advanced mining techniques. A new problem is set-an answer must be found. Some of the problems are noted here, and answered where possible, in what must after all be little more than an excursion into a very comprehensive and detailed subject."

Jan 1, 1967

By J. R. Parga T., P. J. Valenzuela G., L. S. Quiroz C., P. Guerrero G., J. L. Valenzuela G.

"Pressure oxidation is a hydrometallurgical pre-treatment process used for refractory auriferous sulfide ores. In the work reported here, a refractory pyrite ore sample from the Mulatos mine, Sonora, Mexico was characterized. The sample was subjected to atmospheric cyanidation, and simultaneous pressure oxidation and cyanidation under different conditions of temperature and pressure. The mineral characterization showed that pyrite is the main species in the sample. The gold extraction tests were carried out in an 1-litre Parr pressure vessel at a temperature range of 90-120 °C, a pressure range of 87.5–150 psi (using oxygen), and a cyanide concentration range of 0.8-1.2 %wt. The gold extraction results showed that diffusion through product layer is the rate controlling step.INTRODUCTIONIn hydrometallurgical precious metals extraction, the most commonly used process is sodium cyanide leaching, as shown in the next reactions involving gold and silver (Fleming, 1992; Marsden & House, 2006):4Au(s) + 8CN- (aq) + 2H2O(l) + O2(g) ? 4Au(CN)2 -(aq) + 4OH- (aq) (1)4Ag(s) + 8CN- (aq) + 2H2O(l) + O2(g) ? 4Ag(CN)2 (aq) + 4OH- (aq) (2)“Refractory” auriferous ores or concentrates often contain gold and silver locked inside other sulfide phases such as pyrite. This renders cyanidation ineffective, so oxidative pre-treatments are used in order to convert the sulfide minerals into porous oxide minerals and make cyanidation work more efficiently. Reaction (3) shows the oxidation of pyrite in alkaline media and the formation of the porous oxide (Koslides & Ciminelli, 1992):2FeS2 (s) + 15/2 O2 (g) + 8H- (aq) ? Fe2O3 (s) + 4SO4 2- (aq) +4H2O(l) (3)A process of simultaneous chemical pressure oxidation and cyanide leaching for a flotation concentrate produced in the mine of Bacís, Durango, in Mexico, gave good results (Parga et al., 2007). In the study presented here, it was intended to use this treatment for a refractory pyrite mineral from the Mulatos mine in Sahuaripa, Sonora, Mexico, modifying variables such as pressure, temperature and cyanide concentration to find the best conditions for oxidation and leaching."

Jan 1, 2012

By M. M. C Jiménez, D. C. Buzzi, D. C. R. Espinosa, J. A. S Ténorio, G. F. R Oliveira

In this work the extractive and selective capacities of solvent extraction synergistic systems to recover nickel and cobalt were evaluated. The liquor used was from the high pressure acid leaching process (HPAL). Initially the industrial liquor, processed from lateritic ores, was analyzed to identify the concentrations of the metals. Experiments of synergistic solvent extraction were performed later. The extraction liquid-liquid was carried out with a mixture of Cyanex 272 (CY) and Ionquest 290 (IQ) extractants. The process was executed with the temperature of 65 ºC, pH of 5.2 and the ratio aqueousorganic 2:1. Systems of 80% kerosene and CY 20%, CY 16% - IQ 4%, CY 12% - IQ 8%, CY 8% - IQ 16%, CY 4% - IQ 16%, IQ 20% were studied during 20 minutes. The results of this paper showed that the mixture of these two extractants doesn’t improve significantly the recovery of nickel and cobalt from liquor.

Jan 1, 2014

By H. Henao, E. Kohnenkamp, L. Rojas

The slags generated in the copper conversion process are mainly composed of Cu2O-Fe2O3-SiO2 with the compounds CaO and Al2O3 in concentrations up to 10 wt%. The present work contributes to the knowledge of the conversion process, generating experimental data for the diagrams of phases Cu2O-Fe2O3- SiO2-Al2O3 and Cu2O-Fe2O3-SiO2-CaO. The experiments were carried out in a tubular furnace at temperatures of 1150°C and 1200°C under a condition of saturation with tridymite. Once the equilibrium was reached, the samples were fast quenched in water. The phases in the samples were observed in a Scanning Electron Microscope (SEM) and the elemental composition of the phases analyzed by means of Energy-dispersive X-ray spectroscopy (EDS) detectors. The addition of Al2O3 and CaO into the Cu2O-Fe2O3- SiO2 system resulted in an appreciable displacement of the liquidus lines, corresponding to an expansion of the liquid in the tridymite primary phase field. INTRODUCTION The conversion process of copper consists of oxidizing Fe and S present in mattes with 60 to 65wt% Cu (up to 16wt% Fe). This process is separated into two stages: 1- Slag blowing: Fe is oxidized, the addition of a flux such as SiO2 (silica) forms a second liquid phase called slag, this phase is removed from the furnace; 2-Copper blowing: in this stage, the matte with low concentration of Fe (<1% w/w) is again oxidized to remove S as SO2 in the exhaust gases. The product of these two processes is the formation of Copper Blister (> 98wt% Cu) (Schlesinger et al., 2011). Unlike the aforementioned conventional processes, in most Chilean smelters, conversion Peirce- Smith Furnaces are loaded with high copper matte (70–75wt% Cu) (Henao & Moyano, 2016). Due to the low concentration of iron in these matte (up to 5wt%), it is considered that separating the conversion process in two stages is neither operational nor environmentally convenient. Therefore, the process is carried out in a single stage (Pradena et al., 2006), generating a slag phase with a high percentage of Cu2O (wt%Cu>40).

Jan 1, 2019

By M. Sakata, H. Hata, K. Haiki

"Most of the secondary ZnO contains fluorine (F) in large quantities. Serious troubles at the zinc electrowinning are occurred by the cathode corrosion caused by F, therefore we developed iron compounds as F-adsorbents used in zinc sulfate solution. The iron compounds can be reused repeatedly as F-adsorbents because they can adsorb/desorb F alternatively depending on the pH. Moreover, if the adsorptive capacity decreases, we can dissolve and re-synthesize them easily. In this paper, results of the experimental process which consists of five steps (leaching, F removal, Cl removal, purification and electrowinning) to produce high purity electrolytic zinc from the secondary ZnO are reported. INTRODUCTIONThe recycle material for zinc, secondary ZnO, contains large amounts of fluorine (F) and chlorine (Cl) which are halogen elements, compared with calcine obtained by roasting of zinc sulfide concentrate. The halogen elements cause adverse effects in the zinc electrowinning process and particularly F causes corrosion of aluminum cathode plates and eventually sticking of electrodeposited zinc and therefore, F concentration in the electrolyte is controlled to less than approximately 20 mg/L. There are several methods to remove F from secondary ZnO, such as leaching with Na2CO3 or NaOH solution [1-2], vaporizing in a rotary kiln by roasting at 1000 to 1200 degrees C [3-4]. However, up to the moment, there has been no effective method for the removal of F from zinc electrolyte and it has been a big obstacle in treatment of secondary ZnO in electrowining of zinc.The authors, therefore, developed an iron compound used as an adsorbent of F in the zinc sulfate solution [5-8]. This iron compound is Akaganeite that has a crystalline structure of ß-FeOOH. Akaganeite is synthesized by neutralization of FeCl3 solution containing a small amount of SO4 2- with Na2CO3. When this iron compound is immersed into weak acidified zinc sulfate solution, F in the solution is adsorbed. F adsorbed in the iron compound is removed by immersing in weak alkaline solution and the iron compound can be reused as F adsorbent."

Jan 1, 2012

By Evelynn Stirling

"The paper/presentation will review the evolution of diesel technology from older diesel engines (1990 vintage) through to the latest technology as a result of the ever changing emissions regulations. It will encompass the EPA Tier levels as well as the latest Euro Stage V emissions. The next step with technology will be to address the CO2 emissions, which translates to improving fuel efficiencies of the product as well as other technologies like battery electric, hybrid and fuel cells. As technology progresses it also becomes important to improve connective diagnostic systems to support maintenance practices and improve efficiencies. What will also be presented will be the key emissions changes to the different gaseous and particle mass elements as the products have transitioned from the EPA Tier 3 through to Tier 4 Final regulations. Offering a range of different technologies to the underground mining market matters as not all pieces of equipment will perform optimally due to its duty cycle and application. INTRODUCTION Rudolf Diesel built his first well-known prototype of the high-compression engine in 1897. Since that time, the diesel engine has evolved into one of the world’s most capable and reliable forms of power generation. Diesel engines can be found in a wide variety of vehicles and equipment, powering everything from agriculture and construction equipment to power generators and marine vessels. In the early days the emissions from diesels was very poor and extensive work has been accomplished over the decades to make the product more environmentally friendly. This is more important in underground mining where the space is limited and ventilation is expensive and challenging. DISCUSSION The key driver of the development of diesel technology is the legislation globally around engine emissions. The emission level requirements over the years has forced diesel engine manufacturers to build a deep technical understanding of the system and how to innovate and optimize key elements of the engine. Cummins expertise has been built over the years as the diesel engine has evolved from a relatively simple mechanical engine to an electronic system with advanced air handling, fuel system, after treatment, and controls. Cummins has also continued to expand into systems beyond diesel, including natural gas. Many new components have been added to diesel engines to reduce emissions while improving fuel efficiency and reliability and, at the same time, reduce the total cost of ownership to the customer."

Jan 1, 2019

By F. Bélanger, P. Fournier

"The Detour Lake Mine is located in northeastern, Ontario, approximately 300 kilometres northeast of Timmins and 185 kilometres by road northeast of Cochrane. The mill processes a free milling gold ore using both gravity circuit and leaching with a state-of-the-art carbon-in-pulp circuit. The grinding circuit is a conventional SABC circuit with a tonnage of 60,000 mtpd at 95 microns with the addition of pre-crushing upstream of the SAG mill. This paper will highlight the impact of a pre-detox thickener on the cyanide consumption in a gold leach/CIP circuit. While the pre-detox thickener was built with the intention to reduce the cyanide consumption, the opposite effect was observed when the thickener was put temporarily offline. It will show how the re-circulation of a dilute stream of cyanide into the grinding circuit, increases the overall slurry temperature and by the same effect, increases the dissolved copper concentration in the leaching circuit which subsequently increases the cyanide consumption.INTRODUCTION The processing plant is using a conventional gravity, cyanidation and carbon-in-pulp processing facility currently operating at approximately 60,000 mtpd. The comminution process is based on two parallel SABC lines, each fed from an individual reclaim tunnel. Cyclone overflow from the two ball mill circuits is directed to the pre-leach thickener. The thickener underflow is distributed to two (4) parallel leach trains of 5 tanks each, each leach train providing 29 hours of leaching retention time. After leaching, the gold in solution is recovered in a carrousel CIP circuit consisting of two (2) parallel leach trains. Tails from each CIP circuit are combined and sent to a pre-detox thickener to recover as much cyanide solution as is economically practical before being diluted and fed to a cyanide destruction system. The detoxified tailings are sent to the Tailing Management Area (TMA) for settling and retention. The excess water from the TMA is reclaimed and recycled back to the processing plant. The pre-detox thickener is designed to thicken the leach tails slurry to 64% solids with the overflow being recycled to the grinding circuit. It is estimated that the pre-detox thickener will recover 60% of the cyanide in the CIP discharge solution. It is also designed to reduce the SO2 consumption by diluting the thickener U/F to 50% solid using the tailing pond reclaim water which has very little cyanide content."

Jan 1, 2019

By E. Peek, L. Becze, K. Reading

"Gallium oxide is an important semiconductor material used in optoelectronic devices (flat panel and solar cell) catalysts and sensors. One of the methods to produce ?-Ga2O3 is the so-called hydrothermal route. It is practiced by Neo Gallium Compounds and comprises of two steps: (1) the production of mainly gallium-oxy-hydroxide in a pressure vessel by reacting metallic gallium with water at 200-220 ºC and (2) the calcination of gallium-oxy-hydroxide at 700-750 ºC to convert it into ?-Ga2O3. This paper describes this pressure hydrometallurgy process supported with relevant thermodynamic data and presents the characteristics of the ?-Ga2O3 powder produced for commercial purposes. INTRODUCTIONGallium is a relatively new metal, having been predicted by D. Mendeleev in 1871, discovered by P.E. Lecoq de Boisbaudran in 1875, and first commercially produced in the USA in 1943. Gallium is not rare, being more abundant in the earth crust than antimony, bismuth, molybdenum, silver and tungsten. However, few gallium minerals exist in nature, and the dispersion of gallium within other minerals add to the complexity of its recovery. In practice, gallium is found in dispersed state primarily in bauxites and in some sphalerites, and, to a much smaller extent, in some coals. At present, a very large proportion of the primary gallium in the world is recovered as a by-product of aluminum plants, mostly Bayer plants, where gallium is extracted from a bleed of the Bayer liquor (Roskill, 2011). In 2011, world production of primary gallium was estimated at 200 metric tonnes. In addition, there is a significant contribution of recycling to the overall yearly availability of the metal.Gallium exhibits fairly remarkable properties: it is liquid above 29.76 ºC, can be supercooled, and with its high boiling point (2204 ºC), is the metal with the widest liquid range. Gallium is magnetic, and is an excellent conductor of both heat and electricity. Gallium also displays a marked anisotropic electrical conductivity (Roskill, 2011). All these properties render gallium almost irreplaceable in the semiconductors (GaAs, GaN, GaSb, GaP wafers) and the optoelectronics industry (flat panel, solar cell)."

Jan 1, 2012

By D. Markwart, B. Volk

Anode effects are a phenomenon of the aluminium electrolysis process which produce potent greenhouse gases called PFCs (CF4, C2F6). With concerns surrounding global warming, and increasing regulation of GHG emissions, anode effects have become a significant sustainability issue for aluminium producers. In modem smelters, sophisticated computer control and automated alumina feeding systems allow for very tight control of the alumina concentration in the electrolyte and thus very low anode effect frequencies. Older smelters, however, do not have these systems and must either invest heavily to obtain them, or find other, innovative ways to reduce anode effect frequency. This paper will present the integrated approach to anode effect reduction used in the Vertical Stud Soderberg (VSS) potlines at Kitimat Works. Through an innovative combination of simplified signal analysis, modified alumina feed control logic, anode effect prediction, and anode effect prevention using a pager based communication system, Kitimat W arks has been able to make significant reductions to its anode effect frequency.

Jan 1, 2006

By G E. Craig, W. M. Williams

A simple, easily constructed apparatus suitable for the zone refining of iron and other reactive materials is described. After eight passes at one inch per hour, the iron produced showed a marked drop in hardness to 49 Brinell. In addition, an arbitrarily -defined recrystallization temperature was lowered by about 35°C and the rate of grain growth greatly increased. CERTAIN materials, of which iron is one, are so reactive that they cannot be zone refined in any known container without becoming contaminated. For such substances, the floating zone method ( 1) may be used. In this method, the specimen is supported vertically in an inert atmosphere and the molten zone supports itself by its own sur-face tension. The method was first applied to silicon (2) and has since been used for other reactive metals such as zirconium and titanium. Smith and Rutherford (3) have previously reported on the floating zone refining of iron; the efficiency of the method for reducing the car-bon content was demonstrated on

Jan 1, 1962

By E. Herrera, L. Mariscal

"Ilo Copper Smelter operates since 2007 with an ISASMELTTM furnace as a single smelting unit (1,200,000 tpy) associated with two Rotary Holding Furnaces for separation of matte and slag, and which directly produces a discard slag. Southern Peru continually has been improving the slag chemistry of its ISASMELTTM furnace in order to reduce copper losses, given its big economic impact due to large slag mass generation. The present paper describes the influence of the CaO, Al2O3 and magnetite content in the slag of the ISASMELTTM furnace correlated with the SiO2/Fe ratio and its liquidus slag. Also it defines the best slag chemistry and operating practice in order to reduce the copper losses without compromise the bricks life of the furnace.INTRODUCTIONIlo Copper Smelter of Southern Peru (Grupo Mexico) is located on the southern coast of Peru, and treats mainly copper concentrates produced in its own mines (Toquepala and Cuajone).The modernized smelter was commissioned in 2007 and operates with an ISASMELT™ furnace as a single smelting unit (1,200,000 tpy), which is associated with two Rotary Holding Furnaces (RHF) for separation of matte and slag. This slag is directly sent to the dump. Figure 1 shows the smelter flow diagram.The ISASMELT™ process is a bath-smelting process using a single lance. The lance tip is immersed into a molten slag bath contained within the stationary, vertical, refractory-lined ISASMELT™ furnace. The injection of oxygen-enriched air, through the lance into the slag results in a highly turbulent molten bath. Feed material falling into the turbulent bath from above reacts rapidly, resulting in extremely high productivity for a relatively small bath volume."

Jan 1, 2012

By Nicholas Bonderoff, Amily Xu

The evaluation of battery electric vehicles (BEVs) in underground mines involves comprehensive business case analysis beyond just the capital and operating costs of the equipment itself. BEVs demonstrate benefits from an EHS perspective, reduced mine ventilation costs, lower energy operating costs, reduced overall GHG emissions (dependent on the source of electricity), elimination of DPM, lower equipment maintenance costs, and reduced cooling requirements in deep mines. When including batteries and supporting infrastructure, BEV capital costs are approx. 80% greater than that of diesel equipment. The project economics are highly dependent on the cost of electricity and diesel fuel, and these can vary widely depending on the location of the mining operation. Battery charging and swapping methodologies must be evaluated as there are a variety of approaches that can be employed which vary by manufacturer and type of equipment. Careful consideration of the cycle times, charging methodologies, and location of the battery charging infrastructure is necessary. Specific operating conditions must also be taken into consideration. For example, the time for blast gases to clear will be increased by reducing ventilation flow, and the potential impact on production needs to be evaluated. Similarly, the electrical distribution system needs to be evaluated for peak loading conditions when BEVs are charging. Criteria including maintainability, reliability, commercial availability, and performance need to be evaluated. BEVs have fewer components than diesel equipment and this correlates to lower overall maintenance costs, however, BEVs require maintenance personnel with specific skill sets in order to maintain the equipment. Battery lifecycle costs need to be considered as battery replacement incurs significant capital expense. Some manufacturers offer services to offset these capital costs through usage agreements. Recycling and disposal of batteries at the end of their lifecycles also need to be considered. With the increased selection of BEV equipment that will be available in the next 2-4 years, 100% BEV adoption is also possible. We recommend a holistic approach when evaluating BEVs for underground mines. This will ensure that everything is considered in order to evaluate the full impact of BEV implementation.

Jan 1, 2023

By B P. Scott

Podsol soil horizons developed on Pleistocene glacial sediments overlying the Coronation Mine orebody were analyzed for copper and zinc spectro-photometrically, using biquinoline-isoamyl alcohol and dithizone carbon tetrachloride reagents. Copper and zinc are concentrated in the A. and C horizons, whereas the A1, A2 and B horizons are leached. Of economic significance is the fact that the C horizon contains a copper anomaly, in excess of 100 times back-ground, directly over the orebody. Due to the erratic distribution of high copper concentrations in the Ao horizon with respect to the orebody, that horizon is not considered as a reliable prospecting datum. U NDER certain conditions, metallic ore deposits are accompanied by primary halos of trace elements in unweathered rock surrounding the orebodies or by secondary halos in weathered rock, alluvium, soil, or vegetation above or near the mineralized zones. Where such halos occur, chemical analysis, as applied to the detection of trace elements, is a valuable prospecting aid, permitting the detection of mineralization of possible economic value.

Jan 1, 1965