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By F. Nava-Alonso, A. Uribe-Salas, C. Rodriguez-Rodriguez

Ozone has been proposed to pretreat refractory ores before the cyanidation process for precious metals extraction. As pyrargyrite is one of the silver species most common in Mexican refractory ores, the ozonization of this silver sulfide was studied. The effect of pH and ozone concentration on silver dissolution was evaluated by means of a factorial experimental design. Two levels of sulfuric acid concentration and ozone in gas concentration were evaluated: 0.18 and 0.72 mol/L of acid and 0.054 and 0.077 gO3/L, respectively. The highest silver dissolution was obtained when using the higher acid and ozone concentration.

Jan 1, 2011

By Fatemeh Saeidi, Luis Marcelo Tavares, Malcolm Powell, Mohsen Yahyaei

"Understanding a single breakage mechanism is fundamental to the development of breakage testing techniques appropriate for mechanistic modelling of any breakage equipment. In the light of this insight, it is also possible to compare any two breakage events in a mechanistic manner. This paper presents a new method to compare breakage mechanisms of two-point impact with compression, different in their applied strain rates. This approach regards a single breakage event as a process affected by three sub-processes; first fracture, capture and spatial distribution of fragments. Spatial distribution is influenced by the kinetic energy of fragments and their brittleness. Using this methodology allows us to examine how each sub-process is influenced by applied strain rate and its impacts on progeny size distribution. For this purpose, two rock types of widely different strength, magnetite and silicate, were tested at various energy levels using the impact and compression mechanisms. To isolate the effect of spatial distribution of fragments, particles were forced to remain in the breakage zone. In this condition, similar progenies were generated from compression and impact mechanisms at similar energy levels. However, allowing natural distribution of fragments, coarser progeny was produced from compression of silicate. Additionally, using this approach provides a physical meaning and explanation for rock strength parameters such as A×b in the t10-Ecs relationship. INTRODUCTIONComminution models are rapidly progressing toward a destination that enables us to explain the complete physics of a breakage process as well as the properties of the ores. Eventually, they will be able to take into consideration the micro-events that take place during the comminution process (Bourgeois and Banini, 2002). Thus, considerable efforts have been made in the last few years in the area of ore breakage characterisation to comprehend and unlock a single breakage process that has been treated as a black box event in the majority of conventional methods. In this paper, an attempt is made to explain the effect of applied strain rate on the breakage properties of rock by using the knowledge that has been gained by understanding a breakage event. This is particularly important due to its application for various comminution devices that operate within a relatively broad range of speed."

Jan 1, 2016

By Geir M. Haarberg

Electrochemical techniques, mainly linear sweep voltammetry and potential step chronoamperometry, were used to study the behaviour of dissolved phosphorus species in cryolite-alumina melts, The presence of AIPO4 or Na3PO4 gave rise to voltammetric current waves due to electrode reactions involving phosphorus species at potentials where dissolved alumina is stable in cryolite melts, Diffusion kinetics for dissolved P(V) species were studied, Data from industrial cells were used to determine mass balances for phosphorus, For cells being fed with secondary alumina, more phosphorus tends to end up in the produced metal, Laboratory experiments to study the effect of phosphorus in the bath on the current efficiency for aluminium were also carried out.

Jan 1, 2004

By C. W. MacLeod

LOCATION The Goudreau gold area in Ontario extends from a point a short distance south of the main line of the Canadian Pacific railway, at Lochalsh, in a south-westerly direction to the Magpie river. It crosses the Algoma Central & Hudson's Bay railway at Goudreau station, 177 miles north of Sault Ste. Marie. The area is roughly 25 miles in length by 6 miles in width. The potential gold formation is much more extensive but little prospecting has been done outside of the limits mentioned. The actual continuous area of Keewatin formation, in which gold has been found, is one of the largest in Ontario. ACCESSIBILITY Probably no mining area in a similar stage of development has had the excellent transportation facilities which Goudreau enjoys. This field is traversed in part by the main lines of the Canadian Pacific and Algoma Central railways. The Provincial Government has constructed 22 miles of road through the heart of the camp. Sixteen miles of this road is suitable for motor car traffic and several cars and trucks are in constant service.

Jan 1, 1926

By H. R. Taylor

The history and development of this property is more or less familiar to nearly everyone connected with the mining industry, so that only a brief outline of the more important facts will be given in this article. In 1916, a small pilot mill was constructed by the British Columbia Copper Company at Copper Mountain, and during 1916 and 1917 test work was conducted to determine the possibility of concentrating the ore and also to work out a suitable flow-sheet. In the spring of 1917, the location of a mill site at Allen by, which is about 8,% miles from Copper Mountain, and near the Similkameen river, was decided on, and the designing of a 2,000-ton plant was then worked out by Bradley, Bruff and Labarthe. Early in 1918, the actual construction of the concentrator began, and, after considerable labour difficulties, it was completed in 1920. During this period of construction, the West Kootenay Power Company ran a 60,000-volt power line over from Greenwood, a distance of 102 miles, and also built a sub-station at Allenby to take care of the mine and mill. The concentrator was started up on October 20th, 1920, and ran until December 11th, 1920, a total of 18,354 tons of ore being milled. The results of this short period of operation were encouraging, but, due to tlie prevailing low price of copper and high wages, it was necessary to shut down until a more favourable time. During the latter half of 1923, some work was done on remodelling the mill. This work continued until January 8th, 1924, when it was suspended.

Jan 1, 1929

By A. Boeing

Rock-breaker automation and remote operation improves the safety and efficiency of mining operations. This article presents an overview of the Rocklogic rock-breaker automation system architecture that provides collision avoidance, automated parking, and remote operation functionality. The system consists of a distributed computer control system that interfaces with sensors attached to the rock-breaker, the rock-breaker hydraulics, and the site infrastructure. We present results of an automated Transmin rockbreaker installed in a production environment at an underground Australian mine site. The system has been in production use for over 900 days during which there have been no reported collisions, and 100% adoption of the remote operation technology. As a result, Rocklogic has significantly improved the safety of rock-breaking operations and reduced the rock-breaking cycle time, thereby improving the sites overall throughput.

Aug 1, 2013

By E. Trickey

In the mining industry there exists a constant drive for increased safety and productivity and decreased operating costs. This acts as a driver for implementing advanced technology. As more and more mining operations turn to new technologies, an observed bottle-neck for technology advancement has been the limitation of machine vision solutions available. LiDAR has been seen as a possible solution to the machine vision problem. In the past, a few studies on machine vision solutions have been undertaken by various groups involving scanning laser range-finders and millimetre-wave radar. These studies have done little more than highlight the limitations of both technologies in the mining environment. Little work has been done, however, exploring the applicability of LiDAR imaging technology for mining applications. Neptec Technologies Corp. has developed an obscurant-penetrating LiDAR (OPAL) sensor technology which overcomes the limitations faced by traditional LiDAR sensors when operating in a dusty environment, as well as advanced 3D real-time intelligence (3DRi) data processing algorithms that enable the real-time exploitation of 3D imaging data with sensors mounted on moving vehicles. Working with Teck Resources Ltd. and Barrick Gold Corporation, Neptec is adapting the OPAL sensors and 3DRi technology to mining applications. This paper highlights a number of real-time OPAL/3DRi based mining applications demonstrating how this technology overcomes the limitations of traditional LiDAR to provide a real-time machine vision solution that supports mine machine autonomy.

Aug 1, 2013

"Dry crushing trials at pilot scale have shown that the IMPTEC Super-fine Crusher has the capacity to generate ultra-fine products from hard mineral assemblages presenting at either coarse or fine feed sizes. The super-fine crusher was introduced at the 27th International Mineral Processing Congress in Santiago Chile, with results from a range of duties, which demonstrated the crusher’s potentially expansive operating scope. This paper focuses on current preparations to progress the technology from pilot scale to commercial scale within a concrete production plant, where lead blast furnace slag will be crushed to ultrafine sizes to generate an active silica product for use as a supplementary cementitious material, which can replace Ordinary Portland Cement. A key objective of the operation is to demonstrate an economical route to reducing the cost of concrete production, improving concrete quality and reducing greenhouse gas emissions. The paper also highlights the potentially key contribution super-fine crushing can make to the long-term viability of iron ore beneficiation by simplifying comminution flow-sheets and reducing operating costs. There is every indication that the technology has the potential to feature universally in metalliferous and industrial mineral flow-sheets. INTRODUCTIONToday’s IMPTEC super-fine crusher is the successful end product of development work over 19 years and is the third particle size reduction device conceived, built and tested over that time. The concept evolved as engineering design progressively developed a mechanism capable of harnessing a highly efficient combination of fundamental particle breakage mechanisms. Early development trials at pilot scale indicated that super-fine crushing had the potential to establish a wet or dry, media free, low energy route to ultra- fine products from hard mineral assemblages. Having achieved some impressive results from open circuit pilot tests on fly ash and granulated blast furnace slag it became clear that the cement industry may well provide opportunities to apply the technology commercially. Following expressions of interest from local cement and concrete plant operators, IMPTEC negotiated an agreement to undertake commercial trials with a SFC 350 super-fine crusher installed on site at a concrete supply plant in South Australia. Super-fine crushing scope was recently expanded following further expressions of interest from research groups involved in the processing of iron ores. Pilot trials are progressing in these areas."

Jan 1, 2016

By A. Kowalski

Telvis Limited, manufacturer of an emergency communication dispatcher's broadcasting system, now introduces the possibility of a remote software upgrade to its devices. The paper presents methods, features and ways to accomplish this task. It describes the mechanisms used and the opportunities that arise from the use of this type of functionality. The mechanism software update presented applies to devices on the surface and in underground areas of mines. The electronics used currently allow the use of remote software updates, but the mining equipment makes little use of these methods. This paper aims to start the discussion on this topic and tries to lay the path of development by showing one of the first examples of the application.

Aug 1, 2013

By W. Gan

The interactions between bitumen and quartz sands in aqueous solutions were studied with the objective of recovering residual bitumen from Athabasca oil sands froth treatment tailings. It was observed that the presence of various multivalent metal cation (Fe3-, Fe2+, Mg2+,Ca2+, etc.) increased the mutual coagulation between quartz particles and oil or bitumen droplets within certain pH ranges. While the increased coagulation was detrimental to the recovery of the bitumen since it lowered the degree of bitumen liberation from sands, this effect could be reduced or eliminated by the addition of organic chemicals such as citric acid, oxalic acid and EDTA. Among these organic chemicals, citric acid was found particularly effective even at very low concentration.

Jan 1, 2006

By O. Lundhede

Today, systems and machinery usually are designed to meet only one specific customer?s requirements. One reason for this is that underground automation and smart functions are often developed tightly together with a customer. This is natural, since risk and cost can be shared between the customer and the supplier. Nevertheless, when the automation product develops and the market increase this will cause problems: The highly specialized products will not fulfill the next customer?s demands. In order to cope with this problem, Atlas Copco works towards a common platform. Instead of designing solutions for specific customers, we will lift the abstraction and focus on standardized modules. These modules, or function blocks, can then be combined in a large variety of configurations. The benefits of combining modules into products are, for example: increased flexibility when options are available for many machines; easier commissioning and maintenance since less different spare parts and tools are needed; and easier operation since the user interfaces have a similar look and feel. This paper will present the ongoing work towards standardized modules. We will discuss how our Rig Control System (RCS) allows for modular design at Atlas Copco. RCS has number of standardized modules that are used in different surface and underground mining and tunneling equipment. These modules are also used for optional products such as, drilling, radio-remote control, and telematics systems.

Aug 1, 2013

By Li Chongyang, Liu Baolan, Jia Xiaolin, Li Suping

An Al/Al2O3 gradient coating applied on a heat-resistant stainless steel was prepared through a slurry process by using aluminum and ?-Al2O3 powders as the transition filler material, alpha alumina as the surface coating material, aluminum dihydrogen phosphate as the binder, and sodium molybdate as the corrosion inhibitor. The effects of heat treatment temperature, adhesive/filler ratio and ?-Al2O3 content on the bonding strength, microhardness and thermal shock resistance were investigated. The crystal phase and microstructure were characterized by XRD and SEM. The results indicated that the composition of the coating changed continuously from surface to coating-substrate interface. The coating could offer high bonding strength and good thermal shock resistance when heat treated at 700°C.

Jan 1, 2010

By I. A. Kovalevska

Considered problems: elaboration and implementation of resource-saving technologies, low-cost support systems improvement, openings security and support, based on wallrock condition control with supreme implication into the rock pressure occurrence counteraction work. Results of analytic and underground investigations using computer simulation of the finite elements in order to calculate stressstrain state of the multivariable geomechanical systems are presented. Solutions of concrete objectives are found using spatial geomechanical model of solid motion around openings, considering real geomechanical parameters formation of support forms with proper conditions of their contact and real mechanical characteristics. Ultimate solutions of resource-saving technologies implementation based on the analysis of multivariate vertical, horizontal, and reduced stresses components calculation and also near-contour rock, support bearing components and security constructions movements are found. Results of experimental investigations of combined supports and security constructions, which increase openings' stability in difficult conditions of flat coal seams are presented.

Aug 1, 2013

By George W. Bain

Mr. Geo. W. Bain: Dr. H. C. Cooke's discussion of 'The Geology and Mineral Deposits of the Harricanaw and Bell River Basins' possesses many of the elements of a good political address; perhaps his long residence in Ottawa has some bearing upon his method of discussing geological work. The three essential parts of the address are all included. First, the plank - "Contributed discussion on the Geology and Mineral Deposits of the Harricanaw and Bell River Basins"; second, the personal attack upon the opponent, to show antipathy to the opponent as well as to his ideas; and third, controversion of a number of statements, which have been made to appear as planks of the opponents platform, even statements and work which are in no way connected with one under discussion. In the following pages, I will confine my attention to a defense of my work in the Harricanaw and Bell River basins, leaving discussion of the other areas mentioned by Dr. Cooke until results of the re-surveys are published. It is intimated that it was impossible to make a geological examination of an area of 1,600 sq. miles on a scale of four miles to the inch (base map supplied) in three and a half months, because "the area is accessible only from the railway along the northern edge together with a few roads close to it, and from rather wide separated streams?. There is one way, known to most geologists, whereby a place can be reached other than by railway coach or motor boat, and that the oldest of all -- walking. Most of the region was reached in this fashion. The boundaries of all the 18 townships included in the map are surveyed, nine are divided into lots, and the north-south and east-west centre lines of most of the others are surveyed and have mile-posts placed.

Jan 1, 1927

By Jodi Wilding, Barry Lurnsden

The implementation of new technology to mineral separation operations requires rigorous testing to confirm the technology&apos;s technical and economic benefit. The Jaguar Mine owned by Jabiru Metals is located in Western Australia and sequentially separates a copper concentrate and then a zinc concentrate. Fine grinding (80% of zinc in tail is <25µm) is required to achieve efficient mineral separation. All mineral losses are therefore fine mineral losses, and so improvements in metal recovery must focus on this fine mineral. Magnetic aggregation technology has been shown to increase the recovery of fine paramagnetic minerals so it was an appropriate technology to evaluate at Jaguar. Testwork commenced in the copper circuit and it was found that there was a substantial reduction in copper in copper tail and an increase in zinc recovery to the zinc concentrate. The increase in zinc recovery in the latter zinc circuit was an interesting result and initiated the second stage of testwork that was to install and test a second magnetic conditioning unit in the zinc círcuit. This showed a further increase in zinc recovery. Magnetic conditioning technology has now been fully evaluated in the plant and is now part of the Jaguar flowsheet.

Jan 1, 2011

By Mousa Mohammadi

Due to operational advantage of dragline in simultaneous excavation and back-filling, the equipment has gained vast importance in open-pit mining. Besides, absence of auxiliary haulage units and a myriad of other benefits are also credited in favor of excavation of muck piles by the draglines. However, the aspects of production, productivity and economics are of utmost significance in dragline operation and planning. In this light, the present paper is an endeavor to analyze availability and utilization of dragline operations. The paper presents a good amount of data for 4-draglines operating in one of the major opencast projects in India. The study reveals the trends of availability and utilization of these draglines during last 11-years. Furthermore, the study also highlights the salient reasons for loss of available hours and for idling of the draglines. Some startling information and facts have been illustrated in form of graphs and pie charts.

Aug 1, 2013

By I. Imris

The chemical industries are using different type of catalysts, which after application usually produced many tons heap of residues. One of them is cupric oxide catalyst with high content of copper and silica. The recovery of copper from the waste has become major interest from a viewpoint of environmental protection and recycling of resources. The thermodynamic analysis and experimental results suggest that the copper from cupric oxide catalyst can be extracted by plasma reduction process. By plasma reduction process the inert slag and copper with following chemical composition: 99.04 % Cu, 0,042 % Fe could be obtained.

Jan 1, 2007

By R. Salimi

Tricalcium aluminate hexahydrate (TCA) is used as filter-aid for security filtration in the Bayer alumina process. TCA is typically produced on-site by mixing Bayer liquor with slaked lime. Specific properties are required from the TCA to ensure adequate filter throughput, lifetime and importantly effective reduction of solid/colloidal impurities from the solution. The effect of reaction time on morphology and particle size distribution of tricalcium aluminate was studied for a batch experiment at simulated process conditions. It was found that reaction time plays a critical role on the morphology, crystal structure (diameter and crystallinity) and particle size distribution. In the early stages of the reaction, nucleation dominates the crystallization process followed by growth dominated by agglomeration up to a mean particle size of 10 µm. The particle morphology shifted from an irregular shape to more spherical throughout the course of the reaction.

Jan 1, 2014

By Adrian Dance

Newmont Mining Corporation?s Carlin (?Carlin?) operation processes roaster feed through a double rotator, dry grinding mill following secondary crushing. Metso Process Technology & Innovation (?PTI?) was involved in a review of crushing and dry grinding circuit operations in August 2009. A number of opportunities for increased throughput were identified in the PTI study. Extended plant trials were conducted in July 2010 to provide justification for possible circuit modifications and if needed, additional equipment. The trials confirmed that a finer crusher product would reduce the build-up of material ahead of the coarse grinding chamber in the double-rotator. Also revealed were material transport and airflow restrictions in the dry grinding circuit that resulted in a high circulating load. The secondary crushing plant demonstrated it was capable of reducing the amount of +¾? material in the mill feed thus increasing dry grinding throughput. However, wet and sticky feed affected screening efficiency resulting in low utilisation of the existing crusher capacity. The open circuit configuration also made it difficult to control crushing circuit product size. For the dry grinding circuit, changes in grinding media size, transfer grate design and increased airflow were recommended to reduce circulating load issues and increase circuit capacity. This paper summarises the crushing and grinding circuit review, the extended site trials performed by PTI and the improvements in dry grinding operation that resulted from this study.

Jan 1, 2012

By L. Magne, A. Pinto, M. Maldonado, J. A. Finch

Estimation of gas holdup from electrical conductivity measurements has been used in lab and industrial installations. The approach is based on the application of Maxwell's model, which relates the concentration of a dispersed phase in a continuous medium to measurements of the electrical conductivity of the dispersed phase, continuous medium and the resulting mixture (dispersion). When applied to inferring the collection zone gas holdup in a three phase system and to facilitate real-time on-line measurement, the slurry is assumed to behave as the continuous medium and gas bubbles as a nonconducting dispersed phase. This article derives an equation for estimating gas holdup in a three phase system, eliminating the assumption that the slurry behaves as a continuous medium but rather as a dispersion of non-conducting solid particles in water. In this formulation only water behaves as the continuous medium in the sense of Maxwell, and gas holdup in a three phase system is then calculated from the application of the Maxwell model twice: (1) to determine solid content in a two-phase system, and (2) to determine solid plus gas holdup in a three phase system. To validate the new equation and quantify the errors incurred by assuming slurry is the continuous phase a laboratory flotation cell was instrumented to continuously measure the conductivity of two and three phase dispersions with known solids contents. As the amount of gas in a lab flotation machine is difficult to measure directly or by another indirect technique such as using pressure signals, 2.5 mm dielectric plastic spheres having a density of ca. 1.3 g/cm3 were used instead of air bubbles for validation. Experimental results demonstrated that the continuous medium assumption underestimates gas holdup and that the resulting bias error increases linearly with the solid content and decreases with the magnitude of gas holdup.

Jan 1, 2016