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By D. C. McDonald

"IntroductionTHE GIANT YELLOWKNIFE property is on the west side of Yellowknife bay, Great Slave lake, N.W.T., some 600 air miles north of Edmonton. This paper deals with the underground development and mining of the complex system of orebodies which have produced, in the first fifty-six months of operation (May, 1948, to December, 1952), 652,464 tons of ore with an average grade of 0.80 ounces of •gold per ton (1).The mine has been developed from three vertical shafts designated A, B, and C. Figure l shows the positions of these openings with respect to the known ore-bearing zones and the surface plant.A shaft was sunk to a depth of 522 feet in 1945-46, primarily as a prospect shaft for investigation and development of the East Zone orebody. Drifting was carried out on the 200-and 325-foot levels. Before this development had been completed it was clear that the funds immediately available made it imperative to get revenue from production as soon as possible. By the beginning of 1946, the remarkably high-grade character of the ore in the present B Shaft area had been established by surface drilling, and the decision was made to obtain initial production from this source. Since known orebodies at shallow horizons were to be developed quickly, the choice of a suitable rock outcrop for the shaft was something of a problem."

Jan 1, 1953

By J. B. Boisvert, P. Oshust

A significant source of uncertainty in the diamond resource contained in kimberlite pipes is the volume of the pipes. Often the material within a pipe will be mined as ore, leaving the actual geometry of the pipe as a significant source of uncertainty. It is desirable to use stochastic techniques, rather than deterministic methods, to model pipe geometry because stochastic techniques generate multiple realizations that are reproducible and can be used to assess uncertainty in pipe geometry. The proposed methodology uses sequential Gaussian simulation of pierce point locations interpreted from drillholes through a kimberlite pipe. Kimberlite pipes are approximately cylindrical in shape; therefore, the data are transformed to cylindrical coordinates to facilitate the simulation of pipe geometry. Rather than using xyz coordinates to define the pierce points, z, ??and pipe radius are used. The radius variable can be simulated in z-??space to generate multiple realizations of pipe volume. Uncertainty in the volume of the pipe can then be evaluated. This methodology is demonstrated with a kimberlite pipe at BHP Billiton’s Ekati diamond mine.

Jan 1, 2008

By H. Soto, J. Jara, F. Nava

"A combination of oxidation and precipitation was used to eliminate cyanide from gold milling effluents. Preliminary laboratory work developed with both synthetic cyanide solutions and with industrial effluents indicated that ozone can easily destroy free cyanide and weakly complexed cyanide (i.e. copper and zinc cyanide). In this case the reaction is quite fast and seems to be controlled by the mass transfer of ozone to the solution. Experimental results indicate that free cyanide and weak-acid dissociable cyanide in mill effluents can be reduced to less than 1 ppm. However, the iron-cyanide complexes proved to be quite resilient to destruction with ozone and they remained in the solution even after most of the free and weakly complexed cyanide was destroyed with ozone. These results were confirmed in a pilot trial developed at the Sphinx plant in northern Quebec.To deal with the problem presented by the presence of the iron complexes two different approaches were studied: use of a combination ozone-ultraviolet light oxidation, and the precipitation of iron-ferrocyanide complexes in the residual solution after ozonation. This last method proved quite promising since reduced the total cyanide levels of industrial solutions assaying as much as 250 ppm to less than 1 ppm of total cyanide. Control of the · pH of the solution was the key to obtain the precipitation of the iron complexes. The use of iron to precipitate cyanide complexes has the advantage of being less expensive and less toxic than copper (used by the Inco process)."

Jan 1, 1992

By Thomas R. Larson

"Many concentrators use re-circulating “plant” water for dilution in their flotation circuits. However, if crusher dust suppressants, ball mill grinding aids, or even agitator bearing grease are introduced into this water, and the water itself is not subject to cleaning steps, then sufficient quantities of these chemicals may appear in the flotation cells and begin to impact the flotation separation. A bench flotation procedure has been coupled with statistical analysis in order to estimate the impact of small quantities of non-flotation chemicals on flotation performance.INTRODUCTIONCleveland Cliffs produces iron oxide pellets for blast furnace feed, and is developing the capability to produce ferrous metallic products to supply a wider customer base. Cliffs manages five North American iron mines, including the Wabush mine sites in Labrador and Quebec. Based on various characteristics of the ore bodies, the flow sheets of the five mines are diverse. For example, Hibbing Taconite uses magnetic separation alone as their primary upgrading method, but Northshore and Empire use magnetic separation followed by flotation, and Tilden uses flotation alone. Last but not least, the Wabush concentrator upgrades primarily with gravity and electrostatic separation techniques.At Northshore, concentrate from the magnetic separator circuit is fed to a reverse flotation circuit. By design, the magnetic separators operate at the highest possible recovery of magnetite, as the separator tails are discarded, and relatively high silica content was acceptable to Northshore’s customers. As the steel-making industry moved toward lower and lower slag volumes, the silica content in the magnetic separator concentrate became a problem. The flotation step was added in the late 1980s in order to decrease the silica assay of the magnetic separator concentrate to meet the current customer requirements. In this setting, the flotation feed stream contains very little silica that occurs as liberated quartz particles. As the degree of liberation of the flotation feed stream is then a limiting factor for silica removal, the online grind control then was linked to flotation in the overall plant control system so that grind can be adjusted to achieve improved liberation if necessary for the flotation process."

Jan 1, 2002

By C. W. Davis

AN inclined shaft is usually more difficult to sink than a vertical shaft, yet it is often chosen because of the subsequent saving in cross-cuts required to reach an inclined ore body. This paper briefly discusses the factors which led to the choice of an incline and then describes the operations involved in the preparatory work and in the sinking. These operations included a programme of mining out the underground facilities and installing the structures required for a hoist-room, cable-raise, waste-pass, ore pass, two sets of skip dumps, and a collar station equipped with counterbalanced drop-rails. The shaft was sunk 1,000 feet and four stations were cut, each with loading pockets. As the sinking progressed, the rock changed from hard porphyries and dense cherts to blocky limestones and earthy rubble. These conditions called for a change in methods and it is to the red it of the shaft-sinking crew that they overcame the new difficulties as the shaft progressed, while maintaining a satisfactory monthly advance. The section mined out was nine feet six inches by seventeen feet overall. This gave room for three compartments: two skip compartments four feet three inches by five feet nine inches inside the timber, to handle two-ton skips, and a manway three feet six inches by five feet nine inches. The sinking began on December 16th, 1941, and was completed on February 15th, 1943.

Jan 1, 1945

By Adam Moore, Peter Radziszewski, Matt Gallimore

"Stirred mill technology dates back to 1928 where the idea to use “an agitator and spherical grinding media” was presented. In the context of the mining industry, interest in stirred milling technologies has grown over the last 20 years where the typical observation reported inDespite these developments, the tumbling mills are continuing to be used in fine and ultrafine grinding applications. The main reason for this, as communicated at the Canadian Mineral Processors roundtable discussion in 2013, is that the comfort level in understanding stirred milling technologies is not at the level of that of tumbling mills.At CMP 2014, one contribution was made to explore how mill design affects power and energy in a stirred mill. While the 2015 CMP paper explored the application of one scale-up methodology to the Gibraltar case. For the CMP 2016, the aim of this paper is to contribute to increasing the general comfort level with stirred milling technologies by developing a better understanding of the different scale-up methodologies used. This will be accomplished by first completing an overview of the scale-up models found in the literature followed by a review of the different testing and scale-up procedures. This review will be supported by a number of case studies found in the literature. The paper will close with a discussion on some of the challenges that these models and methodologies have and how future research might contribute to overcoming them.IntroductionStirred mill technology dates back to 1928 where the idea to use “an agitator and spherical grinding media” was presented (Stehr, 1988). The year 1948 saw the successful application of Du Pont’s “sand mill” for pigment grinding. Subsequent years have led to the development of different types of stirred mills spanning a number of industries that require fine and ultrafine grinding."

Jan 1, 2016

By Gustav Nillson

There is a difference in design parameters between steel linings and rubber linings for grinding mills. The basic design parameters for rubber are described and a comparison is made between steel and rubber in different applications.

Jan 1, 1979

By A. R. Harrington

BEFORE discussing some of the technical aspects of the steam generating plants of Nova Scotia Light and Power Company, Limited, it might be of interest to go back through history and see the development of steam generation in this public utility. Back around 1902 Nova Scotia Light and Power Company, Limited, had three slide-valve engines in-stalled at its Water Street, Halifax, generating station for a total capacity of 1,800 kilowatts. The plant remained at about this size until 1910 and in 1911 a 2,000 kilowatt steam turbine was installed to raise the total capacity of the plant to 3,800 kilowatts. In 1916, a 3,000 kilowatt turbine was installed and one of the slide-valve engines was removed to make a total plant capacity of 6,200 kilowatts. The total demand in the Company's service 8rea was at that time 4,000 kilo-watts.

Jan 1, 1958

By Peter Broad

"Extracting any metal, especially specialty metals and rare earth elements, requires an in-depth analysis of the costs and potential revenue as well as a due diligence study of other stakeholder interests. Rare earth projects are generally in the billion dollar US range or above, and thus failure to accurately predict any loss of revenue caused by impurities within the product or additional effluent treatment costs can destroy an otherwise viable study. Two prime sources of input impurity are considered: impurities in the material feed and from reagents. The effect of these impurities factor on both the product (in reduced revenue) and on residual “tailings” that may incur additional unforeseen costs.INTRODUCTION“Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident” – Arthur SchopenhauerThe era of unscoped, unbudgeted construction ended about 150 years ago. Today’s engineer must design with confidence; but do so amidst proprietary secrets and unfamiliar pollutants, which present a myriad of interesting challenges. Is it possible to build a viable rare earth plant to a realistic budget, without destroying that which we cherish? Some see this as contradictory but in reality it is the only viable option.WHEN GOOD PROJECTS FAILWithout rare earths the Copenhagen agreement might be null and void. Running a wind turbine with a 30 tonne conventional magnet requires some hefty engineering and prohibitive investment. Despite their ‘Green metal’ applications, production of rare earths have created environmental nightmares, as Folger stated in 2011 when visiting Baotou, or has Jaing Mainheng who has been quoted by Ambrose Evans-Pritchard 6 Jan 2013. This comment is not a criticism of China; the details are from a 2012 white paper published by the Chinese Government that initiated a $6 billion environmental clean-up. Nor is China unique; other plants have had problems as well. There were toxic leaks in the 1990s from Mountain Pass, and the Mitsubishi Bukit Merah Plant (built in Malaysia in 1958) required a $100 million clean-up."

Jan 1, 2016

By Lionel C. Piuze

Introduction and Early History The British Canadian Mine is one of four operating properties of Asbestos Corporation, Limited, and is located in the town of Black Lake, Que., five miles southwest of Thetford Mines. In the early days of as1bestos mining, this .property was owned by a few small companies who later became part of the Asbestos Corporation. First .to commence mining operations on the property was the Coleraine Mining Company who, in 1885, began selling part of their large holdings in the area to various asbestos mining interests. Of these, the earliest active companies were Manhattan United Asbestos, the Glasgow and Montreal Asbestos Company, and the Anglo-Canadian, the last named later becoming the Standard and Dominion Asbestos Companies. Extraction of fibre was limited to what is now known as crude asbestos and the methods were primitive. Drilling was done .by hand and the ore was lifted by derricks operated by band winches. These were later replaced by horse power, but it was not until 1887 that the first steam-operated boom derricks were introduced, at the Anglo-Canadian mine. The ore was hand cobbled and the asbestos roughly classified and bagged. The waste rock, which by today's standards contained a considerable percentage of marketable fibre, was dumped near the pit. The first attempt to separate the asbestos from the host rock by mechanical means was made in 1888 by the G1asgow and Montreal Asbestos Company, then known as the Scottish-Canadian Asbestos Company, whose mill, erected in that year, was the world's first asbestos mill. Though the equipment was crude, the principles employed were the same as those used today with much larger units. The next steps were the use of rock drills, the adoption of steam rail transportation for moving mill rock, and conversion to the more flexible cable-derrick hoisting.

Jan 1, 1950

By V. Budinsky

In recent years the global mining industry has addressed its social and environmental responsibilities and numerous factors have contributed to this. Corporate Social Responsibility (CSR) is an important part of mining company strategy for practical implementation of the goals of sustainability, transparency, accountablity and good relationships with stakeholders:- investors, employees and communities. A key stakeholder for all mining companies is the local community which is affected by the mining operations. Companies must identify the emerging social and environmental trends, study the interests and concerns of various communities, address their needs and maintain a positive relationship. The CSR programmes of Czech coal mining companies are focused on surrounding community initiatives and sustainable responsible business. Mining in the Czech Republic is subject to strict rules and regulations and supervised by the State Mining Authority. Mining projects undergo rigorous approval procedures which encompass all operational measures at the different planning levels ? such as public participation in the authorisation process for mining projects, the application of the Environmental Impact Assessment Directive, environmental sustainability programmes, innovative solutions and flexible options offered by the mining company. One very important part is the preparation of the mining-technology preconditions and developing the integrated planning process in which all socially and politically relevant subjects in the mining operation surroundings are included. In an in-depth debate, all stakeholders may jointly develop the concept, in accordance with democratic principles. The optimally conducted dialogue process needs broad communication bases, including setting up theme-related joint taskforces, together with good moderation and the highly qualified support of technical experts. Using a case study of Severoceske doly a.s. Chomutov (SD Company) and the Czech Coal Group ? Czech leaders in the extraction of brown coal, this paper aims to examine the community development approaches and the CSR effectiveness of large scale mining companies. This paper brings a review of CSR and other such voluntary initiatives in the mining industry's proactive steps to contribute to societal well-being in a meaningful way. Key studies are provided by the projects ? Region with Better Perspective?, ?Stop Dust for Healthy Brezno Village?, ?Clever Heads for the North? and ?Coal Safari?. CSR issues are managed throughout all stages of the mine operation and beyond, long after the mine closes (e.g. post-closure programmes of new landscape, alternatives for reclamation including generation of lakes in former surface mines, conceptualization of industrial heritage). Communities need to be given the opportunity to help themselves through participation in CSR projects rather than being recipients of financial gifts from the company. A fair balancing of interests is the basis of any successful cooperation.

Aug 1, 2013

By Nilce Alves Santos, Vânia Lúcia de Lima Andrade, Keila Lane Carvalho Gonçalves, Harold Wyslouzi1

"When confronted with the difficult decisions on advancing an exploration project to the feasibility and construction stages, it is important to know how various regions of the ore body will react in the milling and concentration processes. While bench scale test work is common and inexpensive, the results and information provided are somewhat limited due to the difficulty in accurately predicting the effects of recirculating middling streams or gradual changes in solution chemistry.Conventional Pilot Plants, processing 100 to 1,000 kg/hour of sample ore, provide the detailed engineering data required to develop a final process flowsheet and to size the equipment. They are, however, expensive to set-up and operate, and are really only viable for major projects that are well advancedIn the latter part of 1999, the Mineral Development Center at CVRD (MDC) purchased a new piece of mineral processing equipment which can run continuous flotation tests using drill core samples. To evaluate its performance, and to compare it with conventional testing methods, various types of flotation tests were carried out using two different types of copper ore. The limitations and advantages of open circuit and locked cycle bench tests, as well as the Mini Pilot Plant and the Conventional Pilot Plant were evaluated.Open circuit tests carried out at the bench scale only provide basic information. More complete and trustworthy information is obtained, in terms of the recirculation of flows and reaching a permanent and stable flotation regime, as the dynamics and complexity of the tests increases. The data obtained showed that the MPP’s metallurgical performance was equivalent to that of a conventional pilot plant."

Jan 1, 2002

By J. H. Archibald

"IntroductionShot-saws are used for sawing rock throughout the dimension stone industry especially in granite quarry mills. Shot-saws, as currently designed, have an inherent wear problem which leads to slow cutting rates and repetitive blade changes which consumes much time. Because the saw blades are made from steel the abrasive shot used with them is limited to a certain hardness which effects the over-all efficiency of the sawing operation. Suggestions are made toward optimization of blade design and the sawing process. Blade DesignA common steel blade design is shown in Figure I. Note the perforations in the blade. These perforations or holes in the blade serve two or three purposes. The most obvious reason is to allow the abrasive shot a pocket in which to collect at the bottom of the blade, so that it can be distributed from these pockets into the cutting zone underneath the blade. The abrasive is fed to the saw in a slurry and usually comes in from the top. The blade must then cut a kerf wider than itself in order that the abrasive grains have a path leading from the top of the blade, down along its sides, and finally reaching the pockets and cutting zones. This circuitous path followed by the abrasive leads to side wear on the blades and high friction which can lead to blade buckling in severe cases. However, the fluidized path of the abrasives down the sides of the blade serves another purpose which is a positive gain if conditions are properly controlled. The abrasive slurry interacts with the perforations of the blade, the blade itself and the rock. This gap and the perforations in the blade, which are fluid filled, are sites of constant shearing motion. Eddy currents form in these gaps and pockets which tend to stabilize the blade by setting up balanced hydrodynamic forces which otherwise might not form in a non-perforated blade. A stable blade produces a more uniform cut in the rock. The third and final reason for the perforations are to allow the blade to wear in such a fashion that new pockets are always being formed and, consequently, new cutting surfaces between these pockets are also formed."

Jan 1, 1993

By Åke Krukka, Heribert F. Broicher

"The iron ores of the Kiruna Mine in Sweden are of exceptional quality but for the phosphorus content in certain zones of the orebody. The prevention of mixing ores high in phosphorus with those low in phosphorus has always been of significant economic importance. The ongoing introduction of tele-mining and automatic haulage by LHDs requires new means in the field of quality control underground, as the experienced miner as well as the underground laboratory assistant no longer are involved in the process. As of 1998 LKAB has been testing prototypes of LIF Analysers for non-contact and real-time measurement of the phosphorus content of ore being transported by LHDs from the stopes to the respective ore pass assigned to a certain ore quality. The principles of the analysis of laser-induced fluorescence, the different test phases and results are described and conclusions made. With bulk sorting of ore underground the mining engineer supports the efforts of the metallurgist in the processing plant.INTRODUCTIONThe Kiruna Mine of LKAB, Sweden is the largest underground iron ore mine in the world. In the early nineties LKAB decided to develop the Kiruna orebody further down from the 775m main level to a new main level at 1045m. This development programme was realised while in the mineral processing section and in the pellet plant further capacity was added (Wyllie 1996).In addition to deepening of the mine, which opened up 330 million tonnes of ore, the exploitation of the so-called lake ore was included in the future planning, adding another 1 15 million tonnes of mineable ore. At an annual production of approximately 20 million tonnes of ore the Kiruna Mine today looks at a developed ore reserve sufficient for the next 20 years.All of the competitors’ ores traded in the world market are from open pit operations. LKAB compensates for the obvious disadvantages by continuous efforts to make the best possible use of her high quality magnetite ore deposit. This objective is realised by combined efforts in the pellet plant, the mineral processing plant and the mine. Propriety processes, latest big scale equipment and high tech solutions for automation lead to high quality sales products at a reasonable cost."

Jan 1, 2002

By D. Holz

In this work we present a novel level set-based model for the real-time simulation of soil deformations. A level set defined by a signed distance function and sampled in a regular 3D grid represents and tracks the soil volume under deformation. Moving away from classical 2.5D heightfield representations of soil to a full 3D volume representation allows for improved tracking of cutting tool operations and the simulation of near-vertical or vertical soil faces. The proposed level set representation furthermore provides a versatile mathematical platform for modeling additional effects such as soil slip, and does not suffer from the sampling limitations of commonly used heightfields. Cutting forces applied to the tool are simulated via a formulation based on the Fundamental Equation of Earthmoving, modified to support inclined soil surfaces and transient states of tool motion. Discretisation of this 2D cutting force model with respect to the tool surface allows capturing the effects of irregular 3D terrain shapes on blades and buckets. The surcharge created during cutting operations is tracked in the form of particles and included in the soil failure force computation. We make use of an adaptive, hybrid level set-based and particle-based soil deformation scheme, which allows the soil deformation to be simulated in real-time.

Aug 1, 2013

By P. Favreau

This paper describes the progress accomplished at the Noranda Technology Centre in the field of three-dimensional computer-aided underground blast design. Traditional methods of laying out underground blasts are reviewed, and the new computer-aided approach is described. Time savings achieved through the use of BLASTCAD can be advantageously used to better engineer blasts, using models and blast vibration analysis. Future work involving the attachment of blast models directly to the system is also addressed.

Feb 1, 1993

By T. T. Chen, W. Petruk

The mineralogy of the feed, concentrates and tailings from the Heath Steele mill in New Brunswick was studied in detail to determine the liberation and recoveries of the major ore minerals, and to characterize the occurrence and distribution of the trace elements. The ore milled during August 1977 contained an average of 4.34 wt % Zn, 1.25 wt % Cu, 1.64 wt % Pb and 90 gr/ton Ag. The main trace elements in the ore are silver, cadmium, indium, cobalt, antimony, bismuth, arsenic, mercury, tin and gold. Silver is carried in solid solution in tetrahedrite-tennantlte, galena, Ag-Sb sulfosalts and Pb-Bi-Sb sulfosalts. Approximately half of the silver is recovered in the lead and copper concentrates and the remainder is lost in the tailings and Zn concentrate. As the major silver-bearing minerals also contain Sb and Bi, recovering silver by ore dressing would involve recovering elements that are troublesome in extraction metallurgy. Cadmium and most of the indium and mercury occur in solid solution in sphalerite and consequently are recovered in the zinc concentrate. Some indium is also recovered in the copper concentrate in a second unidentified indium-bearing mineral. Cobalt and arsenic occur principally in arsenopyrite, cobaltite, a Co-Fe sulfarsenide, pyrite and pyrrhotite, and follow these minerals into the tailings. Recovery of the valuable element cobalt, therefore, would involve recovering the environmentally hazardous element arsenic. Most of the tin and gold report to tailings. The ore was ground to about 80% minus 270 mesh. At this grind, 71 wt % of the sphalerite, 66 wt % of the chalcopyrite and 59 wt % of the galena were liberated. Recoveries of free sphalerite, free chalcopyrite and free galena in the Zn, Cu and Pb concentrates were 85 wt %, 76 wt % and 80 wt %, respectively; recoveries of unliberated sphalerite, unliberated chalcopyrite and unliberated galena in the respective Zn, Cu and Pb concentrates were 48 wt %, 5 wt % and 7 wt %. Some of the unliberated sphalerite and chalcopyrite grains in the tailings are large and would have been liberated at a finer grind.

Jan 1, 1980

By P. Groleau, O. Tavchandjian, D. Marcotte

In open pit mining, each small mining unit (SMU) is selected for mill processing based on an estimate of its true grade. The estimation is usually done using analyses of cuttings from blast holes within that SMU. One common estimator used for selection is the arithmetic average of within-SMU samples. This estimator is conditionally biased. The effect of a conditional bias is to overestimate the profit really recovered from the deposit. For this reason, a conditionally unbiased estimator is preferable. Increasing the number of samples generally improves the accuracy of the estimation (and diminishes the conditional bias, if present, of most estimators). However, there exists a practical limit where an additional sample does not improve the estimation sufficiently to cover the expense of making the analysis. This limit is specific to each deposit and depends on geostatistical parameters, economic factors, and mining parameters. This study examines how the number of samples affects the recovered reserves and the resulting profit. Also, the effects on optimal profit of varying the different factors are examined. Globally, the number of samples required increases with the selectivity of the operation. For a given ore deposit, the greater the number of SMUs selected for processing, the fewer samples are required and vice-versa.

Jan 1, 1998

By M. Drozd, M. Somppi, Z. Yamak

"Granular activated carbon is widely used in the gold mining industry for gold extraction from aurocyanide-containing slurry. The extraction process can employ carbon as part of the gold recovery operation for various circuit designs including carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) circuits. However, various qualities of activated carbon exist and the durability of the material can change significantly from source to source. Handling this expensive reagent can pose challenges when fine carbon losses occur in the CIP, CIC, and CIL circuits. Additionally, any gold that is adsorbed to these carbon fines can also be lost by various mechanisms including carbon attrition and fracturing, inefficient coarse-fine separation, and poor carbon fines capture. With the above in mind, a series of tests were conducted to investigate standardizing simple laboratory methods for testing carbon quality. A standard procedure beyond or enhancing ASTM methods can serve as additional starting points for evaluating carbon specific to the gold industry. The investigation focused on size distribution, flatness, wet attrition resistance, surface area, gold kinetics, and gold loading. The final results provided information to generate an equation for ranking carbon samples to plant performance.IntroductionActivated carbon for use in gold extraction is amongst the most commonly found processes in modern gold-milling plants. Although gold losses are inevitable in the milling process, operators often focus on the importance of maximizing gold recovery. One focus area that is important in gold recovery is optimizing the use of activated carbon and examining potential changes to realize improved economics for carbon-in-pulp (CIP), carbon-in-column (CIC), and carbon-in-leach (CIL) processes."

Jan 1, 2017

By Paul Miranda, Corby Anderson

"The Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently obtained a Mineral Liberation Analyzer (MLA). CAMP has utilized the technology for several projects with excellent results. The MLA is able to both analyze size and quantify mineral phases. Therefore, the MLA is becoming the Sherlock Holmes of the mining and metallurgical industry. For this presentation, four projects have been evaluated and data was collected using the MLA. The first project involved tungsten mine. Previous mining practices have yielded poor tungsten results and recoveries. By using the MLA, tungsten mineral phases, along with possible contaminants, were verified and the results used to try to increase overall tungsten recoveries. The second project evaluated a molybdenite/chalcopyrite concentrate with surprising results. The third project is a silver project. Initial flotation scoping tests were performed by attempting to separate silver from gangue material. Because of the poor recovery results (less than 5%), MLA was used to determine possible scenarios for increasing silver recovery. Finally, the last project involves gold evaluation in tailings. For all projects, MLA application results will be presentedand discussed.INTRODUCTIONThe Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently received a software add-on to a scanning electron microscope (SEM) located at Montana Tech. The Mineral Liberation Analyzer (MLA) technology was developed by Dr. Ying Gu of the JKTech Center of the University of Queensland. Since August 2006, CAMP has received and processed over 50 samples. These samples include a total mineralogy of tungsten ore samples, gold tailings, lead zinc tailings pile, molybdenite concentrates, copper concentrates, as well as others. During analysis of these received samples, the technology allows the samples to be quantified mineralogically with some surprising results.For analysis, the samples were initially sieved between 170 to 200 screen sized mesh. This ensures that received samples mineral size is fairly uniform. The samples are then placed into epoxy and allowed to harden. Next, the samples are polished and carbon coated for MLA analysis."

Jan 1, 2007