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Study on Ball Mill Grinding of a Cassiterite-Polymetallic Sulfide Ore

Sep 13, 2010

By Dave Bulled, Jim Thompson, Tim Leriche, Mark Blake, Troy Wilkie

"A commitment to a core testing, plant modeling and reconciling technique has shown substantial economic benefits to IOC in terms of accurate production forecasting, smoother operation of the mill, improved expectations of throughput and co-operation across production departments from geology, planning, mining, and processing, to shipping of concentrate to market.This paper describes a successful seven year program of forecasting throughput of the autogenous milling circuit at the Carol Lake concentrator of IOC. Work started with audits of the grinding circuit in 2001 and benchmarking of the data collected from samples of mill feed and plant operation to the CEET mill design and throughput forecasting model.Initially 390 drill core samples were tested for SAG Power Index (SPI) to measure the energy required in milling, and the data distributed using a geostatistical technique across the two operating pits, so that hardness was estimated in each of the 40,000 blocks (or 1500 million tons) of potential ore. In 2004 a forecast of energy requirement, i.e. forecast of throughput for a given power availability at the mill, was produced for each ore block using the CEET model and used for mine planning to smooth plant throughput. The forecast for blocks mined on a monthly basis was reconciled with plant results over the next 2 years and minor changes made to the CEET model. The forecasting exercise was repeated in 2006 and in 2008 with the latest model based on the testing of almost 1300 samples of drill core at closer spacing.INTRODUCTIONThe contracting of sales to clients and the timely supply of products to meet those contracts is a cornerstone of good business practice. Ensuring the correct scheduling of production is a major concern of mining companies where the supply and qualities of the raw material is uncertain and production facilities are not flexible. This is particularly challenging when the product is of high volume and produced far from the customer, such as iron ore.Apart from the metal content of the ore being mined, the greatest impact on production scheduling is the throughput of the comminution section of the extraction plant; most notably when size reduction is achieved by autogenous grinding. The response of the mills to variability in the hardness of the ore can change throughput by as much as 50% from day to day at some plants."

Jan 1, 2009

The only significant iron ore deposit in Hungary could be found in Rudabánya. The mine was closed in 1986. The area of Rudabánya was always the home of heavy mining activity. In former times, mainly silver and other non -ferrous metals were excavated.

Jan 1, 2011

By Dave Minney

The South African mines health and safety regulations require that mine management establish a quality management system for rock support material. Quality control of resin capsules used as a support medium in South Africa is specified under SA National Standards No 1534. Experience has shown that this specification, while addressing the chemical and physical aspects of the products, but does not address the required performance criteria. In order to address this shortcoming, the industry has put a lot of emphasis on short encapsulation pull tests, performed insitu, in the underground workings of the mine. This is also fraught with many shortcomings, particularly as regards site availability, cost and repeatability of results. To try and address these issues, the Department of Mechanical and Aeronautical Engineering at Pretoria University were approached to develop equipment and machinery that could produce reliable, repeatable results in a laboratory environment which reasonably simulates installation practice underground. The test method is based on the ASTM F432-95 Strength Index test, but modified to use push test rather than pull tests. The paper describes development of the test method and the preliminary results and findings of the work.

Jan 1, 2007

By C McGuire, W Harris, S Arsenault, D Witow, B Rogers

Mining deep orebodies is increasingly becoming the norm as the ‘easy’ orebodies are depleted. Deep ore mining requires significant ventilation and cooling infrastructure to not only meet regulatory requirements for air quality but also to achieve acceptable workplace temperatures with the higher strata rock temperatures and increased auto-compression. At the same time, advances in battery equipment technology are turning the possibility of a battery powered fleet into reality. The switch from a diesel fleet to a battery powered fleet offers several positive opportunities for the design and operation of a deep mine.The potential to reduce ventilation and cooling requirements due to battery powered equipment results in significant cost savings for mine development and infrastructure. Battery powered fleets are not subject to the same dilution requirements associated with diesel fleets thus allowing lower ventilation rates. At the low ventilation volumes possible with a battery powered fleet, surface refrigeration plants are limited with respect to the amount of cooling that can be delivered to the workface. Considerations for calculating the optimum air flow and cooling requirements are presented. Considerations for locating the refrigeration plant are also discussed. This paper presents these opportunities and considerations; including a case study comparing the ventilation and cooling system design with a diesel fleet versus battery fleet for a planned mine in Northern Ontario, Canada.CITATION:Harris, W, Arsenault, S, McGuire, C, Rogers, B and Witow, D, 2017. Diesel to electric – creating a positive paradigm in underground ventilation and cooling, in Proceedings Australian Mine Vent Conference 2017, pp 169–174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Rozbeh Moghaddam, William D. Lawson, Priyantha W. Jayawickrama, Hoyoung Seo, James G. Surles

"This study provides calibration of resistance factors (?) for design of driven piles to implement Load and Resistance Factor Design (LRFD) for bridge foundations using Texas Cone Penetration (TCP) Test data. The basic research approach was to compile a database of published full-scale load tests including projects from the Texas Department of Transportation’s (TxDOT) historical archive and projects from neighboring state DOTs. Load test results from neighboring states were leveraged by performing new geotechnical borings with TCP tests at the project sites. The final dataset consisted of 30 load tests performed on precast square concrete piles, with pile widths ranging from 356 to 508 mm and penetration depths ranging from 5.2 to 25.5 m, driven in soils. Ultimate capacities for each load test were interpreted based on Davisson, 5%, and 10% settlement criteria. These measured ultimate capacities were compared against predicted capacities estimated from TCP blow count values (NTCP) and design charts following the procedures outlined in TxDOT’s Geotechnical Manual. From the comparisons, statistical parameters of the biases (??= measured capacity/predicted capacity) such as mean and coefficient of variation were obtained. Resistance factors (?) for LRFD were then determined using Monte-Carlo simulations for each ultimate capacity criteria with the target reliability indices of 2.33 and 3.00.INTRODUCTIONThe Texas Department of Transportation (TxDOT) has used the Texas Cone Penetration (TCP) test since its development in the 1940s. The TCP test is an in-situ penetration test to characterize the materials encountered during geotechnical exploration. Texas currently maintains over 53,000 bridges in the National Bridge Inventory (FHWA 2016), and most of these bridges plus other transportation infrastructure in Texas are supported by foundations designed using the TCP test and its associated foundation design method. The Oklahoma DOT adopted the TCP test and foundation design approach in the 1970s, so the foundations for most of the 23,000 bridges in Oklahoma’s inventory were also designed using the TCP method. With this significant body of experience, the TCP method has been viewed as a straightforward, relatively easy-touse foundation design method that consistently yields safe, serviceable, economical, and maintainable foundations. TxDOT’s deep foundation design method is documented in the TxDOT Geotechnical Manual (TxDOT 2012) and currently employs the allowable stress design (ASD) approach. However, the Federal Highway Administration (FHWA) has mandated that the states begin to implement the LRFD method in place of the older ASD approach (Densmore 2000). This paper presents resistance factors at ultimate limit state (ULS) for design of driven piles using the TCP test, resulting from efforts to be in compliance with the FHWA policy."

Jan 1, 2017

By David R. Skuse, Jacek A. Kostuch, Steven M. Fortier

"Particulate ground calcium carbonate (GCC) is used as a filler and coating pigment in a wide range of applications including papers, paints, plastics and films. In this paper we will overview the requirements for GCC used in both filling and coating applications in the paper industry and highlight the processes used in the production of these materials.INTRODUCTIONCalcium carbonate is both abundant and very widely distributed occurring most commonly as limestone, marble and chalk (Harben 2002). Given, the high purity, whiteness and relative inertness of these materials it is not surprising that they are heavily utilised in a range of industrial applications. Worldwide ground calcium carbonate (GCC) capacity is estimated at 50.5 million tonnes per year (Roskill, 2002). This usage is divided between relatively coarse materials that are used in applications such as landscaping, cultured marble and carpet backing and finer grades that find application in plastics, rubbers, inks, paints and paper. Given the usage of calcium carbonate products across a very wide range of consumer products, the outlook for GCC is very promising with growth expected in many markets. Growth is anticipated across many applications in the emerging nations and more specifically in paper applications on a global basis.Over the last several decades the GCC processing industry has evolved to be well adapted to both the cost effective production and delivery of standard products and the production of high performance speciality products. Many of the standard unit operations found in the metaliferous raw material processing industry are also used, albeit in some cases in modified form, in the processing of GCC. Coarse products (diameter > 3 - 10 µm) are typically produced by dry processing routes. Whereas, the finer products are typically produced by a combination of wet and dry processing."

Jan 1, 2004

By Kym Runge, Emmy Manlapig

"The objective of an industrial flotation circuit is to separate valuable minerals from non-valuable minerals utilising differences in their flotation recovery rate. Regrinding and reagent addition are particle modification processes which are employed within these circuits to maximise the flotation selectivity of one mineral with respect to the others present in the ore feeding the process.Batch test nodal analysis, or the ability to compare floatability through mathematical combination of laboratory batch flotation test results, is a powerful technique for assessing the effectiveness of particle modification processes on ore floatability in industrial flotation circuits.In this paper, the use of nodal analysis is demonstrated within an industrial flotation circuit. It is used to show that regrinding and staged reagent addition within Teck Cominco’s Red Dog zinc retreatment circuit is beneficial to pulp flotation selectivity. Optimisation of these processes could potentially improve the zinc recovery within the circuit. Lime addition, which is periodically employed to depress pyrite in the circuit, was found to depress sphalerite in preference to pyrite and to result in poorer metallurgical performance in the circuit.INTRODUCTIONThe objective of an industrial flotation circuit is to separate valuable minerals from non-valuable minerals utilising differences in their flotation recovery rate.Different minerals can only be effectively separated using flotation if they are sufficiently liberated from each other (i.e. do not co-exist within the same particles) and have a sufficient difference in surface hydrophobicity. Size reduction processes and chemical addition are utilised before and within a flotation circuit to achieve sufficient particle liberation and to maximise differences in mineral hydrophobicity. In effect, the objective of these processes is to maximise the flotation selectivity of one mineral with respect to the others present in the ore feeding the process."

Jan 1, 2004

By Craig Naudé

"An enhanced gravity concentrator was installed in conjunction with an Intensive Leach Reactor at the Sadiola plant in Mali last year and commissioned in Dec 2007.There has been much debate over the years as to the effect of gravity concentration on overall plant performance. The late Dr Laplante suggested that for every 10% of gold recovered by gravity, there was a corresponding 0.1% to 1% additional overall plant recovery. The results at Sadiola are consistent with this hypothesis with an overall 4% gain in plant recovery.With total gold recovery of 12% in the gravity section, grades are increased from 3.54g/t in the gravity feed to an average of 2 600g/t in the concentrator feed to the in-line reactor. The recovery of gold in the in-line reactor is in excess of 98.5%.This paper discusses the background to the project, the laboratory testwork prior to the equipment selection, the operational results of the system, as well as the benefits of the future application of high mass yield centrifugal concentrators in base metals, sulphides and industrial minerals. Bench scale, pilot scale and plant practice examples are also presented.INTRODUCTIONBesides picking nuggets off the ground or out of riverbeds, gravity concentration is arguably one of the oldest methods of recovering gold. In circa 6000BC people discovered that gold can be found behind the rocks and in depressions of creek beds. By placing rocks in a stretch of channel with the proper slope the first sluice is built, probably around 4,000 BC, and this method is still practiced today."

Jan 1, 2009

Permitting, engineering and evaluation, detailed design and construction aspects of the Golden Cross goldmining project in New Zealand are briefly reviewed. The extremely lengthy and complicated governmental approval process together with the delaying tactics of opponents of the project are outlined and comment is made on aspects of the draft legislation proposed as part of the overhaul of New Zealand's resource management laws.

Jan 1, 1990

Early in 1940 the development and sampling programmes in hand on the North and British Sections of North Broken Hill Limited were such as to necessitate the drilling of a large number of drill holes ranging up to about thirty feet in length. On the British Section, one purpose was to test the existence, width, and value of narrow lodes believed, for geological reasons, to occur in the walls of the existing workings. Another object was to definitely disprove the existence of payable shoots of ore in certain largerhodonite and quartz-garnet ("garnet sandstone") pillars which had been formerly left as unpayable.On the North Section, the main purpose of the short holes was to delineate the ore-body boundaries by drilling laterally from drives in ore, and thus enable level layout to be planned in advance of sill stoping. It was also desired to test the walls of stopes in those portions of the mine where the economic limit of mining is not rendered obvious by a clear-cut wall, but should be determined by assay. In these latter cases it was hoped to eliminate "prospecting by stoping," a procedure by which any doubts as to the existence of further good ore behind the low-grade walls were settled by continuing to stope laterally until all chance of such an occurrence was removed.LONG HOLE ROCK DRILLINGFollowing an investigation of recorded instances of similar practice elsewhere it was decided to use the rock drill for a series of trial sample holes. A 3-in. drifter was used. This was selected from those in use underground, and was given a special overhaul; had a new machine been purchased, a 4-in. type would probably have been obtained as being more suited to the work. The rods were H in. hollow round steel with a type "1" Jackrod thread. Couplings were of chrome steel, and were H in. in diameter, and 2 in. long. Jackbits (type "1" thread) in sizes from 2 in. to 4 in., with 1-in. gauge changes, gave a range of nine bit sizes. They were resharpened by hot milling, and were not milled to a definite gauge size.After sharpening, bits were sent underground without sorting into sizes, the drillers selecting the next bit with callipers. In view of the small scale of operations, it was not considered worth while to adopt special measures, such as the cold grinding of bits, which might have given a better product. Later, however, new bits were used exclusively, the idea being to accumulate enough blunt Jackbits to warrant a thorough treatment of the sharpening...

Jan 1, 1941

By Anthony T. Iannacchione

The Roof Fall Risk Index (RFRI) is a new method introduced by the National Institute for Occupational Safety and Health (NIOSH) to assist the underground stone mine operator in 1) assessing defects the mine strata and 2) rating the relative roof fall risk these defects pose. The RFRI utilizes observational techniques to identify defects in the roof strata caused by local geologic, stress, and mining conditions. Assessment values for ten defined defect categories provides the foundation for estimating a range of risk conditions between 0 and 100 that define the potential for a roof fall. This paper examines how the defect information is collected using two field verification sites and proposes methods to analyze the RFRI data. These examples provide information on how well the method replicates observed conditions and how it might be applied in practice.

Jan 1, 2006

By G Small, A Lazamanana, C Greet

When conducting gold leach tests on free milling gold ores which method is the best, bottle rolls or the stirred beaker test? Recently, a client requested that gold leach tests be conducted using the stirred beaker methodology. When asked why, because the laboratory was set up to conduct tests using the bottle rolls technique the reply was that the stirred beaker leach test would replicate the plant more closely. Not wishing to upset the client, the instructions were followed. However, the opportunity was taken to complete additional tests so that the two leach procedures could be compared. Further, this comparison was completed on two different gold ores as well as a number of different grinding media types.This paper provides a description of the two laboratory techniques employed, and presents the results of these parallel tests. Interestingly, the assertion that the stirred beaker methodology more closely replicated plant performance was not validated. In fact, the results obtained using this procedure were noticeably different from those observed in the plant, with lower recoveries and significantly higher cyanide consumptions. The bottle rolls test however more adequately replicated plant performance in terms of recovery and cyanide consumption. The reasons for this are discussed in the paper.CITATION:Greet, C, Lazamanana, A and Small, G, 2015. Bottle rolls versus stirred beaker leach testing – which is best?, in Proceedings MetPlant 2015, pp 188–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

Distribution of Settling Velocity of Irregular Particles and its Effect on Jig Separation Efficiency

Sep 13, 2010

By Michael L. Boucher

Copper and nickel sulfides occurring in the Duluth Complex of northern Minnesota were examined at the Bureau of Mines, A microscopic study was undertaken to determine the mineralogy and paragenesis of the ore minerals. Eighty-two samples were taken from one deep diamond drill core located near Babbitt, Minn. Modal analyses are presented for the Duluth Complex rocks and for the are minerals in the major mineralized zone. The major sulfide minerals are chalcopyrite, cubanite, pyrrhotite, troilite, and pentlandite. Results of this investigation suggest that the mineralization is related to the structural features of the enclosing rocks: pores, open fractures, and cavities. The pyrrhotite-troilite-pentlandite assemblage is believed to have formed from an immiscible sulfide melt, probably associated with the troctolitic rocks. Most of it settled to the very porous base of the Duluth Complex, and to the other porous zones near xenoliths; small portions were trapped higher in the section. A later introduction of a copper-rich sulfide melt replaced some of the pyrrhotite-troilite and oxides, and filled in the remaining open spaces and fractures in the Duluth Complex and those of the adjacent footwall rock.

Jan 1, 1975

By Steve Jones

Minor subsidence damage to the Burgettstown Junior-Senior High School building and grounds near Burgettstown, Washington County, Pennsylvania, prompted an investigation of the site in early 1985 by the Bureau of Abandoned Mine Reclamation of the Pennsylvania Department of Environmental Resources. The investigation determined that subsidence over an abandoned coal mine was occurring and that additional damaging subsidence would occur if reclamation measures were not taken. A Pittsburgh Coal Seam Mine which was abandoned in the 1920's underlies the school at a depth of sixty-five (65) feet. This sixty-five foot section is comprised of five (5) feet of unconsolidated overburden and sixty (60) feet of thinly bedded, highly fractured shale. Approximately five and one-half (5-1/2) feet of Pittsburgh Coal was extracted at the school site. A thin shale binder and one (1) to one and one-half (1-1/2) feet of roof coal were left in place. Within the Contractor's Underground Working Area (See Figure 1) approximately thirty (30) percent of the coal was extracted. It appears that the mine was just being developed in the vicinity of the school when it was abandoned for no known reason. Other nearby portions of the mine show extraction approaching sixty-five (65) percent.

Jan 1, 1986

Tumbling mills and some theoretical and practical aspects of milling are discussed. Attention is directed towards the difficulty of relating the dynamical analyses of the motions of particles within mills to the existing treatments of breakage processes. This synthesis may be advanced by a study of milling that utilizes the matrix analysis of breakage processes. Application of the matrix analysis to results obtained on (i) grinding in open-circuit a zinc ore in a conical pebble mill and in a modified conical mill, (ii) "grinding of cement clinker in a compound mill, and (iii) to some drop-weight grindability tests is discussed. It is shown that the 'IT-breakage model adequately describes the breakage processes of each of the tests. (The proportion broken in each breakage cycle is given by 'IT and is independent of particle size.)The size distributions of the products are accurately predicted in the cases considered. Matrix analyses of the breakage of coals, various ores and a cement clinker have been made. Appendices give an elementary account of the matrix methods and give the equations fully describing reverse order closed circuit operations. The matrix analyses of breakage processes and the survey are used to examine briefly closed circuit grinding.INTRODUCTIONTumbling mills are slow-speed crushing and grinding machines which have been developed from some fairly simple types into many widely differing forms. Many of these versatile mills have proved extremely useful in ore dressing and mineral beneficiation, whereas others have been used in the cement industry and less extensively in the coal industry.The performance of even the simplest tumbling mill is very imperfectly understood, whilst the more difficult problems associated with the balancing of complex milling circuits and with the establishment of the optimum operating conditions for the whole of a complex circuit are even less well apprehended.Our knowledge of the performance of tumbling mills is rather sharply divided into two categories: the first consists...

Jan 1, 1957

By D. S. Choi

This paper presents a theoretical analysis of the effect of shape and size on strength of geologic materials. The results indicate that the shape effect is caused by the development of confining pressure at the interfaces. The linearization of the obtained formula is of the same form determined by experiments. The size effect is attributed to the fact that the geologic materials contain discontinuities in the form of fractures, bedding planes, and cleats. The maximum reduction factor for the size effect is the one-sixth power of the volume of a cubic test specimen. The results of this work are particularly useful in determining the strength of coal pillars in underground mines.

Jan 1, 1989

By John Smyth

Mining through in panel entries and the full face recovery method has been successfully practiced at U.S. Stwl, Mine 50. Suppat of the cut-through entries and recovery room is critical. Traditionally, concrete crib or fly ash cement backfill has been utilized. However, these traditional methods are not feasible at Mine 50 due to the difficulties of the plow face mining through these types of support. Recent development of new cable support systems provides an option for cut-through entry support. Mine 50 and Jennmar Corporation personnel have worked together to design and apply the cable systems in the cut-through entries and full face recovery room to eliminate standing support. To date, a number of full face recovery rooms and cut-through inpanel entries have been successfully mined. The results indicate that the cable systems combined with high capacity shields, have provided sufficient capacity to support the roof. Utilizing the Jennmar Finite Element Analysis (JFEA) computer program (Stankus and Guo, 1996), an analysis of the stress and roof deflection changes as the longwall gradually cut through was conducted. From the finite element analysis data, a supplemental support plan was designed. The history and experiences at Mine 50 are presented. Based on the case experiences and modifications made to the finite element analysis, an improved design criteria for future use has been formulated.

Jan 1, 1998

By Gang Chen

This paper explores the possibility of using short-term time-dependent plate loading tests to estimate the elastic and viscoelastic parameters of the weak floor strata typically associated with coal seams in Illinois. Plate loading tests with incremental loads, similar to incremental creep experiments, were conducted until the floor failure occurred. For each increment, the load was held constant for a period ranging from 1-4 hours until a constant deformation rate was achieved. The deformation-time data were analyzed for viscoelastic parameters of weak floor strata assuming its behavior to be adequately represented by the standard Burgers model. The analysis required development of mathematical equations for the time-dependent deformation of the standard Burgers material under a three- dimensional state of stress. Time-dependent pillar settlement data at one mine were also analyzed for elastic and viscoelastic parameters of the weak floor strata using the developed equations. These parameters were compared with similar parameters estimated from plate loading tests.

Jan 1, 1990