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By J. Asfahani

"The Schlumberger configuration used in geoelectrical sounding is slightly adapted here to obtain reliable data for both shallow and deep penetration depths from the same survey. In this configuration, two kinds of current electrode half-spacings are used: the first enables construction of vertical electrical resistivity sounding (VES) curves for shallow depths (<50 m), and the second for depths =250 m. For a given VES location, two field curves are measured and interpreted using two standard approaches. Practical characteristics of such a modified configuration are illustrated with two field applications in Syria. The first aims to characterize the structure of Quaternary and recent deposits in the Al-Ghab depression region, and the second deals with exploration for phosphatic sedimentary units in the Al-Sharquieh mine. La configuration de Schlumberger normalement employée dans les levés géoélectriques a été légèrement modifiée afin d’obtenir des données fiables à faible et forte profondeur durant le même levé. Dans cette nouvelle configuration, deux types de demi-espacements des électrodes sont utilisés : le premier permet le développement de courbes de sondage de résistivité électrique verticales (REV) pour les faibles profondeurs (<50 m), et le second atteint des profondeurs =250 m. Pour une localité REV donnée, deux courbes de champs sont donc mesurées et interprétées grâce à deux approches standardisées. Les caractéristiques pratiques de cette configuration modifiée sont illustrées par deus exemples d’application en Syrie. Le premier vise la caractérisation de la structure des dépôts Quaternaires et récents de la région de la dépression d’Al-Ghab, et le second traite de l’exploration pour des unités phosphatiques sédimentaires à la mine Al-Sharquieh."

Jan 1, 2009

By M. Keen

The backfill system at Cleveland Potash?s Boulby Mine places waste filter cake underground in the form of a high concentration slurry in worked out areas of the mine reducing the mine?s environmental impact. The backfill system delivers slurry approximately 1100 m down the mine and up to 11 000 m horizontally underground. The Boulby backfill system is unique in that the placed backfill waste is not used for the usual purposes such as support, pillar extraction or reducing ventilation requirements. It was specifically implemented for environmental reasons. This influenced the design and resulted in some unique features of the system. A previous paper (Wilkins et al., 2004) described the design and commissioning of the backfill system. This paper describes the operational experience with the backfill system and backfill placement since commissioning in May 2003 and looks at lessons that can be applied in other backfill designs.

May 1, 2007

By T. R. Raponi

"The Williams Mine, Canada's largest gold mine, processes over 6,000 t/d of ore utilizing SAG/ball milling, leaching and CIP, carbon stripping, electrowinning and refining to produce gold dare bullion.Grinding accounts for over 50% of milling costs with grinding media, power and mill liners making up over 75% of grinding costs. Since 1991, several changes in these areas have been made which have significantly reduced costs, while fineness of grind and mill recovery have both been increased.This paper discusses the changes made in the grinding circuit over the past few years and assesses their impact on operating costs and mill operations.IntroductionThe Williams Mine is located in the Hemlo area of northwestern Ontario, about 40 km east of Marathon. It is operated by the Williams Operation Corporation, which is equally owned by Teck Corp. and Homestake Canada Inc. Canada's largest gold mine, the Williams Mine commenced operation in October 1985 at a rate of 3, 000 t/d. Mill throughputs have typically exceeded design, averaging 3, 397 t/d in 1986, and 3,380 t/d in 1987. In August 1988, production was increased to 6,000 t/d. Throughput averaged 4,212 t/d in 1988. Production increased over the next few years averaging 5,477 t/d in 1989, 6,248 t/d in 1990, 5,987 t/d in 1991, and 6,283 t/d in 1992. With a recovery of over 95.5%, production for the first three quarters in 1993 is averaging 6,408 t/d.GeologyThe main ore body is a steeply dipping conformable zone of microcline-quartz-muscovite rock. It occupies the contact zone between hanging wall metasedimentary rocks and foot wall felsic quartz feldspar porpyritic rocks of possible volcanic or subvolcanic intrusive origin. The ore body is enveloped by muscovite schists which are thickest on the footwall side. The schist is enriched with tourmaline, pyrite, and green mica containing vanadium and barium. The ore body contains pyrite and barite which occurs mostly in laminae and bands to veinlets and breccia fillings. The gold occurs as free (native) grains, 20 to 30 µm in size at grain junctions of the microcline and quartz. Visible gold is rare in the main zone. There are commonly two or more discernable layers of economic value which are separated by weakly gold mineralized material which usually consists of muscovite schist, barite rich zones or sulphide poor-microcline-quartz rock and in the upper and western fringes by biotite rich schist with feldspathic fragmental characteristics. Molybdenite is a common constituent as very fine disseminated grains in the microcline-quartz rock and is most prominent with gold enrichment. Stibnite and realgar are two of the more common accessory sulphides."

Jan 1, 1994

By R. G. Hamm

A brief outline covering the shovels and draglines in use in the open-pit mines of Western Canada, including British Columbia, Alberta and the Yukon, is given, followed by the procedure for the selection of the correct wire rope for each application. Such fa ctors as wire rope constructions, lay directions and types of cores are mentioned. Once the correct wire rope has been selected, there are variousfactors that can affect the service fife ofthe rope and the reduction ofdown-time during rope change-overs. Factors such as hairpin winding, types of Becket loops, and shovel drum and bail adaptors are described.

Jan 1, 1979

By V. N. Rampton, C. F. Gleeson

"Exploration results over three overburden drilling anomalies defined by the Ontario Geological Survey in 1981 in the Kirkland Lake area, Ontario are presented. The anomalies come from lowland areas where overburden is thickest. By mapping the bedrock and surficial geology, by prospecting, humus sampling and shallow till sampling over the surrounding upland surfaces, one can initially evaluate such overburden drill anomalies without costly reverse circulation drilling. The drilling should follow, if necessary, only after surficial base data has been obtained. Preliminary work on these three properties has defined the presence of at least two styles of gold mineralization. One occurs in silicified zones in intermediate volcanics closely associated with northwesterly trending faults and shear zones. The second occurs in quartz-carbonate alternation zones in volcanics intruded by quartz-feldspar porphyry dykes. IntroductionThe three examples presented in this paper present first-hand information on an approach to the follow up of several geochemical anomalies that were found by the Ontario Geological Survey when they carried out reverse circulation overburden drilling as part of the Kirkland Lake Initiative Program (KLIP) in 1980 (Routledge et al., 1981). The initial approach is relatively simple, systematic, and cost and technically effective. It readies the properties for further exploration, or conversely, it could downgrade the properties as viable gold targets."

Jan 1, 1987

By Raymond C. Voige

"The use of current electronic technology in the design of new underground mine communications equipment is providing improved and expanded voice communications which can, in turn, contribute to improved productivity and safety. A review of equipment that is now available or under development Includes the following categories:WIRED SYSTEMSI.Pager phones with selective calling, audible and visual alerting and message indicator.2. Mufti-conversation pager phones that use multiwire cable ormultiplexing techniques.WIRELESS SYSTEMSLow-and medium-frequency inductive systems utilizing ""near"" magnetic fields for both vehicular and personal communications.Wired SystemsCommunication systems in underground mines have evolved slowly in many parts of the world. For many years, magnetotype telephones were the only means of communication from one mine level to another and to the surface. These units were located near the shaft and communications to the working areas were limited."

Jan 1, 1981

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 J. Chlopas, D. J. Barratt, M. V. Sharp

"This paper describes the modifications made to the Fox Mine copper concentrate bin in order to obtain a continuous flow condition. The design of these modifications is based on test results obtained on Fox Mine concentrate using the flow factor testing machine in the research facilities of Cominco at Trail, B.C.The original design consisted of a cylindrical steel bin on a concrete slab with two slot-discharge openings. Based on predictions of the maximum mass flow hopper angle for conical and wedge shaped hoppers for the concentrate on various potential bin lining materials, Ultra-High Molecular Weight (UHMW) Polymer was selected as a liner.Using the recommended angles for conical and wedge shaped hoppers, the profile of the bin base was changed to suit the existing slot openings.The initial method of fastening the liner resulted in failure of the connections. Subsequent modification to the zinc concentrate bin fastener system proved satisfactory and it has now been in operation for over one year without any separation of the lining material.Utilization of flow testing procedures on concentrate samples has demonstrated that proper design of storage bins or hoppers to achieve continuous flow can be incorporated into the design of new plants."

Jan 1, 1978

By A. Taylor, M. Blanchette, J. Doucet

"A Z1600 Jameson Cell Test Rig was rented for test work at Vale’s Clarabelle Mill operation. This paper discusses the evolution of renting the unit for test purposes to owning the unit and operating it as a revenue generating process component. The paper focuses on three aspects of the Z1600 project; the initial rental and installation, the test work performed in the cleaning circuit, and the business factors which led to the unit being permanently incorporated into the copper circuit.INTRODUCTION Clarabelle Mill is located in Sudbury Ontario (approximately 350 km north of Toronto) on the southwest rim of the Sudbury basin a meteoric impact crater that is 62 km long and 30 km wide. The result of the meteoric impact was concentrated nickel (Ni), copper (Cu) and platinum group metal (PGM) ore bodies in the outer perimeter of the basin; described in more detail by Hanley (1957). Vale currently has seven operating mines in the Sudbury basin, from which nine distinct ore types are mined. Ores are also received from two QuadraFNX mines. Clarabelle Mill processes all of these ores for the Ontario Operations of Vale. The mill, commissioned in 1971, was originally built as one of four mills operated by then Inco Limited. Between the late 70’s and the early 90’s process changes were made to consolidate the Sudbury Operations milling processes into a single operating mill, Clarabelle Mill. In 1990, the SAG mill was installed resulting in peak mill throughput of 11.9 million short tons per annum (Mstpa), with typical throughputs of ~10 Mstpa. Mill average feed grades were 1.4% Cu and 1.2% Ni. During the resources boom, plans were developed to increase the mill capacity at Clarabelle Mill in stages to a final capacity of 13.5 Mstpa. The project known as the Clarabelle Mill Expansion and Recovery Project (CMERP) included expansion and reconfiguration of the grinding and flotation circuits. The first stage was a planned increase in grinding capacity with the reallocation of existing mills, the existing flotation capacity would be required to treat higher throughput until the new flotation circuit was constructed."

Jan 1, 2012

By Elmer Stewart, Richard May

"The Central Mukur deposit was discovered by the Semipalatinsk Geological Exploration Expedition (GEE) during detailed searches from 1977 to 1980. Andas Altyn Ltd., a Kazakhstanian gold mining company acquired the property and commenced mining in 1995. In 1998, Andas-Altyn Ltd. became a wholly owned subsidiary of Eurasia Gold Corporation.The Central Mukur gold project covers a linear series of parallel, discontinuous zones of near surface oxide gold mineralization that covers a distance of 7 kilometers and extends past the property boundaries. The oxide gold mineralization is a result of the regional oxidization of a primary sulfide gold mineralization emplaced in a series of shallow dipping thrust faults. Resources as calculated by the GEE are 3.45 mt at an average grade of 1.84 gmt Au in the C1 +C2 category and 7.52 mt at an average grade of 1.80 gmt Au in the P1 category. The Central Mukur Gold Heap Leach Mine consists of an open pit, heap leach pads, and an ion exchange resin gold recovery plant. Limited gold production (<2,500 ounces/year) has been achieved over the past three years leaching run of mine oxide gold mineralization. Gold recovery utiling cyanide to dissolve the Au and ionic resin technology to recover the Au for the leachate is approximately 60%. Loaded resin is shipped to a treatment plant at Almaty where the gold is stripped from the resin, refined and sold.This paper will describe the geology, mining, and processing of the Central Mukur ore. In addition, it will describe what it is like doing business in Kazakhstan and the transition from a Soviet style operation to a more western style operation.INTRODUCTIONThe Central Mukur Mine is owned and operated by Andas-Altyn Ltd. a Kazakhstanian gold mining company located in northeast Kazakhstan. Andas-Altyn is a wholly owned subsidiary of Eurasia Gold Corp., a Canadian public company listed on the Alberta Stock Exchange. The Central Mukur mine consists of a small open pit, and a heap leach operation that utilizes ion exchange resin to recover gold from pregnant solutions. In addition to the Central Mukur mine, Eurasia also owns the Myaly heap leach gold project which is also operated by Andas- Altyn Ltd."

Jan 1, 1999

By R. Mohan Srivastava

"The goal of estimation is considered in the light of decision analysis. A simple example reveals the essential elements of decision-making in the face of uncertainty. A second example shows that these elements are also key features of many mining decisions. These two examples cause us to revive an old probabilistic notion that the goal of estimation should be to quantify what is unknown. The conditional probability distribution provides the complete statement of one&apos;s uncertainty. Once the conditional probability distribution has been established, one should retain as an estimate the value which minimizes some objective loss function. A third example shows how the ""best"" estimate depends on the chosen loss function. Current practice is almost exclusively based on the least squares method, which assumes a loss function which penalizes underestimation and overestimation equally. This is unfortunate not only because symmetry is an unrealistic assumption but also because mining offers a rare opportunity to state the loss function directly in terms of profitability. Both the theoretical framework and the practical tools exist to allow us to reconsider the conventional notion of the ""best"" estimate. IntroductionThis paper looks at estimation in the mining industry from the point-of-view of decision analysis. Virtually all decisions depend on estimates since few of the important parameters are ever known exactly. In this paper we will be referring mainly to the estimation of ore grades, though the approach discussed here is generally applicable to any decision in which relevant information is uncertain.In the first section we look at a very simple example of decision-making in the face of uncertainty. We will then tum to a mining example and see that the essential features of the simple example still pertain. From these two examples it will be clear that the decision analysis approach rests on two key concepts: the conditional probability distribution and the loss function. A third example demonstrates how different loss functions produce different ""best"" estimates from the same conditional probability distribution. In the final sections we willexamine the current practice of estimation in the mining industry. Though the tools for estimating the conditional probability distribution already exist, a change in the way we think about ""best"" estimates is needed. Very little attention is presently paid to the loss function even though it is readily available in many mining applications."

Jan 1, 1987

By P. W. Godbehere

"INTRODUCTIONMagnetic mill linings have been developed from an invention by Mr. Bertil Brandt, the originator of the Skega rubber lining. The OREBED magnetic mill lining is a concept in which rubber covered strontium ferrite permanent magnets are arranged on the inside wall of a mill shell so that they attract magnetically susceptible material be it ore, media or tramp, to form a protective layer over the magnets and to serve as an operating surface with indefinite life.Noranda Mines Ltd. through its associate Norcast Division of Noranda Metal Industries formed a joint venture with the inventors to market magnetic mill linings in North America. For the past twelve months trials have been undertaken in conjunction with Orebed Inc. to test and develop these linings for grinding mill applications at the Horne Concentrator. Two independent milling circuits are currently being operated, one treating a siliceous gold ore and the other a copper slag.This paper presents the results of the magnetic lining test programme to date."

Jan 1, 1983

By Steve Massman, Edward Wipf, Gary Beerkircher

"As mine size and tonnage continues to increase, material handling/processing equipment has also increased in size with 400 MT haul trucks, 2000 KW crushers, 12 M SAG/AG mills, 8.5 M ball mills, 3000 M3 flotation cells and 12.5 MW HPGR’s all with planned designs to increase in size further. Related equipment including vibrating screens have also increased in size with screens seeing feed rates of 3000 MTPH. Open circuit SAG Pre-Crush and closed circuit HPGR flowsheets are becoming more common with large screening requirements. Large multi-slope (banana) or horizontal screens are commonly used for these applications, however as the size of these screens has increased, the number and size of the brute force/overhead exciters has increased but with limitations. An example is a SAG discharge screen that will see surges of material from the SAG mill which overload the screen, reducing the screen stroke or throw causing a large reduction in screen efficiency with excessive fines & moisture in the screen oversize feed to the pebble crushing circuit. This paper will present some actual examples of the use of Two-Mass screens as a solution to these overloading problems and the advantages of Two-Mass screens in other high tonnage applications.Brute Force Drive Compared to Two Mass Drive Vibrating ScreensThe standard single mass screen as depicted by figure 1 is generally recognized in the mining industry. It is characterized by the screen body – labeled as the single mass (Mt) that is supported by isolation springs (Kiso). The stroke needed to process material is obtained by incorporating large eccentric wheels and/or drive boxes (Fb) directly mounted to the screen body via a drive tube."

Jan 1, 2017

By Ingrid Hann

The Triple Bottom Line ? Economic Sustainability ? Creation of Joint Venture companies ? Planned evaluation of other kimberlites ? Social Sustainability ? Impact Benefit Agreement and Participation Agreements ? Education and training initiatives ? Environmental Sustainability ? Environmental management ? Mine closure planning

May 1, 2008

By H. Agnerian

"A survey of 925 mineral property transactions worldwide was carried out between 1987 and 2004. These mineral properties with reported Mineral Resources include 457 gold properties, 322 base metal properties, and five platinum group element (PGE) properties. Based on constant Canadian dollars, the results of the survey indicate that:• In general, unit metal values in the ground (e.g. $/oz Au or $/lb Cu) have kept pace with the changes in the respective metal prices during the period of the survey.• A general decrease in unit gold values in the ground has occurred from about $57/oz Au in 1987 to about $11/oz Au in 2002 for Canadian mineral properties, with the exception of a peak of $58/oz Au in 1996.• A similar trend for mineral properties has occurred in the United States, but with lower unit values, in the range from $1/oz Au to $10/oz Au during the last three years of the survey. • Unit metal values in the ground for gold properties in Canada were higher than for those in the rest of the world.• Unit metal values in the ground for copper properties in Canada were in the mid-range compared with other countries in the rest of the world; the United States and Australia were higher and Latin America, Asia, Africa, and Europe were lower than in Canada.• Unit metal values in the ground for zinc properties in Canada were also in the mid-range compared with other countries in the rest of the world; Latin America and Europe were higher and the United States, Australia, and Asia were lower than in Canada.• Unit metal values for nickel properties in Canada were highest compared with other countries in the rest of the world, followed by the United States, Australia, Africa, and Asia.• Gold values in the ground in Canada have ranged from 6% to 14% (with an average of approximately 10%) of the gold price.• The unit values of base metals in the ground have been in the order of 2% of the quoted metal price, during the period of the survey."

Jan 1, 2006

By Shawn Healey, Ray Norcross

"Site IdentificationNew Britannia MineA 50/50 WX Gold Inc. - High River Gold Mines Ltd. Joint VentureTVX Gold Inc. is the OperatorLocationThe New Britannia Mine is located in the town of Snow Lake, Manitoba, which is situated between Flin Flon and Thompson, 420 miles north of Winnipeg.Brief Description of OperationNew Britannia Mine processes 2000 tonnes per day at an average grade of 4.5 g/t. Mill recoveries are currently 91 YO, accounting for forecast of 98,000 ounces for 1998.New Britannia Mine's mill complex incorporates conventional crushing, grinding and carbon-in-pulp technology. The design capacity of the New Britannia Mine mill is 1850 tonnes per day. The mill has processed upwards of 2300 tonnes per day, with no required upgrades.Gold recovery averaged 89.8% for 1997 compared to the planned 87% recovery expected from projected metallurgical test work. Year to date recovery mid December 1998 stands at 91.1 %Cash costs for the 1998 year to date were down to U.S. $221.49 per ounce, down 12% from the 3rd quarter of 1997. Milling costs for 1998 YTD were at Cdn. $9.38 per tonne and Cdn. $73.50 per ounce.Geology - (Orebody Description)The Snow Lake gold deposit is located within the Aphebian Flin Flon / Snow Lake Greenstone belt. This belt is composed of an assemblage of poly-deformed volcanosedimentary supercrustal sequences intruded by pre and sin tectonic ultra mafic and mafic intrusions and sin to post tectonic granitoid.The principal gold bearing rock at the New Britannia Mine is made up of quartzcarbonate material in sequence of basic and acidic volcanic rocks contained within a shear zone. The ore itself is gold associated with the sulphide mineral arsenopyrite and contains some pyrite, pyrotite, plus chalcopyrite. Proven and probable reserves at December 31, 1997 were at 4.04 million tonnes at 4.6 g/t and underground exploration continues to confirm the extension of the ore zones to depth."

Jan 1, 1999

By L. J. Heaslip, J. M. Toguri, T. R. Meadowcroft, R. L. Addinall

"""Pilot Plant Operations"" is a final-year core course given to the Metallurgy and Materials Science students at the University of Toronto. This course involves a laboratory study of an industrial project at an industrial site. Details of this program are discussed and reviewed after eight years of experience. IntroductionEducators in the field of Metallurgy and Materials Science have long agreed that ""hands-on"" experience is an important component in the education of metallurgical engineers. This philosophy is reflected in the undergraduate curricula of most metallurgical schools. The major problems encountered with laboratory-associated courses are the requirements for equipment, space and funds for both purchase and maintenance of equipment. For example, consider an exercise in crushing and grinding treatment in a mineral processing laboratory. Such operations require the handling of tons of material and often equipment of large size. The problems of storage of ore, methods of handling and maintenance of equipment are a few of the concerns facing the department. Considering that metallurgical departments at universities are, in general, relatively small, the support to purchase and maintain largescale equipment becomes an annual budgetary concern. In reality, universities today are not geared to operate mini-pilot plant equipment, either in terms of space or personnel.For the above reasons, in 1972an undergraduate core course called ""Pilot Plant Operations"" was introduced to the fourth year curriculum in Metallurgy and Materials Science at the University of Toronto. This course consists of I to 2 full weeks (8 hrs per day) of pilot plant laboratory study at an industrial site on a project of mutual interest with the industrial organization whose facility is being used. The first 5 years of the program were carried out at the pilot plant facility at the Ontario Research Foundation; Stelco&apos;s Research Centre in Burlington, Ontario, was used for the last 3 years. The nature of the projects undertaken during the 8-year period is shown in Table 1."

Jan 1, 1980

By Robert Hamilton

Aur Resources is Canada&apos;s leading copper mining company with producing mines and development projects in North, Central, and South America. Copper production from Louvicourt Mine in Quebec, Quebrada Blanca, and Andacollo Mines in Chile had a record of 245 million pounds in 2001. Located 600 km North of Montreal, Louvicourt Mine is a joint venture between Aur Resources (30%), Teck Cominco (45%), and Novicourt (45%). Aur Resources is the mine operator with 280 employees working to produce a copper and zinc concentrate. In operation since 1994, the mine has produced a total of 12,606,000 metric tonnes of ore grading 3.6 % Cu, 1.5 % Zn, 26gr./m.t Ag, 0.9gr.m.t Au. This highly mechanized mine reached full production in August 1995 at 4,000 tpd. From 1996 to 2001, the average mine production rate was more than 4,300 tpd. The Louvicourt Mine continued its record of solid performance in 2002 and is expected to continue to do so for the balance of its 2.5 years mine life.

May 1, 2003

By David G. Almond

"Economies of scale and the variable characteristics of many large ore deposits have resulted in grinding installations having large SAG mills fitted with variable speed drives. Problems associated with effective operation of this equipment has created the need for better operator knowledge of mill load behavior and the need for new instrumentation capable of providing accurate information about load movement and composition. This paper discusses two performance enhancing instruments available to address these needs.INTRODUCTIONThe economic demands of new mining projects has resulted in increased equipment sizes and this is particularly evident in milling where there are now many SAG mills operating in the range of 28’ – 40’ diameter with installed powers of 8 – 22 MW. These mills are designed to process very high capacities of ore daily2 and the variable characteristics of many of the deposits mined results in the need to vary the mill speed during processing to cater for the changes in ore hardness. Mill speed changes often result in operational problems associated with high-energy impacts striking the mill liners reducing energy efficiency as well as degrading the grinding media through breakage, accelerating liner wear and in extreme cases even breaking liners. These operational problems have given rise to the need to have instruments aimed at providing operators with accurate information in real time about the load composition and movement within SAG mills.The original concepts for operating SAG mills were derived from past experience of operation of conventional fixed speed ball mills. However, the relatively stable conditions that applies with fixed speed and constant ball charge in ball mills supports theoretical approaches to the grinding process based on energy calculations such as Bond’s Work Index concept. Later a set of parameters Si and Bij were used for describing load kinetics, but all of these methods neglect the details of load movement and how the energy is actually used inside of the mill. It is now commonly accepted as a basic rule that SAG mills grind by impact whilst ball mills grind by attrition and consequently SAG mills are designed and operated to generate a large amount of impacts by the cataracting load without paying sufficient attention to where these impacts are actually occurring. Many mills are operated on the basis that as long as the mill is consuming the expected power there is little attention given to the class of bodies using this energy and this often results in the inefficient use of energy."

Jan 1, 2005

Overview ?G-9 Discovery Hole 420 drilled May 2005 ?14.16% Zn, 1.76% Cu ?Greenfield discovery built into the G-9 Mine in under 4 years. ?Utilized a unique ?Parallel Track? approach to fast-track mine development. ?Raised over $200million in financing without a Feasibility Study. ?Mine built for $149.7 million, only 20% over PEA. ?Commercial Production declared April 1, 2009. ?G-9 Mine has now completed the first year of commercial production on April 1, 2010. ?Initial cash costs per pound of zinc US$0.39/lb -US$0.45/lb range. ?Mill operating at over1,900 tpd in March 2010, well above design capacity (1,500tpd) only one year after starting commercial production. ?Balance Sheet -$167 million assets, $24 million long-term debt, $22 million cash. ?Restarted Exploration ?excellent initial results. ?Strategically positioning Farallon to grow to a mid-tier mining company.

May 1, 2010