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By J de Cuyper, V. M. Lovell, W. Freyberger

The recovery of apatite from the phoscorite ores occurring in the Transvaal, Republic of South Africa, involves a flotation process that is particularly difficult to characterize from a fundamental point of view. However, the reagents used, (tall oil fatty acid, nonylphenyltetraglycol ether, sodium silicate, and sodium hydroxide) can successfully bring about a separation of apatite from dolomitic calcite, which is the most troublesome gangue component. Recently, it has been demonstrated with some flotation feeds that the addition of certain polysaccharides can improve the flotation significantly. It has been shown that the metallurgy obtained is closely linked to the nature of the froth, and this, in turn, is influenced, often dramatically, by the presence or absence of certain of the reagents. The character of the froth depends less on the inherent frothing ability of these reagents than on the presence or absence of fine mineral particles in the froth, and on their surface characteristics and state of aggregation. The polyglycol ether and the polysacchar- ides have been shown to affect these properties, and it is suggested that a major function of these reagents is to modulate the properties of the fine particles in the pulp, thereby changing the character of the froth and giving rise to improved results.

Jan 1, 1976

By Henry R. Tiedemann, Eugene H. Skinner, George E. Wickham

The need for ground support research in underground excavation has been well identified in recent years by many studies in the subject area (1, 2, 3, 4, 5). A typical conclusion from these reports (1, 2) is that the drill-and-blast (D & B) mining or the mechanical tunnel boring machine (TBM) methods are expected to be continued in use for the needs of tunneling in the immediate future. The Organization for Economic Co-operation and Development (OECD) sponsored in June, 1970 advisory conferences on Hardrock and Soft Ground Tunneling (3,4). These two reports were based on the combined response received from approximately six hundred inquiries from 17 nations in the summer of 1969 and which concerned all aspects of present-day inadequacies of, and the needed improvements in the technology of tunneling. Some specific problem areas in ground support and tunnel linings were: 1) the ability to successfully predict rock loads that must be carried by the support system; and 2) inadequate methods for determining the load-carrying capacity of the various support systems. Therefore, the problem area is clearly defined by these two objectives: 1) To find means of predicting rock loads; and 2) To develop methodology for determining safe, efficient, and economical ground support design practices. Noting these research needs from a great number of sources, the United States Bureau of Mines, Spokane Mining Research Center (SMRC), acting as agent for the Advanced Research Projects Agency (ARPA), undertook contract research effort in these problem areas. Work by Jacobs Associates has studied a methodology for specification of temporary artificial support based on the dependent sequence of mining operations and prediction of various rock conditions in the pre-excavation stage. The major thesis is that rock behavior is the

Jan 1, 1997

By Phoebe L. Hauff, Jeffrey P. Kurtz, Paul D. Chamberlin

Clay minerals can be a source of problems in heap leaching operations. The ore for many heap leach operations is commonly acid-sulfate alteration zone rocks which may be found in hot springs deposits as well as the supergene zone of other near- surface gold deposits. Clays can be important constituents of these ores. Swelling clays, such as smectite, can come loose from the agglomerated ore, migrate within the heap, concentrate in pore spaces and often plug up flow channels in the heap Cement is often added to the ore as a binder during the agglomeration process. Lime is added for pH control. Their presence, combined with the sodium cyanide commonly used to leach, can raise the pH of the leach solution to 10 or even 12. This very alkaline solution can cause dissolution of some mineral Some clays, such as kaolinite, are not very stable in high pH solutions. They can be dissolved and reprecipitated as other clay species if sufficient silica and the appropriate cations are available in solution. Silica gels and amorphous materials can also be created from the dissolved kaolinite and other minerals and act as retardants to the flow of leach solutions in the heap. Therefore, before a heap leach operation is built, the operator should evaluate the clays in the ore and test the agglomeration procedure. It is important to know not only the mineralogy and the chemistry of the leach environment but how the minerals and solutions interact and what the products of this interaction are. A hypothesis is presented in this paper that expanding smectite- bearing clays can be generated within the heap. How and why this happens will be explained.

Jan 1, 1987

By Jozef S. Stachulak

Inco Limited operates 11 underground mines in the Sudbury District. The mines are located on the rim of the Sudbury Basin, an oval with the axis in the range of 27 and 60 km. The ore dips to at least 3000 m below surface. The ores are mined primarily for nickel and copper. Total ore production from underground is in excess of 55,000 tons per day. Over 40 surface fans have been installed since the late 1960's. All of the fans are adjustable pitch, axial flow units. A major factor influencing ventilation design in the last 30 years has been the introduction of diesel equipment underground. Volumes per fan have ranged from 60 to 330 (cubic metres per second), with motors from 100 to 2500 hp. Fans of the axial flow type have been in common use for main fan installations at Canadian mines for many years. The standard arrangement has been to mount these fans horizontally, i.e. with the fan shaft and the long axis of the housing horizontal. This is a natural arrangement for an underground fan, but for a surface installation, a vertically mounted fan has definite advantages. The surface area taken up by a typical vertical fan installation is generally about one quarter of that with a horizontal fan of the same capacity. (1) This is not a problem with isolated fans and flat surface outcrop sites, but where the installation is to be near existing buildings, or where there are poor surface soil conditions, space and cost considerations greatly favour vertical fans. MAIN FANS INSTALLED There are 43 main surface fans in operation at 11 mines. Twenty-seven of these fans are supply units, and 75% of them are vertical installation. The remaining 16 units are main surface exhaust fans, with predominantly horizontal installation. Within the last five years, some 20 main booster fans have been installed underground at several mines. Axial flow fans, with adjustable pitch blades, are used for both surface and underground installations. Exhaust fans are equipped with stainless steel or cast aluminum blades. Main underground fans are arranged horizontally and the majority of them have a floating shaft between the fan shaft and the motor. (2) The size of the fans in service varies from 1.8 m to 5 m in diameter, with the majority ranging from 1.8 to 2.5 m. The pressure produced by these fans varies from 0.25 kPa to 2.0 kPa. At Inco Limited, two main fans in parallel are preferred, rather than a single fan, so that if one fan fails, the remaining fan can still supply up to 70% of normal air quantities, while the damaged fan is repaired. This requires closure doors on each of the fans so the fan can be isolated in case of failure. It is more expensive than a single fan, but results in less production interruptions. The fan installations are well away from sharp inlet and outlet bends. FAN DESIGN INTEGRITY Both the mine operator and the fan manufacturer must understand that the main fan is critical to the mine operation, and that everything technically possible must be done in design and manufacture to ensure the highest degree of reliability. Some of the design parameters and criteria, based on Inco experience, are outlined and discussed below. RESONANT FREQUENCIES AND HOUSING MODEL ANALYSIS Any fan assembly will have many different resonant frequencies. It is a challenge to the designer to arrive at a design in which forcing frequencies do not coincide with any of these resonant frequencies to produce unacceptable vibration levels in operation. Finite element analysis is a useful tool that can be used to identify the most critical of these, so that housing and blade stiffness can be adjusted to change any resonances that might be close to forcing frequencies. Shaft critical speeds should be at least 25% above the fan operating speed, and there should be sufficient separation between other resonant and forcing frequencies to avoid excitation that might result in high vibration levels. QUALITY ASSURANCE Radiographic Blade Examination Mine fan blades are normally cast in small lots. To ensure that the castings are sound, a full radiographic examination is recommended in the highly stressed lower 1/3 of the blade.

Jan 1, 1995

By Irwin R. Higgins, Richard S. Dennis

Acid recovery employs ion exchange resin as an adsorption media for the separation of inorganic acids from mixtures of acids and their metallic salts. This technology has been used to treat spent pickling and plating liquors to recover acid for reuse in the bath and to reduce waste acid neutralization costs. Acid recovery can also be used for electrolyte treatment to facilitate valuable metal recovery and to improve product quality. Conventional fixed bed ion exchange (I-X) systems are impractical for acid recovery because of complex control design and large resin inventories needed to process strong acid concentrations. TETRA'S CCIX™ continuous I-X contactor has been used successfully in a simple, continuous operating mode to separate acid from its salt. Efficient separation is enhanced by refluxing which allows acid to be produced as a salt-free product at nearly its original strength. Continuous treatment also recovers heat to the bath and improves metal quality due to consistent acid quality.

Jan 1, 1995

By R. A. Burns

Kaolin clay has a broad range of applications with the paper market representing the largest end-use. Calcined kaolin finds application in paper, paint and plastics primarily for its high brightness and light scattering ability. It is well known as an extender for TiO2. Meta-kaolin possesses a unique set of physical and chemical characteristics finding use in both traditional kaolin/calcined kaolin markets as well as other unique applications. This paper discusses the intricacies of manufacture and the key physical and chemical properties of meta-kaolin. Specific applications and the relationship of the physical/chemical properties to end-use performance are discussed.

Jan 1, 2002

By Ivor Hawkes

INTRODUCTION High energy breaking is an alternative to using ex¬plosives in underground secondary breaking operations. It also is a means of upgrading conventional hand-held breakers, manual sledge-hammer breaking, and scaling bar operations. Major areas of application are in sec¬ondary breaking over grizzlies and at drawpoints. Other applications include breaking down ripping lips in longwall seam mining, scaling in stopes and rooms, general demolition work, and roadway maintenance. There is considerable interest in high-energy impact breakers for use in primary ore breaking, but, as of 1977, all such applications have been only experimental (duToit, 1973; Joughin, 1976; Wayment and Grantmyre, 1976). EQUIPMENT Essentially, a high-energy impact hammer is a boom¬mounted pneumatically or hydraulically actuated breaker. The machine basically consists of a piston that oscillates in a housing and impacts the end of a tool or moil thrust against the rock. The force applied to the rock primarily depends upon the impact energy of the piston-the higher the impact or blow energy, the greater the force and, thus, the greater the rock break¬age. Among drill and breaker designers, a common expression for blow energy is "force of blow." Hand-held breakers are limited to blow energies of about 140 J (100 ft-lb), because the operator is unable to handle heavier machines efficiently or to absorb the recoil energy resulting from higher blow energies. How¬ever, these restrictions do not apply to boom mounted breakers; machines with blow energies on the order of 4000 J (3000 ft-lb) and higher are available commer¬cially for underground use. There is considerable evi¬dence to show that increasing the blow energy also in¬creases the efficiency of the breaking operation; i.e., more rock is broken per unit of energy expended (Grantmyre and Hawkes, 1975). Thus, there is a trend to higher blow-energy machines, particularly where high¬strength rocks are to be broken. In relation to rock breaking, the blow rate of boom¬mounted impact breakers is not as important as it is for rock drills. This is because the breaker must be moved over the work surface between blows. The blow rate is governed eventually by the power supply, and typical blow rates range between 200 and 600 blows per minute. As a general rule, light blow-energy machines have higher blow rates than heavier machines. Table 1 lists most of the boom-mounted impact breakers that were available commercially during 1977, and it gives details of the blow energies and machine weights. Restrictions are placed on the blow energy by the machine weight and size, and by the strength of the boom. Typically, boom-mounted impact hammers have a blow-energy to mass ratio of about 1.5, with lower values for lighter machines and higher values for heavier machines. In addition to supporting the hammer weight, the boom also has to absorb the recoil energy of the blow, which can be on the order of 1400 J (1000 ft-lb) for large hammers operating in a horizontal mode. Interesting exceptions to the general run of impactors are the Joy HEFTI hydraulic hammers. In these machines, the piston impacts onto a fluid cushion that is positioned between the piston and the impact tool. This approach allows very high piston velocities, over 30 m/s (100 fps), to be used without the risk of break¬ing the piston or impact tool. Steel on steel impacts must be limited to impact velocities of about 10 m/s (35 fps) due to the high impact stresses generated; thus, increased blow energies can be achieved only by increas¬ing the piston size. The Joy 514 HEFTI®, listed in Table 1, has a blow energy of 27 100 J (20,000 ft-lb), but, as of 1977, the machine has been used underground only on an experimental basis. Using a fluid cushion between the piston and the impact tool allows the use of light pistons, reducing the overall machine weight. The recoil energy, which must be absorbed by the boom for a given blow energy, is directly proportional to the piston to machine mass ratio, and operating with light pistons provides an addi¬tional benefit in reducing the requisite boom size. Both pneumatic and hydraulic hammers are avail¬able commercially. Although hydraulic hammers are a relatively recent development, they already outnumber the pneumatic machines in use. There are many reasons

Jan 1, 1982

By M. M. Rajkovich, L. Adams, J. J. Zaluski, S. Gardner

In 1998, a group called Kentuckians for the Commonwealth filed an Administrative Petition with the Kentucky Natural Resources and Environmental Protection Cabinet to designate 8,903± hm2 (22,000± acres) on Black Mountain, which contains the state's highest point, as unsuitable for mining. A fast track legislative process was triggered that could have "taken" 91 Mt (100 million st) of coal reserves or, in the alternative, imposed severe restrictions on mining. Even with all parties represented by reasonable individuals, this process can be extremely cumbersome and expensive. The legal and technical preparation for this unusual hearing process as well as issues and strategies of the negotiated resolution are reviewed

Jan 1, 2002

By K. A. Natarajan

This paper deals with the various electro- and biochemical mechanisms involved in the bioleaching of multisulfide minerals such as those containing copper-lead-zinc and copper-nickel-iron. Galvanic series for sulfide minerals consisting of pyrite, chalcopyrite, galena, sphalerite, pentlundite, and pyrrhotite in an acid bacterial leaching system is illustrated, and the role of relative electrochemical activity on selective dissolution is discussed. Typical leaching results are shown to illustrate the practical applicability of galvanic effects in bioleaching of multisulfides. Attachment of Thiobacillus fewooxidans onto chalcopyrite and sphalerite mineral substrates is illustrated through scanning electron micrographs. The role of high-metal-tolerant, specially adapted strains in the leaching of multimetal concentrates is also outlined.

Jan 1, 1987

By K. Osseo-Asare

Metal recovery from solution, i.e., the formation of a solid product from a purified aqueous electrolyte solution, is increasingly becoming more than a simple matter of bulk precipitation. In many cases, operating conditions must be carefully manipulated to control the rate and yield of the precipitation/crystallization process, as well as the purity and physical characteristics of the solid product. A review is presented of the underlying physico-chemical processes, with emphasis on solution and interfacial chemistry. Opportunities for the integration of hydrometallurgical metal recovery and materials processing operations are discussed.

Jan 1, 1989

By André G. Journel

As opposed to graphics applications in medical sciences and mechanical engineering, computer imaging of the subsurface faces a severe problem of data shortage. Most graphics softwares include an interpolation algorithm aimed at producing slick graphic output, irrespective of the attribute being interpolated, the quantity and quality of the data available, and what the map is intended for. It is suggested that the power of modern computers be also used in providing representations of the subsurface that accurately reflect actual spatial variability and the large variety of soft information available beyond hard data. Since any subsurface representation is uncertain, a measure of that uncertainty should be provided which can be used for risk analysis.

Jan 1, 1992

By Marcus M. Key

Silicosis among metal miners is an ancient disease, probably as old as mining itself.' However, the primitive forms of mining were not productive of much silica dust, and the short life span of slaves used in mining probably precluded the development of more than a few sporadic cases of silicosis. Early diagnostic terms of miners' asthma and miners' phthisis suggested an occupational relationship and a tubercular component, but little attention was given to silicbsis until the turn of this century when epidemics of silico-tuberculosis arose due to the great expansion of the mining industry in the United States, especially silver and gold mining. The expansion was accompanied by mechanization and the introduction of pneumatic tools, which generated increasing amounts of fine silica dust. Mining communities were crowded and hygiene was poor.' The tubercle bacillus would probably have flourished even without the predisposition of silicosis.' As is so often the case in occupational health, biostatistical analyses first called attention to the problem, and environmental-medical studies later confirmed its existence. The bio-statistical analyses were occupational mortality statistics compiled by the Prudential Life Insurance Company in 1907, showing evidence of excessive mortality from tuberculosis and relationship to dust exposure. I The

Jan 1, 1971

?Energy-related systems: wind, solar, electric are typically materials intensive. As new technologies are widely deployed, significant quantities of the elements required to manufacture them will be needed. However, many of these unfamiliar elements are not presently mined, refined or traded in large quantities, and, as a result, their availability might be constrained by many complex factors. A shortage of these ?energy-critical elements? could significantly inhibit the adoption of otherwise game-changing energy technologies. This, in turn, would limit the competitiveness of the U.S. industries and the domestic scientific enterprises and, eventually, diminish the quality of life in the US.? -Energy Critical Elements: Securing Materials for Emerging Technologies?- American Physical Society, 2011.

Jan 1, 2012

By Robert M. Anderson

A popular perception by the public and many mining claimants, is that the 1872 Mining Law provides a statutory right to mine and extract minerals from the public lands. This perception in reality, is both true and false, depending on the mining claimants' ability to meet federal and state environmental, cultural and endangered species laws. Land use decisions and proposed legislation affect exploration and development opportunities in California. It is imperative that the mining industry involve itself in the planning process to ensure that BLM decision makers are fully informed of industry's knowledge and concerns. STATUTORY RIGHTS AND ENVIRONMENTAL CONSTRAINTS "No other problem has such a sense of urgency and poses as profound consequences to the quality of life and the creation and distribution of societal wealth as how we protect the environment. Certainly, the environment is the single biggest issue facing mining and mineral activities in the new decade. David S. Brown The 1872 Mining Law was passed, ironically, the same year the nation's first National Park was established. It is a perception that the establishment of Yellowstone National Park was the beginning of the United States' earliest environmental movement; brought on, perhaps, by the rapid clearing of land for homesteading purposes and, the concern that many acres of the public domain were being disposed of through a multitude of public land laws. While there was an effort being made to designate some special and unique public lands as parks for preservation purposes, environmental concern and awareness did not lead to mandatory identification of environmental impacts and appropriate mitigation until the passage of the National Environmental Policy Act in 1970. Consequently, it is not surprising that the original United States Mining Laws of 1866, 1870 and 1872 had no mention of environmental protection. There have been numerous attempts to repeal the 1872 Mining Law over the last 50 years for a variety of reasons. Currently, there is a perception by the general public, media and even some in congress, the mining industry and BLM that a change is needed. The environmental organizations want the industry to be more accountable for reclamation and post mining uses. In Tn nEnvironmental Agenda for the Future," leaders of America's foremost environmental organizations state that the mining law "includes no protection for the environment," and therefore, should be reformed. We can all acknowledge, as stated above, that the mining law, per se, requires no "protection. However, the Bureau of Land Management (BLM) clearly has the authority and the responsibility to fully "protect" non-mineral resources while providing for the extraction and processing of mineral resources by private industry. There are about 13 major federal laws that have indirectly or directly amended the mining laws to require Environmental, Historic and Cultural Protection." There have been many mining law case decisions about the statutory and constitutional rights of miners to explore open federal lands, "stake a claimg" and extract minerals. What needs to be fully understood is how federal laws, as enumerated on Table 1, may affect these rights. What follows is a description of

Jan 1, 1991

By William G. Freeman

As with most industrial minerals, barite is freight sensitive. This paper is given so that others might gain from the experience of barite companies in reducing their transportation costs. Some of the approaches used were unusual and others standard, but by perseverance considerable savings were realized.

Jan 1, 1973

By R. M. Reyes, D. Negrete, G. Herrera

First Majestic Silver Corp’s La Encantada Silver Mine is a producing mine with a capacity of 3,000 tonnes per day. The La Encantada team is currently constructing two small-scale caving mines, including the San Javier breccia caving mine. The new mine is constructed within a mineralized breccia body composed of clasts of varying sizes and with very poor rock quality. Due to this poor rock quality, primary and secondary supports are required to support both the development and production stages. Since the proximity of the new mining levels to existing old workings, correct selection of the support system and proper production controls, instrumentation, and monitoring are very critical to maintain the stability of the pillars and fortification elements. An increased ground deformation due to the load transfer during the production stage is expected. This report reviews the primary and secondary support elements used in the different stages of mining, the monitoring of ground deformation, and the steps taken to analyze and visualize the collected data in order to enable the geotechnical team to manage caving stress and maintain pillar stability. INTRODUCTION First Majestic Silver Corp. (“First Majestic”) is a Canadian mining company focused on silver production in Mexico that operates six producing silver mines, including La Encantada Silver Mine (“La Encantada”). First Majestic acquired La Encantada in 2006. La Encantada is located in the northwestern portion of the state of Coahuila, in northern Mexico, in the municipality of Villa de Ocampo. The mine lies in the northern part of the Sierra Madre Oriental physiographic province. The mine location is shown in Figure 1. La Encantada is a producing mine, with a mill processing capacity of 3,000 tpd, and a 4,000 tpd capacity cyanidation leaching circuit equipped to process fresh underground ore and old tailings amenable to be reprocessed. The mine is currently employing several mining methods, including overhand cut and fill for narrow veins, small mantos, and other minor deposits. A subset of caving methods are applied on the larger, but weak, mineral deposits, such as at the San Javier breccia and La Prieta breccia. La Encantada consists of vein, manto, breccia pipe, and chimney deposits with concentrations of silver, lead, iron, and zinc in oxidized mineralization enclosed by calcareous sedimentary formations of Cretaceous age. At deeper levels, there is sulphide mineralization in skarn with zinc and silver concentrations associated with a granodiorite intrusion.

Jan 1, 2019

By David A. Hedderly-Smith

Sealaska Corporation, the Alaska Native Regional Corporation of Southeastern Alaska, was organized under the laws of the state of Alaska pursuant to the federal Alaska Native Claims Settlement Act of 1971. Large areas of Sealaska's 630,000-acre (250,000 hectare [ha]) fee subsurface holdings are underlain by carbonate, and while much of this material is assumed to be common variety limestone and lesser dolomite, at least two areas in the Silurian Heceta Limestone contain high-quality limestone at tidewater. This limestone has many potential commercial uses. On northern Prince of Wales Island, about 90 miles (144 km) north-northwest of Ketchikan, resource development at Sealaska's Calder deposit has established a reserve of 13 mil- lion short tons (st) (12 million metric tonnes [mt]) of carbon- ate rock containing an average of greater than 98 percent CaC03, approximately 0.5 percent MgO, less than 0.5 per- cent Si02, and approximately 0.15 percent Fe203, with insolubles averaging less than 0.5 percent and an average Hunter Brightness of 92.07 for the -150 mesh grind (with a bright- ness cutoff of 90). The deposit is open at depth and to the south. Ultimate reserves will likely be several times those currently established. In 1998, Sealaska began mining the Calder deposit, with about 100,000 st (90,000 mt) produced, and also completed a marine terminal one half-mile (800 m) from the deposit. The terminal can load ships up to 680 feet (200 m) in length at a rate of 2,000 st (1,800 mt) per hour. 0 m) in length at a rate of 2,000 st (1,800 mt) per hour. On Dall Island at Breezy Bay, about 60 miles (100 km) southwest of Ketchikan, Sealaska has identified a limestone reserve in excess of 150 million st (135 million mt) that (based on 18 surface samples distributed evenly over about a section of land) contains about 98 percent CaC03, and less than 0.5 percent MgO, 0.5 percent Si02, and 0.15 percent Fe203. Brightness of the Breezy Bay carbonate is considerably less than at Calder. Five samples of brighter material from Breezy Bay returned brightness analyses in the high 80s and low 90s; average brightness is probably below the mid- 80s. Sealaska has also identified a deposit containing more than 19 million st (17 million mt) of similar rock near View Cove, a few miles south of Breezy Bay.

Jan 1, 2001

By C. Anderson, B. Schug, C. Cristoffanini, S. Nazari

The Haile Gold Mine in South Carolina is increasing the automation level of their processing plant in order to improve operational stability. One step towards this goal is the application of a Digital Twin concept to provide Virtual Instruments. Haile has engaged ANDRITZ to implement Virtual Instruments at their grinding area hydrocyclones and at their tailing thickener underflow pump. These virtual instruments provide density values in a traditionally difficult location for reliable slurry density measurement. The Digital Twin is a first principles IDEAS1 ™ simulation model, connected in real time to the control system. Results have been promising, with the virtual instrument values matching the physical instrument under normal operating conditions, and showing better prediction under upset conditions. Haile plans to use the virtual instruments as optional process control parameters. INTRODUCTION OceanaGold’s Haile Gold Mine is located near Kershaw, South Carolina, about 50 miles southeast of Charlotte, North Carolina. This location was first mined in 1827, and has produced gold through several operating periods since then, including a heap leaching operation from 1985 through 1992. In October, 2015, OceanaGold acquired Romarco Minerals, the previous owner of the Haile Operation. The current operation began in 2017 as an open pit mine with additional underground resources. The nameplate throughput is 6,350 tpd ore, and 2017 production was 118k oz gold, with 140 to 155k oz gold expected in 2018. Proven and Probable reserves exceed 3 Moz. The process, as shown in Figure 1, includes a primary jaw crusher, comminution with a Semi-Autonomous Grinding (SAG) mill and ball mill circuit, flash flotation, rougher flotation, regrinding, pre-aeration, carbon in leach (CIL) leaching, carbon elution and regeneration, cyanide recovery, electrowinning and refining. The Haile Operation’s inaugural gold pour took place January 20, 2017. Mine life is expected through at least the year 2030. Based partially on prior experience of some key OceanaGold personnel with automation services from ANDRITZ on other projects, OceanaGold decided to include ANDRITZ on the Haile project. The scope of these services for Haile included design and supply of the process control application software, an ANDRITZ dynamic process simulator for operator training, and ANDRITZ Advanced Control Expert (ACE) ®2 systems for the SAG mill, ball mill, and rougher flotation areas. Since startup, ANDRITZ has continued to provide services for the site, particularly related to PLC and HMI equipment, programming and support, ACE system expansion, and the implementation of Virtual Instrumentation. The implementation of this new Virtual Instrumentation technology at Haile is consistent with Haile goals: increased automation, a change in the role of the operator from interactor to monitor, and improved stability by removing human error.

Jan 1, 2019

By J. A. Cervantes

A statistical model for assessing the risk of ground subsidence in abandoned mine areas is presented. The model is based on the relationship that exists between .the frequency and the location-of subsidence events in a given area and the physical conditions of the ground. These conditions can be described by a series of geological, mining, and physical variables. The model suggests the existence of regions in the multidimensional space of variables which are associated .with increases or decreases in the frequency of subsidence events. Regions associated with an increase in the frequency of subsidence events correspond to regions of higher risks, and vice versa. Risk assessment is based on the ability to express the limits of these high and low risk regions in the, space of variables, and on the ability to express the degree of membership of blocks of land within any of these regions. The theoretical framework for the model is extracted, from discriminant analysis. Risk is quantified by the probabilities of membership of blocks of land into any of these regions. Risk maps are produced by displaying membership probabilities in. appropriate contouring levels. The model has been applied in two urban areas where subsidence of the ground has been active in the past. The two areas are Penn Hills, near Pittsburgh, and Scranton/Wilkes-Barre in northeastern Pennsylvania. In this paper, only the results for the Scranton/Wilkes-Barre area are presented. Those for the Penn Hills area have been presented elsewhere (Cervantes, et al, 1990). In the- Scranton/Wilkes-Barre area, geostatistical estimates of variables likely to affect the stability of the ground were made using samples from 53 drillholes. The estimates were made for 2000x2000 ft squared blocks of land covering the study area. Discriminant functions were computed from the estimated variables and used to establish regions for classifying blocks of land into one of these two populations: 1) blocks not likely to have a subsidence event, and ii) blocks likely to have one or more subsidence events. The same, discriminant functions were used to compute membership probabilities for blocks of land to tall within any of these two populations. These probabilities were contoured to produce a risk map. The risk map produced compares well with the location of the subsidence events which have occurred to date in the area.

Jan 1, 1992

By K. J. Reid

A historical background of the development of automated material balance packages is presented including a summary of currently available packages and a description of the present work at the Mineral Resources Research Center of the University of Minnesota. A brief mathematical statement of the problem is given and solution techniques discussed. The problems and difficulties normally associated with material balances, both hand calculated and computer calculated are described. Several aspects of the available material balance packages as related to the "user/computer" interface are evaluated in detail. Elements of the material balance packages that affect the solutions are examined and the relative performance of the main packages on specialized problems presented. Finally, areas associated with automated material balances that require further work before computer packages can be widely used in industry are outlined.

Jan 1, 1982