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By Martin F. Grier

The Mt Todd Gold Project is located 300km to the south of Darwin in the Northern Territory of Australia. The identified resource comprises 46 million tonnes at 1. 65g/t using a 1. 0g/t cut-off ( 50 million short tonnes at 0.05oz/st). The resource is open to the north and at depth. Mineralisation comprises easterly dipping sheeted quartz/sulphide veins, typically 10 to 20 millimetres in thickness, hosted by hornsfelled greywackes. The majority of the ore body is primary ore with only 10% classified as oxide ore. Early testwork showed that the ore was not suitable for heap leaching, giving only 50% recovery at a -3mm crush size. Acceptable recoveries were obtained at a P80 of 75 micron. However, the ore is extremely hard.

Jan 1, 1992

By Howard N. Egan

The importance of coal as the major energy source has led to wider interest in the recovery of waste coal fines as a usable product. An additional incentive for fine coal recovery has been the increased emphasis on environ- mental pollution control and conservation of the nation's natural resources, Accordingly, a series of studies and tests were performed to investigate the feasibility of the recovery, concentration, balling and pelletizing of coal fines as a marketable adjunct to existing mining and beneficiation operations. These studies were conducted at the existing operations of the Eastern Coal Corporation at Stone, Kentucky, and the Metallurgical Laboratory of Arthur G. McKee & Company in Cleveland, Ohio. The purpose of the investigations was to recover the fines from the effluent waste waters of an existing preparation plant and transform them into a high carbon, low sulfur and ash product capable of being handled with a minimum of degradation and dusting problems. The fines were relatively high in ash content prior to processing, and flotation pretreatment served a combined function of beneficiation, recovery and water clarification, The minus 28 mesh coal concentrate containing 40 to 45 percent minus 325 mesh size material had an ash content varying between 5 and 7 percent and a sulfur content of less than 0.5 percent. Chemical and size analyses of the effluent and concentrated fines are presented in Table I for comparison.

Jan 1, 1967

By K. L. Browne

After a decade of high copper prices, major mining companies are renewing their interest in purchasing operating properties and/or developing ore bodies. An existing operation carries with it a history that can present unique opportunities, while a greenfield operation allows for the establishment of a defined culture. Capital investments are distinctly different. A comparison of BHP Copper's Robinson operation, a greenfield property, and BHP Copper's Tintaya operation, a government owned Peruvian property, will provide insights into mining, concentrating and cultural differences between North and South America operations. The Broken Hill Proprietary Co. Ltd. (BHP) is Australia's second-largest company. Fiscal year 1996 sales were US$16 billion, profits were more than US$1 billion and total market capitalization was about US25 billion. In 1885, BHP began mining silver, lead and zinc at Broken Hill, New South Wales, Australia. Throughout its 112-year history, BHP achieved an impressive record of performance and expansion. Today, BHP is one of the world's leading companies (66th on the Standard and Poors 500), having diversified into steel, petroleum and mining with more than 65,000 employees in 70 countries.

Jan 1, 1997

By P. T. Luckie

The selectivity curve -- a continuous function which predicts the expected proportion of feed material of a particular size that will appear as coarse material -- is the preferred model for describing classification. In a previous paper (I), the authors presented a technique for determining the selectivity curve of a classifier from experimental data. The separation process is defined by a binomial distribution of the form [ ] where s(x), the probability of particles of size x reporting to the coarse stream, is obviously the selectivity value for material of size x.

Jan 1, 1975

By Randhir Sehgal

Heavy media processes have been used for cleaning +28 mesh coals for a number of years, Two applications, i.e., the vessels and the cyclones are widely used in the U. S. for this purpose. The basic reason for the popularity of these systems is their extremely high efficiencies for particle sizes above 28 mesh, However, application of heavy media technology to fine coals below 28 mesh, has been limited due to the following reasons: o Inability to make size separations effectively at sizes below 28 mesh o Necessity of feeding large quantitites of magnetite to the separators o Difficulty of recovering magnetite in the presence of large quantities of coal o High levels of coal contamination in the recovered media, leading to high circulating loads and ineffective control of media gravity

Jan 1, 1981

By Peter K. Achireko, Samuel Frimpong

Design and optimization of open pit limits are of paramount importance because they provide information for evaluating the economic potential of a mineral deposit and for developing short and long range mine plans. Many algorithms and their modifications have been used to design and optimize open pit limits. These algorithms have provided mine planning engineers with pertinent information in designing, optimizing and extracting ore reserves by open pit technology. However, they do not address the random field properties associated with the ore grades and reserves and commodity prices, and thus, fail to yield the truly optimized pit limits in any time horizon. In this paper, a new algorithm, MCSIMFNN, which overcomes these limitations is proposed and used to optimize open pit limits. The random field properties of the ore grade and reserves have been modelled using the modified conditional simulation based on the best linear unbiased estimation and local average subdivision techniques. Artificial neural networks are used to classify the blocks into classes based on their conditioned values. The error back propagation algorithm, in the neural networks, is used to optimize the pit limits by minimizing the desired and actual outputs error in a multi- layer perceptron under the pit wall slope constraints. The optimized pit value obtained by this algorithm has been compared to that from the Lerchs-Grossman's algorithm in a case study. The results are the same, but in random multivariable states, the MCSI MFNN algorithm is the most suitable for pit optimization. The method is also fast since it mimics the operation of the brain in the solution of the pit optimization problem.

Jan 1, 1996

By W. E. Sabina

In the short period of one mans? career we have seen specifications for bulk material handling systems and equipment grow from two or three pages to as much as two or three volumes for a single contract. The old 'short form' described what the purchaser expected the equipment to do. The long form does the same but also includes nut, bolt, and lockwasher depth of detail. What are the events that led to this proliferation of verbiage, and does it benefit the buyer in the final analysis? Is there a better way to purchase complex equipment while ensuring the highest quality for the dollar spent?

Jan 1, 1986

By François Martin, Roland Plassart, François Laigle

"MOTIVATION The storage of nuclear waste gives rise to a lot of innovative issues for underground space technologies. The nuclear activity of waste generates temperature effects on both the lining and the surrounding rock mass. In order to avoid these unfavorable effects, the number of waste containers is controlled in the gallery section. The galleries section has consequently ranged from a diameter of 4 to 6 meters. However, in the case of intermediate-level nuclear waste, due to the lower temperature, the number of containers in a cross section of a gallery is assumed to be safely increased. Despite technical difficulties, a large diameter gallery (typically 12m excavated) seems to be more cost effective. This paper demonstrate the feasibility of such a gallery in the specific context of CIGEO (French Geological Repository Project for nuclear waste), located in the Bure area in the north-eastern of France. The geology of Bure at the project’s depth (about 520 meters) consists in a quite homogeneous layer of Callovo-Oxfordian argillites (COx argillites). With such an overburden, this rock is known to have a high plastic behavior with significant time-dependent effects. These mechanical properties require complex behavior laws in computational modeling used for the design of underground facilities.EXPERIENCE OF LARGE DIAMETER GALLERIES In order to identify some specificities in the design of such openings, a research has been run on existing galleries of large diameter (more than 10 meters), like the tunnel of Chamoise, Lötschberg, Tartaiguille or Saint-Martin-La-Porte. Two of these representative examples are detailed hereafter. Tunnel of Chamoise (French Jura) In spite of a lighter overburden (400m versus 520m), an anisotropic initial stress state and a variable rate of carbonates, the highway tunnel of Chamoise is quite similar to the planned gallery for intermediate-level nuclear waste, with a geology very close to the CIGEO’s one in some sections. Because the northern tube encountered difficulties during the excavation a few years before (several over-excavations and spalling, especially in the bench), the excavation of the southern tube has been carried out in two steps, but with a high bench and a small curved invert (Figure 1). The design of the immediate support consists in long bolts and a shotcrete layer. The concrete lining is about 50cm thick."

Jan 1, 2016

By Joseph M. Chelini

The report shows the sensitivity that nine different cash-flow factors have on the discounted rate of return calculated from feasibiliity- studies on potenital open-pit orebodies of silver, copper, and uranium. Cash-flow factors of "grade", "market value", and "recovery" are. the most sensitive. This verifies the need of reliable estimates for these factors. The cost of evaluation of "preproduction cost" is the least sensitive. This gives credence to the fact that more consideration should be given to compiling sufficient data, as the largest financial losses are not in the cost of evaluation but rather in the abandonment of an unprofitable mining operation after a commitment of capital is made on the basis of an incomplete evaluation. Sensitivity analysis of cash-flow factors enhances evaluation programs by disciplining the collection of data and allowing more realistic distribution of evaluation monies.

Jan 1, 1971

By John M. Marek, David E. Nicholas

INTRODUCTION The purpose of this article is to outline the data requirements for selecting a proper underground mining method and to discuss the general steps taken in selecting that method. Determining the appropriate mining method is an iterative process that continues throughout the life of a mineral deposit. We will discuss the subject from the standpoint of a feasibility study, where a realistic assessment is necessary in order to determine investment merit. The feasibility stage of a project is that point where the drilling program has defined sufficient geologic reserves to consider mining the deposit but little or no underground development has been done. Primary parameters for consideration in choosing a mining method are 1) geometry of the deposit; 2) distribution of grade; 3) rock mass strength for the deposit, as well as the hanging wall and footwall; 4) mining cost and capitalization requirements; 5) mining rate; 6) type and availability of labor; 7) environmental considerations; and 8) other site-specific conditions. Of these parameters, the first four have the most impact on determining the general mining method to be employed.

Jan 1, 1981

By Sertaç Dündar, Bilgehan Kekeç, Arif Emre Dursun, Niyazi Bilim

"Estimation of rock drillability is vital for mining and boring operations. For this purpose, many researchers have developed various models and equations to estimate rock drillability. Most of these models aim to determine the drillability of rock and the penetration rate by using the physical and mechanical properties of rocks. Although drillability primarily depends on rock properties, other parameters have an impact on drillability as well. One of these parameters is the rotation speed of the bit. This study investigates the effect of rotation speed of the bit on drilling performance. Drilling tests were performed in the laboratory using rotary core drilling and a diamond drilling machine. The relationships between the physical rock properties and the penetration rate were investigated on 15 different rock types and four different rotation speeds were applied to determine the effect of rotation speed of bit on drilling. The uniaxial compressive strength, density, and P wave velocity show strong correlations with the penetration rate. In addition, if the values of the physical and mechanical properties of the rock increase, the effect of the rotation speed on the penetration rate decreases, i.e., increasing the rotation speed of the bit slightly affects drillability on hard and solid formations. 1. Introduction Drilling is one of the most essential operations in the mining industry, beginning from the exploration phase and continuing throughout all stages of production to the end of mine life (Taheri et al. 2016). In addition, drilling is widely using in the construction industry and other engineering operations. Various drillholes (blastholes, injection holes, borehole, diamond wire holes in natural stone mines, etc.), are needed during development and production activities in underground and open-pit mines as well as in dam, tunnel, road construction and sewage systems. For effective drilling operations, it is first necessary to gather information about the formation to be drilled. Drilling should then be performed after selecting appropriate drilling equipment and drilling parameters (thrust, pressure, rotational speed, flushing). Prediction of the drillability of rocks is vital for planning and performing the drilling process. Although, drilling is affected by several factors, the most important ones are related to the geological and mechanical properties of formation (Protodyakonov 1963, Paone et al 1969, Tandanand and Unger 1975, Pathinkar and Misra 1976, Rabia 1985, Perrin et al 1977). Determining the penetration rate is vital for planning a project and calculating the operation costs. The prediction of drilling affects the selection of drilling equipment, the efficiency of drilling equipment, project costs and the process of drilling operations."

Jan 1, 2017

By Douglas M. Deason

Swelling clays, such as montmorillonite, contribute significantly to the poor dewatering and consolidation behavior of the Florida phosphate clay wastes. Understanding and to a degree, control of the forces which cause the swelling behavior may aid in supplying a solution to this problem. The technical feasibility of utilizing control- led dispersion for aiding dewatering of phosphatic slimes was investigated. This technique is based upon inhibition of swelling and self-dispersing tendencies of the montmorillonite clays by dispersing the solids in electrolyte solutions. Through this process, significant improvements in settling rates and sediment solids content were achieved in both pure clay systems and on simulated phosphate slimes.

Jan 1, 1983

By Jozef S. Stachulak, Bruce R. Conard

INTRODUCTION The concern of occupational exposure to diesel exhaust pollutants is an important workplace issue for the mining industry. During the last three decades of diesel operations at Inco, a significant amount of research and improvement has been made in the area of work environment, and effective diesel operation. This paper will review the experience gained by Inco's Ontario Division from the implementation and the use of modern engines, improved fuel quality, and the exhaust control technology, coupled with adherence to proper maintenance and ventilation design and practices. Past monitoring practices and the current occupational monitoring program at lnco are outlined. A major new research initiative involving multi-stake holders in diesel performance is described. MINING IN THE SUDBURY AREA The discovery of nickel-copper ore in the Sudbury area dates back to the year 1856. The existence of this orebody was noticed when a strong compass deflection was observed by a provincial surveyor. This discovery, even though documented in official re- ports, failed to arouse any public attention at that time. In 1884, a rock-cut was blasted through a small hill near the village of Sudbury to permit laying track for the Canadian Pacific Railway (Boldt 1967). The rock-cut uncovered a body of massive sulfides with a copper content of over nine percent. The mineralization is concentrated along the outer margin of the Sudbury Basin, an oval-shaped structure having a dimension of 55 x 95 kilometres. The ore extends down-dip to to at least 3000 metres below the surface. The mining methods at lnco can be divided into two categories: "filled-stope" and 'bulk" mining. This division, in the broad sense, may also reflect the environmental conditions of the mine. In the past, the selection of a mining method was based on the size, shape, grade and the strength of the ore and its surroundings. The recent development of improved technology and mining equipment permitted wider application of low cost bulk mining methods. UNDERGROUND DIESEL EQUIPMENT The first diesel-powered machine, a 145-horsepower scooptram, was put into operation in March 1966, in a cut-and-fill stoping complex at Frood Mine. The number of diesel machines underground in the Inco, Ontario Division, mines was increased to 360 units by 1971,550 in 1977 (Rutherford 1978), and over 830 diesel-powered units in 1995. The following list indicates current mobile diesel equipment. LHD 194 Loaders 81 Trucks 28 Jumbo Drills 78 Personnel Carrier 101 Service Equipment 155 Locomotives 50 Bolters 30 Scissor Lift 113 About 20 percent of the LHD and truck units are equipped with electronic fuel controlled engines. COMPOSITION OF DIESEL EXHAUST Diesel exhaust contains hundreds of pollutants (Watts 19921, including components of unburned fuel and lubricating oil and products of incomplete combustion of the fuel and oil. These pollutants are emitted either as gases or as particles. Gaseous pollutants include carbon monoxide, nitrogen oxides, and sulfur ox- ides, as well as a variety of organic compounds, such as hydro- carbons, aldehydes, and polynuclear aromatic hydrocarbons. The particle phase, also known as diesel particulate matter (DPM), is the filterable portion of diesel exhaust. Figure 1 depicts the trimodal particle size distribution that arises from different mechanisms of aerosol generation (Cantrell and Rubow 1992). Primary combustion aerosols, including diesel exhaust aerosol, are formed as very small particles (in the 0.001 to 0.08 micrometre range), but physical mechanisms such as condensation and coagulation quickly transfer the aerosol mass from the nuclei mode to the accumulation mode. These processes result in a mass median diameter of approximately 0.2 micrometres for diesel particulate matter, and 90% of the particles are less than 1.0 micrometre in size. These particles have a high surface area, permitting the adsorption of different substances produced during combustion. Mechanically generated aerosols, on the other hand, typically contain particles greater than 1 micrometre in diameter. The particle phases of diesel exhaust contain three components (Bagley, et al, 1996) shown by Figure 2, namely: a carbon- aceous fraction composed mainly of solid-carbon particles, a sulfate fraction containing small hydrated sulfate particles, and a soluble fraction that contains compounds that are soluble in organic solvents and are adsorbed or condensed onto carbon core particles. These compounds consist primarily of higher molecular weight hydrocarbons and PAH's and may contribute 15% to 45% of the weight of the total particulate matter (Schuetzle, 1983). The control of these pollutants is necessary to ensure a healthy work environment. Proper engine maintenance, engine design modifications, improved fuel quality, and use of exhaust control technology, coupled with good ventilation practices, all

Jan 1, 1997

By J. D. Miller

Pilot-scale tests indicate that effec¬tive concentration of fine gold from Colorado River sands can be achieved by flotation with the air-sparged hydrocyclone. The fine sands (55% minus 400 mesh and 0.01 opt*) from gravity concen¬tration were processed with a 5-cm air-sparged hydrocyclone (capacity -1.0 tph dry solids). Concentrate grades as high as 5.0 opt were produced in a single stage at a recovery of 75.0%. The separation efficiency was significantly better than that achieved in conventional batch flotation experiments.

Jan 1, 1985

By M. Heger, V. Lund, P. Mongeon, D. Bogunovic, V. Kecojevic

The U.S. coal mining industry consumes a significant amount of energy, primarily diesel fuel and electricity. The continuous global increase in energy demand, high energy prices and environmental issues related to carbon dioxide emission represent a substantial challenge for the mining industry. This paper presents the result of research on development of an integrated data environment system for analysis of energy consumption in a surface coal mine. A case study on an operating surface coal mine is carried out to demonstrate the practical application of the developed system. The research work presented here may be used by mining professionals to help provide the answers to the crucial questions of when, where and how much energy is being used. This developed system represents a framework for efficient management of energy consumption.

Jan 1, 2009

By H. C. Morehead

The United States Cement, along with other industries, is being devastated by an unprecedented penetration of domestic markets by imported products. The overriding questions are: 1. Have foreign manufacturers improved their processes to an extent they can outperform U.S. producers in their home markets? 2. Is it gross inefficiency on the part of the U.S. producers that is allowing foreign producers to be capable of replacing a local U.S. producer in his normal home market? 3. Is there a combination of the first two questions that economically justifies this type of market overrun? The answer is a simple NO!. In a fair trade market atmosphere, U.S. producers are definitely competitive.

Jan 1, 1985

By J. R. Sturgul

Thompson and Adler (1988) present a new simulator for use in designing conveyor belt systems for underground mines. Their model uses a large Fortran program to do a Monte Carlo simulation. Their approach is similar to that done by other researchers, such as Stanford (1965) and Newhart (1977). All Fortran based simulation models use an imaginary clock that is advanced a time increment. At each advance of time increment the program has to determine what is to take place in the system. Since many things can take place at different places in the system, this approach requires that a large amount of logic is needed at each step of the program. This, then, necessitates a great amount of jumping between different portions of the program. In fact, the Fortran program, CMBCS, takes up to 15 to 20 minutes to run on the mainframe and several hours for the PC. Such execution times are typical of Fortran based simulation studies. There have been other examples of Fortran based simulation studies in mining. Cross and Williamson (1969) presented a model of a working open-pit copper mine. Fosinato (1982) presented a model of the bucketwheel excavators for the large open-pit mines in Southern Victoria in Australia. These excavators discharge into a complex conveyor system, which can be thought of as being similar, but more complicated than the one modeled by CMBCS. All previous simulation studies using Fortran as the source code have several things in common: they all are very lengthy, often being of the order of 10,000 lines of code and take a great deal of CPU time to execute. The program of Fosinato takes more than 4.5 hours to run on a large mainframe. Also not mentioned by Thompson and Adler is the actual time it took to write the Fortran code. This, too, can be considerable, as Fosinato's program took several man years to write and de-bug. In order to change it, as the parameters change or as the mine increases, further large amount of time is needed. An alternate to such Fortran based programs is provided by using a special computer language known as General Purpose Simulation System (GPSS). This language is designed to solve a wide variety of discrete event simulation problems and appears to be particularly suited for mining situations as shown by Sturgul and Yi (1 987). Although GPSS was introduced as far back as 1961, it has not been used in mining to any great extent. However, the original form was quite crude and inefficient compared to modem versions. Perhaps with the increasing popularity and availability of these recent versions, this will change. Two such versions are GPSS/H for the mainframe and GPSS/PC for the personal computer. GPSS/H allows for interactive usage, such as allowing input data to be entered via a menu. GPSS/PC has excellent graphical capabilities and one can actually view the simulation in progress. In addition, one can halt the simulation and change values of various parameters. If a particular portion of the simulation is in progress via a concept known as "microwindows." These new versions have greatly increased the potential for using the language for mining situations. Mining applications of GPSS have been given by Sturgul and Yi (1987), Sturgul and Harrison (1987), Sturgul (1987), and Sturgul and Singhal (1988). Schriber (1987) presents a summary of the recent advances in GPSS.

Jan 1, 1987

By Daniel T. Hegyan

The employment of continuous rotary vacuum disc filters to filter refuse from the fine coal washing circuits has been increasing as it has become more important to close the water circuits and eliminate sludge holding ponds. This paper will discuss our past experience filtering refuse, effects of solids concentration in the filter feed, use of polymer flocculation aids, effect of flocculation devices, and effects of particle size and ash content on the filtration rate. Detailed tests were performed on existing installations utilizing coal refuse filters to determine optimum flocculant dosage, solids concentration, and disc rotation speed to form a dischargeable cake. Information was also obtained showing effect of flocculant addition on the moisture of the filter cake. Our test work has shown that the continuous filtration dry cake rates for fine coal refuse correlates very well with the data developed and presented by Silverblatt and Dahlstrom1 except that the curves have moved up the scale by use of polymer flocculant additions. These polymers were not available at that writing. Finally, our tests also confirmed the general premise stated by S. K. Mishra2 that controlled additions of polymer flocculants will reduce filter refuse cake moistures somewhat.

Jan 1, 1974

By Kanaya Koichiro

Doyashiki Concentrator in Hanaoka mine of Dowa Mining Co., Ltd. started the operation in 1943, treating the ore mainly from Doyashiki ore deposits. After the cessation of mining of Doyashiki ore body in 1973, Doyashiki concentrator began to treat the ore from Fukazawa mine instead in the same year, and furthermore the ore from Ezuri mine In 1979. Currently Doyashiki concentrator treats 30,000 tons of ore per month from both mines. The ore treated is complex sulfide ore, called "Kuroko" (black ore), and the principal minerals contained in the ore are chalcopyrite, galena, sphalerite, pyrite, and barite, accompanied by bornite, tetrahedrite, tennantite, covellite, stromeyerite, argentite, polybasite, pearcite, and electrum. The Principal gangue minerals are quartz, gypsum and clay. The grade of the feed to the concentrator averages 0.9 p/t Au, 110 g/t Ag, 1.1 %Cu, 2.8 %Pb, 9.2 %Zn, 5.0 % Pyrite-S and 13% BaS04. The feed is, after washing and two-stage crushing, ground to 88% minus 200 mesh in a rod mill and ball mills with cyclone classifiers, and five concentrates are recovered by flotation. Primarily copper-lead bulk concentrate is recovered by sulfurous acid-lime flotation method, and then from the bulk concentrate copper concentrate is floated by hot pulp flotation method, sinks being lead concentrate. Zinc concentrate is recovered from the tailing of copper-lead bulk flotation, pyrite concentrate from zinc flotation tailing and barite concentrate from pyrite flotation tailing. The final tailing is sent to the dam.

Jan 1, 1982

By E. A. Metz

It has been approximately four years since the International Agency for Research on Cancer (IARC) reclassified crystalline silica as a "group one" substance. Since then, crystalline silica has been considered a human carcinogen. Silicosis is a preventable disease, and several aggressive campaigns have been developed to increase awareness of silica-dust-related problems in the industrial environment. New analytical techniques are now being developed to determine quantitatively the amount of crystalline silica in materials. Yet, still much is to be learned about the surface properties of silica and the way in which the disease progresses into full-blown silicosis. This paper discusses the interaction of free radicals generated by the mineral particles and lung tissue. It is the cell injury and DNA damage that progresses to fibrogenesis. Freshly fractured surfaces of silica contain free radicals. These free radicals play an important role in the stimulation of the alveolar macrophage and the development of the inflammatory reactions leading to the fibrotic response caused by silica. Engineers, scientists and physicians need to discuss the mineralogy of silica and the technical issues concerning the development of silicosis.

Jan 1, 2000