Search Documents

Zinc sulphide concentrate from Mount lsa, Australia, was leached in acidic sulphate-chloride solutions using ferric ions as oxidants under atmospheric pressure. The parameters of temperature, particle size and concentrations of ferric and chloride ions were evaluated.The shrinking core model can be used to describe the leaching which is limited by the electrochemical processes in the initial leaching stage, and by both surface reaction and pore diffusion processes subsequently. The apparent activation energy measured in the initial leaching stage is 49 kJ/mole over the temperature range 60 to 90°C.About 99 per cent of the contained zinc in the -45+38 µm particle sample dissolved at 90°C in a 0.5 M H2SO4/0.1 M Fe2(SO4)3/0.8 M NaCI solution within two hours. Some nine per cent of sulphide sulphur was oxidised through to sulphate; the remainder was convened to elemental sulphur.The mixed sulphate-chloride system has advantages over separate chloride and sulphate systems due to the low reagent cost, high leaching rate and possible selective leaching of zinc sulphide concentrate with high lead contents.

Jan 1, 1994

By R. Day

Nahcolite is a naturally occurring sodium bicarbonate mineral found principally in the Piceance Creek Basin of northwest Colorado. An 8-m thick nahcolite bed, 610 m below the surface, is the target of this first commercial nahcolite mine. A chamber and pillar mining system is developed by solution mining parallel 8-m tall by 18-m wide by 450-m cavities initiated along horizontally drilled holes. Hot water leaching, cooling crystallization and flash drying is the process. The sodium bicarbonate product is consumed by the baking, animal feed, industrial and acid rain abatement markets. A project overview, emphasizing the combination of horizontal drilling and solution mining technologies, will be presented.

Jan 1, 1994

By F. Sill

The disposal of residual material from processing and combustion of coal, from incineration of domestic refuse and sewage sludges kind to the environment is a prior task for the future. Deutsche Montan Technologie (DMT) has developed a new technique which makes possible to fill-up goaf cavities behind running caving systems in coalmining. In a mixing and pumping station on the surface high concentrated suspensions are produced from the above mentioned materials. The paste is pumped through pipes to the coalfaces and via trailing discharge pipes stretched to the fracture zone in the caved-in goaf. Since three years a special designed plant is working successfully on a coal mine of Ruhrkohie AG.

Jan 1, 1994

By K Ramachandra Rao

This paper explains the methodology for assessing the efficiency of rockmass fragmentation by explosive blasting, from ground vibration frequency spectrum analysis of the blast event. Explosives are used in the mining, quarrying and construction industries for fragmenting rockmass to a suitable size. When an explosive charge is detonated, in addition to fragmenting the rockmass, it will also generate ground vibration and air vibrations. Efficiency of a blast depend upon percentage of blast energy wasted in generating ground vibrations and air vibrations.

Jan 1, 1994

By Haydn H. Murray, Sam M. Pickering

The term kaolin is used here, in a commercial sense, for near- white clay deposits which are dominantly comprised of the mineral kaolinite, or for products refined from such deposits. The term "china clay" has been used in the past as a synonym for kaolin, a reference to its first being mined some 3000 years ago at a hill near Jauchau Fu, Jiangxi Province, China as a porcelain raw material. The name kaolin was derived from the Chinese Kauling, which means high ridge. For most modem industrial applications kaolin must be extensively refined and processed from the crude state to enhance whiteness, purity, and other important commercial characteristics. After such processing, kaolin ranks as one of the most valuable of industrial clays, and it is used to some extent in most manufactured consumer products. In 1991, the United States alone produced kaolin valued at $1,072,366,000. It is applied very widely as a pigment, filler, coater, extender, ceramic raw material, catalyst base, electrical insulator, and pharmaceutical. Some more prominent uses include paper filling and coating; paint, plastic, adhesive, and ink pigment; rubber reinforcing agent; ceramic raw material for porcelain, dinnerware, tile, and enamels; catalyst base for petroleum cracking and auto exhaust emission catalytic control devices; cosmetics base; and digestive coating remedy. Those properties of kaolin clay which make it suited to these applications are related to its physical, optical, mineralogical, and chemical nature.

Jan 1, 1994

By Subhash B. Bhagwat

No economic activity would take place without human ingenuity, driven by our needs and wants. Economic activity is made possible by the energy from fossil and other energy sources, our technological hardware, the buildings and infrastructure made from materials such as metals, plastics, wood, water, and numerous industrial minerals. Industrial minerals are difficult to define; however, they generally include utilitarian minerals other than metals and fuels. Some of the industrial minerals form an exception to this categorization and, as explained elsewhere in this book, belong to more than one category because of the manner in which they are used. Industrial minerals are so numerous, and their applications so ubiquitous that they often do not receive the attention given to metals or fuels. Nevertheless, without industrial minerals, many of our most fundamental economic activities such as construction of our cities and towns, control of floods, transportation of our people, the search for minerals, the smelting of metals, and the delivery of supplies of clean water would be impossible. How then do we assess the economic importance of such a variety of materials lumped together under the general designation of industrial minerals? The price per ton or the total amount consumed do not satisfactorily explain the relative value of these materials to the economy. For example, the current price of limestone is about $5/t and the price of fluorspar is about $190/t. However, nearly 1.1 Gt of limestone, valued at about $5.5 billion, are consumed in the United States annually, compared with 590 kt of fluorspar, valued at about $1 12 million. It would not, however, be accurate to conclude that the mineral with the higher total value is always more economically important. Many other questions must be answered before making judgments of this type. These questions include how many people are employed in the production, processing, and distribution of the mineral? How is the mineral used? Is it partly or entirely imported? Where do the imports come from? How is the mineral transported? Is the mineral considered critical to national security? Is there a substitute material available in case the mineral supply is interrupted? Where would the substitute be produced? What would be the basic material from which the substitute will be produced? Even when these questions have been answered satisfactorily, the economic importance of the mineral is not completely known until the consuming sectors are studied as well. For example, even though the manufacture of fighter aircraft is vital to the national security, it employs only a fraction of the number of people employed in the housing and construction industry or the automobile industry or the appliance industry. Mineral commodities consumed in these latter sectors of the economy are more significant than those consumed in the production of fighter aircraft, because nearly two-thirds of the Gross Domestic Product (GDP) depends on the purchasing power of individual consumers. In comparison, the entire defense budget accounts for only 6% of the GDP. There is no easy way to present the importance of industrial minerals to the US economy because most minerals have diverse applications and products made from industrial minerals often con- tribute to the production of other goods and services. One way of highlighting the value of a mineral would be to relate it to the GDP reported by categories such as construction, machinery, stone, clay and glass products, electrical and electronic equipment, paper and allied products, and chemicals and allied products. These GDP categories represent industries fundamental to the economy totaling $644 billion, or about 12% of the GDP in 1990. However, these categories are not convenient for discussion of the many minerals that are used in our complex economy. In a general way, minerals are the 5% of our economy that make the other 95% possible. This chapter, therefore, discusses a selected few industrial minerals to illustrate their importance to various sectors of the economy.

Jan 1, 1994

By Glenn Kosick, John Starkey, Glenn Dobby

"A practical new test has been developed for SAG hardness determination. Using two kilogram samples of minus one inch diamond drill core or crushed muck samples, the Starkey SAG Test has been shown to give accurate predictive information which directly relates to on-stream SAG mill performance. Typical results and test criteria are discussed in the paperAchievements to date include:• Identification of hardness profiles and the location of hard and soft zones in a large ore body.• Accurate prediction of the hardness of a bulk sample by using an adjacent diamond drill hole.• Derivation of a plotted curve relating pilot plant power to laboratory relative hardness.• Demonstration that for every test done to date, the Starkey SAG Test produced a product size distribution identical to that produced in a pilot plant or full scale plant SAG operation.This test can now be used for blast hardness monitoring and short term control of mine production in existing plants and for identifying the proper locations for bulk samples in new projects. In addition, new SAG mill design can now be rationalized in a low cost way to eliminate unforeseen production shortfalls.IntroductionThis paper is presented to introduce the Starkey SAG Test, a practical new laboratory tool for measuring the relative hardness of small ore samples in a semi-autogenous grinding (SAG) environment. The test was first designed for use on diamond drill core samples during the prefeasibility stage of new mining projects, to provide new information about the ore body at reasonable cost. It is a new tool and does not replace existing pilot plant test requirements.The test will also be useful for throughput prediction in existing SAG plants by assisting in short and long term mine planning, where forecasting of metal grades and milled tonnage is used to control mine profitability. Because in-plant hardness testing has previously been unavailable on small samples, this test offers exciting possibilities for SAG mill operations where hardness variation is or could be a problem.The Starkey SAG Test provides the following benefits to the mining industry"

Jan 1, 1994

By P. L. Sibrell

Previous research by the U.S. Bureau of Mines showed that autoclave cyanide leaching of used automobile exhaust catalysts for recovery of platinum group metals (PGM) was technically feasible. This work involves a more detailed investigation of the chemistry of the dissolution of PGM in cyanide solutions. The PGM species in solution identified by ultraviolet spectroscopy. Pt and Pd cyanide complexes were square were The planar in geometry, while the Rh complex was octahedral. The rate of dissolution of the PGM was also investigated using a rotating disk technique. Dissolution rates increased in the order of Rh, pt, and Pd, respectively.

Jan 1, 1994

How many of you have felt tired and light-headed after standing or working in the sun or by the oppressive, hot, muggy conditions of an Australian summer? For those of you who have, you've experienced the minor effects of heat stress. Heat

Jan 1, 1994

By Nekitel S, Arumba J, Kopi G, Findlay RH

The Kainantu area lies within the composite Scrapland terrane which is composed of Mesozoic metamorphic and intrusive units, overlain by Cenozoic marine sediments, volcanic and intrus-ive units and Quaternary fluvial sedi-ments.Four deformations (Dl, D2, D3, D4) are recognised within the Mesozoic sequences, which consist of greenschist to amphibolite facies schist derived from felsic to intermediate pyroclastic rocks and pelitic sediments. The second, third and fourth fold events are present in the Cenozoic sequence, and these rocks are broken by thrusts related to northwest trending D3 folds. South-dipping, possibly lystric, normal faults are recognised and may be related to uplift and exposure of the metamorphic rocks as core complexes.Known mineralisation in the area consists of gold and copper skarn deposits, porphyry copper deposits, shear-hosted gold deposits, epithermal vein deposits and gold placer deposits. Over 35 hard rock and 18 gold placer deposits are known within the area. Of significance are the Kathnell shear-hosted auriferous quartz veins; such structurally controlled veins may be more widespread than proposed prev-iously and offer a new exploration target.

Jan 1, 1994

By Ashwani Jain, D K. Soni

Compressive strength of rocks is often required by mining engineers and quarrying authorities for blasting operations. Uniaxial compressive strength of rocks can be predicted with reasonable accuracy with the help of point load strength tests which can be easily conducted at site by the field staff, simultaneously as the cores are recovered from drilling operations. A number of diametral point load tests and uniaxial compressive strength tests have been conducted on the specimens of different rock types under air dried, and saturated condition as well to study the effect of ground water saturation on strength. It has been observed that due to saturation uniaxial compressive strength and point load strength get reduced to a maximum of 32 and 29 per cent respectively. It has also been observed that uniaxial strength is sixteen times the point load strength in air dried as well as saturated condition. However, this factor used for calculating uniaxial compressive strength may be reduced to a lower value for the safety of miners in field blasting operations.

Jan 1, 1994

By I. H. Douglas

All grade control methods in use currently by the mining industry are imprecise. The methods suffer from being locally inaccurate, leading to are loss and contact dilution. An ore/waste indicator variable can be used to predict the probability of ore occurrence at a given location, Po. Then, an ore grade Zo for an ore location and a waste grade Zw for a waste location are obtained. The expected revenue is calculated at each location, based on its probability of being are or waste, the corresponding grade, and on the cost of mining and processing the ore or the waste. Finally, the decision of whether to recover the block is based on the expected revenue value for that block. The method is illustrated with an example taken from the Jerritt Canyon district in northeastern Nevada.

Jan 1, 1994

By J. P. Kennedy

Process data managers or historians are recognized as essential for reengineering projects in industrial plants. With increasing automatic data collection, the knowledge of how to use these data profitably grows as well. This paper is a summary of the data historian and its components plus examples of benefits including environmental reporting, performance monitoring, and exception reporting to management.

Jan 1, 1994

By M. S. Celik, G. Onal, S. Atak

The beneficiation of boron minerals flotation with well defined systems has been only slightly, investigated in the literature. The difficulty arises from fact that boron minerals cover a spectrum of solubilities. Colemanite (a calcium-containing, relatively insoluble, boron mineral) and borax (a highly soluble boron mine, have been used to exemplify the flotation of boron minerals. Using sodium dodecylsulfonate (SDS) and dodecylamine hydrochloride (DAH), the floatability responses of these boron minerals are considerably different. This has been ascribed to variations in the solubilities of boron minerals and the presence of cations in the lattice structure. In study, flotation tests and zeta potential measurements used to determine the flotation mechanisms of boron minerals.

Jan 1, 1994

By S. Middlemiss

The Indentation Fracture technique is being developed as a tool for use in comminution and mineral liberation analysis. Fracture toughness measurements for a number of mineralogical materials were made and comparisons were drawn between these and properties measured with the Ultrafast Load Cell drop weight apparatus. The technique has also been used as a probe to quantify differences in fracture properties at different areas in the microstructure of a material. In both a Utah limestone and a South African quartzite, material near a grain boundary fractures very differently to that in the bulk. Ongoing work is ultimately aimed at producing a comprehensive fracture model for a multi-mineral system based on its micro-fracture characteristics.

Jan 1, 1994

By J. D. Lane

The U.S. Bureau of Mines is conducting research on guidance systems for computerized haulage in underground mines. This report describes the process of component selection, installation and testing, perception algorithm development, and steering control algorithm development, to produce a real-time steering control system for an articulated haul truck for underground mining. Ultrasonic transducers were mounted on the truck to provide perception data by measuring the distance to the ribs. Linear potentiometers mounted inside the steering cylinders measured the steering angles. Algorithms, implemented on an inexpensive, robust onboard computer system, analyzed the data and controlled the steering via an electro-hydraulic proportional valve. The steering algorithm presented follows a zone defined by the relative position between the truck and a rib. Experimental verification of the ability to follow the zone in a test corridor on the Colorado School of Mines campus is presented. The automatic steering system successfully negotiated straight sections, curves, and the transition zones between straight and curves with the truck in first and second gears. The resulting real-time automatic-steering system can be applied to many underground articulated machines.

Jan 1, 1994

I trust you know now or will know by the time you havecompleted your degree and added a little on-the-job experience,how to make the product from the mine you are working for. Butyou may not know the process to turn it into dollars, which ofcourse will be the life blood of your company. I am not going topromise to turn you into super salesmen, but I hope I can takeyou beyond the level of believing that selling our mineralproducts is as simple as putting in it on to a train, waving itgoodbye and waiting for the cheque to turn up in the mailbox afew weeks later.

Jan 1, 1994

By Robert H. Peters

This U.S. Bureau of Mines report identifies the types of serious accidents that occur most frequently at small underground coal mines and describes the strategies that could help prevent these accidents. A wide variety of methods for improving safety are suggested, including improvements in the design of equipment, work procedures, work schedules, safety programs, and emergency response plans, as well as techniques for diagnosing the potential hazards associated with new technologies and work procedures. Some of the papers in this volume focus on preventing specific types of mining accidents--ones associated with materials handling (primarily back injuries), equipment maintenance, improper machine guarding, and ground failure during retreat mining. Although the recommendations in this volume are heavily influenced by research performed at underground coal mines in the Appalachian coalfields, most of the papers contain advice that is equally pertinent to almost any type of mine.

Jan 1, 1994

By F. H. (Sam) Froes, C. Suryanarayana, K. C. Russell, C. M. Ward-Close

"Far from equilibrium synthesis allows development of novel crystal structures and microstructures, leading to achievement of enhanced physical and mechanical properties. A number of ""far from equilibrium"" techniques are reviewed with emphasis on the amount of departure from equilibrium. The ability of two such techniques, mechanical alloying (MAl, and physical vapor deposition (PVD) to develop novel structures are discussed in detail. For the MA process emphasis is placed on intermetallic compound compositions. Solubility extension, beyond rapid solidification (RS) levels, is found in terminal compositions but not for the intermetallics. Nanostructure-sized grains (< 100nm) form which can be retained after ""low temperature"" compaction. On continued milling in many cases the nanometer-sized grains transform to an amorphous structure. Ordering is destroyed by MA, except in those intermetallics with large negative enthalpies of formation. For the PVD process, a review of application to terminal light alloy compositions is presented. This includes a new high-temperature aluminum alloy, layered materials with nanometer spacing, corrosion-resistant magnesium alloys and low-density titanium compositions. IntroductionTo enhance the mechanical property combinations of advanced structural materials innovations in process/synthesis are required [1-6]. In this paper the capability of various ""far from equilibrium"" synthesis techniques [7,8] to produce novel constitutional and microstructural effects, and hence potentially enhanced physical and mechanical properties, in advanced materials is presented. The application of two such methods, mechanical alloying (MA) and physical vapor deposition (PVD) is discussed in detail. For the MA process emphasis is on intermetallic compositions with consideration given to solid solubility extension, microstructural refinement, amorphization, and formation of intermetallic compounds. For the PVD process application to terminal light alloy compositions is discussed."

Jan 1, 1994

By Browne TJ

On 13 October 1993, a shallow earthquake registering 7.1 on the Richter Scale occurred near Tauta in the Finisterre Range of Papua New Guinea (PNG) killing 37 people. The aftershock series lasted three months and resulted in considerable landslide damage that destroyed villages, food gardens and airstrips, and blocked rivers causing catastrophic flooding. These effects have irrevocably altered the form of many of the valleys and rivers draining into the Markham and Ramu valleys.The earthquake occurred in a pilot study area for a landslide hazard mapping project being carried out by the PNG Geological Survey that commen-ced in April 1993. Comparisons made between areas identified as unstable during the study with those damaged by the earthquakes show good correlation.It is concluded that aerial photograph and Landsat TM imagery interpretation can be used with a high degree of confidence to identify potential landslide hazards in mount-ainous terrain. Landslide hazard maps are promoted as a tool for use in the route planning of roads and powerline corridors, as well as for identifying vulnerable communities.

Jan 1, 1994