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By J. Danoczi

Specially designed X-ray machines are used extensively on diamond mines for the recovery of diamonds from ores. These machines are extremely expensive and, at present, there are no reliable methods of determining if the equipment is performing efficiently. The objective of this work was to manufacture translucent X-ray diamond simulants, which would emit varying but known luminescence signals when exposed to X-rays. These X-ray diamond simulants could then be used to determine the efficiency of diamond recovery operations.

Jan 1, 2008

By O. A. Olaseinde

The 2101 lean duplex stainless steel has wide potential application in storage, heat exchangers, and in the oil and gas industries. This work investigates the electrochemical behaviour of 2101 duplex stainless steel with an addition of 0.15 wt% ruthenium, using potentiodynamic techniques in 1M H2SO4 at 25º, 40º, 60º, and 80ºC. The microstructures of samples were characterized using optical metallography and scanning electron microscopy. The results showed that the ruthenium addition moved the corrosion potential of alloy 2101 to a more positive potential. All samples containing ruthenium displayed longer passive regions at 25°C and 80°C compared to those without ruthenium. Alloys without ruthenium had higher critical current density (icrit) values when compared to the alloys with ruthenium. Ruthenium additions decreased the passive current densities and inhibited anodic dissolution. At room temperature the corrosion rate of alloys with ruthenium was lower than these without ruthenium.

Jan 1, 2012

Following a short review of selected literature, a back analysis of stress measurements of stress regeneration in a closed mini-longwall is shown. The agreement is good, lending confidence to the parameters used in the proposed numerical model. Foundation yielding was modelled in the absence of total stope closure. A ?Prandtl? wedge was formed, coinciding with the yield point of the pillar/foundation system. Some theoretical work is used as a starting point for the formulation of a new design methodology for strike or dip stabilizing pillar/foundation systems in deep level goldmines. The existing guideline for the stability of foundations (APS< 2.5UCS) is critically examined. Finally, the advantages of the new approach, and the work required to substantiate the proposed new design methodology, are outlined.

Jan 1, 1998

By K. Morsi

Carbon nanotube (CNT) reinforced metallic composites have been recently generating significant scientific interest, due to their expected superior properties compared with other composites. Out of the metallic matrices investigated for reinforcement with CNTs, aluminum has received considerable attention. A major problem has been the dispersion of CNTs in metallic matrices. This paper discusses preliminary results on the mechanical dispersion of CNTs in aluminum powder, powder processing, stability and characterization of aluminum dispersed with CNTs at reinforcement levels equal to and below 5 wt.%.

Jan 1, 2009

By G. M. Ritcey, K. E. Haque, S. H. Lucas

"Laboratory-scale hydrochloric acid leach tests were conducted on an Elliot Lake uranium ore. Hydrochloric acid leaches without an oxidant or with molecular oxygen (i.e., air or pure oxygen gas) as an oxidant favoured uranium and radium extractions. Conditions for maximum uranium, thorium and radium extractions with hydrochloric acid in the presence of sodium chlorate were determined. The highest extractions of uranium (96%), thorium (81%) and radium (91%) were obtained using a mixture of 44.0 kg HCI and 2.5 kg NaCIOJ per tonne of ore at 75°C with 18 hours &apos; retention.Flowsheets for two-stage leaching are proposed. The residues obtained from the second-stage leach contain uranium (0.002%), thorium (0.006%) and radium (15 to 20 pCi/g). Tailings of this nature are considered suitable for mine backfill, and, if pyrite is removed, suitable for surface disposal.IntroductionThe nuclear energy industry forecasts an increasing demand for uranium. This increasing demand requires not only largescale mining and processing of conventional and complex uranium ores, but also leads to the consideration of new and nonconventional sources of uranium, e.g., black shales, phosphate rocks, granite, sea water and fossil-fuel ash."

Jan 1, 1980

The 20th annual American Mining Hall of Fame Awards Banquet sponsored by the Mining Foundation of the Southwest will be held at the Westin La Paloma in Tucson, AZ, on Saturday, Dec. 7, 2002. This year’s inductee, guest of honor and featured speaker is J. David Lowell, one of the preeminent exploration geologists of the past 30 years. Among his most recent discoveries is the world-class Pierina gold deposit in Peru, currently owned and operated by Barrick Gold. As representatives of mining heritage, the Hall of Fame will induct Howard Allen Twitty, Sr., and Bernhardt Rohe. Twitty was a respected public lands attorney. He made significant contributions to the mining industry by representing several major companies in many court cases. He was also the author of numerous papers on mining law. Rohe was managing director of Peñoles. In that position, he helped guide the Mexican mining company for its growth into the international mining company that it is today.

Jan 1, 2002

By Ronald L. Bruening

IBC has developed a cost effective MRT process for the selective extraction and recovery of gold, copper, and a mixture of other base metals from mine leach cyanide solutions. This is a two-stage system in which the gold is first recovered selectively as a high purity salt. The copper is then recovered separately as a sulfate salt. The other base metals are then collected as a cyano anion concentrate. Three different SuperLig® materials are used. The first stage can be used alone on gold leach solutions where copper and other base metals are not a problem. The two or three stage system is used when the base metals build up in the leach solution, resulting in increased costs. The cyanide or cyanide/cyano anion concentrate can be recycled back to the leach solution until the build-up of other salts, etc. becomes too high, or this too can be controlled with a percentage bleed stream.

Oct 1, 2003

By S. G. McDowell

This paper discusses the utilization of automation to increase productivity of continuous miners. Automation techniques are used during the design stage to decrease the time required and ensure the accuracy of the design. This is followed by automated manufacturing processes to reduce manufacturing time and improve the quality and consistency of parts. Combined, the result is a more reliable machine which can provide ongoing production capability. With the use of automation to enhance operator effectiveness and monitoring machine condition the productivity of machines is also improved.

Jan 1, 1991

The Mount Angelo prospect outcrops as two copper rich gossans, the larger of which is 250 ft long and 70 ftwide. The mineralization is epigenetic and replaces part of a brecciated and disturbed lime tone and calcareou sediment sequence.Magnetic and self potential survey indicated a substantial body of sulphide mineralization, the top of which was approximately 100 ft below the surface.Diamond drilling confirmed this and established the presence of a mineral body of at least 500,000 tons, extending to a depth of 300 ft. Of the 500,000 tons, 200,000 ton are primary copper ore which a ays 2 per cent copper.This mineral body is not economic at present, but could become economic if copper mining is established elsewhere in the district...

Jan 1, 1966

By C. G. Maier

Relatively infrequent use by metallurgists of the term "sponge chromium" as contrasted to more than occasional reference to "sponge iron" may be ascribed to the fact that the former material is not a commercial product, while the latter has been known and used, at least in one form (Swedish sponge iron), for several decades. It is doubtful whether a true sponge chromium ever has been prepared heretofore in the laboratory by more than one or two investigators. Nature presents a much. more difficult problem to the investigator endeavoring to make sponge chromium than pertains to the production of more easily reducible elements such as iron or nickel. Recent widespread interest among metallurgists in the possibilities of powder metallurgy is ample incentive to explore the feasibility of producing pure chromium metal in finely divided form. The shift in terminology of this statement from "sponge" to the "finely divided form" is deliberate in emphasis of distinction between terms that occasionally have been used loosely. It would seem desirable that a uniform usage descriptive of finely divided metals be adopted. While to some it might seem preferable that the terra "powdered" metal be reserved for a finely divided form produced by mechanical means, as, for example, chromium produced by the mechanical comminution of electrolytic sheets or flakes, current usage of the term "powder metallurgy&apos; involves no distinction as to source type of material. It is usually accepted, however, that a sponge metal is one reduced from oxide or other combined form at temperatures below the melting point of metal or oxide so that the particles of metal are pseudomorphic, at least macroscopically, with the source material, and, in consequence of the loss of material without change of external shape of the particles necessarily have an open, porous, or "spongy" structure.

Jan 1, 1942

Let’s start off with your assessment of the mining industry. Today, the status of the mining industry is stronger than it has been over the previous few years. While mining continues to be a major part of the world’s economic foundation, the industry is gaining strength due to rebounding metals and minerals prices. And now, with these rising prices and the changes the industry instituted during the years when mining-related commodities were selling at low prices, our stronger, more productive and internationally competitive industry should flourish. Mining remains an essential business and the industry is far ahead of the game when it comes to the trend of globalization as a key to sustained growth. Also, the industry continues to realize increased productivity through technological innovations. And an increasing number of countries are moving towards capitalism, which opens doors for exploration and mining within their borders. After looking at all of these factors, I believe that the mining industry will only continue to gain momentum in the future.

Jan 1, 2004

By Christopher J. Bise

INTRODUCTION A mine&apos;s power system represents the driving force behind all of the extraction and auxiliary operations, because the production and transportation of mined material and the operation of equipment, such as fans and pumps, are all dependent upon a power source. Once, compressed air was the primary power source in mining; today, however, electrical power dominates. This chapter reviews the basic theories of com- pressed-air and electrical power and provides several examples of applications in mine power systems. COMPRESSED-AIR POWER General Compressed air has been, and should continue to be, an important source of power in mining operations. It has been used as a means of blasting coal in conventional mining and is widely used to operate stopers, mucking machines, and other air tools in both coal and hard-rock mines. Such applications demonstrate the suitability of compressed air for applications requiring linear motion, but it is also utilized for its reliability and safety. A compressed-air system is composed of a compressor, a receiver, a distribution network, and the air-operated machines. A compressor takes in air at normal atmospheric pressure (free air) and compresses it to a higher discharge pressure. The discharge pressure must be high enough to overcome the friction in the distribution system of pipes and hoses and deliver the compressed air to the machines at the pressure recommended by the manufacturer. The most common type of compressor used in mines is the reciprocating compressor in which the air is compressed by a piston in a cylinder. An air receiver is a container or storage tank that is located in the distribution system between the compressor and the machines. It stores compressed air, when the full capacity of the compressor is not being used, and gives a more steady flow of air to the machines. The distribution network consists of pipes, Oalves, elbows, tees, and hoses that transmit the compressed air from the receiver to the machines in the mine. It is essential that the distribution system be designed with the proper sizes and lengths of pipe, hose, and other components to keep pressure losses well within allowable limits. The air-operated machines consist primarily of drifters, stopers, pluggers (sinkers), slushers, and several other pieces of equipment. Compressor Operation Every compressor is made up of one or more basic elements; a single element, or a group of elements in parallel, comprises a single-stage compressor. Many compression problems involve conditions beyond the practical capability of a single compression stage. Too great a compression ratio (absolute discharge pressure divided by absolute intake pressure) may cause excessive discharge temperatures or other design problems. It, therefore, may become necessary to combine elements or groups of elements in series to form a multi- stage unit, in which there will be two or more steps of compression. The number of stages commonly used in reciprocating compressors is as follows: Pressure Number of stages 0- 150 pig 1 80- 500 psig 2 500-2500 psig 3 2500-5000 psig 4 When pressure is referred to as pounds per square inch gage (psig), it means the pressure (in pounds per square inch) above barometric pressure as measured by a gage. The sum of barometric pressure and gage pressure is the absolute pressure (in pounds per square inch). The gas is frequently cooled between stages to reduce the temperature and volume entering the subsequent stages, thereby reducing the work required for compression. The basic reciprocating compression element is a single cylinder compressing on only one side of the piston (single-acting). A unit compressing on both sides of the piston (double-acting) consists of two basic single-acting elements operating in parallel in one casing. The reciprocating compressor uses automatic spring-loaded valves that open only when the proper differential pressure exists across the valves. Intake valves open when the pressure in the cylinder is slightly below the intake pressure. Discharge valves open when the pressure in the cylinder is slightly above the discharge pressure. In Fig. 1, Diagram A shows the basic element with the cylinder filled with air at atmospheric pressure. On the corresponding theoretical pressure-volume

Jan 1, 1986

The re-use of waste water from coal preparation plant tailings is always desirable, but is generally problematic in terms of solid-liquid separation. Dewatering and disposal of coal slurry at a high percentage of moisture poses a major technological and environmental challenge to mining and mineral processing industries world-wide. Characterization and flocculation of these coal tailings reveals that the separation of fine coal tailings depends on factors such as size distribution, slurry viscosity, zeta potential, pulp density, circuit design, plant operating parameters, and the behaviour of solid particles in an aqueous medium. The present study was carried out on -600 mm coal tailings collected from a coking coal preparation plant of Jharia Coalfield, India, using anionic flocculent. Characterization studies revealed that the zeta potential was highest (-44 mV) at a pH of 9.0, the size range of the particles was 1.1?700 m, and the average ash content was 62.57%. Flocculation studies were performed at different solid concentrations, pH values, and polymer dosages. The results indicated an efficient settling rate of 178.15 mm/min at 8% solid (w/w) at a flocculent dosage of 32.50 g/t solid. The turbidity of the clear liquid obtained was 7.42 NTU.

Jan 1, 2014

By Robert Jakiel

The following paper is being presented to provide a basic understanding of the equipment and procedures used in multi-auger deep soil mixing as part of the program for the Deep Foundations Institute (DFI) Deep Soil Mix Seminar. The paper is written as a summary of the author&apos;s experience using multi-auger deep soil mixing equipment while working with SMW Seiko, Inc. on several east coast projects in the United States, particularly the soil-cement mixing for the soil stabilization of the Fort Point Channel area in Boston, Massachusetts, one of the largest and most difficult soil mixing projects completed thus far in the United States. The summary provides a brief summary and insight into some of the operational aspects of the equipment and procedures, and some of the important considerations when using multi-auger deep soil mixing. This paper is intended for use by both the contractor and the designer involved in selecting appropriate soil mixing equipment and procedures for various types of soils, depths or applications, or for a better understanding of the operational aspects, potential benefits, and impacts that the performance criteria may have on the operational capabilities of the soil mix equipment, when specifying multi-auger soil mixing for a particular project. Prior to reading this article it is important to become more familiar with the various acronyms and terminology used in soil mixing technology. A Definitions section has been provided at the end of the paper that will help the reader become more familiar with some of the terms used throughout this paper.

Jan 1, 2001

By P. W. Lotz

Traditionally, bottle roll tests have been used to optimize the extraction process for best gold extraction and recovery. Such tests typically involve exposing the ore to defined reagent concentrations (lime, cyanide and sufficient oxygen) and balance the gold input with recoveries and losses. With mounting pressures to accommodate sustainability issues during development work, it became apparent that much more information would be required on the interactions and kinetic behaviour of solid and solution species during the entire leach process. This information is vital to enable proactive management of critical issues such as cyanide, arsenic, water and tailings management. Inadequate management of these aspects has led to temporary closures and, in cases of non-compliance, to the dynamically changing regulations. MINTEK?s advanced leach facility (ALF) is being developed with the aim of bridging the knowledge gap between the gold leach process and the predictable environmental impacts upon discharge. The facility aims to monitor all parameters of relevance such as pH, Eh, dissolved oxygen, metals, cyanide species, and viscosity during the entire process to enable more informed decisions on practical interventions. The presented set of data reflects first experiences gained from processing a refractory gold ore concentrate. Attempts at optimizing the process were limited due to the developmental nature of the work. Data relating to leaches with differing preoxidation conditions and cyanide staging is presented.

Jan 1, 2009

By W B. Edgar, I M. Platten, C A. J Towsey, B W. Cuffley

The evaluation of historical goldfields has been common over the past 15 years, reflecting changing economic conditions, improvements in knowledge and technology and lack of greenfield sites. Many goldfields comprise narrow gold-quartz veins, which are structurally complex with an irregular distribution of gold, have variable geometry and architecture and display late deformational effects. The study of historical mine records can be an important tool during early and advanced project evaluation, since it contributes to understanding the orebody, exploration target size and setting expectations. Mine records include documents such as plans, sections, reports, news cuttings, production tabulations, etc. A major advantage for the modern explorer is the capability of computer modelling to display this data in 3D. Historical records can give the explorer substantial information on various deposit characteristics, not least grade and geological continuity, geometry and architecture, mineralogy, metallurgical properties, bulk density and ground conditions. From an evaluation perspective, historical records can be used to support a Mineral Resource estimate, though its application will depend upon the quality and quantity of the data and judgement of the Competent Person. Effectively used, historical records can reduce geological uncertainty and focus evaluation efforts û thus reducing project risk.

Jan 1, 2009

By Ewan Selers, Gary Cavanough

Drilling automation technology is well advanced and automated drill rigs are in use at a number of operating mines. This is not the case for the other drill and blast processes due to significant technical challenges to overcome. These challenges, with regard to the current “on bench” practices, include placing the initiators, loading the explosive and connecting up the initiation system. Although difficult, these challenges will be solved with engineering advances.

Jan 1, 2016

A Good Product Range - So What! While in terms of water, waste management and environment protectrion, the Gippsland Basin may appear to have a good product range, what does this really mean? What it means is that, like any product range, the virtues of the product range must be sold and accepted by a majority of the public. The social, economic and environmental benefits of any enterprise using these products must be sold and accepted by the regional population. Many a budding entrepreneur has failed because he assumed that the public would accept his product, so good did it appear to be! However, we know that such an assumption must be avoided and that a great deal of time and effort needs to be invested in promoting and gaining acceptance of a product to ensure a long term and viable market.

Jan 1, 1992

There are no large rivers in Western Australia capable of supplying water for processing magnetite ores. If sea water is used there are severe corrosion issues and the requirement to wash the concentrates with potable water. If groundwater is used there is a need to treat the water and sustainability is an issue for large projects because of potential drawdown of the aquifer.If sea water is desalinated the cost of the water is high because of the power requirement. At the same time the necessity to conserve water has lead to flow sheets where all of the tailings have to be filtered to minimise the water requirement.Managing the various water qualities and optimising water recovery and quality has resulted in optimising the water balance and issues meeting environmental obligations. Reverse flotation is a critical final step in reducing the silica level in the final concentrate and requires good quality water.

Jan 1, 2009

Filtration systems with disposable filter elements (DFEs) are used in the underground coal mining industry to control particulate matter emissions from diesel-powered permissible and nonpermissible coal mining equipment. This study was conducted in underground mine conditions to evaluate three types of high-temperature DFEs used in those filtration systems. The DFEs were evaluated for their effects on the concentrations and size distributions of diesel aerosols and concentrations of nitric oxide (NO) and nitrogen dioxide (NO2). Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. After an initial DFE degreening period, the filtration system with all three DFEs was found to be very effective at reducing total mass concentrations of aerosols in the mine air. The effectiveness of DFEs in filtering aerosol mass was found to be a function of the engine operating conditions. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the DFE elements. The effectiveness of DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. Initial heating of certain DFEs resulted in visible white smoke and substantially elevated aerosol number concentrations. The effects of the DFEs on total nitrogen oxides (NOX) concentrations were found to be minor. The NO2 fraction was found to be generally lower for the DFEs than for the muffler. The engine-out NO2 fraction of the total NOX was found to be substantially higher for low-load modes than for high-load modes.

Jan 1, 2011