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By C V. B Cunningham

The assessment of blasting results under production conditions is extremely difficult. As a result, it can take months or years to establish objective and valid estimates of explosive performance in achieving rockbreaking goals. This fundamental problem often results in decisions related to the manufacture, marketing, purchase and use of explosives being largely swayed by calculated energies from detonation codes. However, these codes are by no means standardised. Different energies are given by different codes because these employ varying combinations of fundamental science and empiricism. After a basic review of code operation, important guidelines to dependability are given with reference to ICI’S state-of-the-art codes IDEX and CPEX. Distinctions are drawn between Ideal, Non-Ideal and Blasting Codes. Concepts of explosive energy are discussed in brief.

Jan 1, 1991

By Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Mehmet Aksoy, Kagan Ozdemir, Adiguzel Deniz

This paper presents the results of ground vibration measurements induced by blasting during the construction of the Istanbul Kadiköy-Kartal metro tunnel which has been driven at a depth of approximately 20-40 m deep under a highly urbanized region of Istanbul city in Turkey. This tunnel is being constructed by a joint venture group. The formation encountered during the construction is classified as hard and strong rock by laboratory and field tests performed by the joint venture group. Within the scope of the study, for the prediction of the peak particle velocity and to determine the slope of the attenuation curves together with the maximum charge per delay for the S4 shaft tunnels and S12 shaft tunnels of this tunnel route, ground vibration components were measured carefully by using four vibration monitors (Instantel Minimate Plus model) during the advancement of the tunnels which required blasting. The particle velocities and frequency values of all blast events are evaluated according to the United States Bureau of Mines (USBM) and German DIN 4150 Norms in order to predict, and compare the influence grades to the neighbouring buildings, and structures. Also, data pairs of scaled distance and peak particle velocity obtained from 114 records at S4 shaft tunnels and 79 records at S12 shaft tunnels were analysed statistically. Empirical relationships with correlation at the 95 % confidence interval were established for different rock units (diabase and arkose) and suggested for the test sites in order to estimate particle velocity of the ground vibrations.

Jan 1, 2007

By M. S. Delibalta, S. Kahraman, R. Comakli

The block cutting machine is one of the most important noise sources in the stone processing factories. In this study, the assessability of the noise from the block cutting machines in the stone processing factories using the P-wave velocity was investigated. The noise levels of some block cutting machines were firstly measured during the cutting of the three different rocks. Then, core samples of the same rocks were cut by an automatic cutting machine in the laboratory and noise levels were measured. A conversion factor was obtained by dividing the site noise levels by the laboratory noise levels. Then, thirty seven different rocks were cut by an automatic cutting machine in the laboratory and noise levels were measured. The P-wave velocity of rock samples were also measured in the laboratory. A strong relation between the laboratory noise levels and the P-wave velocity was found. The noise level from the block cutting machines can be assessed using the derived relation and the conversion factor.

Jan 1, 2011

By Y. Y. Emelianov

The results of the test work of four treatment options of three refractory gold-pyrite and gold-arsenic flotation concentrates are presented. These concentrates were obtained during the concentration of primary ores of large gold deposits. It was found that ultrafine grinding of refractory flotation concentrates did not increase the recovery of gold during subsequent cyanidation. The elimination of sulfur and arsenic during oxidative roasting is 99 per cent. 88-93 per cent of gold is recovered by cyanidation from calcines. After biooxidation of the flotation concentrates with a mixture of strains Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans 88-91 per cent of gold is recoverable by direct cyanidation. The recovery of gold from flotation concentrates by pressure oxidation is 88-99 per cent. These results suggest that gold recovery is important but the following strategies would have an impact on a plant performance and would be considered when developing an option to treat refractory ores: capital and operating costs, ore reserves, mine location, infrastructure and qualified staff. Keywords: gold, flotation concentrates, recovery, cyanidation, roasting, biooxidation, pressure oxidation

Sep 1, 2012

By Bearman R. A

The majority of published material regarding the operation of crushing machinery is concerned with simulation of performance rather than design of equipment. The reason underlying the bias in published material relates to why research is carried out and who undertakes the research. Two distinct types of research can be identified: 1. Internal research by crusher manufacturers - generally related to mechanical design, value engineering and to the commercial realities attached to sales demands. Any work on basic crusher geometry or rock/machine interaction is of a sensitive nature and rarely enters the public domain. 2. Academic research - mostly confined to modelling of crusher performance and simulation. This is not because of any bias, but crusher design requires access to manufacturers data or at least an in-depth understanding of crusher design, which is rarely available. The crushing of rock is a complicated problem. It involves three aspects; the machine geometry, the material composition (type of rock/feed size distribution) and the machine/rock interaction. The machine geometry is often ignored in empirical mineral processing simulations, while the response of different feed materials is only nominally addressed in machine specifications provided by manufacturers. The manner by which the machine produces a stress field and causes different types of breakage for different rocks (or the machine/rock interaction) is sadly neglected by both groups. All three aspects must be considered collectively to successfully understand and model the entire crushing process. 1. Centre for Mining Technology and Equipment, Julius Kruttschnitt Mineral Research Centre, University of Queensland, Isles Road, Indooroopilly 4068 Qld. The importance of crushing is often underestimated. In mining and mineral processing the invisibility of the crushing process is understandable as it merely provides a coarse reduction stage prior to the intricacies of mineral extraction. However in the quarrying industry crushing and screening basically provide the finished product. A brief overview of the quarrying industry shows the importance of crushing. Figure 1 gives production figures for most of the western European countries, Australia and the USA.

Jan 1, 1995

By C. Atilla Öztürk

Determining the cutability and mechanical properties of rocks is vital for the feasibility studies of a mine or tunnel projects. Many scientists have investigated the correlation between these parameters in order to predict specific energy (SE) and other important rock cutability properties for many years. On the other hand, textural properties of rocks have been quantified in detail by Howarth and Rowlands (1987). Hence, it was possible to correlate mechanical and textural properties of rocks by using a parameter known as the texture coefficient (TC). The main objective of this study was to use the test results taken from a research project carried out by Bilgin and Shahrair1tocorrelate the mechanical and cutability properties of rocks with textural properties of rocks. For this purpose, uniaxial compressive strength (UCS), uniaxial tensile strength (UTS), cone indent or (CI),point load index (PLI), unit volume weight (?), porosity, SE, and normal and cutting force values, were correlated with textural properties of rocks. Hence it was possible to make illuminating interpretations about the relationships between the mechanical and cutability with the textural properties of rocks. Keywords: Cutting properties, mechanical properties, specific energy, texture coefficient.

Jan 1, 2004

By A. Kijko, C. W. Funk

Methods for the analysis of seismic hazards in mines are reviewed as illustrations of the techniques that are being used in some South African mines. The classical parameters that describe a hazard are the seismic activity rate, ?, the Gutenberg-Richter value, b, and, occasionally, the maximum regional magnitude, mmax The activity rate is calculated readily owing to the inherent simplicity of its definition. The evaluation method presented for the Gutenberg-Richter b value takes into account the presence of mmax Three statistical procedures are described for the assessment of mmax which the maximum observed magnitude, Xmax a crucial role. Often, the configuration of mine seismic networks is changed, or the networks are improved, which inevitably gives rise to changes in the completeness of the seismic catalogues. The routine analysis of seismic hazards must account for these time dependent changes. A method for the evaluation of hazards is reviewed that accommodates varying levels of quality in the catalogues. Finally, the concept of the volume of ground motion (VGM) is presented. This is a technique that allows for most aspects of seismic hazards in mines. The advantage of the VGM is that a hazard can be described by one physically significant value: the volume of rock (cumulated over a time period) in which the ground motion exceeds some critical particle velocity. Data from the gold mining region in South Africa known as the Far West Rand is used in a demonstration of the discussed methods of hazard analysis.

Jan 1, 1994

By M. H. Basiri

The application of aluminum matrix composites, due to their unique properties, is significantly growing in the variety of industries such as aerospace and automobile. In comparison to other light metals, such as magnesium and titanium, aluminum is lower in price. These are the advantages that this metal dominates the others. In this research, first by applying the lost foam casting method, the SiCp/A356 composite was cast in the bottom and side gate conditions with 690°C and volume fraction of 10%. Furthermore, the effects of reinforcement particles (60 µm, 75 µm) were examined. The results present the particles distribution in the side gate methods is more homogeneous than the bottom gate casting method. Also, by increasing the particles sizes, the fading rate in the side gate are reduced from 22% to 19%, as well as from 26.4% to 25.4% in the bottom gate. Key words: Carbide-Silicone Particle, Gating System, Composite Micro-Structure, Foam Casting

Feb 27, 2013

By N T. Byrom

This paper is essentially in two parts. It describes how risk assessment fits into the overall framework of the activities required to control risk effectively within an occupational health and safety (OH&S) management system. It then goes on to describe the assessment of an OH&S system by the process of auditing.

Jan 7, 1996

By F. A. Champion

The work described in this paper was carried out in the Research Laboratories of the British Aluminium Company Ltd., under the general direction of A. G. C. Gwyer, Scientific Manager of the Company. In considering the effect of stress?corrosion conditions on metals, or the failure of metal through stress corrosion, it is evidently advisable to adopt a clear definition of the meaning of those phrases. There appears to be general agreement that stress-corrosion conditions may be defined as the continuous application of static stress to a metal while it is exposed to corrosive conditions, but recognition of the occurrence of true stress-corrosion in a metal is often a difficult matter giving rise to some confusion. For the purpose of this paper stress corrosion in a metal is defined as the acceleration of corrosion by the application of static stress. On this view it is necessary to test a metal not merely under stress-corrosion conditions, but also under the same corrosion conditions without the simultaneous application of stress, if the liability of the metal to stress corrosion is to be assessed. Failure of a metal under stress-corrosion conditions is sometimes quoted as evidence of stress corrosion (for example, by Althof(1)2), but this evidence is totally inadequate if the above definition is

Jan 1, 1945

By S Henderson, J V. Lawless

The worldwide association of low-sulfidation epithermal gold mineralisation, bimodal rhyolitic-basaltic volcanism and rifting is confirmed in New Zealand. In the currently productive Coromandel epithermal-gold province reported Ar-Ar dating of adularia from low sulfidation deposits falls into two groups at 6 and 7 Ma. Bimodal rhyolitic-basaltic volcanism has been reported to be K-Ar dated at 9 to 7 Ma and 6 to 5.5 Ma. Epithermal gold mineralisation in Northland is spatially associated with bimodal basaltic-rhyolitic volcanism, with rifting cogenetic with that in the CVZ. The Taupo Volcanic zone (TVZ) is sufficiently young that the presence of a segmented rift with recent bimodal rhyolitic-basaltic volcanism can be genetically associated with epithermal gold mineralisation, which occurs as both fossil occurrences and in active geothermal fields. This reinforces the known potential prospectiveness of the Coromandel area and increases that of Northland and the Taupo Volcanic Zone.

Jan 1, 2005

Tourmaline-bearing rocks are a rare rock type of Suites 3, 4 and 5 at Broken Hill. Minor laminated plagioclase-quartz-tourmaline rocks occur in association with the quartz- magnetite rocks of Suite 3 with the greatest abundance of tourmaline-bearing rocks present in Suite 4 intimately associated with lode horizon, scheelite mineralisation and zinc mineralistion - all approximate strike equivalents of the Broken Hill Pb-Zn-Ag deposit. Bedded quartz-tourmaline rocks, tourmalinites, tourmaline-rich pelite and tourmaline-bearing lode horizon have been recorded from suite 4. The bedded tourmaline rocks rarely display cross bedding, graded bedding, slump structures and small scale intraformational breccias. Minor tourmaline-gahnite-bearing pelites are present in Suite 5. The sedimentary structures, metamorphic textures, the stratigraphic position of the tourmaline-rocks and the presence of quartz-tourmaline-gahnite-spessartine (-fluorapatite) lode rocks indicates that the mineralisation at Broken Hill and the tourmaline-rich rocks are all products of submarine exhalative hot spring systems which were most active during deposition of Suite 4 rocks. Tourmaline is chemically different from that associated with granitic activity and from other submarine exhalative tourmaline-rich rocks because the premetamorphic alteration at Broken Hill involved addition of Fe, Ti and F and subtraction of Mg - a feature reflected in the chemistry of tourmaline from Broken Hill.

Jan 1, 1983

By L. L. Sirois

Because segments of the Canadian mineral-based economy are dependent totally or in part on foreign sources of certain minerals, their well-being may well be affected by inability to obtain these minerals. Where such dependency exists, it is therefore important that contingency plans be available to counteract possible price increases or lack of supplies by means of technology, developed well in advance of any pending crisis . Canada is vulnerable to possible future real or artificial shortages of certain foreign-produced mineral commodities, and science and technology can provide information for the development of policies for counteracting efforts by foreign exporters to control prices or limit supplies.

Jan 1, 1977

By HJ Marais, J A. van Niekerk

An investigation was initiated by BILLITON Process Research and Gold Fields Limited for the efficient removal of thiocyanate and cyanide from leach solutions. This led to the development of the ASTERTM process, an acronym for Activated Sludge Tailings Effluent Remediation. The biological degradation of thiocyanate and cyanide in effluents provides an alternative treatment to the more traditional processes. This occurs with a large number of micro-organisms which include bacteria, actinomycetes and fungi. Cyanide and thiocyanate are degraded to ammonia and carbon dioxide. Most forms of cyanide-metal complexes are generally removed through a co.mbination of oxidation and sorption into the biofilm/biomass. Since the ASTER™ process has commercial applications, a patent has been lodged for the ASTER™ process. A culture containing thiocyanate degrading organisms has been deposited with the Australian Government Analytical Laboratories (AGAL). The identification of the bacteria is in progress. Tailings arising from a cyanidation process tend to contain cyanide and thiocyanate. The presence of these species prevents the recycling of this water upstream to a bioleach circuit due to its toxicity to the bacterial culture. Increasingly stringent legislation for the land disposal of cyanide containing solutions also necessitates the treatment of the solutions before disposal.

Jan 1, 2000

By L. B. McConville

The general term "tar sand" refers to sand that contains varying amounts of dense, viscous petroleum. Tar sand deposits have been found throughout the world, often in the same geographical area as conventional petroleum. The largest one by far is known as the Athabasca Tar Sands, in the province of Alberta, Canada. Actually a group of three deposits, these particular sands underlie an aggregate area of more than 12,000 sq miles. Current estimates place the contained raw petroleum at about 700 billion bbl; and via currently available technology, the amount of recoverable synthetic oil may be as much as 300 billion bbl-which is roughly equivalent to five times the combined US and Canadian total crude oil reserves. With the ever-widening gap between energy supply and demand, mining and petroleum companies are now evaluating all possible energy resources-both developed and underdeveloped-and, certainly, the Athabasca Tar Sand deposit is one of the more important ones to merit such attention. The first section in ME deals with the geology and historical developments; the other four sections, with mining methods, extraction technology, economics, and outlook.

Jan 1, 1975

By L. B. McConville

The general term "tar sand" has been used to describe sand containing varying amounts of dense, viscous petroleum. Deposits of tar sands have been found throughout the world, often in the same geographical area as conventional petroleum. The largest one by far is known as the Athabasca Tar Sands, and is located in the province of Alberta, Canada. Actually a group of three deposits, these particular sands underlie an aggregate area of more than 12,000 square miles. Current estimates place the contained raw petroleum at about 700 billion barrels, from which as much as 300 billion barrels of synthetic oil may be recoverable under presently developed technology. For comparison, this latter quantity is roughly equivalent to five times the combined total of U.S. and Canadian crude oil reserves. With the ever-widening gap between energy supply and demand, attention is being directed to all possible energy sources - both developed and underdeveloped - and certainly the Athabasca Tar Sand deposit is one of the more important ones to merit such attention. This paper will review some of the more significant developments and attempt to place in perspective the role that this source of energy could possibly be expected to play in the foreseeable future.

Jan 1, 1974

By Don Rose

I. INTRODUCTION The Atlanta Research Chamber is an UMTA-sponsored applied research facility studying tunnel design, excavation and support systems. It is located directly below Peachtree Street in downtown Atlanta, Georgia. It is included in the CN-120 contract to build the Peachtree Center subway station, a part of the Metropolitan Atlanta Rapid Transit Authority (MARTA) multi-billion dollar "Phase A" 53-mile transit project, which is 80 percent funded by UMTA with 20 percent provided by local authorities in Atlanta and Fulton and DeKalb counties (Figure 1). The Research Chamber is located immediately south of the main Peachtree Center Station cavern, and is in part an enlargement of the pre-existing Pilot Tunnel excavated to provide bidders on the CN-120 contract a view of the rock conditions (Figure 2). The Research Chamber lies some 3 meters above, and is approximately parallel to, the twin Running Tunnels. The Research Chamber is 18 meters long and has the same 5.5 meter diameter horseshoe shape design dimensions as the twin Running Tunnels.

Jan 1, 1979

By Refik Elibay, Lawrence A. Williamson, George D. Barnes

Under an extremely aggressive schedule, final design of 13.5 km (8.4 miles) miles of 8.2 m (27 ft) diameter deep rock tunnel, 322 ML/day (85 million gallons / day)submersible pumping station and associated facilities were accomplished ahead of a federal court mandated consent decree schedule. Challenges overcome by the project team in enabling timely completion of the construction documents will be presented. Discussion includes evolution of final design, consideration of future O&M requirements, and risks identified for construction and operations, together with measures to manage and proactively prepare for such risks.

Jan 1, 2005

By R. D. Hamer

"The Atlantis II Deposit comprises metalliferous sediments (Zn+Cu+Ag+Au) accumulating in a composite, axial basin, 2,000m beneath the surface of the Red Sea. The basin contains warm, highly saline water. It is located approximately half way between Jeddah and Port Sudan within the Exclusive Economic zones of Saudi Arabia and Sudan. The Deposit was discovered in 1963 and evaluated by drilling in the 1970s and 1980s. This phase defined an initial resource of approximately 90Mt. More recent estimations have refined this figure to an Inferred Resource of approximately 80Mt (CIM compliant).The Mining Licence to develop and extract the Atlantis II Deep Deposit was granted to Manafai International Trade in 2010 by the joint Saudi-Sudanese Red Sea Commission. Manafai is poised to embark on a renewed phase of exploration and evaluation, including the completion of a Definitive Feasibility Study (DFS) and leading to the successful exploitation of the Deposit in a safe, environmentally sound, economically viable and socially responsible manner.The Deposit is forming in a complex basin adjacent the median rift, where sea floor spreading has operated during the last 5Ma. It is a Hydrothermal-sedimentary Deposit. The mineralised sedimentary rocks rest directly on sea floor basaltic rocks. They are produced by the exhalation of metal-rich, hydrothermal brines from fissures associated with the central rift and cross-cutting fracture zones. Up to 25m of metal-rich sediments have accumulated over an area exceeding 57km²."

Jan 1, 2017

By Ramon B. Santos

The Atlas Concentrator, reputedly the largest in the Far East today, is located on the island of Cebu in the Republic of the Philippines. It started operation on a 4000 TPD capacity in 1955. An expansion program, coupled with significant improvements both in the Crushing Plant and the Mil, made the Atlas Concentrator what it is today, treating about 14,000 tons of ore per day at a comparatively low cost of about $0.50 per ton treated. The Atlas Copper Mine is at present mainly an open pit operation, with ore supplied from two pits (Lutopan and Biga) north of the Concen¬trator. Development of an Underground Mine, situated on the main ore body at Lutopan, which will be a block caving operation, has been underway since 1963, and this underground mining operation is expected to b e in full production by the latter part of 1966.

Jan 1, 1966