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By Eric Kelley

Having been retained as a legal expert for the fatality at the Canberra, Australia project, it made me aware of how good intended blasters profess to be implosion experts. Owners and contractors can be misled by these representations, seeing a video of Directionalized Structures constructed of reinforced concrete may be impressive to watch, but lack sound evidence of the true mechanics of an actual “implosion”; on steel structures more prevalently. If any well intended blaster comes to a determination that he can implode a structure, it should be not be construed he cannot. It should be well investigated that the specific blaster has verifiable experience. What happened in Australia reflects on all end users of explosives. I have heard a direct quote in our project in Alberta, “We don’t want to have what happened in Canberra”. Such a tragedy could have, and should have been avoided. Simple by using the “Right Tool for the Job”. We should sideline egos and economics. Would any competent blaster compromise his or her reputation, company or insurability? More importantly, have an honest conscience knowing that if the proper explosive is available, use it, don’t shortcut it. If possible expand the schedule. Better, yet, examine all avenues before the project, and last, cancel the project. A human life is our best asset and should not be compromised.

Jan 1, 1999

Forecasting, particularly when applied to meaningful issues, is known irreverently as 'futurology'. There is quite a range of opinion ext.ant in the world when mineral resources are looked at. The opinions range from the doomsday view that there will be acute shortages of all essential commodities, to the optimistic outlook that new 'discoveries will prevent any possibility of shortages. The environment is, as yet, only studied locally and quite parochially; surprisingly there is little integration when considering the spatial atmosphere, the seas in depth and the earth's crust.

Jan 1, 1981

By S. Hardcastle

Various controlled and ambient tests were undertaken to evaluate the performance of a variety of digital heat stress monitors, psychrometers and simpler temperature/relative humidity data loggers that measure, or determine, such parameters as: dry-bulb, natural wet-bulb, psychrometric wet-bulb and globe temperatures. In this comparison, funded by the Deep Mining Research Consortium, it has been found that all the instruments can competently measure dry-bulb temperature but the accuracy of other sensors could introduce significant uncertainty. For example the quality of relative humidity sensors and failure to correct for the barometric pressure difference in deep mines, directly impacts upon the calculation of psychrometric wet-bulb. The comparison has shown that the response of dry-bulb and globe temperature sensors can vary widely under different radiant heat conditions; however this would be negligible in most mines. Of more concern is the differing performance of the natural-wet bulb sensors especially at low relative humidity and low air velocity. Furthermore, from these tests and the currently available theory it was not possible to determine if any of the natural-wet bulb instruments measured that value correctly or validate any relationship between psychrometric and natural wet-bulb temperature at low air speeds where their difference is greatest. Consequently the uninformed use of some of the commercially available environmental heat stress monitors or derivations from other instruments could provide erroneous results affecting the work load category that can be accommodated or the rest ratio regime required.

Jan 1, 2009

By P. N. Mohan Das, K. Harikrishna Bhat

"The major ilmenite reserves are located in India at Chavara (CH), Manavalakurichi ( MK) and Chatrapur, Orissa (OR). India stands first in terms of ilmenite reserves, which are estimated to be 278 million tonnes out of which, 142 million tonnes are processable. Mineralo-chemical analysis showed that Chavara ilmenite is the most weathered one with about 60% TiO2 while Chatrapur is the least weathered with about 50% TiO2. XRD and SEM studies of different magnetic fractions of these three mineral deposits established the co-existence of ilmenite with pseudorutile, rutile and haematite phases in substantially varying amounts. It is observed that the tropical weathering rather than the source rock difference has apparently played an important role in imparting major compositional and structural dissimilarities among the ilmenites in different places. Further, the chemical analysis, XRD and SEM characterisation of differently weathered samples of MK ilmenite separated by the magnetic fractionation showed that the degree of alteration was invariably associated with the decrease in magnetism, increase in the rutile phase and the change in Fe2+/Fe3+ ratio of ilmenite grains. Magnetically separated fractions when subjected to metallisation with carbonaceous reductant such as coke showed that the degree of reduction increases with the degree of alteration and with the decrease in the Fe2+/Fe3+ ratio.In the processing of ilmenite through the Becher process, aeration rusting of pre - reduced ilmenite is found to be the rate-limiting step thus, affecting the productivity and economy of the process. Investigations have proved that the addition of some organic compounds such as glyoxal, sucrose etc., to the system accelerates the reaction to such an extent that the rusting time has been reduced to less than half. The formation of acids by the these organic compounds during the rusting reaction was proved responsible for maintaining the pH of the solution in the range 3-4 at which iron hydroxide do not precipitate and block the pores in the reacting surface of the grain."

Jan 1, 2003

By Greg Rasmussen

"Huckleberry Mines Ltd is an open pit porphyry copper-molybdenum mining operation located 120 km south of Houston, British Columbia with a 18,000 tpd milling facility. Huckleberry Mines is owned 60% by Princeton Mining Corporation, the operator, and 40% by Japanese partners.The Huckleberry deposit is one of several porphyry systems located in the Tahts a district of the intermontane belt of British Columbia. The principal economic minerals are chalcopyrite and molybdenite. The ore deposit is split into two ore deposits, the Main Zone, consisting of24,241,000 tonnes of mineable reserves grading 0.484 %Cu and 0.013 %Mo, and the East Zone, consisting of 66, 131,500 tonnes of mineable reserves grading 0.523 %Cu and 0.014 %Mo.The milling begins with gyratory crushing. This sizes the product down to 100% passing 6 inches. This product is discharged onto a stockpile by a stationary conveyor. The stockpile was designed for a capacity of 144,000 tonnes with a live capacity of 20,000 tonnes. Two apron feeders draw the ore from the bottom of the stockpile and discharge onto a SAG mill feed conveyor which in turn feeds a grinding circuit consisting of one 32' x 15' SAG mill and two 30' x 16.5' ball mills. The grinding cyclone overflow feeds bulk flotation at 55 -65% minus 200 mesh.The bulk flotation uses conventional rougher and column flotation methods to float a bulk concentrate recovering 92.6% copper on the East Zone and 95% copper on the Main Zone with 75% recovery molybdenum on both zones. The bulk concentrate feeds the bulk thickener which produces a density of 60 %solids. This in turn feeds the molybdenum circuit, which separates the copper and molybdenum, by depressing the copper then using conventional rougher and column flotation produces a copper concentrate of 27 %Cu and 0.02 %Mo, and a molybdenum concentrate containing 1.5 %Cu and 54 %Mo at 67% recovery. These concentrates are separately thickened, filtered, dried, and shipped to the smelter for processing."

Jan 1, 1998

Train services through the Channel Tunnel linking Britain and France where scheduled to be fully restored in February 2009 following several months of repairs after a major fire in the tunnel on Sept. 11, 2008. A lorry caught fire on a shuttle train carrying heavy goods vehicles bound for France through the 50-km- (31-mile-) long northern tunnel. The fire, that spread to other vehicles, raged for about 16 hours. The extreme temperatures of up to 1,000º C (1,832° F) caused extensive damage to about 600 m (2,000 ft) of the 7.6-m- (25-ft-) diameter tunnel?s concrete lining, approximately 11 km (7 miles) in from the French entrance. The Channel Tunnel operator, Eurotunnel, awarded the repair con-tract, estimated to be between ?50 to 60 million, to a consortium of Freyssinet, Eurovia Travaux Ferroviaires (ETF) and Vinci Energies. Freyssinet was appointed to look after the civil engineering works, while ETF would be responsible for track and overhead wire restoration and Vinci Energies responsible for other equipment. The technique of hydrodemolition, which uses high-pressure water jets to remove concrete from various structures, was specified as the method to remove the fire damaged concrete. Freyssinet subcontracted the concrete removal to the specialist hydrodemolition and industrial cleaning contractor Philip Lasserat.

Jan 1, 2009

By V. Osterholt

Sustainable development of mineral resources is based on a spatial model of the orebody that is only partly known from exploration drilling and associated geological interpretations. As a result, orebody models generated from the available information are uncertain and require the use of stochastic conditional simulation technique. This paper considers three methods for simulating orebody geology: (1) pluri-Gaussian simulation that limits the allowable contacts between the various units; (2) sequential indicator simulation using indicator kriging; and (3) an experimental multiple-point approach that captures some higher-order spatial statistics. The data requirements of the methods, how to meet them in mining applications, and performance characteristics are discussed. The application of these methods in a hypothetical deposit consisting of three geological units provides a comparison and illustrates the advantages of the different simulation approaches.

Jan 1, 2005

By Sohta Takatsu, Hachiroh Mizubata, Shigeki Kudoh, Kazuya Takekuni, Yoshinori Yamada

A special type of shotcrete is used to improve the performance of open-type TBM in difficult situations. The Hakamagoshi and Johana tunnels are expressway evacuation tunnels of 3.2 km and 5.1 km in length, respectively (total 9.1 km) that were excavated by one open-type TBM. The geological conditions at the sites were estimated to be good before excavation. However, 95% of the rock turned out to be two ranking orders worse than the estimated classes. Therefore, we used a special shotcrete for bad rock conditions, and succeeded in excavating the tunnel at an average rate of 270 m/month.

Jan 1, 2001

By Philip E. Niebuhr

A procedure, which can be performed in the field by nonanalytical personnel, is given for sensitive spot tests for detecting tellurium or selenium. The expressed need of a field test for detecting small amounts of tellurium, which may be accompanied by relatively large amounts of selenium, has led to the development of this method. Tellurium search has been impeded by the lack of a satisfactory test from the standpoint of sensitivity and specificity. A quantitative laboratory method exists, but it is expensive and relatively laborious. Several other qualitative tests are known, but they require unstable solutions, which must be freshly prepared for use, and a greater variety of laboratory equipment. The particular advantages of the test described are its simplicity and the stability of the reagents required, there-fore is is well adapted for field use. Also, this test was found to be of practical use in the analytical laboratory when screening samples, thereby reducing analytical costs. The roughly quantitative interpretation of the results can save time by indicating the approximate size of the sample taken for a quantitative determination.

Jan 1, 1962

By John C. Machisak

INJURY and employment figures for nonmetal mines and mills in 1959 are presented in this publication. Data for nonmetal mines are presented separately from those for nonmetal mills. The Bureau of Mines is authorized to send questionnaires to the nonmetal mining industry each year requesting their voluntary submission of injury experience and employment data. The voluntary response to these requests has contributed greatly toward the promotion of safety in the industry, and every effort has been made to make the information as complete as possible.

Jan 1, 1963

By T. J. Goff, G. M. Denton

Mintek has developed the EnviroplasTM process for the treatment of solid wastes from the metallurgical industry, especially steel plant dusts, without requiring agglomeration to produce inert slag and at the same time recover metal values such as nickel, chromium and zinc. The products that are generated in the plasma-arc process are usually a metal and a non-toxic slag, which are tapped from the furnace in liquid form. The metal is mainly composed of chromium, nickel and manganese. During the production of stainless steel between 30 and 70 kg of dust and fine waste is generated per ton of steel. Mintek has successfully processed around 1000t of AOD/EAF dust on a toll treatment basis in order to recover the contained Cr and Ni. The metal produced contained 18.5 per cent Cr, and 5.5 per cent Ni. All slag samples tested conformed to US EPA regulations for disposal. The chromium and nickel recovery to metal was 90 and 98 per cent respectively, on a once through basis i.e. no baghouse dust recycle. Slag tapping temperatures varied between 1650°C and 1750°C. The average actual energy requirement excluding furnace heatlosses of smelting steel plant dust with anthracite as reductant was 1.36MWh/ ton of dust. The total mass of feed reporting to the off-gas stream was 10 per cent. The average ZnO content of the fume was 35.5 per cent.

Jan 1, 2004

By Edward (Ted) Dowey

City Water Tunnel No. 3 is being built in order to provide a redundant system for delivering 4,542,500 m3 (1.2 billion gallons) of water per day throughout the five boroughs of New York City. The present tunnels, City Tunnel No. 1 and 2 (Figure 1), were put in service in 1917 and 1936 respectively, and both have been in continuous service. Tunnels No. 1 and 2 can-not be shut down for inspection or repair until City Tunnel No. 3 has been completed. City Tunnel No. 3 has two stages (Figure 1).Stage One is 20.1 km (12.5 mi) long and is presently delivering drinking water to the boroughs of the Bronx and Manhattan. Stage Two consists of the Brooklyn-Queens Tunnel 17.7 km (11 mi) and the Manhattan Tunnel 14 km (9 mi). The Brooklyn-Queens leg is complete and is set to be put in service soon. The Manhattan Tunnel is being constructed and is the subject of this paper. The Manhattan Tunnel (Figure 1) is comprised of three legs: the north, south and east legs. The con-tract includes the excavation of 8,976 m (29,500 ft) of tunnel and the lining of 14,561 m (47,773 ft) of tunnel. The south tunnel, 5,705 m (18,720 ft), was excavated but not lined, under a previous contract. The tunnel ranges from 181 m (600 ft) to 152 m (500 ft) in depth in the bedrock under Manhattan. The tunnel contract also includes the construction of nine new shafts, 161 m (530 ft) average depth, and the completion of a tenth shaft (the previously built construction shaft). The Manhattan Tunnel contract was awarded to the sole bidder Schiavone/Shea/Frontier Kemper Joint Venture (SSF) for $668,532,680.00, on January 31, 2005. The Manhattan Tunnel was designed ?in house? by the New York City Department of Environmental Protection (DEP) and the construction management was provided by a combined staff of the DEP and a joint venture of Jenny Engineering and URS.

Jan 1, 2008

Drilling at Ipswich during the last twelve years by the Queensland Department of Mines has proved large quantities of reserves which have assured the security of the field for many years to come. This is perhaps the greatest contribution to the development of the field since its discovery in 1827.The drilling campaign commenced in 1950 and by the end of 1961 comprised 242 holes totalling 180,220 ft.Intersections of formations and seams, accompanied by detailed surface mapping, led to more precise knowledge of the geology of the field than was previously possible, and clarified many problems of correlation. Productive formations are part of the Middle Triassic Ipswich Coal Measures, a 4,300 ft sequence of fresh-water sediments with some interbedded volcanics. They are overlain by the Upper Triassic Bundamba Group and the Lower Tertiary Booval Group.Reserves disclosed by drilling amount to 171,487,000 tons, comprising 109,407,000 tons "measured" and 62,080,000 tons "indicated". The security of these reserves encouraged many collieries to instal modern efficient mining machinery and washing plants.The climax of recent development of the resources of the field will be the commissioning in 1966 of a £33 million 360 MW power station in the Swanbank district which will consume 14 million tons of coal during its 30 year life and will have a peak demand of some 20,000 tons per week.Drilling is continuing and is expected to prove additional reserves which will justify further development of the field.INTRODUCTIONUntil 1949 there had been no concerted effort to test systematically the resources of the whole Ipswich field. Fifty two known holes totalling 30,500 ft had been drilled, eight of them by the Department of Mines, but because of poor core recovery and inadequate records most of them were of little use in a comprehensive assessment.Development of the field was being retarded by uncertainty regarding reserves and by the general state of the coal mining industry. Numbers of comparatively small independent companies and owner groups were operating coal...

Jan 1, 1963

By Steve C. Albrecht

The objective of this study is "to assess the impact of surface mining on soil compaction in the Midwest". The study revolves around a unique field sampling program targeted at four mine sites utilizing four distinct types of soil movement of midwestern prime land. Through the preparation of a final report for use as a guidebook, an assessment is made of the degree to which surface mining operations contribute to the soil compaction problem. The final report is formulated through the use of field study data as well as information gathered in an intense literature review. The final report centers on applying collected data to practical field applications. Soil sampling on the four mine sites centers on a comparison of natural and replaced soils for moist bulk density. This characterization evaluates changes in density and texture throughout the soil profile to a depth of 48 inches. Fertility of the topsoil is also assessed for natural and replaced soils. During field sampling and observations, a base of information has been gathered to compile a case study on each mine site. The report accesses the regulations in the prime farmland areas through the use of a matrix. The regulatory matrix allows easy access of mining personnel to State and Federal regulations.

Jan 1, 1982

By Narendra Gupta, Gaurav Srivastava, Abhinav Sharma

From the days when plain detonators and safety fuse were used for initiation of commercial explosives, the commercial blasting and mining industries have made rapid strides. With the advent of electronic detonators in the late ‘90s, the face of commercial blasting was changed forever. The Mining Industry in India initially took a while to embrace Electronic Blasting Systems (EBS), however, more recently the industry has taken to EBS in a big way.

Jan 1, 2015

By Sam Spearing

Free-standing supports are commonly used in coal mines in the USA, particularly when longwalling. A recent trend has been the development of prop supports. Prop supports have many advantages over bulky, crib-type secondary standing supports, particularly in regard to material handling and installation. The challenge in prop design has been to develop load capacities that can compete with crib type systems and to develop reliable (stable) yielding capability. This paper will focus on the design aspects of steel prop supports, specifically, and evaluate the various concepts that have been developed to provide easy height adjustment and sustainable stable yielding under load. The design and resulting improvement provided by recent support developments called the Quik Stik and Ball Buster are discussed in detail. Performance areas that still need improvement in the design and usage of free standing supports in general are identified and possible solutions outlined.

Jan 1, 2008

By Gustavo Quiquia Mucha

El presente texto describe las experiencias realizadas por la Compañía Minera Milpo SAA en el marco de una gestión social basada en la consulta previa, libre e informada en la Exploración Minera Responsable. En ese sentido, es importante la cooperación entre la empresa minera y la comunidad, así como la incorporación del marco ideológico empresarial y metodológico, basado en los principios del Convenio 169 de la OIT sobre Pueblos Indígenas y Tribales en Países Independientes, las estrategias y las líneas de intervención social de la Compañía Minera Milpo SAA en los proyectos de exploración minera responsable.

Sep 12, 2011

By Jan J. Cilliers, Nicolas Barbian, Esther Ventura-Medina

"Froth structure and stability are known to play an important role in determining flotation recovery and selectivity. An industrial sampling campaign was performed to develop a clearer understanding of the effect of flotation variables on froth stability and the role played by the resulting stability on flotation performance.Froth stability was estimated as the fraction of bubbles bursting on the surface of the froth through image analysis and the solids loading on the bubbles at the top surface. The image processing was performed using the Smartfroth software on the top surface of the froth. The system gives measurements of bubble size distribution, average bubble size and froth velocity. The froth velocity was used to estimate the volume of bubbles overflowing the weir yielding to the fraction of air overflowing the cell. This measurement is the complement of the rate of bubble bursting on the top surface. Also samples of the lamellae were taken by touching the top surface of the bubbles with a glass slide. Then, the amount of solids and liquid per unit area in the bubble lamellae was estimated gravimetrically. Both measurements were used to establish stability criteria.It was generally found that high air flowrates resulted in a drop of froth stability showed by a drop in the fraction of air overflowing and a decrease in the solids loading and simultaneously produced low copper recoveries and low concentrate grades. Deep froths only allowed a small fraction of air to overflow and consequently produced low recoveries. An increase to high frother dosage did not result in an improved fraction of air overflowing, hence producing low recoveries. Likewise, low frother addition only allows low recoveries because the resulting unstable froth cannot support itself. Low aeration was found to be preferential as it allowed high particle loading, therefore high bubble stabilisation, and low gangue entrainment, resulting in the highest flotation performance."

Jan 1, 2003

By Krzysztof Kotwica

The steady demand for rock materials leads not only to on increase in mining but to the need for decreasing the loss of material in the process of exploitation as well. It brings about an increase in using of explosives in open pits and as a result an increase of after blasting gases volume, vibrations, the scattering (dispersion) of stone ect. All these factors affecting the environment lead to the research work for applying the electrohydrodynamic methods both in open casts and underground mines. In the article the authors describe the concept of this method and construction of equipment which recently have been successfully introduced in mining, the results obtained determine the possibilities of using this method and the future directions. The results of combined method with high-pressure water jets cutting and prototype equipment for separating rock blocks from the rock mass using special head with high-pressure water jets are also described.

Jan 1, 2006

By F. A. Camisani-Calzolari

The latter half of the 20th century has seen the proliferation of a series of codes to address commodity needs which were brought about by rapidly advancing technologies and the globalization of markets and consumerism. This paper addresses the specific needs and the origin of this surge and presents these codes in the context in which they were developed. It also compares the main codes or groups of codes and elaborates upon their strengths and weaknesses. Three main categories of codes are identified, namely codes for reporting to international agencies, codes addressing government needs and, finally, codes for the investors and the stock market. Codes governed by international agencies usually relate to strategic commodities which have highly specialized fields of usage such as nuclear power generation where international cooperationis eventually the only viable approach for both the development of technologies and their applications. Codes for reporting to governments address the necessity of each state to exploit its mineral potential profitably and to secure the preservation of wealth for future generations. Reporting to investors is experiencing a considerable popularity as of late because of globalization in mining and the growing need for outside financing of mining projects, whose capital requirements are getting out of reach for the average mid-cap mining company. All these codes have advantages and shortcomings dictated by the specific circumstances under which they were developed, therefore necessitating the definition and implementation of some kind of international standard whereby investments and the spread of information across political boundaries would be facilitated. Though none of these codes might ever become international in the true sense of the word because of significantly different legislations at national level, a step that would greatly contribute to the cross-border disclosure of information would be the reciprocal recognition of competent persons by the major mining countries, including China and Russia. It is also becoming essential that financial institutions and investors be properly advised on mining projects by reporting reserves and resources in a transparent and responsible way with the relevant public disclosures being compiled by professionals who take full responsibility for their submissions. Keywords: reporting codes, mineral resources, mineral reserves, competent person, UN Framework Classification, IAEA classification, JORC Code, SAMREC Code and CRIRSCO.

Jan 1, 2004