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By Gerald P. Kelton

Over the past quarter of a century, the success of the hydrocyclone as a classifier in closed circuit grinding installations has permitted the introduction of the cyclone into virtually all fields of wet industrial processing. Research and experience gained in these applications have established the optimum cyclone sizes and designs necessary to provide the required performance. Although cyclones are used in widely diverse liquid-solid applications, their use for ultrafine separation clearly demonstrates the importance of a familiarity with previous case studies. Krebs Engineers is firmly dedicated to serving the process industry and has acquired the unsurpassed knowledge and experience to handle all types of separations and classification problems. Cyclones have been used for a number of applications to make what might be considered fine separations. A typical example is in an iron ore grinding circuit where a 381 mm diameter cyclone will classify an overflow product to 85% -44 micron. There is no question that this is a fine separation, but still finer separations are possible, and these are known as ultrafine separations.

Jan 1, 1983

Hydrofluoric acid (HF) is traditionally used in plant operation to separate feldspars from quartz. It acts during the conditioning step as a pH regulator and an activating agent providing an excellent selectivity. However, a corrosive chemical environment and the ecological impacts from the potential fluoride ion contamination are limiting factors to use this chemical agent at an industrial scale. Investigations of the amine-feldspar interactions in the absence and presence of non-linear long-chain alcohols were carried out on two ore samples. The presence of alcohol molecules led to form a closed packed layer only on the surface of feldspars. The highest order and packing at the feldspar surface were observed with a particular alkyl chain structure as Guerbert alcohols. A new flotation process was developed and tested at both lab and pilot scales on different feldspar ores. The Guerbert alcohols allow to perform a feldspar concentrate with very low content in quartz (2.3-3.5 %) and feldspars recovery from 78 to 81 % while the aliphatic isoalcohols show a more higher recovery level (88-89 %). New HF-free process is strongly dependent on the pH range (1.7-2.5) and sulphuric acid consumption during conditioning steps. Optimal amine/alcohol weight ratio is ranged between 0.8 and 1.0. The values below 0.8 decrease strongly the flotation selectivity and the quartz recovery within the feldspar concentrates is higher than that occurs with HF.

Sep 1, 2012

By J. W. Tsai

Both diamond crystals and diamond films were grown on silicon and copper substrates using a methane/hydrogen gas mixture as a precursor with thermal CVD techniques at low pressure environment. In addition to diamond particles, other crystalline phases including graphite and aluminum silicon carbide were observed on the substrate surface. ?The grown materials were analyzed with X-ray diffraction, electron microscopy, Auger electron spectroscopy and optical microscopy. Most synthesized diamond crystals were twinned. The flow rate of reactant gases, substrate nature, substrate temperature, decomposition temperature of the precursors, total pressure of reaction chamber, methane/hydrogen ratios and other possible parameters were varied during the growth processes, and the significant effects of these factors on nucleation and growth rate were evaluated.

Jan 1, 1989

By G. Babut

The restructuring of mining operations in Valea Jiului coal basin imposed by the transation to the market economy calls for an increased coal production. Under the circumstances, the role of drainage networks grows ever more important. The paper describes an original mathematical model and software developed on its basis, with enables the ventilation engineer to assess the configurations of different systems, as well as to test their reliability and prognose their future performance before conceiving another methane drainage system or changing the existing one. The paper also includes the underlying principles of an optimization program for methane drainage networks, which will enable the detection of the optimal methane drainage system, both from a technical and an economic point of view.

Jan 1, 1996

By F. Burat

The present research covers the results of experiments carried out with high frequency vibration screen on dewatering of coal fines. In the tests, the addition of surface active reagents was studied employing a high frequency vibrating screen. To increase the efficiency of mechanical dewatering processes, ultrasonic treatment was applied along with surfactants and optimum dewatering conditions were obtained. The moisture content of the feed material was from 82.5% to 41% by the optimization of operation parameters including the angle of the screen, vibration frequency, feed rate and screen opening size. Optimum parameters obtained in dewatering processes carried out with the vibrating screen were kept constant and the effects of surface active reagents and ultrasonic treatment on dewatering were investigated. Finally, the moisture level of the material was further reduced from 41.0% to 37.66%.

Sep 1, 2012

By Frederic P. Dewey

(New York Meeting, February, 1912.) By the old method of determining platinum in ores and bullion, the silver-alloy first obtained in the regular course of assay is parted in strong sulphuric acid and the residual metal weighed. This is re-alloyed with silver by a second cupellation and parted in nitric acid, the residual metal being again weighed. Any difference shown between the two weighings is assumed to be, and is called; platinum. Sometimes it is so, and if any considerable amount of platinum be present, there will be a decided difference between the two weighings; but a slight difference is no real evidence whatever of the presence of platinum. On the other hand, the second weight may equal or possibly exceed the first, even when traces of platinum are present. Again, other members of the platinum group may go into solution in nitric acid more or less. If present, these would be called platinum and escape detection. The method does not provide any direct tests whatever as to the presence or absence of platinum. It is often indecisive, and sometimes jives erroneous results. It is, therefore, quite unsatisfactory. Being called upon many times to determine platinum in a wide variety of materials, particularly when present in very small amounts, I have realized the disadvantages and defects of this old method. In an article on the solubility of gold in nitric acid, 1 I have briefly outlined a method of gathering a little gold out of a solution containing much silver, which furnishes the basis of

Apr 1, 1912

By D. H. White

The term "block caving" as used in this text includes panel caving and mass caving as described by Julin and Tobie (1973). This method reportedly was conceived in 1895 when a block of ore ranging up to 200 ft (61 m) in width was undercut at the Pewabic Mine on the Menominee Range in Michigan (Bucky, 1956). Over the years this method has evolved largely as a consequence of trial and error in which operators became acutely aware of what nature would allow and what it would not. Today block caving remains somewhat of an art rather than a science where experience often dictates what needs to be done. With the plunging prices of base and specialty metals in the early 1980s caving mines sought to reduce operating and development costs in order to return to profitability. For some this became an impossible task given the design, grade and operating costs of the day and closure became the only alternative. One lesson learned from the experiences of the 80s is that survivability depends on cost competitiveness and this implies the efficient use of resources and technology. To this end applied rock mechanics serves as a useful tool. The purpose of this paper is to show how Geomechanics can be used? in block caving to facilitate sound decision making and how this equates to dollars saved. Features of mining method selection, design and operation are discussed as related to this theme.

Jan 1, 1990

By J. R. Parry

Over the past several years, computerized financial models have been an important part of Newmont's strategic planning process. Two applications will be discussed in this paper: a general purpose financial model of Newmont, and a detailed operational/financial model of Magma Copper Company. Newmont?s general purpose financial model was developed using Lotus 1-2-3. It was designed to aid management in assessing the financial consequences of investment and financing decisions associated with long-term strategic planning by simulating the consolidated effect from individual transactions. Not only is the model capable of assessing the sensitivity of specific decisions to changes in the external economic environment (i. e., commodity prices, interest rates, inflation and exchange rates), it can also evaluate the effect from operating and financial decisions, including changing production levels and cost structures at individual operating units as well as simulating several types of transactions, including equity and debt issues, acquisitions and divestitures. The analysis of Magma Copper Company required the development of a detailed operating and financial model of the Company. The model was developed using IFPS in the corporation?s UNISYS (then Burroughs) B7900 mainframe computer and included separate pro forma financial statements for each of San Manuel-Pinto Valley's mines and concentrators, as well as Magma's smelting and refining operations. The outcome of this analysis was the decision to merge Magma Copper and Pinto Valley Copper Corporation, and to recapitalize the new corporation in order to provide funds for a retrofit and expansion of its Arizona smelter and expansions of its refinery and SXEW facilities.

Jan 1, 1989

Quality Assurance has become a buzzword amongst governments and industry. Notwithstanding the world class work done by its committees in developing codes of ethics and of practice in field geological handbooks, mining cost estimation handbooks, and reserve estimation, the AusIMM could better prepare its membership for QA. MICA could provide a simple set of guidelines to enable consultant members to develop their own QA procedures manual conforming to AusIMM Codes and to IS09003, and AS3903.

Jan 1, 1994

[Adams, Leonard E .................... 8 19 Newhouse Bldg., Salt Lake City, Utah Adams, V. H ............................. 422 E. San Miguel, Colorado Springs, Colo: Allen, Earl W ........................... 2636 S. Gilpin St., Denver 10, Colo. Allen, Thomas ......................... State Coal Mine Inspector, State Office Bldg., Denver, Colo. Ambler, J. B .............................. P. 0. Box 591, Denver, Colo. Andrew, William . Boulder Valley Coal Co., Louisville, Colo. Apperson, A. B. .................... Brown Hotel, Denver, Colo. Arnold, G. O. ........................ Dawson, New Mexico Audin, Abel .......................... Somerset, Colo. Audin, Clement, Jr ................... Paonia, Colo.]

Jan 1, 1947

By S. Frimpong, D. Ali

For achieving bulk economic excavation, large dump trucks are being used in majority of the earth moving operations resulting in high impact shovel loading operations (HISLO) which exposes the operators to high levels of whole body vibrations (WBV). As the truck ages, hydro-pneumatic suspension struts loses their capability to effectively attenuate the vibration. A system is required to monitor and predict the performance of the suspension struts in real time. Machine learning and artificial intelligence (AI) has been applied for modeling and predicting the suspension system performance for lighter/smaller vehicles. However, no work has been done to implement machine learning or AI for modelling and predicting the performance of hydro-pneumatic struts in large dump trucks. Therefore, current work is going to be a pioneering effort towards developing machine learning and AI models for solving this problem. Support vector machine (SVM) and regularized dual non-linear regression has been implemented in order to achieve the goal. 3D virtual simulator for CAT793D was used to conduct experiments in MSC.ADMAS environment. The two main recorded outputs were the RMS accelerations in the vertical and horizontal directions at the operator seat for characterizing the performance of the suspension system. During the development and the training of the models, eighty percent (80%) of the total experimental data was used and the remaining 20% was used during the testing and validation of the developed models. SVM model showed the desired accuracy in terms of hydro-pneumatic suspension system performance prediction for large dump trucks. These models can be implemented in the dump truck controller which can then be used to monitor the performance of the suspension system in real-time, and with that proper maintenance and/or replacement can be scheduled by the maintenance personnel. Workplace safety, operator’s health and the overall system efficiency can be greatly improved with an implementation of such an intelligent system. INTRODUCTION Large capacity dump trucks are being employed in any earth moving operation throughout the world for achieving bulk economic excavation [1, 2]. A large dynamic impact force is produced with large capacity shovels dumping material weighing 100 tons or more in to the dump truck under gravity. This dynamic impact force generates high frequency shockwaves which travels throug0068 the truck body, chassis and reaches the operator’s cabin and thus exposes the operator to severe levels of whole body vibrations (WBV). Recommended safe limits have been listed by the International Standards Organization (ISO) in sections 1, 2, 4 and 5 of ISO 2631 (1997, 2003, 2001 and 2004). An operator can got through a long term back, shoulders, arms and neck disability and disorders if exposed to the WBV levels beyond those limits. The dynamic impact force generated as a result of the high impact shovel loading operations (HISLO) was modelled by Ali and Frimpong [2]. Furthermore, the complete methodology for optimizing the dumping process and reducing the impact force has been provided by Ali and Frimpong [1]. The vibration attenuation system present in the dump truck requires improvement in addition to the dumping process optimization. The vibration attenuation system in the dump truck commonly consists of hydro-pneumatic suspension struts. As the dump truck ages, its suspension system deteriorates and therefore loses its capability to effectively attenuate the shockwaves and the resulting vibrations produced by the dumping process. The deterioration tales place due to the contamination of the hydraulic oil or oil and nitrogen mixing or due to the gas accumulator diaphragm rupturing. The monitoring of the output vibration levels can be used to evaluate the effectiveness of any suspension system. With the dump truck suspension system, the vibration levels at the operator’s seat can be used for the evaluation of the effectiven

Jan 1, 2019

By E. Ghali, J. F. Dorion

This paper presents the results of on-going investigations on the influence of corrosion on the performance of support systems in selected underground gold mines. Rock support is exposed to various conditions that can be aggressive. Samples of corroded support were analysed using SEM and photomicrography to determine the main corrosion forms. Tests are on-going in controlled corrosion chambers to qualify and quantify the impact of rock and minerals particles on steel corrosion. As more data become available these relationships can lead to useful information on the choice of support systems and reliable estimates of their longevity.

Jan 1, 2011

Education for the Mineral Industry in Australia developed in an uncoordinated but effective fashion till the mid 1960's, with recognised quality in graduates, with output matching demand, and with industry needs being fulfilled. Then in the space of a further 20 years, as company structures expanded, as the number, complexity, and costs of mineral projects escalated, as educational facilities, costs and politics increased, as community perceptions and aspirations changed, as government control of minerals and education increased, and as mineral sales cycles and markets fluctuated widely, the very fabric of Australian Mineral Education fell in tatters. Extractive Metallurgy Education suffered most in this collapse, and no compre- hensive remedies have been initiated. We are all the losers. In the 1990's, the extraction of Australian minerals and metals will increase in international significance, and the education of Extractive Metallurgists must meet this need. After examining the current situation, a series of management strategies are proposed to enable Extractive Metallurgical Education to survive and prosper in the next two decades and beyond. These strategic proposals involve industry, the government, the educational bodies, and individuals, in a range of short and long term objectives, policies, and actions.

Jan 1, 1984

By John P. Briand III, Douglas J. Aghjayan, Robert E. Fosse

This paper highlights the successful pile load testing program for the redevelopment of Pier One in East Boston, Massachusetts. Pier One is a 5.4-acre parcel on a dormant waterfront site used in the 1950s as a warehouse and distribution facility. The developer plans to re-use the existing 14-inch-diameter concrete-filled steel pipe piles to support four 5- to 7-story apartment buildings above a 2-story parking garage. A pile load testing program was developed to establish if the existing piles could support design loads of 240 kips for project financial feasibility and up to 300 kips for a significant reduction in future foundation costs. The Phase 1 program consisted of statnamic and dynamic load testing on two piles with two loading intervals (200 and 240 kips). Based upon the favorable results of the Phase 1 program, the Phase 2 program involved statnamic load testing on two piles and dynamic load testing on ten piles with three loading intervals (200, 240, and 300 kips). The Phase 2 program confirmed the favorable results which were applied across varying strata thicknesses and pile embedment depths. The average allowable capacity for the piles tested was greater than 300 kips with pile movement up to 0.3 inches.

By M. D. Raganya

The Kriel Colliery is an Anglo Coal mine which is contracted with Eskom to produce No. 4 seam for Kriel power station. The mine previously found it uneconomical to mine No. 5 seam due to the low qualities and tonnages of the seam, both at the opencast and underground sections. An area has been encountered for the first time at Kriel Colliery opencast pit 5, where the tonnage and qualities of No. 5 seam warrant further investigation. The primary reason for the investi¬gation of No. 5 seam by Kriel Colliery is because of the advantage of the high selling price (R450/t) that the market is currently prepared to pay for the No. 5 seam. The aim of this project is to mine No. 5 seam economically without interrupting No. 4 seam mining operations. The problem is that the equipments that are currently being used at the mine belong to Eskom and are dedicated to mining No. 4 seam only, not No. 5 seam. Through geology investigation, it is found that the whole No. 5 seam (No. 5 seam upper and lower) has an average thickness of 1.8 m. It also contains a parting of carbonaceous shale which divides the seam into two parts. No. 5 seam upper contains less tonnage compared to No. 5 seam lower. The calorific value and ash content of No. 5 seam lower is far better than No. 5 seam upper, but would still require washing the coal. This makes No. 5 seam lower the preferred seam to mine because it meets the requirements of the customer which is Highveld Steel. It is a coincidence that the area containing No. 5 seam under investigation encounters high overburden problems. The problem of drilling to No. 4 seam was going to be encountered because the thickness of the overburden ranges from 35 to 39 m. The Gardner Denver at the mine can drill blastholes only to a depth of 34.5 m, meaning the full overburden will not be drilled at once. This means the mining of No. 5 seam will do favours for Eskom because the overburden thickness will be minimized. This then led to an agreement between Anglo Coal and Eskom to mine No. 5 seam because both companies benefit from the project. In order to identify a suitable mining method for No. 5 seam lower, literature studies took place. It is found that San Juan mine from the USA has similar geological features to Kriel Colliery's No. 5 seam. Through comparisons, it is found that truck and shovel mining would suit the geology of Kriel Colliery's No. 5 seam since San Juan mine is using it. The sequence of mining No. 5 seam lower allows for a clearance of two cuts between the truck and shovel operation and the dragline. The mining sequence of No. 5 and 4 seam will be in the order of top soil removal; soft overburden pre-stripping; pre-strip drilling; pre-strip hard overburden; No. 5 seam lower coaling; interburden drilling and blasting; interburden stripping and No. 4 seam coaling. Financial evaluation of the project shows that a contractor will charge Kriel Colliery (Anglo Coal) approximately R 102.2 million to mine No. 5 seam successfully. The sales of No. 5 seam lower will provide a profit of R99.4 million at a yield of 70% from the washing plant. The project is beneficial to both Eskom and Anglo Coal because Eskom will have eliminated the problem of pre-stripping and Anglo Coal will generate additional profit. Through investigation and analyses of the project, it is proven to be viable and should take place. This is after looking at the advantages that the project has for Anglo Coal and Eskom. Keywords No. 5 seam, truck and shovel mining, Kriel Colliery, No. 5 seam mining at Kriel Colliery opencast, Anglo Coal and Eskom, No. 5 seam upper and lower, top soil removal, soft overburden pre-stripping, pre-strip drilling, pre-strip hard overburden, No. 5 seam lower coaling, interburden drilling and blasting, interburden stripping, No. 4 seam coaling.

Jan 1, 2011

By Mariana Xavier Milagre

As tensões residuais são geradas, sobre um material em equilíbrio, após a deformação plástica não uniforme causada por cargas mecânicas, térmicas ou mudanças de fase. Falhas estruturais podem ocorrer por uma combinação dos efeitos das tensões de serviço e das tensões residuais o que torna importante a medição e avaliação de como estas afetam as propriedades mecânicas dos materiais. Neste trabalho investigaram-se os valores médios das tensões residuais da fase austenítica de amostras de aço inoxidável duplex UNS S32304 por técnica de difração de raios-x. Acompanhou-se o comportamento do plano 420 com radiação CuKa (?= 1,5419 A ) em difratometro de geometria Bragg-Brentano. As amostras foram tratadas a 600°C com tempos de encharque de 10 minutos, 20 minutos e 8 horas em atmosfera ambiente e resfriamento ao ar e água do mar. Os resultados foram analisados pelo método do sen²? e indicam que as variações microestruturais e térmicas, relacionadas aos diferentes tratamentos, influenciam o valor médio das tensões residuais da fase em estudo.

Aug 8, 2018

By G. L. Gates

The Bureau of Mines in cooperation with the City of Long Beach) Calif.) studied some physical factors effecting the deposition of barium sulfate scale in oil-well rotary pumps. Freshly formed barium sulfate was obtained by combining sulfate in sea water with barium from a barium chloride solution. The rate of scale deposition was measured quantitatively by weighing the pump impellers and diffusers. The results of the tests showed that coating the impellers with plastic significantly reduced the rate of barium sulfate deposition.

Jan 1, 1967

The locality from where these specimens come is distant about 12 miles due south from the township of Bingara New South Wales, and is known locally as Carney's Reef, Barrack's Creek, Top Bingara. The formation traverses the western side of a serpentine spur from the main range, which runs through the country from the other side of Tamworth to Inverell, in the New England District. It has a due north and south trend, with an easterly underlay slightly out of the vertical. The formation has been opened up at different points for a distance of over two miles, and each place showing gold in the stone, and no place more than three to four chlins apart, the whole distance along the line of Reef being leased. The formation varies in thickness, the smallest being about 1 foot and the widest about 10 feet. The following is a list of properties, and description of work done on them at present. First south, and about one and a half miles from Hanion Brothers' old BalIarat claim due north, Court and patty hold a tenacre lease. The formation outcrops near the south boundary, and gold is obtainable in the stone. In the centre of the lease a costeen pit has cut the capping, which shows gold, and about two chains from the north boundary another one cuts the capping, also showing gold. The reef averages, where exposed on this property, 3 feet wide.

By R. V. Higgins

A computer program is presented to calculate the shape factors and volumes of cells from a potentiometric model, using coordinates of the inter-sections of the stream lines and equal potentials and a few additional coordinates. Shape factors are used in flow computations when the geometry is complicated. The program also includes computer instructions to divide the channels into cells of equal volume and to obtain the shape factor for each of these equal volume cells. An illustrated example using the potentiometric model for the waterflood of a seven-spot well-spacing pattern is presented. The information contained in the report is of value not only to those allied to the subject but also to others, because many of the techniques can be conveniently used in formulating other computer programs.

Jan 1, 1966

By Basil W. Mercer

Increased emphasis on industrial pollution control has intensified investigation of waste treatment technology for methods of reducing the amount of pollutants discharged by industry. The mining and mineral processing industry can point to a record of considerable accomplishment in the field of wastewater treatment and reclamation because these operations are so frequently an integral part of the entire operation of an ore dressing facility. This is amply demonstrated by metal producers in the arid regions of the Southwest where water shortages require maximum use of available water. For example, the copper industry in Arizona during 1960 employed an estimated 184 billion gallons of water of which 87% was reused water. (1) Only 0.0003% was discharged to streams and the remainder was consumed by evaporation (8%) and seepage (5%). The most severe pollution problem facing the mining and ore processing industry today is that resulting from acid mine drainage. This problem is largely associated with the mining of coal although it occurs to a lesser degree with the mining of other materials. The degradation of streams by acid mine drainage in the vicinity' of the Appalachian coal fields has been widely publicized and a major effort is underway to determine the best means of correcting this situation. Other forms of pollution from mining operations are less well-known, but it is anticipated that improved or advanced waste treatment techniques will be required for segments of the industry to comply with new pollution control regulations. The current emphasis on redefining hazardous levels for heavy metals and various chemicals with regard to the total environment will in all likelihood lead to tighter discharge controls in some cases. It is the purpose of this paper to review some of the waste

Jan 1, 1971