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This investigation was planned to determine:1. The precipitation-hardening properties of the copper-nickel-phosphorus alloys; and2. The influence of arsenic and bismuth, singly and together, on the mechanical properties of these alloys.It was carried out in conjunction with an investigation, previously published in these Prooeedings on "The Influence of Various Elements on the Mechanical Properties of Copper containing a small percentage of Bismuth," and also formed part of a study of the influence of bismuth, nickel and phosphorus on the properties of commercial arsenical-copper.The first part of the present investigation arose out of a discovery some years ago of precipitation-hardening in phosphorus-deoxidized coppernickel boiler tubes, containing approximately 2% nickel and 0·03% phosphorus, supplied to an Australian Railways Department. At that time there was little information available on precipitation-hardening in copperrich copper-nickel-phosphorus alloys, but at the end of 1935 a short paper on the subject was published by E. C. Rollason and T. G. Bamford(2) and at the beginning of 1940 a comprehensive account was published by D. K. Crampton, H. L. Burghoff and J. T. Stacy.(3) Although the investigation carried, out independently by the present author was not as comprehensive as that of Crampton, Burghoff and Stacy, the results are in agreement with those of the American as well as of the British authors; hence, only a summary of this aspect of the work is needed here to establish a basis for a study of the influence of bismuth and arsenic.PREPARATION OF TEST PIECESAll alloys were melted under charcoal in plumbago crucibles in an oil-fired furnace and were poured out of contact with air into oil-dressed moulds to give billets either 7· 5 in. long X 0.83 in. diam. X 1·3 lb. weight or 12 in. long X 1·125 in. diam. X 3·3 lb. weight depending on requirements (the larger size was used, for example, in establishing the annealing characteristics of the precipitation-hardening alloys). The raw materials were electrolytic copper of the composition described in the previous paper(I) 6% copper-arsenic, 14% copper-phosphorus, 1:7% copper-bismuth, and Mond nickel in the form of "shot." The method of producing test pieces from these billets and the annealing treatments ana tests to which the pieces were subjected have been described in the previous paper.

Jan 1, 1944

By Nino Catalano

The combination of two top levels of cross-lot braces designed and installed to act as a truss, and vertical post-tensioning of the panels allow the unbraced excavation of a 36' span. Philosophy of Excavation Support System The excavation of interest is for the cut-and-cover box sections of the southern approach to the Third Harbor Tunnel, which is part of the Central Artery/Tunnel project in Boston, Massachusetts. The 60' deep excavation is located very close to an existing building which is supported by piles, as shown in Figure 1. Therefore, it was necessary to minimize ground movement which may damage the building.

Jan 1, 1994

By R. B. Booth, W. F. Linke

The continuous interest of the American Cyanamid Company in producing superior polymeric flocculants and dispersants for the mining industry has resulted in a broad, general study of the physical chemistry of mineral-polymer systems. The aim of this program has been to establish a sound theoretical basis on which practical problems could be analyzed, and which would lead to the development of new and improved flocculating and dispersing agents. This study has required the cooperative effort of physical, analytical, and polymer chemists, as well as engineers familiar with mining problems. This report summarizes the results of some of our investigations over the past two years. Further studies along these and other lines are in progress and will be reported in the near future. MEASURING FLOCCULATION IN THE LABORATORY The foremost problem in studying flocculation in the laboratory has been to establish reproducible methods of comparing and evaluating the effectiveness of various reagents. Previous workers have measured settling -rates 1,8 filtration rates2 , and sediment volumes3 . Direct observations of the floc size, or the clarity of the supernatant liquid, can also be used. AIthough these parameters are all interrelated, they do not always measure the same physical properties of the suspensions, and hence are not equally useful or reliable. Whatever the method of comparison selected. the testing procedure must be carefully defined and standardized. The results must be satisfactorily reproducible, and for practical purposes must accurately reflect the results obtained in mill use. In order to compare the data obtained in these various types of test, the physical nature of the flocculated system must be examined in some detail. In an unflocculated system, only the larger or denser particles (the "sands") settle at a useful rate. The sediment can be observed to build up from the bottom of the cylinder, while the fines remain in suspension for a long period of time. If the system is not disturbed, even the microscopic fines can be seen to classify themselves as they fall over a period of days. When a high molecular weight polymer is added to the system, the colloidal particles are tied together randomly in flocs, and the sands and fines settle together. The line of demarkation between solid and liquid phases moves downward from the top of the cylinder. The settling rate of the flocs depends on their size and on their effective density. For a given mineral sample, the larger the flocs, the faster the settling. Since the large flocs cannot pack as closely as small ones, they produce a sediment with more pore spaces, and hence of larger volume, which is easier to pump and to agitate. Although it is nearly impossible to measure individual floc sizes, it is relatively easy to determine settling rates and sediment volumes. Of these two, the settling rate is simpIer to measure, and hence generally more practical. Reproducible sediment volumes can only be obtained by allowing the solids to pack for a rather long period of time (e.g., hours to days), and although the volumes thus observed are directly related to the degree of flocculation (average floc size), it is often impractical to wait so long for the results.

Jan 1, 1961

By Bali. D. D., S. Chattopadhyay

"The planning and construction of prime coking coal beneficiation plants in the nationalized mines in India are reviewed. Flow schemes, construction practice, materials consumption, and costs are detailed.Medium-capacity beneficiation plants with multiple loops are recommended under Indian conditions.IntroductionThe reserve of high-grade and easily washed metallurgical coal in India are quite limited. Prime coking coal constitutes approximately 22% of the total resources and occurs exclusively in the Jharia coalfield in the state of Bihar. Bharat Coking Coal Limited (a subsidiary of Coal India Limited (CIL) the nationalized mining sector of India) owns 80% of the Jharia collieries. The development of Jharia coalfield in the pre-nationalized period before 1971 has been characterized by a large number of small mines with primitive mining methods and low productivity. The production of prime coking coal to meet the demand of the steel industry in India has to increase from the existing level of 11.1 million tonnes to 43.4 million tonnes per annum by 2000 AD, thereby producing 5.61 million tonnes and 22.7 million tonnes of clean coal respectively. An ambitious program has been undertaken for development of bigger mines with an average production of 1 to 3 million tonnes per annum. With the fast dwindling reserves of good quality coking coal, more inferior grade coal seams, having difficult washing characteristics, are now being mined. All the coal from the future mines will have to be beneficiated to make it suitable for consumption of steel plants; the following washeries are being planned for construction by 2000 AD:"

Jan 1, 1986

By John A. Kiefer

Ground fault and overcurrent protection criteria for coal mine a.c. distribution systems were examined under a Bureau of Mines funded investigation. The report begins with a literature review which discusses relaying topics including instrument transformers, ground-fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground-fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter, which discusses relay system maintenance, introduces a unique test set which was developed by KETRON and used to test the performance of relaying systems in coal mines.

Jan 1, 1980

Dynamics of Three Phase Contact Line Motion in Liquid-Liquid-Solid Systems - Impact of Surface Roughness

Sep 13, 2010

By Robert A. Jankowski, J. Drew Potts

In this U.S. Bureau of Mines study, four underground respirable dust surveys were conducted to determine factors affecting belt entry dust levels and how using belt air to ventilate work areas affected dust exposures. Belt entry dust levels on the surveyed longwall and continuous miner sections averaged 0.59 and 0.26 mg/m3, respectively. The stageloader-crusher contributed an additional 0.5 to 0.9 mg/m3 of dust to belt air, while the feeder-breaker contributed 0 to 0.2 mg/m3 of dust. A 1,000-ft increase in belt entry length or a 200- to 500-st-per-shift increase in production resulted in roughly a 0.1-mg/m3 increase in dust. Using the belt entry as an intake entry on the continuous miner section appeared to reduce dust levels by 0.1 to 0.3 mg/m3 during cutting. Belt air was not used to ventilate the face on the longwall section.

Jan 1, 1992

By Ernesto Zelaya P

En el Perú, muchas de las empresas mineras se desarrollaron por la configuración de sus yacimientos explotados. Sin embargo, también se generaron limitaciones y restricciones en el transporte, extracción de mineral y/o desmonte dentro de las operaciones mineras. En este sentido, el presente texto señala una forma de inversión a través de un sistema de izaje, donde se realice un costo menos y una mayor productividad en la Unidad Minera Animón – EACH S. A. C. (Pique Jacob Timmers) y en la Unidad Minera Andaychagua – U. P. Yauli (Pique Roberto Letts) que son partes integrantes de las operaciones mineras de Volcan Compañía Minera S. A. A

Sep 12, 2011

By Fred N. Kissell, Andrew B. Cecala

In This Chapter [Where methane is emitted at longwall faces Where methane accumulates at longwall faces Using the modified shearer-clearer to eliminate ventilation eddy zones Using a walkway curtain to reduce methane buildup during the headgate cutout Control of frictional ignitions and The best location for the methane monitor] The methane released along a longwall face represents only 10%–20% of the total methane emitted from the entire longwall panel. Nevertheless, in very gassy coal seams, this methane released at the face can pose a problem because the shearer is a ready ignition source. Preventing methane ignitions at longwall faces requires four actions. The first is to provide better ventilation around the shearer to eliminate the ventilation eddy zones at the drums where methane builds up. These eddy zones are eliminated by mounting additional water sprays on the shearer to direct air into them. The second action to prevent methane ignitions is to install a water spray behind each cutter bit and regularly replace worn bits. Water sprays behind each cutter bit act to quench the hot metal streak that follows a worn bit when it strikes rock. The third is to ensure that no ventilation eddy zones are inadvertently created by poor placement of water sprays. The fourth is to ensure that the methane monitor on the shearer is in the best location to detect methane accumulations. ADDRESSING METHANE ACCUMULATIONS AT LONGWALL FACES3 Cecala et al. [1985a, 1989] and Denk and Wirth [1991] studied methane emission and ventilation patterns at longwall faces to find where methane accumulations are most likely. Although not always the case, the major source of methane at longwall faces is usually the breakage of coal by the shearer. Stress-related fracturing of the coal seam at the face, called bumps or bounces, can cause the release of additional gas (Figure 4–1).

Jan 6, 2006

By M. Seeger

The demographics and the growing numbers of people provide a strong signal that the demand for electrical power in Southern Africa will grow considerably over the foreseeable future. Without a steady and increasing supply of electricity development of the continent is likely to be constrained. The inventory of solar, wind, hydrothermal, geothermal and biomass resources will probably provide sources of energy for the future The parallels between extraction of natural resources in the minerals industry and the green energy industry is striking, and the well-established project development process in the minerals industry provides an ideal and useful template for comparing the establishment and development of green energy projects. The potential levels of power generation and carbon savings are described.

Jan 1, 2010

By Shepherd J

Megascopic and microscopic studies of cleats and mining induced cleavage in Ihe first workings at Leichhardt Colliery reveal the presence of four distinct fracture sets. Microscopic studies confirm underground observations of the fracture sets.The most likely order of formation of the fractures is (i) "butt" cleats (ii) facc cleats (iii) shallow dipping faults (iv) mining induced cleavage. Three fracture sets apparently formed by tensiIe failure. Microscopy shows that the mining induced cleavage surfaces have preferred starting or lerminating points at the extremity of a "butt" cleat and a vitrite-dull coal band boundary. It is postulated that the induced cleavage begins at 'butt' cleats which behave as Griffith flaws under high compression around Leichhardt Colliery faces. Instantaneous outbursts of coal and gas are associated with only those workings which are affected by mining induced cleavage and occur at or adjacent to working faces.

Jan 1, 1981

Reduce haulage truck accidents resulting from blind spots, with a special emphasis on reducing accidents during backing operations.

Jan 1, 1997

By J Wallis

The stability of a raise bore is often assessed using the rock mass classification system published by McCracken and Stacey as a modification of the Q system. Often the assessment is done using a spreadsheet to manipulate geotechnical log(s) of boreholes. This paper discusses the inherent difficulties with this approach. Recent work by others to provide guidelines to the classification system is discussed. A recent example of the design and raise bore performance at Macraes Gold Mine, New Zealand is presented. A key issue is that a visual assessment of the drill core and/or core photographs is necessary to æground-truthÆ the classification.

Jan 1, 2008

Professor Skeats said: I wish at the ,outset to express my appreciation of the h0!-l0ur conferred on me by my election as President of this Institute for the ensuing year. The selection of a geologist for this position by a body of mining engineers andmetallurgists may be taken as an indication of the recognition that the subject is one which may play a useful part in the great metal industry. Among the records of primitive man the finding of implements of bronze and of iron indicated one of the important, advances made in human civilization, and shows that...

Jan 1, 1924

By H. J. Uananisa, M. J. Papo, C. W. Siyasiya, W. E. Stumpf

"SynopsisThe need to reduce weight while maintaining good mechanical properties in materials used in the automotive industry has over the years seen an increased exploitation of various steels to meet this new demand. In line with this development, the ferritic stainless steel family has seen a wide application in this industry, with the AISI 436 type increasingly being used for automotive trims and mufflers for exhaust systems, as well as a significant part of this steel’s application being for the manufacture of wheel nuts and wheel nut caps in trucks, mainly through the deep drawing process. However, there have been reports of some poor surface roughening of this material during deep drawing, with tearing and/or cracking also reported in some instances. This has been suspected to possibly be associated with some local differences in localized mechanical properties between grains and grain clusters of the rolled and annealed material.In order to investigate the poor surface roughness exhibited by AISI 436 ferritic stainless steel (FSS) during deep-drawing, Lankford values (R-mean and ?r), grain size, and microtextures of various sheet samples from this steel were studied. The chemical composition range for the samples was 0.013–0.017% C, 17–17.4% Cr, 0.9–1% Mo, and 0.4–0.5% Nb. The steels were subjected to various hot and cold rolling processing routes i.e. involving industrial direct rolling (DR) or intermediate annealing rolling (IR), and the drawability and final surface qualities of the steels were compared. It was found that the DR route gave an average R-mean and ?r value of 1.9 and -1.4 respectively, while the IR route yielded an average Rmean and ?r value of 1.6 and 0.52 respectively. The high ?r value for the DR processing route had a substantial adverse effect on the drawability. IR samples exhibited a smoother surface finish on visual inspection, while clear flow lines were visible on the DR samples, despite the fact that DR is the preferred industrial processing route due to the reduced production costs it offers. This observation was also confirmed through SEM examinations. The difference in the surface quality was attributed to microtexture. However, the mechanism responsible for this difference still needs to be identified."

Jan 1, 2015

Advances in Coarse Particle Recovery - Fluidised-Bed Flotation

Sep 13, 2010

By J. A. López-Molina, S. García, V. Castellanos-Pedroza

"Groundwater inflow into underground constructions may cause hazardous working conditions and environmental problems. It is essential to localize and characterize potential flow paths and to estimate the amount of water leakages, so that appropriate sealing works can be performed. Estimating the amount of water ingress is a multi-phase process starting from qualitative and quantitative examination of rock mass. Due to association of uncertainty, vagueness and incompleteness with the monitored data set, particularly resulted from the in situ tests, accounting relevant approaches such Fuzzy Logic and Recurrent Neural Networks, are proposed in this research for learning acquisition, extraction of rules and prediction of behaviors. The computational set of artificial tools permits using the complex information entities or information granules (rock types, geologic structures, hydro-fracture potential) for data abstraction and derivation of knowledge from records (numerical or linguistic format). This is more a theoretical perspective than a set of methods or principles. As a theoretical perspective, this proposal encourages an approach to data that recognizes and exploits the information present in indexes at various levels of resolution or scales. In this sense, it encompasses the methods which provide flexibility and adaptability in the resolution at which knowledge or information is extracted and represented. The product of merging these tools is a 3D artificial-mapping of rock classification (Qi-system), geological conditions and Lugeon units that permits, as far as possible, to understand more and better the flow behavior."

Jan 1, 2015

By W. Barnett

The Limpopo Metamorphic Belt is a complex geological terrane with at least three major deformational events. Tectonically juxtaposed lithology, open to isoclinal folding, crosscutting and re-activated shear zones and metamorphic gneisses and schists make pit slope design and maintenance a risky business. Venetia diamond mine?s Cut 3 is planned to reach 360 m by 2011. The difficult rockmass created problems in the original pit and a new more comprehensive slope design was necessary. Nearly 9 km of geotechnical drilling were undertaken to produce a new geological model and provide geotechnical information near the final Cut 3 face. All existing data from the pit were brought together into a database. SRK Consulting were brought into the project to audit the process and provide most of the manpower for the data analysis. Existing failures were back-analysed and the geotechnical domains identified. Analyses of only the southern domains are discussed in this paper. Geotechnical engineers can design slopes at any angle, but it is up to the managers at the mine to decide what risk they are willing to accept in a slope design. Once the issue of risk was discussed and settled in respect of the consequences of failure, each of the main geotechnical domains were analysed to produce a slope design at5% probability of failure with 15% above the first ramp. A risk assessment of the design was then undertaken to determine what risk the design placed on the equipment, personnel and the profitability of the overall mining operation. The risk assessment indicated minimal risk to the operation. One of the main assumptions of the final design is that the pit slopes will be dewatered. A project was immediately put in place to determine a groundwater model for the mine and to thereby determine the best dewatering procedure. However, it should be obvious that it is practically impossible to prevent benches from getting briefly saturated with water during storm conditions. It was therefore necessary to look specifically at supporting the crests of the ramps in the problematic southern domains to guard against the possibility of crest failure during heavy rains. The data available were re-analysed toward this objective. Spiles were recommended as the most cost-effective support system, and a probabilistic approach was used in the design. The final design has a 5% probability of failure, and the analyses indicate a strong sensitivity of the required spile spacing to the strength of the reinforcement material that will eventually be used. The pit slope parameters derived as per the discussion in this paper have just begun to be implemented at Venetia Mine.

Jan 1, 2001

By Dwayne C. Kicker

This paper introduces the concept of design theory and methodology as applied to rock mechanics for more innovative and efficient design. This is a "frontier" research area in rock mechanics because although design is a fundamental foundation to all engineering branches, very little attention has been paid to this aspect in mining. In discussing the theoretical premise of design, this paper identifies the principles which form the basis of design activity. Also, from a practical viewpoint, the findings from a series of interviews with mine design engineers are presented. These findings lead to the identification of needs arising from overlooked design methodology in practice.

Jan 1, 1989

By F T. Suorineni, L Baird, A Papaioanou, D Hines

The Mathews et al (1981) stability graph was developed to provide guidance in the determination of stope sizes to control dilution in bulk mining of large orebodies. Longhole and sublevel open stoping (LHOS and SLOS) are the lower end in scale of underground mass mining with panel and block caving (PBC) at the higher end. Currently, the stability states of stopes in the stability graph are described qualitatively as stable, unstable or cave. The alternative quantitative option to the qualitative stability graph is the Equivalent Linear Overbreak Slough (ELOS) stability graph. The ELOS stability graph only applies to narrow vein orebodies. It is easy for the Mathews et al (1981) and the ELOS stability graphs to be applied outside the limits of their databases. What is currently referred to as ‘stable’ in the present stability graphs has diverse interpretations at different mines depending on their acceptable dilution values. In 2014, a research program was conceptually conceived at the UNSW Australia School of Mining Engineering to develop a quantitative dilution-based stability graph independent of orebody width to address some industry concerns on the use of the stability graphs. A dilution-based stability graph provides the mining engineer the flexibility to determine open stope sizes based on what dilution amounts are acceptable. The graph also unifies both the Mathews et al (1981) and ELOS stability graphs for wide and narrow vein orebodies, thus, eliminating their potential misapplications. To date, the concept is proven with case studies from metalliferous underground mining operations located across Australia. This paper presents the dilution-based stability graph concept, the initial results and future plans to account for other critical factors and increase confidence in its application with the addition of more data outside Australia.CITATION:Suorineni, F T, Papaioanou, A, Baird, L and Hines, D, 2016. A dilution-based stability graph for open stope design, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 511–522 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016