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By J. M. Gregg, C. J. Persellin, I. D. Somerville, E. A. Atekwana, K. L. Shelton

"Zn-Pb sulfide mineralization at Abbeytown mine and Twigspark quarry comprise the only known car¬bonate-hosted base metal sulfide deposits in the Sligo syncline, northwest Ireland. Limestone sedimentation occurred uniformly throughout the region during the Early Carboniferous (Mississippian) as observed by field relationships and lithofacies; however, petrographic and stable isotope evidence indicate that host-rock dolomitization occurred under different conditions at localities to the west and east of the Ox Mountains inlier, suggesting significant uplift and geologic isolation of these areas prior to dolomitization. Localized fluid flow systems are thought to be responsible for sulfide mineralization and associated epigenetic carbonate cements. West of the Ox Mountains inlier at Abbeytown, evidence of three geochemically distinct fluids are observed: (1) a lower-temperature, lower-salinity fluid (70°-130-°C, 4-9 wt.% equiv. NaCl); (2) a lower-temperature, higher-salinity fluid (70°-140°C, 15-24 wt.% equiv. NaCl); and (3) a higher-temperature, moderate-salinity fluid (165°-220°C, 8-14 wt.% equiv. NaCl). Similar fluid types were observed at the Twigspark deposit. The source of the higher-salinity fluid is likely seawater evaporated to near the point of halite precipitation. The higher-temperature fluid is thought to have been derived from deep circulation of basinal brines. It is speculated that mixing of the higher-salinity fluid with the high-temperature fluid was vital for ore formation at Abbeytown because fluid inclusions in sphalerite have homogenization temperatures and salinity values that fall along a mixing trajectory of these end member fluids. Also, areas where the high-salinity end member fluid is absent are barren of sulfides. Less complex fluid systems are indicated for sites east of the Ox Mountains inlier where no sulfide mineralization was observed. Data from base metal sulfide prospects in northwest Ireland indicate no connection with the regionally extensive flow system thought to be responsible for Zn-Pb deposits throughout the Irish Midlands.Les minéralisations en sulfures de Zn-Pb de la mine Abbeytown et de la carrière Twigspark sont les seules gîtes de métaux usuels à encaissant carbonaté connus dans le synclinal de Sligo, au nord-ouest de l’Irlande. Ces carbonates se sont déposés d’une manière uniforme dans la région au Carbonifère inférieur (Mississippien) tel que l’indiquent les relations de terrain et les lithofaçiès; les données pétrographiques et d’isotopes stables indiquent toutefois que la dolomitisation de l’encaissant s’est faite sous des conditions différentes aux localités situées à l’ouest ou à l’est de la boutonnière des Ox Mountains, ce qui suggère un soulèvement et une isolation géologique significative de ces secteurs avant la dolomitisation. L’action de systèmes de circulation locaux sont considérés être à l’origine de la minéralisation sulfurée et des ciments carbonatés épigénétiques qui leur sont associés. À Abbeytown, à l’ouest de la boutonnière des Ox Mountains, on note les effets de trois fluides géochimiquement distincts: (1) un fluide à basse température peu salin (70°-130°C, 4-9% poids équivalent NaCl); (2) un fluide à basse température fortement salin (70°-140°C, 15-24% poids équivalent NaCl); and (3) un fluide formé à plus haute température et salinité modérée (165°-220°C, 8-14% poids équivalent NaCl). Des fluides similaires ont été observés au gîte Twigspark. La source présumée du fluide le plus salin est de l’eau de mer amenée par évaporation près du point de précipitation de la halite. Le fluide à plus haute température est probablement dérivé de la circulation profonde de saumures dérivées d’un bas¬sin sédimentaire. Il est possible que le mélange du fluide à haute salinité avec celui à haute température ait joué un rôle central dans la genèse de la minéralisation d’Abbeytown parce que les températures d’homogénéisation et les valeurs de salinité des inclusions fluide"

Jan 1, 2009

By Fredrik Sarvell, Leo-Ville Miettinen, Veli-Matti Uotinen

"Abstract The continued concentration of building activities in cramped areas of city centres means more underground construction and facilities. Demand to minimize execution time and any kind of disturbance to business, general traffic, people and nearby technical structures is increasing. To answer these challenges foundation business has to develop schedule-wise and technically reliable deep excavation and foundation solutions in vulnerable surroundings and challenging soil conditions.Drilled pipe pile wall – RD-pile wall – is a combination of Ruukki drilled steel pipe piles and interlocking sections. Individual RD piles, typical diameters between 219 mm to 610 mm, are connected to each other with interlocks welded to the piles on the automated welding line at the workshop. The matching dimensions of the drilling system and interlocking sections allow the installation of RD piles through stones and boulders and even into the bedrock, if necessary, in a single operation. Installation is done by a down-the-hole hammer (DTH) using the centric drilling system and oversized ring bits or a drilling system consisting of a pilot bit and reamer wings.RD-pile walls have been used as permanent and temporary retaining walls for different kinds of demanding excavations and structures, such as bridge foundation, as quay wall and as sealing structure in rehabilitation of an existing dam. Rigidity and watertightness of the lower end of the RDpile wall is being researched as well as fire design issues examined. One of the most fascinating RDpile wall solution is to utilize the wall as a permanent underground basement wall. Reliable and rigid connection to bedrock decreases the bending moment and deflection of the wall and good fire resistance in addition to large variety of pile dimensions and steel grades gives possibilities to design and execute a cost-efficient basement wall and foundations without temporary retaining wall works. 1. IntroductionIn northern Scandinavian soil conditions, installation of sheet pile walls, or even secant pile walls, is often problematic due to the existence of hard and large boulders in the overburden, and especially when the retaining wall structure should penetrate to or into the hard bedrock. On the other hand, an efficient and reliable piling technique suitable for the demanding soil conditions described above, percussion drilling, has been developed since the 1960’s, and especially from the mid-1990’s, when the concentric drilling method with the ring bit and pilot was introduced. A new retaining wall application, the RD pile wall was developed by combining that drilling method with the widely used retaining wall solution based on steel pipe piles and welded interlocks (a pipe pile wall normally installed with vibratory or impact hammers)."

Jan 1, 2014

An understanding of the origin of mineral deposits and their relationship to local and global geotectonics is essential if regional targets for mineral exploration are to be chosen. Volcanism, metamorphism and tectonism are especially significant for the origin and emplacement of mineral deposits, which, far from being fortuitous oddities of nature, occupy well defined positions within distinctive lithofacies. Thus, suggestions for mineral exploration targets can be made taking into consideration the position of 'fossil' convergent and divergent plate tectonic boundaries to indicate areas of specific types of mineralisation. To be borne in mind, though, that level of exposure, time and location of magma generation are all additional and important controlling factors. To further understand the importance of the above parameters, one must refer to the concept of paired metamorphic belts (Miyashiro 1973) which develop during an orognic cycle. These belts are generally constructed in such a way that an ophiolite type complex with metamorphic grades related to high pressure and moderate temperature regimes is flanked by an area of calc-alkaline volcanism and granitic activity with metamorphic grades within a region of high temperature and low pressure. The former situation is usually the seat of primary magmatic mineralisation, whereas the latter contains base metal. Deposits of acid plutonic and volcanic association. As will be seen later, this particular metamorphic-volcano-orogenic situation is well developed in some parts of New Zealand. For the present purpose a distribution of potential ores as related to plate tectonic processes is given below:a) Divergent plate boundaries: primary magmatic Ni-Cu, Pt,Cr, PeS2 and Cu, Pb,Zn in hot brines-hydrothermal environments Mn deposits.b) Convergent plate boundaries: stratabound Cu-Fb-Zn-Ag of felsic volcanogenic association. Porphyry eu-Au of island arc type, porphyry Cu-Mo of continental type. Cu, Au, Y, Sn, Hg, Sb of vein type and replacement lode related to granitic activity.c) Au of hydrothermal vein association, related to late dynamo-metamorphic events. By virtue of ocean floor spreading, regions of divergent plate boundaries are eventually juxtaposed or welded n to areas where plate collisions occur. This is then followed by partial melting due to various causes, just above the descending plate; thus creating a zone of acid to intermediate magmatism. The final picture is that of an orogenic zone with the paired metamorphic belts outlined above.

Jan 1, 1976

By James R. Cosby

This report describes work performed for the Bureau of Mines to evaluate available portable instruments for their effectiveness in detecting and locating damaged metallic shields in Types SHD and SHC cables. A second phase of the program is also covered wherein several instruments of a type which show promise are purchased for modification and testing to verify their performance.

Jan 1, 1980

By R L. Brathwaite

The epithermal gold-silver deposits wall poster is one in a series of posters on different mineral deposit types being produced by GNS Science to raise awareness of the characteristics of New Zealand mineral deposits and their prospectivity. Epithermal deposits consist of quartz veins, quartz vein stockworks and hydrothermal breccias that are mainly hosted in subaerial andesitic or rhyolitic rocks of Tertiary age. The deposits were formed at depths of typically less than 1 km and at temperatures between 180¦ and 320¦C, although ore grade mineralisation was generally deposited at less than 270¦C.   In New Zealand, epithermal deposits occur in association with late Cenozoic volcanic rocks in the Northland, Coromandel and Taupo volcanic regions. All of the past and present gold production, estimated at greater than 380 t (along with 1300 t Ag) comes from the Miocene-Pliocene Coromandel Volcanic Zone, where about 50 epithermal gold-silver deposits occur over a 200 km long belt. In Northland, silver and mercury have been produced from hot spring type epithermal deposits, and several gold-silver prospects have been identified. Ore grade gold-silver mineralisation is currently being deposited in several active geothermal fields of the Taupo Volcanic Zone, and extinct geothermal systems occur on the western side of the zone. The active systems have provided natural laboratories to help understand the processes of epithermal mineralisation.

Jan 1, 2005

By R Young, D OÆSullivan

When Centaur Mining and Exploration produced nickel metal fromlaterite ore at its Cawse nickel project in January 1999, a new era in the nickel industry was heralded in. One of three new laterite projects commissioned that year, new technology and a unique process design has been combined at Cawse to launch what will be amongst the worldÆs cheapest nickel production. However, the road to success has proven to be long and challenging. This paper explores CentaurÆs approach to the Cawse start-up and discusses a number of issues that have been confronted and overcome. * Originally published in the Proceedings of the Seventh MillOperatorsÆ Conference, published by The AusIMM.

Jan 1, 2001

By J P. Ashby

Compared with elsewhere in the world, New Zealand quarries have tended to be mostly small. The reasons for this are a combination of the relatively high transport costs, low population density and a pioneering, self-employed attitude. The small size of the operations is reflected in low productivity, a tendency to repair and rebuild equipment rather than replace it, designed flexibility in the processing plant, minimal reserves investigation or development planning and a versatile and innovative work force who are generally not professionally trained. The Resource Management Act and the Health, Safety and Employment Act as well as a customer driven demand for higher quality and consistent products will have even greater influence upon future direction of the Industry. The trend will be towards fewer quarries operated by companies and professional managers that can adapt to the new demands.

Jan 1, 1993

By M. Mikolás, L. Pomothy, K. Špakovská, M. Vanek

"Enterprises are faced with increasing economic competition and managers are obliged to look for methods that will ensure a competitive edge in their companies’ markets. These methods include managerial concepts that employ common sense and are low cost. One of these approaches is the KAIZEN methodology, of Japanese origin; kaizen means continuous improvement (CI) when translated. A mining company, despite some of its idiosyncrasies, is just an enterprise where the application of KAIZEN can be advantageous. The company investigated, OKD, is the only domestic producer of hard coal in the Czech Republic and operates four mines that produce 11 Mt of coal annually. The OKD management team opted for KAIZEN as their principal method of continuous quality improvement. This paper suggests ideas for development and application of processes that provide for continuing improvement of production and management. The authors have taken the OKD Company to be their benchmark in the field of mining activities. The paper also focuses on possible difficulties accompanying the introduction of CI sustainable methods. Three years of application of CI methods has increased the income of the company by almost US$38.1 million, which provides a strong argument for continued application."

Jan 1, 2015

By M. Kawakami, K. Suzuki, T. Takenaka, S. Yokoyama

Molten NaNO3-NaNO2-KNO3mixture is used as a heat transfer medium at high temperature. One of the most important properties of this mixture is the heat capacity. In the present work, the enthalpy change with temperature was measured by the drop calorimetric method to evaluate the heat capacity. The results are summarized as follows: The enthalpy of the mixture increased linearly with the temperature. From the slope of the line, the heat capacity was evaluated. The heat capacity of pure NaNO3, NaNO2and KNO3was 0.129,0.110 and 0.142 kJ/mol/K, respectively. These values are in fairly good agreement with the published data. In the binary and ternary systems, the molar additivity of heat capacity, which is well known as Neumann-Kopp’s law, was obtained. The heat capacity of HTS1and HTS2, which are well known ternary mixtures of practical use, were in the range of published data.

Jan 1, 2004

By D. L. Murr, J. R. Jensen

Testing was conducted on a Minnesota Iron Ore concentrate with Cook Clay as a binder using compressive sheer mixing to enhance the performance of the agglomeration mechanism. The testing was conducted on a bench scale at the Midland Research Center the summer of 2004. Results of the test program will be presented that shows the impact of compressive sheer mixing had on the strength achieve in a green ball.

Jan 1, 2006

By J. P. F. Charpin

The transport of large boulders in a furrow from a mining area to a nearby pond was considered. The furrow is filled with a mixture of water and soil particles flowing down to the pond at high velocity. Due to operating constraints, the slope of the furrow is reduced progressively. A relationship is derived, relating the slope of the furrow and the composition of the fluid to the maximum size and shape of the transported boulders. The characteristics of the boulders carried all the way down to the pond may then be determined.

Jan 1, 2007

By S Hapugoda, M Kilburn, M Adam, L Lu

Lump ore is one of the key ferrous materials used in the blast furnace ironmaking process, typically accounting for 5–25 per cent of the blast furnace ferrous burden. Like other ferrous materials, the characteristics of lump ore have an important impact on stable operation and productivity of a blast furnace. As the cold burden lands on the top of the hot burden in the furnace and descends, it is inevitably subjected to thermal shock, which will likely lead to breakdown of the lump particles, or decrepitation and affect the gas permeability inside the blast furnace adversely. An ISO decrepitation test has therefore been developed to assess this behaviour of lump ore. However, the results obtained according to the existing standard decrepitation test method vary considerably between laboratories even for the same lump ore. To improve the test procedure of the existing decrepitation test, this paper first discusses the mechanisms leading to decrepitation and then studies the factors affecting lump ore decrepitation. Understanding the key factors affecting lump ore decrepitation is particularly important to improve the existing test procedure that enables researchers to achieve a higher degree of precision when conducting the decrepitation test.CITATION:Lu, L, Adam, M, Hapugoda, S and Kilburn. M, 2017. Decrepitation of lump iron ores, in Proceedings Iron Ore 2017, pp 91–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By David G. Borg

"Although researchers have realized varying degrees of success in numerics modeling, computer blast simulations and small scale in-situ testing, most will agree that the greatest uncertainty in total success stems from the uncontrollable field variables. Given the diverse nature of field conditiorencountered, no reliable and proven method of evaluating fragmentation quantitatively, and the lack of adequate field controls found in many operations, it is unlikely that a universal plug-in model will be developed for all blasting in the imediate future. This does not imply that all research devoted to modeling should cease, for it is precisely here where more research efforts are desperately needed."

Jan 1, 1989

By Nilce Alves Santos, Vânia Lúcia de Lima Andrade, Keila Lane Carvalho Gonçalves, Harold Wyslouzi1

"When confronted with the difficult decisions on advancing an exploration project to the feasibility and construction stages, it is important to know how various regions of the ore body will react in the milling and concentration processes. While bench scale test work is common and inexpensive, the results and information provided are somewhat limited due to the difficulty in accurately predicting the effects of recirculating middling streams or gradual changes in solution chemistry.Conventional Pilot Plants, processing 100 to 1,000 kg/hour of sample ore, provide the detailed engineering data required to develop a final process flowsheet and to size the equipment. They are, however, expensive to set-up and operate, and are really only viable for major projects that are well advancedIn the latter part of 1999, the Mineral Development Center at CVRD (MDC) purchased a new piece of mineral processing equipment which can run continuous flotation tests using drill core samples. To evaluate its performance, and to compare it with conventional testing methods, various types of flotation tests were carried out using two different types of copper ore. The limitations and advantages of open circuit and locked cycle bench tests, as well as the Mini Pilot Plant and the Conventional Pilot Plant were evaluated.Open circuit tests carried out at the bench scale only provide basic information. More complete and trustworthy information is obtained, in terms of the recirculation of flows and reaching a permanent and stable flotation regime, as the dynamics and complexity of the tests increases. The data obtained showed that the MPP’s metallurgical performance was equivalent to that of a conventional pilot plant."

Jan 1, 2002

By I. Ocak

Initial investment for mechanical boring of tunnels is found to be high in most cases. Conventional drilling and blasting is not the possible especially in urban area. In these conditions impact hammer offers many advantages over conventional drill and blast techniques and boring tunnels. These include improved safety, minimal ground disturbances, elimination of blast vibration, reduced ventilation requirements, reduced cost etc. Therefore, hydraulic impact hammers have been used widely in metro tunnelling projects in Istanbul since 1992. Accumulated and published data from various tunnelling projects serve to improve predicting the machine performance and scheduling of job duration. This paper is prepared under this objective. Machine utilization time of impact hammer was evaluated in this study. The main rock formation named Kartal formation arepaleozoic aged sedimentary rocks, shale, sandstone, siltstone, andesite dykes and sediment fillings. The first stage of the project is commissioned to Yapi Merkezi- Yuksel- Dogus- Yenigun- Belen consortium.

Jan 1, 2011

By William I. Busenbark, Elmer C. Newman

At Bingham Canyon, the world's largest open-pit copper mine, annual grease consumption is in the neighborhood of 109 000 kg (240,000 lb), all of which was 544 (120-16) purchased, warehoused, and distributed in 54-kg (120-1b) and 180-kg (400-1b) drums. While perhaps a menial and mundane chore, grease distribution shows on the ledger as a significant expense item. To improve labor and cost performance, Kennecott maintenance engineers undertook a study to find the most direct method for moving multi purpose grease (MPG) from the refinery to the point of final consumption. What they found was a direct vendor system for hulk grease so simple and flexible that long-established drum distribution is being phased out in favor of the newer method throughout 75% of the operation.

Jan 9, 1977

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 T. R. Jr. McMillan

Introduction Examining the short- and long-term job prospects for engineers in the coal industry might include looking at coal tonnage projections, future export markets, federal regulations, and the decrease in overall graduates. But coal is the US most competitive basic industry. As such, why not go back to basics? That is, there are three basic challenges that need to be faced by students, faculty, and members of the coal industry. These challenges are counseling, career placement, and professionalism. Counseling Counseling can include elementary, high school, and college students, as well as individuals already employed. But what happens to students after they have selected a course of study at a particular university? As shown in Fig. 1, only 87,000, or 7.25% of our graduates have technical degrees. Generally, there is a strong market projected for these engineering graduates. However, many students who have majored in other nontechnical curriculums, have to scramble for jobs. This says something about our ability to make students aware of where the real job opportunities are. As a student spends four or five years pursuing a degree, he or she is looking for professional guidance. The student has the right to expect "real world" counseling - counseling that is not "the way it should be" but "the way it is." The influence of faculty members is significant. They should take this long opportunity to tell students not what they want to hear or what the problem's of academia or the industry are, but what the real job market is all about. If faculty do not use this opportunity, they in-advertently-through omission - mislead their students. Once a student graduates and is a working alumnus, faculty should take advantage of their relationship with the student and continue to stimulate conversation leading to a two-way exchange of ideas and information. Faculty should also encourage and solicit financial support for their mining departments from their alumni. These monies, in many cases, will be matched dollar for dollar or more, depending on the company the alumnus works for. In the private sector, the responsibility is to communicate with faculty and students. Alumni can be effective by participating in this two-way dialogue with their professors at meetings, technical seminars, and conventions. In many cases, alumni will employ summer or co-op students in their organizations. While getting to know these students, industry members should level with them on where the true opportunities are and what it takes to be successful. It is important to communicate with both faculty and students candidly on both the posi-

Jan 2, 1985

By C. Bazin

Grinding circuits are operated in the presence of disturbances due to ore changes and equipment malfunctions. One of the challenges faced by the operators is the detection of a disturbance, the identification of its origin and of the action to correct the problem. Hydrocyclones overloading, worn or partly plugged apexes of the units of a nest, surging and internal liner detachment may cause a loss of classification capacity and quality leading to a less efficient grinding operation. A dynamic simulator is used to assess rules for the diagnosis of hydrocyclone faults from the trends produced by sensors.

Jan 1, 2009

By Tapio Leskinen

"l. IntroductionA reliable sampling system is the basis for an on-stream analyzer. This was realized in Outokumpu company when the development work of the Courier 300 On-Stream X-ray analysis system was started. Because Outokumpu Oy is a mining and mineral processing company, its engineers have been able to thoroughly test sampler prototypes in actual operating situations. The sampler development has been going for several years in close co-operation between company's concentrators, the Institute of Physics and the Instrument Division of Outokumpu Oy. The most active part of the work was done between 1969- 1972. Besides the reliable operation of a sampler special attention was paid to the representatively of the samples taken by the samplers. 2. The Courier 300 Sampling SystemThe sampling system comprises up to fourteen sampling circuits in one Courier analysis system. Each circuit consists of the following components:1. Primary sampler 2. Secondary sampler 3. Cleaner screen 4. Feeding tank5. Sample cell6. Timer-controlled sampler7. Pumps, sumps and pipesSecondary samplers, cleaner screen and feeding tanks are included in the secondary sct1npling system. The sample cells are located in the spectrometer cabinet of the analyzer."

Jan 1, 1976