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he Wyalong goldfields were discovered in September, 1893, Messrs. Neeld and Sons, owners of the principal mine, being the pioneer prospectors. During the earliest days of the field the ore was sent to Barmedman, a distance of eighteen miles, for treatment at a battery there. The field rapidly increased in importance, and it was not long before a public battery was established on the spot. After some considerable quantity of ore was treated by this process, it became apparent that battery treatment was quite unsuitable for the richer ores, involving, as it did, considerable loss in the tailings. Recognition of this fact led to the erection, in 1895, of plants by the Wyalong Chlorination and Cyanide Works, owned by Mr. Walter Sully, for treatment by their processes; followed, at a later date, by Messrs. Neeld and Sons Chlorination Works. The Wyalong Chlorination and Cyanide Works, after a delay of twelve months in the erection of their plants, have since catered continuously up to the present time for the requirements of the field.Their plant consists of a No. 3 Gates' rock·breaker, a revolving dryer, a No. 5 Krupp mill, revolving roasting furnace with finishing hearth, two chlorination vats of 20 tons capacity each, "nine cyanide vats of 30 to 100 tons capacity, two Wheeler pans and three chlorine generators. The ores are purchased outright on assay at a fixed scale of charges, and treated by the owner of the works on his own account.

Jan 1, 1903

A study of the accessory opaque iron-titanium oxide minerals of the Oiles Complex, central Australia, was an Important complement to an investigation of the magnetic properties of the Complex. These minerals constitute no more than 10 per cent of the rocks sampled, and generally less than 1 per cent of the ultramafic rocks ("magnetite" concentrations were not sampled for magnetic investigation).Titanomagnetite is the main opaque mineral present, although ilmenite exsolution has been widely developed. High-temperature oxidation of these produced mainly titanohematite, pseudobrookite and rutile. Both exsolution and high-temperature oxidation developed along specific crystallographic directions (along {111}), and in Irregular patches. Low-temperature oxidation is generally not well-developed, indicating the small degree of weathering in the rocks sampled.Although the Oiles Complex is layered, no apparent overall preferred orientation of the iron-titanium oxide minerals was observed, other than crystallographically controlled alignment of very fine grains within pyroxene crystals. Other textural features of the opaque oxides are restricted to symplectic intergrowths mainly with the ferromagnesian silicates.

Jan 1, 1971

By David Davidson

Overview- Points To Be Addressed ? Review the building blocks of a successful and vibrant industrial economy ? China?s current position in the global economy ? China?s voracious appetite for raw materials ? Distortion in import/export trends ? Areas of strategic importance for China - Steel and its components - Agriculture self sufficiency - Energy now and for the future ? Do current valuation techniques fairly value ?strategic? assets? China ? The Economical Miracle - Massive shift in population from rural to urban - ?Middle class? growing rapidly, hence strong consumer growth - China is the manufacturing center for the world ? cheap labour and - modern facilities - Infrastructure build out ?US$585b stimulus package and 5 year plan - Rail ? 30,000 kms of new track planned by 2020 - Power ? 50% capacity increase, including 35 nuclear reactors - 100 major new airports - State of the art process and manufacturing facilities - Port capacity ? 100m TEU capacity increase by 2020 Class 1 national highway ? 35,000 km?s by 2020

May 1, 2010

By Julver Álvarez

El presente trabajo describe el comportamiento estructural y mineralización del estaño-cobre en la mina San Rafael, Puno. En este sentido, las pizarras de la formación Sandia del Ordovisco Superior, por metamorfismo de contacto con el intrusivo, han sido transformadas a hornfels, que junto a las cuarcitas se presentan algunas veces como una cubierta superficial sobre el intrusivo. Asimismo, los intrusivos y las pizarras son favorables para la mineralización de estaño, aunque los cuerpos del mineral son más definidos y persistentes en el intrusivo.

Sep 13, 2001

By Kristen E. Coose

Concrete is a mixture of a fine aggregate (sand), a coarse aggregate (gravel), cement, and water. Cement itself is the most expensive of the ingredients but generally amounts to only about 10% of the concrete mixture. Cement raw materials include calcium, alumina, iron oxide, silica, and gypsum. They are heated and chemically changed into clinker "minerals," which are then ground and shipped as cement. Each of the four main clinker minerals-tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite-impart specific strength and compositional properties to the final concrete product. During hydration of the cement, chemical changes produce new minerals that include calcium silicate hydrate gel (C-S-H, the main constituent of hydrated cement paste), calcium hydroxide, and calcium, sodium, potassium, and sulfate ions, among others. Two main reactions can occur that may be deleterious to concrete. Normal cement pore solutions, in a hydrated cement, contain sodium hydroxide and potassium hydroxide. If these alkali concentrations are too high, they can react with the siliceous aggregate (alkali-silica reaction, or ASR) to form an alkali-rich calcium silicate hydrate gel (C-N+K-S-H), which, upon prolonged contact with water, can expand to crack the concrete. The other deleterious reaction occurs when the mineral ettringite (Ca6A12(S04)3OH12. 26H20) forms after the concrete is hardened (delayed ettringite formation) and cracks the concrete. Many of the concrete bridges and structures built in New Mexico in the past 20 years are in need of replacement due to deterioration. Many others constructed very early on in the century are still sound. By collecting and analyzing samples of both old and new concrete and good and bad concrete, we compared their differences on both a microscopic and macroscopic scale. Samples taken from concrete sidewalks, parking lots, drainage canals, spillways, and a railroad-trestle foundation have construction dates that range from 1923 to 1997. They were analyzed by electron microprobe and by petrographic microscopy. Cracks, air voids, and aggregate alteration were primary locations for investigation and analysis. Using the electron microprobe, ettringite was found in voids of most of the samples, both in good and bad concrete. This leads us to believe that ettringite formation is not causing distress in the concrete. There was one exception in which ettringite was found lining a crack. In this instance, ettringite may have the ability to further the cracking and cause distress. No alkali-silica gel was identified with the microprobe. Using the petrographic microscope in cross-polarized light, a light-brown material was observed that lined some of the air voids and cracks; however, exact mineralogic identifications were not made. Although many instances of chalcedony and other deleterious quartz phases were found, no clear evidence of ASR-gel deterioration was present in our samples using these methods. However, positive identification of the ASR gel was made on an in-place concrete near one of our sample sites and in several sample cores using a newly developed chemical test for the soluble potassium ions associated with the gel. The chemical used in this test is sodium cobaltinitrite, Na3Co(NO2)6.

Jan 1, 1999

By Ronald F. Balazik

This Bureau of Mines study identifies and examines the costs of Federal, State, and local environmental protection controls on domestic phosphate rock mining, The costs include the expenditures needed to comply with government regulations and the effects that these expenditures and regulations have on supply. The study analyzes costs of environmental impact assessments, air and water quality standards, reclamation laws, potential solid waste controls, and local government restrictions. In addition, an industry survey and the Bureau's Minerals Availability System (MAS) are used to evaluate land management policies that restrict access to phosphate resources, Conclusions drawn from these analyses confirm that (1) domestic phosphate mining has incurred substantial control costs and may be subject to significant new regulatory costs in the next several years, (2) certain environmental controls can discourage mining investment, (3) environmental policies governing land-use controls affect the disposition of sizable phosphate resources, and are key determinants in the development of those resources on the Federal do- main, and (4) environmental costs could diminish the competitiveness of domestic producers.

Jan 1, 1983

By J. Borlée, J. P. Birat

"ULCOS is a large European program launched by a consortium of 48 partners led by arcelor and a core group of steel producers, which was started in 2004 with the support of the European Commission (RFCS and 6FP programs) to search for breakthrough process routes that could, in the future, when fully developed, demonstrate the potential of large cuts in CO2 emissions for the production of steel from iron ore.The timescale for commercial implementation is the post-Kyoto period, i.e. 15 to 20 years from today.The present paper presents the progress made in the first 2 years of this 5 year program.Several concepts are being investigated in parallel: re-engineering of the blast furnace to incorporate CCS in the core of the process, smelting reduction with CCS capabilities, massive use of natural with more CO2-lean technologies than today, hydrogen steelmaking and electrolysis of iron ore. Biomass also offers very attractive perspectives, while raising major challenges.None of these new steelmaking routes are ""no regret"", which means that the European Steel Industry has already incorporated extensive energy saving steps in its present process technology and is working as close to thermodynamics limits as is cinematically and economically feasible, and that decreasing GHG emissions further means introducing breakthrough technologies that add significant costs to the operation of the Steel Mills.They will also require much research and development before they can be proven and implemented commercially.IntroductionThe ULCOS program (Ultra Low CO2 Steelmaking) is a large research program of the European Steel Industry and its industrial and research partners launched in September 2004 to investigate steelmaking technologies that have the potential of reducing the CO2 emission of the Industry by a large amount, typically in the order of 50%. It is supported in the European Community by the 6th Framework and the RFCS programs through 3 complementary European projects [1,2].The present paper summarizes the work carried out in the phase 1 of ULCOS and in framing the program of phase 2."

Jan 1, 2008

By S. L. George

The semi-solid metal casting process results in a unique solidification path. The microstructural features that were identified during the characterization of the as-cast microstructure, were used as evidence of the process history in order to determine the solidification path followed during the evolution of the microstructure. The morphology of the grains was characterized using SEM and the extent and distribution of the elemental segregation within the grain structure was analysed using EDS. Keywords Semi-solid casting, solidification path, segregation.

Jan 1, 2011

By F. Calizaya

This paper describes the basic requirements for the utilization of belt air to ventilate working sections at remote locations in relation to the main fans. It highlights the risks involved, potential problems, and the provisions that must be followed by mine operators for the safe use of belt air. The paper also presents a brief review of the current regulations, conveyor belting tests, atmospheric monitoring system requirements, and the experience gained by mine operators to utilize the belt entries to ventilate remote working sections or areas where mechanized equipment is being installed or removed. The paper concludes with a set of recommendations with respect to the utilization of belt air and the composition of belt material in under-ground coal mines.

Jan 1, 2008

By Bianka Nani Venturelli

Estudou-se o efeito do tamanho de grão austenítico nas propriedades de tração do aço Hadfield refinado com Hf. Estas propriedades foram comparadas com as de um aço Hadfield sem refino, ambos com a composição química de acordo com a norma ASTM A128 – grau B2. Adicionalmente, foram usadas técnicas de caracterização macroestrutural, microestrutural e fractográfica. A caracterização macroestrutural mostrou que o aço Hadfield com adição de Hf apresentou tamanho do grão austenítico (600 ?m) aproximadamente cinco vezes menor do que o do aço Hadfield sem refino (3000 ?m). Os resultados do ensaio de tração mostraram um pequeno aumento (~6%) no valor do limite de escoamento com o refino do grão, em acordo com a Equação de Hall-Petch para materiais austeníticos. No entanto, os resultados dos ensaios de tração do aço Hadfield refinado mostraram aumentos que não foram previstos para as propriedades de resistência à tração (~37%), alongamento (~53%) e tenacidade (~88%). O exame fractográfico dos corpos de prova de tração indicou predominância do mecanismo de fratura dúctil para o aço Hadfield sem refino, enquanto que o aço Hadfield refinado apresentou predominância do mecanismo de fratura intergranular dúctil.

Oct 30, 2017

Despite technological improvements and better understanding of the hazards, coal dust explosions stilI occur. Experimental explosions in galleries in various countries extend knowledge with the constant aim of providing safer working conditions. The inadvertent ignition of an accumulation of methane is the traditional initiator of the coal dust explosion.There are specific parameters of coal dust explosibility and explosion propagation, including the important volatile matter in the coal, fineness and dispersibility of the dust and its concentration. Accepting that initiation cannot be absolutely prevented, it is necessary to consider explosion suppression. While both limestone dust and water are the chosen explosion suppressants, in practice water has more limitations to its efficacy when related to the degree of explosion violence. These data give rise to the criteria for explosion suppression, differences in favoured mining geometries, and using the same principles, to differences in suppression treatments.

Jan 1, 1988

By B. Mishra, A. Staley, D. Kirkpatrick

The major waste product of the alkaline extraction of alumina from bauxite [Bayer Process] is known as red-mud. Approximately, a ton of red-mud is produced for every two tons of bauxite mined. The red-mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that over 90-wt. pct. alumina can be recovered from red-mud by soda-ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of over 94 pct resulting in attempts for magnetic separation. These separations are desirable in the notion that there is no waste product generated from this type of processing and consequently an opportunity for complete utilization of the waste material. Conversely, the pre-separated material could be charged through the tuyeres in an iron blast furnace or smelted to produce pig iron. If smelted, the concentration of titanium oxide in the slag will be significantly high justifying its recovery by established acid-leach process. This paper describes the results of alumina recovery and the plans for titanium oxide recovery from red-mud. In addition, the situation of ongoing efforts in iron extraction, particularly, the method of magnetic separation of the reduced material. The problems associated with the use of reduced red-mud as an alternative to direct-reduced iron [DRI] has also been discussed. Critical assessment of the recovery sequence chosen for the products has been described based on economics.

Jan 1, 2001

By M Stewart

Alluvial gold deposits in the area studied are preserved on the valley floor and elevated terraces due to a sequence of glacial/interglacial events during Pleistocene and Recent times. Continued regional uplift has overprinted these events. Prospecting by drilling and bulk sampling has demonstrated a complex alluvial gold resource which is now being mined.

Jan 1, 1989

By Dippenaar R, Evans T

Twin-roll continuous casting technology is rapidly approaching commercialisation. Fundamentally different than conventional continuous casting, heat transfer and hence solidification during twin-roll casting are governed by the interfacial melt/mould thermal resistance, as opposed to the resistance of the solidifying shell. Under these conditions the interface resistance is predominantly controlled by the melt/substrate wetting behaviour. The very early stages of melt/mould contact are characterised by highly transient heat transfer conditions. The overall melt cooling rates prior to the formation of the first solid are reported to be in the range of 1000 - 50000 K/s with melt undercoolings of up to 300 K. At the points of intimate melt/mould contact the thermal resistance is approaching zero, where cooling rates and undercooling much larger than those reported in the literature are probably occurring. Improved wetting will reduce the energy barrier for nucleation while at the same time increasing the cooling rate of the liquid. Since the overall nucleation rate is controlled both by the rate of cluster formation and the rate of atom transfer to the nucleus, a critical cooling rate will exist above which the nucleation rate is expected to be reduced. Under these conditions, it is possible that the first solid phase to form is a metastable glass which subsequently transforms into a crystalline phase. The implications on nucleation and early growth are also discussed.

Jan 1, 1999

By Daniel Alves Sodré

O processo de eletroerosão por penetração permite a usinagem de componentes metálicos nas mais variadas condições de tratamento termo mecânico e durezas. Entretanto, as tabelas e fórmulas tecnológicas empregadas para a execução deste processo não consideram essas distintas condições do material com uma variável. Desta forma, este trabalho objetivou avaliar a influência dimensional na usinagem via eletroerosão por penetração em componentes com e sem tratamento térmico de têmpera seguida de revenimento. Foram avaliadas amostras de aços ferramenta largamente empregados na indústria, representados pelas normas ABNT NM 122 Graus D6 e O1 e ABNT NM 87 Grau 1045. Observou-se uma variação dimensional de 20?m entre as amostras.

Aug 17, 2017

By R. Bitmead, R Barker, A. Drake

The opencut coal mine is located about 50 km west of Brisbane, the capital city of Queensland in Australia and produces about 140 000 tonnes per annum of high grade steaming coal utilising a small team (ten) of personnel to mine remnants of the Aberdare and Bluff seams left by previous underground mining. This, in itself, is not remarkable except that one of the seams has commenced spontaneously cornbusting resulting in temperatures in excess of 55’C commonly being encountered with portions of the p’it being wreathed in steam. To extend mine life, the mine required a blasting system that would: . Safely blast in temperatures below 100°C . Significantly reduce overall unit costs . Not increase the current vibration impacts on nearby housing . Not increase flyrock.

Jan 1, 2002

By A. W. JR. Whitaker

Introduction Within the last quarter of a century the Lake St. John-Saguenay valley has been converted from a quiet agricultural district to one of the important industrial centres in the Dominion. First there was the expansion -of the pulp and paper industry, and then, starting a little over ten years, ago, the development, in large .blocks, of the enormous hydro-electric power resources of the Saguenay river. Coincident with this power development, the world aluminum industry was rapidly expanding and looking for a new source of cheap power. This was found in the Saguenay valley-and so, in 1925, Arvida was established by the Aluminum Company of Canada as a location for one of the largest aluminum plants in the world. Arvida, an incorporated city comprising an area of some ten square miles, is ideally located on a more or less level plateau about 350 feet above the Saguenay river. Seldom has industry stepped boldly forth and carved out of Nature a community with full city status. The process usually goes through the steps of camp, village, town, and city, involving improper planning or lack of planning; all of which has been avoided at Arvida by starting out in the right way. While this community has only a population of approximately 2,000 at the present time, it is carefully planned for a population many times this figure. Streets, city parks, business and residential sections, have been definitely planned, and, with a City government, proper ordinances were passed at the beginning to ensure the building and maintenance of a model industrial community. As the crow flies, Arvida is about 35 miles due east of lake St. John, and 0 miles west of the St. Lawrence river at Tadoussac. From a shipping standpoint, it is well served by the Canadian National railways, with direct lines to Quebec and Montreal, and by ocean shipping facilities at Port Alfred, which is about 15 miles to the east on the Saguenay river and is served by the Roberval & Saguenay railway. The latter has interchange connections with the Canadian National at Arivda, and also operates a branch line into the city of Chicoutimi.

Jan 1, 1933

By Ray. K. Filip

The concept of installing a steel sheet pile retaining wall into the ground by "pressing" has resulted in the development of various equipment solutions over the last thirty years e.g. Taylor Woodrow ?Pile Master', Giken 'Silent Piler" & Tosa 'Still Worker?. Dawson Construction Plant Ltd (DCP), have recently advanced the pile pressing concept with the introduction of their 'Push-Pull' system. This advancement offers significant improvements in the quality of installation compared with traditional pressing solutions but also greater versatility, higher productivity and, most importantly, generates new opportunities through a wider range of applications for "silent piling'. This paper will focus primarily on the use of the Push-Pull concept in the construction of a unique "integral" bridge in Milton Keynes, England. Finally, the paper touches on the development of quiet, vibration-less pile extraction equipment, which allows steel to be considered the foundation material of choice for truly sustainable construction. It is no longer acceptable to leave unwanted piles in the ground.

Jan 1, 2006

By C. L. Schneider, C. O. Gomes, R. P. King, J. A. Finch, D. Lin

Discussion is presented by Prof. King and Dr. Schneider of the paper by Lin, Gomez and Finch published in Trans.IMM C, vol.104, 1995, p.C155-C161. They conclude that the correction procedures used for simulated observations of simulated capped spheres are not reliable when applied to mineralogical data and that their relative ranking should not be extrapolated to other situations. Properly regularised solutions obtained with the use of appropriate kernels can be safely used for routine mineral liberation work and can be calibrated accurately against real mineralogical samples in the laboratory

Jun 19, 1905

By S. L. R. Lenharo, H. Kahn, H. Born

Different ore types result from the irregular spatial distribution of the associated alkaline/carbonatite rocks and the zoned alteration profile within which apatite may have undergone reprecipitation. Different flotation responses are caused by their mineralogy, iron oxide impregnation and grain-size characteristics. Samples from seven deposits were crushed, screened and separated before being studied by chemical analysis, optical microscopy, X-ray diffraction, FTIR spectroscopy, cathodoluminescence and scanning electron microscopy. Two main apatite varieties with peculiar crystal morphology were identified: hydroxy-fluorapatite as the primary phase and carbonate-fluorapatite as the reprecipitated phase. The former occurs as prismatic or ovoid grains and the latter as polycrystalline aggregates or crusts on the primary grains; both are associated with iron oxide coatings (primary) or intergrowths (secondary). Microflotation tests showed variations in flotability for particular apatite associations as well as intensity of iron oxide coatings. The differences in flotation behaviour can be related to morphological properties and chemical substitution in the apatite structure

Aug 1, 1996