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By Elipio Pérez Coronado

El presente trabajo describe la aplicación del método de corte y relleno descendente mecanizado y el método de almacenamiento provisional en la mina Santa Bárbara, ubicada en Cerro de Pasco. Para el primer método, son mayores e intedependientes las operaciones unitarias, limitando la producción y generando mayores costos en el relleno chancado. Mientras que el segundo método, es aplicable en los cuerpos "Vasconia" y "Manuel", siempre que cumpla con tres condiciones principales que hacen posible su efectividad en la mina: la primera, señala que la explotación se realice en los pisos superiores y luego, en los inferiores; la segunda, refiere que la explotación son mayores las se haga en retirada y la tercera indica que el espacio no debe ser rellenado. En este sentido, el método de almacenamiento provisional resulta ser el más idóneo para la explotación de cuerpos irregulares en la mina Santa Bárbara puesto que su capacidad al término del acarreo de mineral es ilimitada.

Nov 8, 1984

By Hiroyuki T. Takeshita

Ca-Ni based alloys were investigated on structures, hydrogenation properties and the effect of additive elements on hydrogenation properties. CaNi, samples were decomposed to form a new hydride with a CsCl-type structure on the constituent metal atoms at high temperatures such as 673K in a hydrogen atmosphere. The candidate of the third element which was added to stabilize the original compound was investigated by using the Miedema's semi- empirical model and, as a result, Pd was chosen. The hydrogenation of CaPd was conducted with a Sieverts' type apparatus and the synthesis of Ca-Ni-Pd ternary alloys was performed by high frequency heating.

Jan 1, 2002

By P. M. Sullivan

The principles and application of amalgam electrolysis to the recovery of zinc and tin from secondary products were studied; this Bureau of Mines project was one phase of investigating the development of more efficient methods for processing iron-bearing zinc and tin to produce both base metals of high purity. Zinc of 99-99-percent purity was recovered from galvanizer's dross with recovery efficiency of 98 percent. Tin of 99.9-to 99.99-percent purity was recovered from hardhead with recovery efficiency of 81 percent. Both materials were treated by the same method in separate systems. Mercury was used to leach zinc from dross and tin from hardhead to form amalgams of each metal, both of which were subsequently refined electrolytically to produce high-purity metal. Impurities that were contained in both secondary products behaved as theoretically predicted; impurities that were insoluble in mercury remained as sludge in the leaching column. Except for lead, the readily amalgamated impurities were prevented from fouling the electrolyte by the blocking action of the amalgam electrode. Lead impurity in the tin-refining system dissolved and immediately precipitated as the sulfate. The primary advantage of the amalgam refining method lies in direct recovery of the extremely pure base metal from highly contaminated secondary material.

Jan 1, 1961

Beaches contain the residue of eroded rocks which have resisted weathering, and it is common to find in all beaches some of the harder, heavy minerals. The natural sorting action of waves and winds tends to concentrate the heavy minerals into banded deposits.The value of such deposits is extremely variable. Even amongst the more concentrated deposits, the principal minerals, in the vast majority of cases, are magnetic, titaniferous magnetite and other forms of iron oxide, which, in the present state of mineral economics and technology, are of little or no value.Valuable minerals of fairly common occurrence in beach sand deposits are rutile, zircon, ilmenite, monazite and chromite, and each of these minerals, as well as others of less common occurrence, is obtained from beach deposits in various parts of the world.Along a stretch of 300 miles of coast from Coff's Harbour in New South Wales to North Stradbroke Island in Queensland, occur unique concentrations of heavy minerals. The principal minerals which occur are rutile, zircon and ilmenite, and for some years these deposits have contributed half to three-quarters of the world's consumption of rutile and zircon 1, ,2. The only other notable beach sand concentrations in Australia are at a number of places in the southwest of Western Australia, where deposits containing highgrade ilmenite are being developed.

Jan 1, 1950

By J. D. Sudbury, J. E. Landers, D. A. Shock

The external corrosion of casing is one of the most important problems facing the present day production man. A 1953 NACE report' estimated the annual cost of casing corrosion at $2,200,000 in 22 fields studied. The fields represented only 10 per cent of the wells in the United States. It was significant that 77 per cent of the failures reported were due to external corrosion. A variety of means for combatting the casing corrosion problem have been discussed in papers such as the NACE survey' mentioned previously. No attempt to revicw these will be made in this paper. Thc scope of this paper has been limited to a discussion of the following major items: (I) an instrument for studying external electrolytic corrosion; (2) use of this instrument to determine the quantity of protective current required to prevent corrosion of casing; and (3) problem of accelerated external corrosion of the oil string at the base of the surface string. ELECTROCHEMICAL MECHANISM OF CORROSION It IS gcncrally belleved that one major cause of external corrosion is the existence of electrolytic cells operating between various formation waters. A theoretical discussion of the role of earth potentials in casing corrosion has been presented by L. de Witte and F. J. Radd.2 A brief picture of the electrolytic corrosion action between two differcnt formations (A and B) is presented in Fig. I. This picture is a review to many but is given to insure clarity. In the anode area, oxidation takes place as iron ions go into solution in formation A as a product of corrosion. In the cathode area. reduction takes place and hydrogen atoms are formed at the boundary between the pipe and formation B. The flow of electrons. as indicated. is into the pipe at the anode or corroding area and out of the pipe into the formation at the cathode. In order to conform with regulations of this journal, the flow of a conventional current (I! is also indicated in this sketch. All subsequent references will be to this so-called conventional current flow and will be indicated by the symbol (I). As this action takes place the layer of hydrogen developed on the cathode offers a resistance to the flow of current in the cell. It is said (hat the cathode has been polarized. This polarizing film can be rcmoved by addition of a so-called dcpolarizing agent which reacts with and removes this hydrogen film. Such an agent must be present in ordcr for this corrosion reaction to go at a rate sufficient to cause a severe corrosion problem. The two common depolarizing agents are: (I) oxy-sen. which readily reacts with hydro gen to form water, and (2) certain bacteria which use atomic hydrogen as part of their life process. It is not difficult to explain the presence of these agents. Oxygen may be present in some very shallow formations. Sulfate reducing bacteria are found to exist in nearly any ground where mud pits might be dug. THE CASING POTENTIAl-PROFILE Instrumentation A sketch of the equipment* uscd in determining casing potential profiles is shown in Fig. 2. The tool is run in the hole using a hoist truck with a three-conductor cable. This tool must be run with tubing and rods out of the hole and should be run with the flow line disconnected. By proper choice of electrode size it can be run in any size casing. The electrodes must be run in an open hole or a hole filled with oil. Measurements cannot be made while immersed in water. The tungsten carbide-tipped knives serve as the electrical robes and arc spaced 25 ft apart. The potential difference along a 25-ft section of casing is measured with a potentinmeter to an accuracy of about 5 mv. Current flowing in the pipe can then

Jan 1, 1956

By D Kentwell

A resource model serves two main purposes depending on the stage of a project. The first is to provide an early indication of likely tonnages and grades at certain cut-offs so that decisions can be made on whether continued spending on the project is justified. The second is to provide a basis for mine planning, feasibility studies and reserves. Resource models are not designed for selection of actual blocks in the ground for processing. This is the purpose of a grade control model, which is created at a stage beyond both resources and reserves.Inferred, Indicated and Measured Resources contain different levels of uncertainty with respect to the accuracy of the resulting grade and tonnage curves. These uncertainties arise from three broad areas: quality of information, geological assumptions and estimation technique. This paper focuses on known problems with the ordinary kriging (OK) estimation technique. Resource estimates often produce smoothed block grade distributions with much lower block grade variability than true selective mining unit (SMU) block grade distributions. There are two main factors that are involved in this smoothing. Firstly, where the block size used for estimation is larger than the SMU block size, this will smooth the block grade distribution and move the grade and tonnage curves away from the true SMU block grade and tonnage curves. Secondly, and less well recognised, is that smoothing is inherent in the OK estimator. This also moves the grade and tonnage curves away from the true SMU grade and tonnage curves, even when the estimate is done at the SMU block size. There are a number of techniques, such as simulation, uniform conditioning and degraded search neighbourhoods that can provide a better approximation of the true SMU block grade and tonnage curves at the expense of individual block accuracy.This paper aims to explore the extent to which OK resource estimates designed to maximise individual block accuracy can differ from (an estimate of) the true resource at SMU block size in terms of grade and tonnage curves. The differences at economic cut-offs and above are examined. In some cases these differences are significant. Both the OK estimation technique and block size play a part in the differences observed. To do this we will examine a number of commodities and deposit types using real project data.The conclusion is that the current industry standard default practice of targeting maximum individual block accuracy (conditional unbiasedness) using OK at resource stage, without consideration or evaluation of the extent of associated smoothing at SMU scale, can lead to significant errors in fundamental mine planning decisions. This then has implications for resource classification if the classifications are based heavily on the OK quality without consideration of the true SMU distribution.CITATION:Kentwell, D, 2014. Aligning resource estimates with mine planning, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 185–192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By Xuanxue Mo, Kaihui Yang

"Abstract- The Laochang mine, located in the Sanjiang area of southwestern Yunnan Province of China, is a volcanogenic massive Pb-Zn-Cu sulfide deposit. It is hosted by a pyroclastic sequence of Barly Carboniferous age, namely the lower member of the Yiliu Group, which was intruded by syenite and rhyolite porphyry . The volcanic suite is basaltic or basaltic-andesitic in composition, has alkaline affinities, and is associated with the initial rifting along the margin of the Baoshan-Shanstate continental rnicroplate (Yang, 1989). The ores are typically Pb>Zn>Cu in composition, averaging 3.820Jo Pb, 3.51% Zn, from 0.01% to 1.85% Cu (0.107% av.), a high average content of Ag (113 g/t) and recoverable amounts of Au, Tl, Gd, Ga, Ge, In. A massive sulflde zone, in which lenticular and stratiform orebodies are localized in a sulflde-carbonate-silica shale unit or sulfldic tufflte horizon that usually overlies coarse-grained pyroclastic rocks, is underlain by a stringer sulflde zone developed in a subvolcanic intrusion or volcanic sequence. The sulfide mineral assemblages, from the top to the bottom of the deposit, are: realgar + orpiment - galena + sphalerite + pyrite- chalcopyrite + pyrite + pyrrhotite + arsenopyrite. Oxide and sulfate minerais occur rarely in the massive ores. The massive ores are generally fine-grained and banded, but coarse-grained ore, colloform and framboidal texture, and growth-zoned pyrite and sphalerite are common. Sedimentary features such as graded bedding, brecciated and deformed ore clasts, and chaotically emplaced blocks, are well preserved, indicating that the massive orebodies have undergone slumping and dis­ placement. Alteration is weak in the hanging-wall rocks, but strong in the stringer zone. Two dis­ tinctive alteration zones have been identified: the upper zone, characterized by an assemblage of quartz, carbonates, chlorite, albite, zeolite and sericite, and the lower zone containing diopside, trema­ lite, actinolite, gamet, clinozoisite, and epidote.The general features of the Laochang deposit are in accord with the descriptive mode! of VMS deposits (Lydon, 1984). However, it falls into neither the Zn-Cu group nor the Zn-Pb-Cu group chemically (Franklin et al., 1981). The depositional setting of the Laochang deposit is quite different from Cyprus or Besshi-type massive sulfide deposits. Laochang is hosted by alkaline lavas that were erupted in a submarine continental rift. Although some features of the Laochang deposit are similar to those of Kuroko-type deposits, there are remarkable differences in the alteration mineral assemblage, the proportion of ore-forming elements (lead enriched) and the amounts of oxides and sulfates. These suggest corresponding differences in ore fluid composition and the associated ore-forming environment. Thus, the authors suggest that the Laochang deposit may be a distinct type of VMS deposit."

Jan 1, 1993

By Shengping Li, Wei Lv, Gangqiang Fan, Xuewei Lv, Yingyi Zhang

The electrical conductivity of high titania slag, as being an important fundamental physical property utilized in the theoretical understanding of mass transfer phenomena and requirement of practical electric smelting processes, were measured by AC Impedance Spectroscopy using four-electrode method for ternary TiO2–FeO–Ti2O3 slag system based on 85 type of titania slag in Panzhihua in this work. The experiment results show that the slags have a high magnitude of the order of 80–180 s/cm−1 in the whole experimental temperature range from 1523 to 2013 K. The Ti2O3 exhibits very strong effect on increasing the electrical conductivity of high-titania slag since the specific values averagely increase by 55 s/cm−1 with corresponding Ti2O3 content range from 10 to 16 wt%. the X-ray diffraction gram and phases calculated by FactSage are presented and interpreted to discuss the impact of phase change on the electrical conductivity.

Mar 1, 2017

By N. Grosland, G. Kopp, T. Hunstad, D. Wilder, M. Contratto, S. Rahmatalla, T. Xia

Chronic whole-body vibration exposure, as expected in large construction and mining vehicles, has been associated with neck and back pain and injury.1 While work has been done towards gaining a better understanding of the relationship between vibration and shock and muscle activity of the back musculature2, relatively little information regarding the activity of neck, shoulder and upper arm muscles is known. Today’s equipment designs must conform to domestic and international standards, however these standards do not specifically address the vibration exposure in the head and upper quarter. Further it is not well known how the control configuration within a vehicle (e.g. steering wheel versus arm controls) influences muscle voluntary and reflex activity levels. Greater muscle activity may lead to greater muscle fatigue – which in turn may be associated with greater risk of injury.2 Thus, muscle contractions needed to maintain static postures as well as those resulting reflexively should be considered during an analysis of seating position. Unfortunately, little is known regarding the influence of arm position on head and neck muscle function. The purpose of this study was to investigate the relative muscle activities of 5 neck, shoulder, and upper arm muscles during riding simulations of large construction equipment, using three different arm control options. Methods Five typical heavy equipment ride files were “played back” through a man-rated Servo Test 6-degree of freedom (dof) vibration system. Each ride was repeated using 3 seat and control configurations (steering wheel (SW), floor mounted arm-rest controls (FM), seat mounted arm-rest controls (SM)). Two trials were performed for each ride and seat control combination (each trial: 60 sec of 6-dof and 60 sec of vertical vibration). Five channels of surface electromyography (EMG) of the right-side cervical erector spinae muscles (neck extensors), sternocleidomastoid (neck flexor), upper trapezius (shoulder elevator), biceps brachii (elbow flexor) and triceps brachii (elbow extensor) muscles were collected throughout each ride (~ 2min) using pre-amplified (10x), 1 cm silver bar electrodes, with 1 cm fixed inter-electrode distances (Delsys, Inc). Further analog amplification was set at 10k (1k for one subject), and sampled at 1000Hz using a 12-bit DAQ card and Labview 7.1 software (National Instruments). A total of 7 right-handed male subjects were tested, but only 5 had complete EMG data sets to analyze for this sub-study. EMG was analyzed using root mean square (RMS, in mV) of 20 ms moving windows, and then averaged across the entire trial for a measure of mean total muscle activity (voluntary and reflexive). The muscle activity to maintain the static posture was estimated as the mean RMS EMG over a 1 sec interval just prior to and/or after completion of the ride. Repeated Measures ANOVAs were used to test for with-in subject differences using a = 0.05.

Jan 6, 2006

By Barbara Rutter, Phillip Mulligan

This research investigates how changes in shock tunnel geometry affect the pressure versus time waveform. The Large Arena Test Simulator (LATS), which is composed of four different rectangular sections connected by three expansion sections, was used to determine how the changes in geometry affect the shock wave profile.

Feb 1, 2020

By Danilo Gonçalves de Oliveira

A linha de Decapagem e Laminação a Frio da ArcelorMIttal Vega vem recebendo constantes investimentos para aumento da sua capacidade produtiva sendo o mais recente a instalação do quarto tanque de decapagem química realizada em março de 2015. Para que esse investimento trouxesse o resultado esperado, eram esperadas melhorias de desempenho no processo de Laminação a Frio. O presente trabalho expõe a metodologia empregada para identificar os projetos necessários e os expressivos resultados obtidos com a sua condução ao longo do ano de 2014.

Aug 16, 2017

By E. W. Thorton

"This paper is intended to show that grinding media can effect flotation results, and in some instances the results are vastly different. I do not suggest that autogenous grinding is beneficial in the separation of all complex base metal ores, in fact I know of a case where autogenous grinding would be disastrous to any selective flotation. I do however contend that prospective flow sheets and reagent balances of any complex base metal ores should be tried with both types of grinding. I feel fortunate that the paper to be presented later in this meeting by Rene Klymouski will, I think, compliment and perhaps explain some of the results of my research.This paper will be in four parts. The first part deals with a literature survey on the subject. Surprisingly enough, very little information has been printed on the subject. The second part deals with results obtained in bench scale tests on an ore from Chester Mines Limited. It was in these tests that we realized that steel grinding was giving us serious problems. So bench scale tests are shown giving results with a stainless steel grind, a mild steel grind and a grind in a ceramic mill with ceramic billets.The third part of the paper deals with results obtained in the Mines Branch Pilot Plant, when again we ground the ore with three different types of grinding media. Incidentally, this has been the only pilot plant test made at the Mines Branch in which flotation products were made on both steel grinding and autogenous grinding on the same ore. The fourth part deals with two other New Brunswick ores and is intended to show that changing the grinding media effects ores other than that of Chester Mines Limited."

Jan 1, 1973

By Arnold K. Reese

It is not the purpose of the writer to set forth in these notes anything new or surprising in blast-furnace practice, but simply to lay before the Institute the somewhat unusual results obtained during a period of six consecutive months, ending April 30, 1896, at the Dover furnace of the Penn Iron and Coal Co., and to give, with these results, the conditions under which they were obtained, and all figures pertaining to that period. This plant was entirely rebuilt, on thoroughly modern and improved plans, in the spring of 1895, by Frank C. Roberts & Co., of Philadelphia.

Jan 1, 1898

Pressure drops were measured in a column packed with glass spheres and wax particles, both in random and preferential distributions. Variables investigated included wax content, gas flow rates, and temperatures.It is shown that for random distribution of wax, pressure drop is exponentially related to wax content above the melting point of wax and that below this it increases with increasing gas rate and temperature.For preferred distribution of wax the highest increase in pressure drop is obtained with horizontal distribution of wax and the least with vertical distribution.Comparison with operating blast furnace data and application of results to practice are also included.

Jan 1, 1970

By Cláudio S. S. Pinto

Em face do agravamento da situação da energia elétrica no Brasil, com disponibilidade cada vez mais restrita e custo cada vez maior, torna-se urgente reduzir o seu consumo onde possível. Ventiladores centrífugos de processo de médio e grande porte são grandes consumidores de energia elétrica e podem ter um elevado potencial para a redução do seu consumo. Este texto mostra como identificar a possibilidade de economizar o uso da energia elétrica em um determinado ventilador e que modificações ele necessita para cumprir este objetivo.

Sep 25, 2017

By R. F. Winkle

Shortly after World War II, considerable impetus was given to use of truck haulage in open pit mines by the manufacture of large off-highway trucks. Mine management was quick to utilize this more flexible approach to open pit operation and in the ensuing years much time and energy has been spent to improve the basic concept. Dramatic progress has been made in drilling, blasting, loading and hauling with much emphasis placed on equipment improvement. In general, haul roads in open pit mines and quarries have received rather perfunctory treatment in studies of surface mining operations. Their importance to the successful pit operation requires more than a brief sentence saying, "Good haul roads must be maintained." Haulage costs account for approximately one-third of total mining costs including general costs and about 90 percent of the total loading-haulage cycle time is consumed in travel, hence, good haul road planning, construction and maintenance are mandatory for a viable operation.

Jan 1, 1976

By Geovane Viturino da Silva

Um dos parâmetros relevantes no controle do fluxo gasoso em um alto-forno é o tratamento físico da matéria prima. Nos Altos-fornos da CSA através de ajustes em telas das peneiras de sínter elevou-se o rendimento de finos, trazendo benefícios significativos para o controle do fluxo gasoso. Neste trabalho é possível verificar a influência do aumento da eficiência de peneiramento na variação do fluxo gasoso e por consequência a redução no desvio padrão da carga térmica na cuba superior do Alto-forno. Com o fluxo gasoso mais estável, foi observado um aumento no rendimento de gás de topo e redução da variação na parede, assim foi observado os benefícios no fuel rate e produtividade dos Altos-fornos.

Oct 30, 2017

By W. J. Miles

At the beginning of the 20th century, barite was a mineral of minor importance in the USA. Its primary use was to extend lead oxide in white paint. Barite also added the special qualities of hiding power and flatness to paint. Because white lead sometimes turns black or yellow and barite does not, ground barite became a pigment on its own merit. Barium chloride was added to bricks before firing to stop efflorescence when exposed to weather. Barium carbonate or nitrate added luster and brilliance to glass. Barium chemicals were added to refining sugar, enameling iron, making oilcloths and paper collars, and in the manufacture of paper, artificial ivory, rubber and lithopone. Lithopone became a major paint ingredient in the 1920s; its use lasted until the 1950s, peaking at 150,000 metric tons of barite in both 1937 and 1947 for the manufacture of lithopone. Later in the 20th century, titanium dioxide replaced lead oxide, barite and zinc oxide in the coatings industry. In the 21st century, barite is used as a filler, extender, or weighting agent in products such as paints, plastics, and rubber. Some specific uses include its use in brake and clutch pads for automobiles, automobile paint primer for metal protection and gloss, add weight to rubber mud flaps on trucks, and add weight to the cement jacket around petroleum pipelines under water. In the metals casting industry, barite is part of mold release compounds. Because barite significantly blocks X-ray and gamma ray emissions, it is used as aggregate in high density concrete for radiation shielding around x-ray units in hospitals, nuclear power plants, and university nuclear research facilities. Ultra-pure barite consumed as liquid is used as a contrast medium in medical X-ray examinations. Barite is the raw material for barium chemicals, such as barium carbonate, which is an ingredient in faceplate glass in the cathode-ray tubes of televisions and computer monitors. In the 21st century, barite industrial uses account for an estimated 78,000 tons per year in the United States. Another barite use was patented in 1926 by the oil industry. In this patent, barite is primarily used as a non-abrasive weighting agent for drilling for oil and gas exploration and production. As a weighting agent, it provides the downward force in a water based or oil based drilling fluid for cutting through rock with a tri-cone diamond drill bit. In order to minimize the wear on the drill bit and drill stem, minimum abrasion of the weighting agent is preferred. In recent years in the USA, 95% of the barite produced and about 80% on a world basis are used as a fluid weighting material during the search for oil and gas. During the latter part of the 20th century, barite was used in the drilling mud of oil and gas wells, particularly for wells deeper than 2000 meters, and petroleum well drilling demand for barite became the mineral?s major end use during economic expansions after World War II and subsequent increased use of oil and gas in the USA. The profitability of oil and gas production had a strong effect on the number of drill rigs and consumption of barite. The United States was the leading petroleum well drilling country starting in 1970, reaching 4,530 drill rigs in December 1981, and was the largest consumer of barite. In the USA, record highs of about 2.6 million tons of barite produced and 4.3 million tons consumed were reported in 1981. From 1997 to 2006, barite production declined from 662,000 to 589,000 metric tons. However, USA imports increased from 1,470,000 to 2,530,000 metric tons for lump barite. World production of barite increased from 6,780,000 to 7,960,000 metric tons during the same period. Table 1 (see Appendix) lists USA production, imports and exports and world production from 1997 to 2006. Major sources of imported barite include China, India and Morocco. Table 2 (see Appendix) lists the USA imports and price of barite by country. China, India and Morocco are the three largest exporters of barite to the USA and the world. Vietnam is a new producer, beginning in 2006. IMPACT OF CHINA ON DRILLING GRADE BARITE In the 1970s or before, China began supplying barite to the world drilling market in order to help develop their economy. When China first entered the barite export market, their high production volume, low pricing and low ocean transport expenses to the Gulf Coast forced barite producers in the USA to supply only regional markets, such as Battle Mountain Nevada barite for the western and Rocky Mountain states and Canada. Until recently, it was China?s government policy for domestic consumers to use barite below the API 4.20 specific gravity specification, leaving higher grades for export, but this is no longer the case. In recent years the internal demand for barite in China increased tremendously as their economy rapidly developed. China reduced their former 15% VAT tax rebates to 5% for Chinese barite producers, and then eliminated all VAT tax rebates on December 15, 2006. On the supply side, some high-grade barite deposits in China have been depleted. In particular, the low heavy metals sources are less plentiful. Additional mine capacity is being developed, but the new mines are underground and therefore costs will be higher. China?s appetite for other raw materials has tied up a large portion of the world?s bulk vessel fleet, including Panamax vessels (preferred for barite ore transport). Ocean transport freight rates have increased in recent years, and receiving ports in the USA are congested with imports of higher-added-value products. The Panamax Index, which tracks maritime shipping rates, more than doubled in 2006. China has also devalued its currency from RMB8.30 to RMB7.80 per dollar. These factors are driving up the import price of crude and ground barite for drilling. In addition, in the USA, rail congestion and high fuel prices led to higher trucking rates, increasing the delivered cost of ground barite to oil customers. India is the second largest supplier of crude barite to the USA and world drilling market. It produces all of its barite from a single deposit in the Cuddapah region of Andhra Pradesh State. More than 90% of production comes from the State-owned Andhra Pradesh Mineral Development Corp., and the government continues to closely control production, export volumes, and prices. India saw a dramatic increase in barite prices as a result of its last 3-year tender in 2004. However, in 2004 and 2005 their shipments of crude barite to the USA were not significant. In 2005, India began supplying barite pulverized to meet API specifications to the Gulf Coast. In 2006, Indian production was reduced owing to severe flooding in November 2005 that curtailed mining until mid-April 2006. Morocco has been the third largest supplier of crude barite to the USA and world drilling market. In 2003 and 2004 their shipments of crude barite to the USA were not significant. In 2005, Morocco resumed shipment of crude barite to the Gulf Coast and began supplying barite ground to meet API specifications to the Gulf Coast.

Jan 1, 2009

By R. W. Leonardson

Tectonic activity in northern New Mexico during late Oligocene and early Miocene time presaged events which led to the development of molybdenite deposits at Questa. East-northeast directed crustal extension produced north-northwest striking tensional fracture systems paralleling the early Rio Grande rift. A sequence of Oligocene andesite flows and breccias is overlain by a thick early Miocene rhyolite ash-flow tuff. Eruption of the tuff initiated collapse of the Questa cauldron: the south margin of which occurs as an east-northeast striking, north-dipping structurally weak zone. Continued east-northeast post-cauldron extension permitted the high level emplacement of granite stocks with coeval rotational deformation of fault blocks composed of cauldron fill and [ ] floor. The stocks occupy north-northwest fracture zones in the south margin of the cauldron, and porphyry dikes occupy east- northeast striking faults that define the south margin. These two fracture systems have played a dominant role in localizing the intrusive porphyries and associated mineral deposits at Questa. A molybdenite-bearing breccia matrix and related stockwork mineralization generally occur within volcanic rocks. Mineral deposits are spatially related to fault zones and the upper con- tact of their source intrusives. Deposits are localized in fault zones up to several thousand feet long and 100 to 500 feet in diameter. Magmatic-hydrothermal solutions from the source aplite porphyries have produced potash metasomatic alteration which is strongly centered on the mineral and ore zones. Alteration in ore is represented by orthoclase, quartz and secondary biotite. This pattern grades into secondary biotite and propylitic zones forming successively weaker alteration assemblages away from ore. Younger phyllic and argillic assemblages are particularly widespread only where strong north-northwest extensional fracture zones cross the south cauldron margin.

Jan 1, 2013

By Leila Figueiredo de Miranda, Leonardo G. de Andrade e Silva, Anderson dos Santos Mesquita

ThisworkseekstounderstandifPETcompoundswithcarbonblackcan be uses to replace polypropylene and polystyrene for anti-static packaging mate- rials. PETcompoundswerefabricatedcontaining10.0;11.0;12.0and15.0weight % of carbon black with a particle size 325 mesh. We determined the thermome- chanical properties (Dynamic Mechanical Analysis—DMA, Tensile Properties, Fracture Toughness, and Hardness) and Electrical properties of the compounds. In conclusiontheresultsshowthecompoundbased onPETfilledwith 15.0% carbon black might be used in the handling, transportation and storage of electronic components because their mechanical properties, thermal and resistivity are satis- factory for this purpose. (cid:1) (cid:1)

Mar 1, 2018