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By P. M. Prasad

The last two decades have witnessed the emergence of numerous hydrometallurgical and direct processing techniques for the extraction of some metals from pocketed/lean/complex sulfide ore deposits. A new approach with some inherent technological merits, investigated in recent years, is the lime-enhanced reduction of metal sulfides. Thermodynamic aspects relevant to the lime-enhanced reduction of metal sulfides by H2,C0 and C are discussed. A survey of the researches on the basic features of and factors influencing the lime-scavenged reduction of selected sulfides and sulfide concentrates reveals that lime tremendously enhances the sulfide reduction rates (up to 100 times) and drastically reduces the sulfur emission into off-gas to negligible levels. Further successful practice of lime-enhanced reduction requires only a moderate temperature of reduction (characteristic of each sul¬fide) and, in the case of gaseous reduction, relatively low gas flow rates. Relevant kinetic aspects of the concerned reactions that have a bearing on process development and its understanding are also briefly discussed. A conceptual scheme of general applicability for the processing of sulfide concentrates by the lime-enhanced reduction technique consists of three main steps: (0 lime-enhanced reduction by a suitable reagent (e,g., H,2, CO, gasified coal, water gas), (ii) separation of the product metal from the dry slag (CaS + unused CO) by mechanical separation, magnetic/gravity concentration or flotation and (iii) melting and refining by standard procedures. This novel approach, which is patently less complex, is expected to employ basically simpler flow sheets at comparatively lower operational temperatures and aid in pollution abatement. Potential for developing such a route for the small scale extraction of metals like copper, molybdenum and antimony is indicated. Possibility of utilizing this technique for the production of fibers/ filaments of some metals is also outlined.

Jan 1, 1983

A list of publications of the United States Bureau of Mines, complete from its establishment to the end of June, 1931, may be had upon request. In addition a monthly leaflet of new publications is issued and is sent to those on the mailing list of the Bureau. Publications are separated into three main divisions: 1. Sales Publications.-Those for which a charge is made. Any orders or remittances in payment for sales publications should be sent directly to the Superintendent of Documents, Government Printing Office, Washington, D. C., and not to the Bureau of Mines. Sales publications are classified into (1) Bulletins, (2) Technical Papers, (3) Economic Papers, (4) statistical reports of the mineral resources of the United States, (5) Monographs, (6) Handbooks, and (7) Schedules. Bulletins and Technical Papers present the results of scientific and technical investigations. Economic Papers are analytical studies of production statistics, sources, resources, .distribution, and industrial flow of mineral commodities. The Annual Report, entitled "Mineral Resources of the United States," includes chapters, published separately, on the production and consumption of metals and of nonmetallic minerals. Monographs give detailed results of extensive cooperative investigations of special

Jan 1, 1933

By E. C. Winegartner, A. A. Ubbens

The company attempting to sell coal to large utility plants is faced with a confusing array of quality parameters and specifications which are often poorly understood by both the utility company and coal supplier. While these specifications are placed on the coal by the utility company, many of them originate with the boiler manufacturer who must guarantee that his product will perform satisfactorily on the design coal. A proper understanding of these parameters by both the coal supplier and utility company can lead to a better understanding of their mutual problem. This paper brings together most of the parameters in common use today and attempts to show what the parameters mean to the boiler designer, particularly in the area of boiler slagging and fouling.

Jan 1, 1977

By N Murphy and, S Santomartino, M Cramer

Acid rock drainage (ARD) can have detrimental effects on mining infrastructure, water reuse options and environmental discharge. As a result, some form of short- or long-term treatment is required at many mine sites. Successful treatment depends on a number of factors including the selection of an appropriate treatment technology and its correct implementation. A variety of passive and active technologies are available for dealing with ARD. Passive treatment solutions do not require continuous chemical inputs but take advantage of naturally occurring chemical and biological processes. They are often low cost, site specific approaches and are predominantly used in post-closure situations. Passive systems are well suited to drainage with low acid loads and low soluble aluminium concentrations, and are more effective with highly reduced (ie low oxygen) water. While they are often regarded as permanent fixes, most require some form of ongoing maintenance and all have an engineered life expectancy (ie finite carbonate and organic matter budgets). Passive treatments include, oxic limestone drains, anoxic limestone drains, limestone diversion wells, various reducing and alkalinity producing systems, pyrolusite limestone beds, aerobic and anaerobic wetlands, permeable reactive barriers (organic ¦ carbonate and zero valent iron), slag leach beds, and gas redox and displacement systems (GaRDS). Active treatment solutions require a continuous or semi-continuous activity (eg reagent dosing) to correct water quality issues. They can be engineered to treat virtually any type of drainage or site specific ARD issue, and have no set acid load or redox limitations. Tasks handled by active treatment systems are almost invariably larger and more costly than for passive systems. Active treatment approaches include; pH control, adsorption/absorption, ion-exchange, electrochemical concentration, biological mediation/redox control, flocculation/filtration and crystallisation. A range of generally available and proprietary technologies has been developed around these approaches. Active treatment involving pH correction with alkaline amendments is the most common and cost-effective form of ARD treatment. A variety of fixed plant and portable treatment systems are available. Calcium-based reagents, including quicklime (CaO), hydrated lime (Ca(OH)2) and limestone (CaCO3) remain the reagents of choice for the majority of active ARD treatment worldwide. This is principally due to their widespread availability, non-proprietary nature, and variety of proven dispensing technologies and cost-effectiveness. Limestone, in particular, is a very low cost reagent. However, due to æefficiency of useÆ problems with limestone in passive treatment systems, combined with its very low cost, there has been a recent emphasis on developing active treatment systems that use limestone efficiently. As the requirement for treatment increases, there is a growing emphasis on treatment sludge management and sludge stability. The final choice of a suitable treatment technology is dependent upon water chemistry (eg pH, type of metal contamination, acidity), flow rates, acid load, local natural resources (neutralising materials, topography), climate, site logistics, environmental risk and economics. The benefits and limitations of both passive and active treatment technologies are summarised.

Jan 1, 2003

By K. G. Wang, M. E. Glicksman, P. Crawford

"We formulate the mathematical solution to late-stage multi particle diffusion in finite systems. The transition from finite system behavior to that for an infinite system is established. Large-scale simulations are reported regarding the dynamics of phase coarsening. Even in the case of a small volume fraction (Vv = 10-4), the particle size distribution is broader than that for the well-known Lifshitz-Slyozov limit at zero volume fraction. We also report the first simulation studies of extremely low volume fraction, for which corresponding experiments, as well as other simulations, do not exist at present for comparison. However, in the case of moderate volume fractions (Vv = 0.1), the fiucutations in the volumetric growth rate of particles are extracted from our simulations. These simulations provide additional insight into the statistical nature of diffusion interactions, including multiparticle stochastics during microstructural evolution.IntroductionPredicting microstructure evolution in alloys remains one of the cornerstones of materials science. Phase coarsening is a common process in microstrucural evolution that leads to a decrease in the excess total interfacial energy of the system. The system typically consists of separate and identifiable units, or domains, such as second-phase particles distributed in a matrix. During phase coarsening, larger particles grow at the expense of small particles. Over time, this ""competition"" results in an increase in the average size of the particle population, and in a concomitant decrease in the number of particles.Particle size and microstructure of many cast alloys depend on similar coarsening processes. Indeed, properties of these materials, such as strength, toughness, ductility, and electrical conductivity, depend on the material's average particle size and particle size distribution (PSD). Understanding and controlling microstructures in two-phase systems are clearly of widespread technological importance."

Jan 1, 2001

By E. Oshima

In May 1991, a New Mitsubishi Continuous Copper Smelter Line started operation at Naoshima. Recently, it has been continuing steady operation and one and a half year campaign life has been achieved. In 1996, new records of on line time, the amount of copper concentrate treated and copper anode production were achieved. 1t proves the superiority of the process with respect to pollution control, energy efficiency, flexibility and easiness of the operation and over all economy including off gas handling cost. Furthermore, .plans are underway to prolong the campaign life for two years and to improve the process efficiency. This paper describes recent operation, improvements, and a future capability study.

Jan 1, 1998

By Andrew A. A, Hamilton P. J

Constraints on pore water evolution in the aquifers of a sedimentary basin may be realised through stable isotope analyses of present day waters, and their comparison with water compositions calculated to have been in isotope equilibrium with the products of diagenesis during burial. Integrated with detailed petrographic observations, and thermal, structural and stratigraphic analyses, fluid migration patterns at various stages in a basin's history can be identified. This has important implications for modelling basin hydrology, hydrocarbon distribution, and reservoir quality in the Latrobe Group, Gippsland Basin, and oil-prone successions Elsewhere.

Jan 1, 1992

By J. D. Allen

In the coal preparation plant at U.S. Steel Corp.'s Concord mine in Alabama, the product moisture was reduced from about 20% to 9% through the development of a workable flowsheet for dying the clean coal. Some of the high points of the conversion of the Concord washer from vibrating screen dewatering to centrifuge drying are presented in this article. The coal preparation plant at the United States Steel Corp.'s Concord mine near Bessemer, Ala., began operations in June, 1950. The basic cleaning circuit consisted of a Chance cone for cleaning the 2-in. x 3/8-in. fraction and concentrating tables for cleaning the -3/8-in. coal fraction. Dewatering of the final product was accomplished with 35-mesh vibrating screens. However, because Concord coal is very friable with 85% passing 3 mesh and 25% passing 28 mesh (Fig. I), a considerable quantity of fines passed through the dewatering screens. To recover these fines, the dewatering screen effluent was sent to two 70-ft-diam hyd rose para tors from which the underflow returned to the dewatering screens and the overflow went to a 175-ft-diam thickener for water clarification, as illustrated in Fig. 2. As might be expected, there was considerable recirculation of the -35-mesh coal in this system. This degraded the coal and led to higher moistures. It also resulted in a fines bleed-off of plant water and thickener underflow to a fine-coal settling pond. In 1961, vacuum filters were installed to supplement the screens and to recover the fine coal lost in the bleed-off. The above system resulted in a product moisture of about 20%. Further reduction to approximately 11% was accomplished by drainage from railroad cars during transit to the coke plant. Control of the moisture at unloading was poor because of variations in operating levels and railroad car availability, but since the Concord coal constituted a relatively small percentage of the over-all coal mix at the coke plant, its high moisture and fluctuations did not seriously hamper coking operations. Early in 1964, however, the proportion of Concord coal was increased with a resulting increase in the moisture of the total coal mix, and this caused difficulties in the coke plant. The increased participation of Concord coal also brought about a shortage of railroad cars which raised the moisture content to a point where the coal became almost impossible to handle. In an effort to alleviate this problem, U.S. Steel initiated a research program to develop a flowsheet for reducing the moisture to approximately 10% and to determine whether the resulting product would be satisfactory for the coke plant. Under this program, an experimental flowsheet for evaluating both a vibratory centrifuge system and a solid bowl centrifuge system was drawn up as shown in Fig. 3. A horizontal vibratory centrifuge was installed to reduce the moisture in the dewatered coarse coal, and a four-cell, flotation machine was installed to clean the -65-mesh portion of the 3/8-in. x 0 table raw coal feed. Several shortcomings in the above circuits were apparent. For one thing, large quantities of repulping water were required. Furthermore, since about half of the flotation feed was of a size consist that could have been cleaned on the tables, these circuits would result in an unnecessary increase in reagent costs and facilities. Maintenance of the hydro separators and pumps for pumping the underflow to the filters,

Jan 1, 1969

By Ivor Jenkins

PROCESSES employing controlled atmospheres in the heat-treatment of metals and alloys are now well established on an industrial scale, and the general principles involved and the advantages to be gained in the use of the technique have received considerable publicity over a period of years. During this time the greatest emphasis has been on the establishment of the process in industry, the main effort being devoted to development work on various types of atmospheres, their useful fields of application and the design of suitable heat-treatment furnaces in which they are to be used. The various types of controlled atmospheres are fairly well standardized, but there still remains a considerable field for the investigation of related problems, in connection with both the gas-generating equipment and the surface chemistry of the heat-treatment of metals, especially in complex controlled atmospheres. This paper describes certain investigations of this nature that were carried out in England up to 1939. The development of processes employing controlled atmospheres has been associated to a very large extent with the heat-treatment of steels, both because of the major importance of steel in industry and the many diverse and difficult problems of surface chemistry involved when steels of such a wide range of composition are heated in the presence of active gases Controlled atmospheres such as dissociated and burnt ammonia or charcoal gas are used in the heat-treatment of low-carbon and high-carbon steels, but from certain points of view a suitable atmosphere generated by the partial combustion of city gas is to be preferred. Both the ammonia derivatives are comparatively expensive, and even if the burnt ammonia is regenerated, thereby reducing operating costs, the capital expenditure of the gas plant may make it prohibitive for the smaller type of furnace installation. Charcoal-gas generators are not without their operating difficulties: especially those associated with the quality of the charcoal, clinker formation and the removal of carbon dust from the generated gas. City gas has the advantage of being comparatively cheap and "on tap" in most if not all industrial centers. The use of raw city gas as a protective atmosphere in the heat-treatment of steels has been described,1 but it presents certain difficulties because of its complex composition and its explosive nature when mixed with air. These factors, together with the tendency toward sooting at elevated temperatures, arising mainly from the hydrocarbon gases present, all militate against its use as a protective atmosphere in industrial furnaces. The following analysis, based on the analyses of city gas in different localities in Great Britain, indicates the wide limits existing

Jan 1, 1947

By Z-Y Pi, B Zhang, S Wen

"The paper introduces the structure and work processes of outside auger hollow claw tipped mechanical sampler for coal. Twenty sets of claw tipped sampler performance tests show that: The design of inner hollow cylinder-type (?180 mm) can ensure to take a coal sample with nominal top size of 60 mm. Built-in self-cleaning piston pusher ensures no adherence and blocking of the sample. The operation practices show that the mechanical sampler can operate in order for taking coal sample with up to 16 per cent of total moisture. Claw closing design can avoid sample leaking or spilling during the claw lifting and ensure the integrity of primary increment. Ultrasonic positioning device makes the sampler capture the materials no less than 10 cm from the bottom of the wagons, basically meeting the requirement taking full depth of the sample. The precision and bias test indicates that the moisture and ash have no relative bias under the sampling process; the sampling precision is in accordance with the requirement in IS013909.At present, the spiral mechanical sampler is widely used for coal sampling but there are many limitations during application, for example: It is difficult to capture a large size sample, so the size range of a coal sample taken is limited. There is easy adhering or blocking for high moisture coal, which will result in the mixture of different increments, wear of sampler and the difficulties for cleaning and maintenance of sampler. It is difficult to capture the coal sample at lower than 30 cm from the bottom of the wagons, in order to avoid damage of the vehicle. It is possible for coal sample loss and spilling during the sampler lifting, due to the unsealed sampler.For the outside auger hollow claw tipped mechanical sampler designed for solving the above problems, the opening distance of the claw is the opening size of the sampler and makes the size range of the coal sample to be taken wide. During sampling, the two pieces of claws open and the sampler rotates vertically downward to capture an adequate coal sample after reaching the specific point. Then the two pieces of claws close tight automatically to ensure there is no coal leaking or spilling. The inner pusher of the sampler will prevent from the adherence and blocking of the coal sample effectively.CITATION:Zhang, B, Pi, Z-Y and Wen, S, 2012. Outside auger hollow claw tipped mechanical sampler for coal, in Proceedings Sampling 2012, pp 41-44 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By Zhongxue Li, Wenguang Li, Yiqing Zhao, Shuaiqi Wang

"Faced with the serious managerial situations and diverse conditions and needs for mine safety, occupational health and environmental stewardship in Chinese mining communities, an evidence-based approach is proposed for the management of mine safety, health and environment integrity. By the proposed approach, tangible and effective scientific evidence should be collected and accumulated, and the authenticity, accuracy and applicability of the evidence should be assessed to form an evidence-based approach for characterizing mine safety, health and environmental hazards and risks from multidimensional perspectives. The results are then used to formulate diverse safety, health and environment functional requirements. In an evidence-based approach, the evidence is combined with the professional experiences and the actual economic and technological situations, availability and affordability of a mine. This approach is helpful to establish scientific, reasonable, acceptable and effective solutions for identifying and mitigating hazards and improving the level of mine safety, health and environment integrity of mining operations.Introduction / Background In recent years, economic reforms have opened China's economy so that Chinese society has rapidly modernized. Along with this advancement, the exploitation and utilization of mineral resources continues to be active and the scale of mining production continues to increase, which has created a deterioration in resource reserves and as well as the general condition of mining technology. There are many hazards and safety problems in mine production and occupational health as well as in the community environment in China’s mining industry. These problems threaten the security of China's mines and present serious obstacles and challenges to the industry and the government. According to the statistics from the State Administration of Work Safety Supervision, there were 50,500 mine safety incidents in China between 2001 and 2013, which consisted of 31,439 coal mine safety accidents and 19,061 non-coal mine safety accidents, resulting in 30 deaths (Qin 2014). At the same time, mineral dust and radioactive material from mine production processes have increased the morbidity rate of silicosis and cancer in mining workers."

Jan 1, 2017

By Willard L. Cumings, Benjamin L. Miller

(Glen Summit Meeting, June, 1911.) I. THE CAMAGUEY DEPOSITS. 1. Location. THE Camaguey brown iron-ore deposit covers the top of San Felipe hill, the nearest point of which lies 14 miles NW. of the city of Camaguey. While there are several low flat-topped hills in the vicinity covered with a more or less continuous mantle of brown iron-ore, the deposit of San Felipe hill is the only one of any size and importance, and the name "San Felipe district " is proposed for the region. The deposit extends in a NW-SE. direction for a distance of about 10 miles, with an average width of 5 miles. The location is shown in Fig. 1, a sketch-map of the eastern part of Cuba. Fig. 2 is a map of the San Felipe district. 2. Description. The district is mentioned by Spencer,1 who says: "The Cubitas iron-ore fields are situated from 12 to 15 miles north of Camaguey City, in the province of Camaguey Within an area measuring roughly 10 miles east and west and 4 miles north and south, there are several flat-topped mesas rising 300 to 400 ft. above the level of an almost featureless plain which extends for many miles in all directions except toward the north." With the exception of the discrepancy in his statements as to the distance from Camaguey and the area of the hill, which is over 50 sq. miles, his description is a very good one. Kemp 2 has the following to say of ores in Carnaguey Province * Geologist, Bethlehem Steel Co. + Professor of Geology, Lehigh University. 1 Bulletin No. 540, U. S. Geological Survey, p. 324 (1908). 2 The Iron Ore Resources of the World, printed by the Eleventh International Geological Congress, vol. ii., p. 795 (1910).

Mar 1, 1911

By H. Arima, Y. Kudo

In general, the iron content of zinc leach residue produced by sulphuric acid leaching from calcine is disposed as jarosite or goethite into a tailing dam. More recently, these iron residues have been treated pyrometallurgically to avoid waste disposal. The Iijima refinery selected a different zinc leach residue treatment process for iron control when it was established in 1971. The Iijima refinery is the only plant in the world that has processed a zinc leach residue by the combination of SO2 pressure leaching and O2 pressure hematite precipitation. The process enhances zinc recovery and recovers gold, silver, copper, lead and rare metals in saleable by-products. This paper focuses on the two stages of autoclave application in the zinc leach residue treatment process. The detailed flowsheet and recent advancements to improve the quality of by-products are discussed.

Jan 1, 2004

By H. C. Chang, N. J. Grant

REEP studies and measurements in most in-V> stances are based on a relatively gross gage length. Even in some recent theoretical studies on the mechanism of creep, changes were followed by means of X-rays and metallography without regard for the behavior of the individual grains and grain boundaries.'" Analytical studies of creep have frequently indicated that more than one competing process is operative and that the ultimate creep performance depends on the effects of temperature, time, and strain rate as well as grain size.'-" he grains and grain boundaries are known to respond differently to these variables but the extent of the response is still little known, especially in poly-crystalline materials where the relative orientations of grains and grain boundaries are important. This paper reports some experimental observations of the behavior of the grain boundaries and their effect on the deformation in the grains. High purity aluminum was used to avoid complications of aging reactions, second phase, inclusions, etc. Experimental Procedure A small vertical nichrome wound furnace was built to permit direct loading on the test specimen. This furnace is capable of operating up to about 1300°F with reasonable temperature distribution. A ground rectangular quartz window, 1.25x0.5 in., is imbedded in the external stainless steel tube to permit observations of the creep process with a microscope. An argon atmosphere ,was provided to prevent oxidation. The quartz window caused a temperature gradient between the back and front surfaces of the specimen of 15" at 700°F. The temperature gradient could be cut down to 3°F along the length of the specimen by adjusting shunts across the furnace windings. An ordinary metallurgical microscope with a working distance of 14 mm was rebuilt so that it could be moved in three mutual perpendicular directions. Visual examination could be made with either a 30X eyepiece or a 15X filar eyepiece. Using an objective of focal length 24.3 mm and a numerical aperture 0.20 a total magnification of 120X or 240X could be obtained. High purity aluminum rated at 99.995 pct was supplied by the Aluminum Co. of America as % in. then the gage portion was further machined to 3/16 in. diam. The ends were Y4 in. diam and threaded to fit available specimen holders. Two opposite flat surfaces of the gage portion were obtained by milling, giving final dimensions of the gage portion of 3/4x3/16x3/32 in. Machined specimens were first electropolished in Jacquet's solution.' Reference marks were produced by pressing a thin sewing needle into the surface of the specimen. The specimen was then annealed at 900°F for 24 hr and at 1150°F for 12 hr. Typical macrostructures of specimens treated in this manner are shown in Fig. 1. The range of the grain size was 1 to 5.5 mm (see Fig. l), but most of the grains were of 2.5 mm and went through the whole thickness of the specimen. The specimen was re-electropolished and etched electrolytically to reveal the grain boundaries. In order to reveal the orientation difference of the grains, etch pits were produced on the surface of the grains by etching in a mixture of hydrochloric and nitric acids (HC1, 45 pct; HNO,, 10 pct; H,O, 45 , by volume). The specimens were very carefully put into the holders and furnace; yet even with this care, fine slip lines were developed on the specimen surface.

Jan 1, 1953

By L. C. Lang

Effective and profitable mining begins with good blasting results. While the importance of sufficient energy to break the rock is recognized, more attention should be paid to the time factor in blasting. Fragmentation, looseness and the shape of the muckpile can be improved and energy levels lowered through the use of proper delays. The long delay is also the most important parameter in establishing stable walls along the final limits of the pit. The time factor in blasting is explained through the rock acceleration process and its practical application is demonstrated by case histories.

Jan 1, 1981

By H. S. Geismer

There are three general methods available for obtaining commercial brown iron-ore: hand-screening; washing; and washing and concentrating. Hand-screening has produced a large tonnage of ore in the past, but is rapidly falling into disuse, except as a preliminary step, largely because modern furnace-practice requires all forcigii material to be separated from ores before they are deliv-

Jan 1, 1912

By O. J. C. Runnals

The intermetallic compounds NpAl2, NpAl3, and NpAl have been prepared, and examined by X-ray diffraction methods. The compounds are isostructural with the corresponding U-Al compounds. NpAl3 is face-centered cubic with a = 7.785A and has the MgCu2 structure. NpAl is simple cubic with a = 4.2624 and has the AuCU3 structure. NpAl4 is body-centered orthorhombic with a = 4.428, b = 6.268, and c = 13.71A. The published description for the atomic positions in UAl, applies also to NpAl4 THE U-Al system has been examined by Gordon and Kaufmann.1 They identified the following intermetallic compounds: UAI2, UAl3, and a third, tentatively identified as UAl5. A structure analysis of the latter compound by Borie2 proved that the formula UAl4 was more consistent with the X-ray data. The crystal structures of UAl2 and UA have been reported by Rundle and Wilson.3 UAl2 was found to be isostructural with MgCu. The atomic positions in the simple cubic UA1, cell were found similar to those in the AuCu3 structure. Three analogous compounds exist in the binary system Np-Al. X-ray data for the compounds NpAl2, NpAl3, and NpAl4 are reported below. The neptunium used in the investigation was supplied through the courtesy of the Argonne National Laboratory as neptunium (V) nitrate. It was stated to have a radioactive content of 99.25 pct Np237. The impurity limits had been established by a spectrographic analysis given in Table I. Any titanium, boron, or bismuth impurity should be effectively removed during the fluorination of NpO2 to NpF4, and sodium, lithium, magnesium or strontium during the alloying procedure. The oxalate ignition technique, described by Westrum for the preparation of finely-divided reactive PuO2, was used.The neptunium (V) nitrate solution, containing 100 mg Np, was evaporated to dryness on oxalic acid crystals. The resulting oxalate was calcined to NpO, by heating in platinum at 650°C for 2 hr. An equimolar mixture of anhydrous hydrogen fluoride and purified hydrogen was passed over the NpO2 for 2 hr at 500°C. According to Fried and Davidson" the above fluorination conditions should produce the purple-black fluoride, NpF3 However, the light-green product showed only NpF4 lines on an X-ray diffraction pattern and contained only an estimated 5 pct of finely dispersed black NpF3 particles on microscopic examination. NpAl3: An intimate mixture of 50 mg of neptunium fluoride and aluminum powder (99.99 pct pure, —28 to $60 mesh) was heated to 900°C in a BeO crucible in vacuum by a tungsten coil for 2 hr, to allow the following reaction to proceed: NPF4 + 7Al + NpAl, + 4AlF. [1] The formation and sublimation of aluminum mono-fluoride in this system was verified from an X-ray diffraction analysis of the sublimate. The diffraction pattern was similar to one obtained in the aluminum reduction of UF4 to UF3,6 showing both Al and AlF3 lines. The resulting alloy was sintered at 1100°C for 1 hr. A powdered specimen of the crystalline product was sealed in a thin-walled quartz capillary for X-ray examination. The photograph was taken on a 14.32 cm General Electric powder diffraction camera, using filtered copper radiation. The films were calibrated in terms of a NaCl standard pattern. The wavelengths used in the calculations were 1.5418A for Cu K and 1.5405A for Cu K The powder diffraction pattern showed that NpAl is simple cubic with a = 4.262 % 0.005A, and is isostructural with UA13 where a = 4.27A1 or a =

Jan 1, 1954

By Rob Morrison, Peter Cameron

"Many products and technologies have been developed from outcomes of research projects carried out by the Julius Kruttschnitt Mineral Research Centre (JKMRC). When these products and technologies are applied to the design and optimisation of blasting, comminution and separation, improvements in profitability can be realised.In 1970 Alban Lynch promoted two practical ideas to improve plant operations:• Ore and equipment properties can be separated allowing experience with one type of ore or equipment to be transferred to other types of ore and equipment. If this experience was encapsulated in a mathematical model, then these properties could be combined and used to simulate (ie. to design and to optimise) complete mineral processing circuits.• Many problems associated with scale-up from laboratory to industrial equipment could be eliminated by experimental work on full-scale equipment in the plant.Many JKMRC research projects have focussed on the development of models of unit operations in mineral processing and their application to process simulation.Models of comminution and classification developed at the JKMRC have been used since the early 1980's. Ore characterisation techniques developed to support these models are licensed world wide through JKTech. The application of comminution modelling techniques to blasting, which optimises the process feed size distribution is used in Mine-to-Mill® projects. The advances in the understanding and modelling of froth flotation over recent years have provided the opportunity for integrated ore characterisation and process optimisation from resource to product.JKMRC project outcomes often provide proven opportunities for the mineral industry to improve performance and productivity. JKTech was established in 1986 to commercialise and market the most promising outcomes and thus ensure their continuing availability to the mineral industry.They include:• Commercial software (JKSimMet, JKSimBlast and JKMetAccount).• Monographs (Comminution and Blasting).• Technologies (Mine-to-Mill® and flotation optimisation).• Hardware products (JKFrothCam, JKJetLift® and the Mineral Liberation Analyser).This paper summarises these technologies and their benefits."

Jan 1, 2003

By D. Marcus

A methodology was developed wherein. the increase in compressive strength, mineralogical changes and pore water composition were all studied simultaneously as a function, of moisturized spent shale curing time. From these results the relationship between the nature of cementation process and the composition of pore water was established. Heavy metals were entrapped in the cementing constituents and the pore water became mainly a solution of alkaline sulfates. While the specific data are applicable only to the material studied, the methodology and general conclusions are useful for evaluating the environmental factors in spent shale disposal and expected leachates composition.

Jan 1, 1984

By D. J. Reddish, B. N. Whittaker, G. X. Sun

An image analysis technique has been used in the assessment of subsurface fracture levels in the context of water inflow into longwall mine workings. The technique was used to analyse results from physical modelling which are represented by black and white photographs taken directly from the model tests. Binary images of fracture patterns are obtained by scanning the photographs with an image analyser coupled to a video camera. The images are manipulated by a C program which allows them to be processed in vertical and horizontal directions and filtered to differentiate quantitatively between vertical and horizontal fracture intensities. The fracture density distributions provide a valuable database for further numerical and statistical analysis. This allows assessment in terms of water inflow into the excavation. A comprehensive image analysis was undertaken on several extraction models. Results indicate that extraction thickness has a significant effect on the fracture pattern and the fracture density distributions. The results can be used to adapt model findings to situations with a range of extraction thicknesses. The technique has allowed improvement in image enhancement and in the interpretation of model results. In particular, a qualitative comparison between different models is possible.

Jan 12, 1992