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By Ruxton B. P, Rhodes J. M

Two Rb-Sr ages are discernible in data concerning the leucocratic granite which is the youngest pre-sedimentation phase of the crystalline basement complex at Rum Jungle, Northern Territory, Australia. Whole-rockdata suggest that intrusion of this unit took place at about 2400 my ago, with a probable initial ratio around o·707; whole rock-potassium feldspar tie-lines indicate redistribution of strontium at about 1800 my ago. The former age correlates with other measurements on rocks which form basement to the mantling Pine Creek Geosyncline; the latter correlates also with isotopic evidence for regional metamorphism and emplacement of some younger intrusive granites elsewhere within the geosyncline. A few K-Ar ages, from scattered localities, conform generally with the later event or events which appear to have some connection with the structural deformation clearly observable both in the complex and the surrounding metasediments. It is these younger events which appear to match the residual evidence for the earliest detectable concentration of uranium minerals in the Alligator Rivers district.

Jan 1, 1977

By B. R. Stewart, L. W. Zelazny

The exclusion of coal fly ash from regulation as a hazardous waste has led to increased interest in returning ash to the coalfields for co-disposal. A multi-year column study used coal refuse with high potential acidity (4% total-S), and two alkaline ashes in various bulk-blends. The unamended refuse acidified rapidly, producing acidic (pH 1.7) leachates, high in dissolved metals. Treatments blended with sufficiently high amounts (20 to 33%) of alkaline ash produced alkaline (pH >8.4) leachates with low metal levels, while lower ash blending rates acidified over time to produce metalliferous leachates. Examination of solid materials indicated that pyrite oxidation was occurring to some extent in all treatments. A regression equation (r2 = 0.95) was developed to estimate time to net acid release for mixtures of these materials. Ash alkalinity and refuse potential acidity must be balanced to insure water quality for co-disposal environments, or the ash materials should be isolated away from acidic drainage waters.

Feb 24, 1997

By Q. C. Reynolds

Keywords: Pyrometallurgy, plant, photography, GIS, satellite images, Google Earth Google Earth is a piece of software able to display an interactive three-dimensional map of the world, combining aerial and satellite photography with maps, terrain, and user-generated geographical information systems (GIS). Many structural features of the planet, both natural and man-made, are of great interest to the mining and metallurgy field, and in this paper a study is made of the current state of the art of data accessible by Google Earth.

Jan 1, 2006

By Jian Li

Developing the Generation IV nuclear reactor is an international collaborative effort. One of the most promising Gen IV nuclear reactor designs is the supercritical water (SCW) concept, in which the water coolant runs at about 625 oC at the outlet. Under this temperature and high pressure condition, the cooling water is at supercritical state, which poses significant demand for both in-core and out of core materials. High-temperature mechanical properties, corrosion resistance and radiation damage are some of the key challenges. At present, no single commercial material can meet all the requirements of the severe SCWR conditions. Corrosion experiments per-formed under SCW condition yield various kind of corrosion modes, some are very challenging to characterize using conventional techniques. A combination of various advanced characterization techniques proofed to be essential to understand the root cause of materials? degradation.

Jan 1, 2010

By Sam Palombo, James José Varela

"Washing can be defined as the process used to eliminate or reduce the dirt (presence of fines or slimes) of one material. It is also the basic and oldest process applied to ore preparation for further concentration. This process, in combination with commnution and screening, form the so called washing plant and in many cases produce end products. This work describes the factors that influence the performance of the washing process and main washing technologies used in the mineral processing industry.The Hydro-Clean represents, since 1998, a state of the art technology in this area and is comprised of one of the most innovative solutions developed at HAVER & BOECKER. HAVER & BOECKER design and manufacture technology for mining and related industries. Today the Hydro-Clean is manufactured and sold throughout the Haver Screening Group (HSG) which is comprised of HAVER & BOECKER Maschinenfabrik Münster, HAVER & BOECKER Latinoamericana – Brazil and W.S. Tyler Canada.The Hydro-Clean is a washing technology based on utilization of high pressure water jets. To follow we will discuss how the Hydro-Clean’s different modes of operation result in several advantages related with mine waste reduction, recovery of saleable product, lower capital costs, superior washing results, less stress for the material, a wider range of application and less maintenance cost. Aside from these positive factors, its lower operation costs related to the consumption of energy and water are presented. It is important to note that the quantities, tonnages, data and management concepts presented in the paper are accurate for the time of writing and are subject to change and modification as operations progress."

Jan 1, 2009

By L. E. Lynd

Ilmenite concentrates prepared from beach and dune sands of Florida, India, Australia, and other localities deviate to varying degrees from the theoretical composition of pure ilmenite, and generally contain more TiO2 than the formula FeTi03 would indicate, and some Fe2O3. This variation in composition is due to different amounts of altered ilmenite in the concentrates. (') The alteration has been shown to take place by oxidation and leaching of the iron in ilmenite, to yield residual products consisting of amaphous or very finely crystalline titanium dioxide and ferric oxide. Other studies(2) have stressed that ilmenite may alter first to an amorphous titanium-iron oxide, or to an amorphous mixture of titanium and iron oxides, with later alteration to crystalline titanium dioxide. There has been some speculation as to whether alteration of ilmenite is usually caused by weathering or by hydrothermal pr0cesses.(3,4,5 Three main methods of approach were used to study the mechanism and rate of ilmenite weathering. (1) Etch tests were used to learn the relationship between crystallographic orientation and the rate of chemical attack on ilmenite. (2) Altered ilmenites in New Jersey sands were compared with ilmenite in rocks of the area from which the sands were probably derived. (3) Experiments were carried out to determine at what rate, and by what agents, originally fresh ilmenite could be altered in the laboratory under simulated weathering conditions. ETCH FIGURES ON ILMENITE CRYSTAL PLANES A rather large ilmenite crystal from Sannidal, Norway, about 11/2 x 11/2 x 2 inches, bearing a few natural faces with imperfect surfaces, was prepared for etching by grinding and polishing crystal planes whose Bravais-Miller indices (referred to hexagonal axes) had been determined by X-ray methods to be 00.1, 10.0, and 10.2. Metallographic examination showed that the crystal was homogeneous, and uniform in orientation, except for the presence of twin lamellae which were oriented with their broadest surfaces parallel to the 00.1 planes of the large crystal. Since ilmenite is rather inert to standard etch reagents, strong solutions of hot sulfuric acid and cold hydrofluoric acid were used. Preliminary tests established that better etch figures were obtained using HF than with H2So4 solutions. The etch figures produced on 00.1 and 01.0 planes of ilmenite by etching 3 to 5 minutes in cold concentrated HF solution are shown in Figures 1, 2, and 3. The figures on 00.1 are "etch hillocks", rather than pits, and according to Honess(6), this phenomenon

Jan 1, 1961

By David M. Spatz

The way people interact, collaborate, learn and improve can have a profound impact on a company’s efficiency, performance, productivity and return on investment. This is the motive behind corporate efforts today to replace the traditional hierarchical structure with team-oriented organization. The increased importance of communication and collaboration during the past 20 years has been propelled by rapid advances in technology and increased availability of information. Companies must take advantage of the information that is required for competitive performance and for the continued production of quality products. So it is essential that outstanding communication, cooperation and collaboration take place among multidisciplinary specialists assigned to work together to solve common problems and achieve common goals. Companies are searching for ways to increase knowledge transfer and learning, particularly among people who work on related topics. This will improve efficiency and quality and reduce redundancy and costs.

Jan 1, 2000

By R. R. Oder, R. E. Jamison, E. D. Brandner

This paper presents preliminary test results obtained with a 0.38 kg/s (3000 lb-hr) beta prototype MagMill™. In processing Upper Freeport coal the beta prototype recovered 82% of the weight of the feed and 91% of the heat content while reducing the potential emissions of sulfur, kgSO2/GJ(lbSO2/MBtu), by 61%. Pyritic sulfur in the MagMill™ product was reduced by 78% compared to that in the feed. For all runs, the mill product was controlled between 70 to 80% finer than 74 µ particle size. Recoveries of mercury, arsenic, and selenium ranged from 35 to 45% of that in the feed. Power draw was reduced by 26% and mill throughput was increased by 9% compared to the pulverizer operating with no magnetic separator attached.

Jan 1, 2000

Upgrading and Removing Phosphorus from Low-Grade and High Phosphorus Containing Iron Ores

Sep 13, 2010

In this paper a numerical formulation is presented for determination of the axial load along a cable bolt for a prescribed distribution of rock mass displacement. Results using the program CABLE indicate that during excavation, the load distribution that develops along an untensioned fully grouted cable bolt depends on three main factors: (i) the properties of the cable itself, (ii) the shear force that develops due to bond at the cable-grout interface (i.e. bond stiffness), and (iii) the distribution of rock mass displacement along the cable bolt length. In general, the effect of low modulus rock and mining induced stress decreases in reducing bond strength as determined from short embedment length tests, is reflected in the development of axial loads significantly less than the ultimate tensile capacity even for long cable bolts. However, the load distribution is also dependent on the deformation distribution in the reinforced rock mass. Higher cable bolt loads will be developed for a rock mass that behaves as a discontinuum with deformation concentrated on a few fractures, than for one which behaves as a continuum, either due to a total lack of fractures or a very high fracture density. This result suggests that the stiffness of a fully grouted cable bolt is not simply a characteristic of the bolt and grout used, but also of the deformation behavior of the ground. In other words, the same combination of bolt and grout will be stiffer if the rock behaves as a discontinuum than if it behaves as a continuum. This paper also explains the laboratory test programme used to determine the constitutive behavior of the Garford bulb and Nutcase cables bolts. Details of the test setup as well as the obtained results are summarized and discussed.

Jan 1, 1996

By Cadia Geology Team

The Cadia Hill Gold Mine, located near Orange in Central Western New South Wales, is owned and operated by Cadia Holdings Pty Ltd, a wholly owned subsidiary of Newcrest Mining Limited. Construction including pre-strip mining occurred from 1996 to 1998. The mine was officially opened in October 1998 following commissioning of the concentrator and mine fleet in June of that year. The Cadia Hill orebody is a porphyry related gold and copper system. The final pit has a strip ratio of approximately 1.3:1.0. Mining is undertaken on 15 metre benches using large capacity diesel hydraulic face shovels at an annualised rate of up to 70 Mtpa. The concentrator is currently rated at 17Mtpa and includes the worldÆs largest single line grinding circuit. The feasibility Mineral Resource was estimated at 352 Mt at 0.63 g/t Au and 0.17 per cent Cu. Initial reserves totalled 200 Mt at 0.74 g/t Au and 0.17 per cent Cu yielding a mine life of approximately 12 years. During the pre-production period mine geology systems were developed to support the operation. By design these systems were intended to add value to the business through minimisation of material miss-classification, provision of accurate and timely production information and mapping and reconciliation as a continuous model improvement tool. Variances that would prove to be material to the life of mine plan were recognised during the first year of production. These included identification of additional ore tonnes, higher copper grades and higher gold recoveries relative to the model. Gold grades and copper recoveries also reconciled favourably. Testwork was undertaken to determine the underlying causes of each variance. Re-modelling was then undertaken to capitalise on those variances. The Cadia Hill Gold Mine life of mine plan was re-evaluated with updated geology, grade, geotechnical, metallurgical and environmental inputs. Operating strategies were also reviewed and revised. Despite application of reduced metal prices in the evaluation, the outcome was one of extended mine life with more metal produced at lower cost. Development of robust mine geology systems, including a pro-active reconciliation process contributed to tangible improvement of the Cadia Hill Gold Mine operation. On-going system development and improvement initiatives are planned to add further value for the future.

Jan 1, 2000

By Michael Valencia, Alonso Marchena, Fredy Arcos, Miguel Chumbe

Cobrepampa es un depósito de cobre ubicado en Acarí (Caravelí-Arequipa). La mineralización se emplaza en pórfidos dioríticos pertenecientes al intrusivo Cobrepampa (Superunidad Linga) y está constituida por bornita, calcosina, covelina y calcopirita y en la zona de oxidación cuprita, crisocola, malaquita y hematita. El magmatismo es calcoalcalino con alto K. El intrusivo Cobrepampa evoluciona por fraccionamiento y contaminación en una corteza más delgada que la superunidad Linga. Petromineralógicamente se tiene epidotización con diseminaciones de calcopirita, pirita y bornita, gangas de cuarzo y calcita con hematita acicular. Las inclusiones fluidas muestran temperaturas de homogenización de 165.5 - 266.43 °C y salinidad 3.5 - 16.8 % eq. peso NaCl de un mesotermal o epitermal, pero que por sus características geomineralógicas sería un mesotermal. Por tanto, Cobrepampa presenta más de un evento de mineralización: una con magnetita y actinolita, y otro mesotermal de vetas de cuarzo con sulfuros.

May 22, 2019

By A. J. Wainwright

The Coffee Creek lode gold discoveries are located in the White Gold district (Dawson Range), west-central Yukon, 130 km south of Dawson City and 30 km south of the Golden Saddle gold deposit (Figure 1). Extensive structurally-controlled gold mineralization has been discovered during the 2010 and 2011 exploration drilling campaigns, highlighting this part of the Dawson Range as a significant emerging gold district. [ ] In this contribution we review the geological framework and describe the mineralization styles and metal signatures observed to date on the Coffee project. The main Coffee area is underlain by a 15 km by 4 km geochemical footprint, characterized by discrete linear gold-in-soil anomalies that correspond to various mineralized corridors. Of several mineralized areas tested in the past two drill seasons by diamond core and reverse-circulation (RC) drilling, we focus on the Supremo, Double Double, Latte and Kona zones; areas with the most information obtained from drilling thus far (Table 1; Figure 2).

Jan 1, 2012

By Kumar A, Mishra N. C

For each tonne of chromite ore mined in Sukinda, approximately ten tonnes of fine overburden material is generated. The overburden typically contains about 30 - 60 per cent Fe2O3, 0.3 - 1.1 per cent Ni, four to nine per cent Cr2O3 and 0.04 - 0.2 per cent cobalt and is being discarded leading to loss of valuable metals and creating environmental pollution. In order to take the advantage of presence of iron, nickel and chromium, the present studies advocate the utilisation of nickel lateritic chromite overburden for production of Ni bearing pig iron through blast furnace extracting maximum iron and nickel from the chromite overburden. The present paper deals mainly with the beneficiation of chromite overburden, sintering characteristics and thermodynamic studies. The beneficiation study shows that a beneficiated concentrate having Fe - 50 per cent and Ni -- 1.1 per cent can be achieved from chromite overburden having Fe - 30 per cent and Ni -- 0.7 per cent. Sintering studies have been carried out with bed height of 300 and 450 mm at a suction of 600 and 900 WG respectively. The results reveal that good quality sinter can be produced from chromite overburden concentrate with a basicity of about 1.0 and coke breeze consumption rate about 16 per cent. In all the experiments, Tumbler Index, Abrasion Index and Shatter Index was found to be in the range of 65 - 70, 4.5 - 5.5 and 85 - 90 respectively. The other parameters namely softening temperature, melt down temperature, reduction degradation test and relative reducibility have also been determined. A thermodynamic analysis has also been carried out to make a technological assessment of the process for the production of alloyed pig iron from chromite overburden in blast furnace which shows that it is possible to produce nickel bearing pig iron in blast furnace using the sinter up to 80 per cent. Techno-economic analysis reveals that this route will yield a substantial profit even after accounting for cost of beneficiation, extra coke, raw materials and extra slag produced.

Jan 1, 1999

The results of self potential geophysical surveys conducted over base metal prospects near Orange, Goulburn, and Wellington, N.S.W., indicate that this rapid and inexpensive exploration procedure merits wider application within eastern New South Wales, and in similar environments elsewhere.

Jan 1, 1973

The final criterion of the payability of gold production must necessarily be the cost per ounce. While the cost per ton or per cubic yard is a convenient comparative measure, and a necessary one for operating control, it is obviously insufficient as a means of judging whether or not, in a given set of circumstances, a gold production operation can be carried out economically.. An alternative method, which brings in the ton or cubic yard as a unit of measurement, is to determine what the cost per ton or per cubic yard is equivalent to, in terms of pennyweights or grains at the ruling price of gold. But this is really only another way of stating that the cost per unit of product is the ultimate measure of profit or loss, and not the cost per unit of input material.It is accordingly of interest to determine the cost per ounce of Australian gold production and to compare it with the cost of gold production in some other parts of the world which are important gold producers. The attached Appendix, which it, is believed comprises practically all Australian mines of any consequence (except Big Bell and the de Bernales group, for which. insufficient information is available), shows this information for financial years ending between 31st December, 1938, and 31st December, 1939, the production of gold dealt with being some 1,084,000 oz., or 66% of the total Australian production for 1939. For comparative purposes the cost of producing gold at representative mines in New Guinea, New Zealand, Fiji, Canada, India, West Africa and Rhodesia, and the average cost of production at the Rand mines, has also been included.It is obviously necessary in a study of this sort that the basis of the cost should be clearly set out and should be as nearly as possible uniform. The "cost" as calculated herein comprises the following items:

Jan 1, 1940

By George Koenig

I have been granted the outstanding privilege... and pleasure to introduce you this evening to the Grand-Duchy of Luxembourg and to tell you in a few words how this country came into existence, how it managed to survive and what role it nowadays plays in the International Community. Luxembourg, situated between Belgium, Germany and Prance is a small, a very small country... just a dot on a map. After all, it is only a matter of 62 miles from top to bottom and 37 miles across at it's widest... barely covering some thousand square miles... so be careful about stepping on the accelerator... you might be in and out without having realized it... which would be a real shame as the Grand-Duchy enjoys a fairly unique geographical feature in so far as it provides the visitor with an outstanding variety of scenery concentrated in a minute spot.

Jan 1, 1987

By J. A. Finch, J. Vergouw

"Flotation selectivity becomes progressively more difficult to achieve with decreasing particle size. One of the possible problems is agglomeration, i.e. particles clustering together. One mechanism derives from the surface charge all particles develop in water. Agglomeration driven by surface charge is known as coagulation. One form is coagulation between particles of two different minerals of opposite charge. Another is coagulation between particles of the same mineral when conditions are such that the charge approaches zero.The paper describes the method of measuring charge and a new automated settling technique for measuring agglomeration. The phenomena are illustrated with galena and pyrite. Methods of assessing the importance of agglomeration in the plant environment are still to be developed.IntroductionFine particles can agglomerate (i.e. adhere to each other) under certain conditions. This is counter-productive for any physical separation process, including flotation. One cause of agglomeration derives from the surface charge that all particles develop in water. Agglomeration due to surface charge effects is referred to as coagulation. There are two forms of coagulation. If the surface charge is brought to near zero then the force of repulsion is lost and particles coagulate. This usually applies to particles of one mineral type and the technical tenn is homocoagulation. On the other hand, if two particles have opposite charge there is an attractive force. Since the particles in this case are usually different minerals this is known as heterocoagulation.Both types of coagulation can cause minerals to be misplaced. In the case of heterocoagulation this is fairly obvious. One example that may be familiar is slime coating (fines of one mineral coating larger particles of another) But even homocoagulation can be a problem an agglomerate of the same mineral particles can entrap particles of another mineral."

Jan 1, 1997

By J. Utt

Recent developments in circulating fluidized bed (CFB) once-through supercritical technology (OTSC) have enabled this technology to be offered as a utility-scale alternative competing head-to-head with pulverized fuel (PF) OTSC offerings. One clear example is the CFB supercritical unit at the Lagisza Power Plant in Poland, owned by PoludniowyKoncernEnergetyczny SA (PKE). This unit has now been in commercial operation for three full years, exhibiting very good performance, and has validated Foster Wheeler?s performance model at this utility scale as well as for units in the 600 MWe and 800 MWe size ranges offering net efficiency of ~43 per cent (LHV basis). This operating unit has also proven the use of the world?s first FW/BENSON? vertical-tube OTSC low mass flux technology. Since the Lagisza original international tender specified OTSC PF technology, it is important to note that the alternative selection of CFB OTSC technology over conventional PF technology is of historic significance, not only for the validation of the CFB supercritical platform as a viable alternative to conventional PF technology, but it also positions the CFB OTSC with fuel flexibility for offering of sizes up to and including 800 MWe units. This paper explores the differences between CFB OTSC technology and standard PF OTSC in utility power generation. Selection criteria, fuel burning range in both technologies, and other selection drivers are discussed. Economic analysis of both technologies, based on existing cases, is also provided. Also discussed are the technical advantages and uses of each technology. Foster Wheeler has recently been awarded a contract for four units of CFB OTSC technology, which utilizes a 2 on 1 configuration of two 550 MWe CFB OTSC boilers on two single 1000 MWe turbines. Essentially this provides a fuel-flexible low-emissions alternative to a 2 × 1000 MWe solid fuel power block.

Jan 1, 2012

THE Talisman mine is situated on the Waitawheta (pronounced Wytaffetta) river just above its junction with the Chinemuri (pronounced Chinnemurre) river near Karangahake, NZ. The explored reef-bearing portion of the claim includes the angleformed by the junction of the rivers and extends southwards for slightly over a mile (See Plate V.). The country is mountainous both rivers flowing through precipitous gorges.The trig. station on Karangahake mountain is almost directly above the workings on the Bonanza section and is 1680 ft. above river level, the adit from the gorge giving 1200 ft. of backs measured vertically. The officers of the N.Z. Geological Survey are engaged in a detailed survey of the Waihi district and the rocks of Karangahake are under examination. The rocks of the district are andesites and dacites much altered and silicified. One of these exhibits a columnar structure in the mass in the Waitawheta gorge near the surface workings on Taukani hill, also on the southern bank...

Jan 1, 1912