Search Documents

By M A. Noppé

"Mining is an inherently risky business: from the technical, environmental, social and economic uncertainties associated with advancing an exploration concept to a viable project; to the risks associated with the operating, market, and safety risks and uncertainties attached to a developed mine; and the final mine closure process.Investors and other stakeholders assessing the risk, opportunity and relative value associated with a resource project need to appreciate the project in its correct context. Errors, omissions, biased reporting or conflicting information in reporting may result in a misinterpretation of technical and financial results, leading to biased estimates or assumptions on project value (Noppé, 2016).Simplistically, a project can be assessed on three key areas for positioning the project in its correct relative context, namely: the project development stage the confidence in the estimated quantities and qualities of the resource, reserve and/or product the level of accuracy, precision and confidence in the technical and economic studies supporting the project.In the latter case, the ‘technical and economic’ information includes assessing the necessary social, environmental and commercial/legal/governmental approvals for the project.Responsible management of a resource project through its full life cycle relies on competent and dependable control and direction being effectively provided by the technical, business and board leadership of the organisation. In turn, the project information must be effectively communicated between various disciplines, these disciplines and the company, and the company and its stakeholders.CITATION:Noppé, M A, 2016. Responsible management and transparent reporting across the project life cycle, in Proceedings Life-of-Mine 2016 Conference, pp 5–7 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 28, 2016

Jan 1, 1925

Jan 1, 1881

Jan 1, 1961

Jan 1, 1931

By Jian Wang, Hongyang Cao, Binxiu Wu, Junhong Li, Jimin Wang

"The enrichment and separation of scattered metal indium component in the pressure leaching solution with sulfuric acid from vacuum furnace germanium slag were studied by iron substitute and P204 extraction, which is supplied by shaoguan smelter. The experimental results show that the extracting power of P204 for indium from pressure leach solution is powerful. The optimal technological condition were the ratio of P204 and sulphonating serosene 3:7, phase ratio 1:3, solution pH 1.2, and extracting 5 minute. The enrichment indium solution of 21.7 g/L In at 95.2% recovery ratio was obtained by three-stage counter flow extraction and four- stage counter flow stripping.IntroductionScattered metals, such as Indium and germanium, were inriched as intermediate product or by-product during the metallurgy process of other non-ferrous metals, such as lead, zinc, copper and tin. For example, the indium and germanium were inriched in vacuum furnace germanium slag, which is the by-product of zinc vacuum distillation operation from hard zinc. It is difficult to recovery the indium from the vacuum furnace germanium slag, because the indium content is low, and the chemical composition and phase compositon were complex.Recovery indium from bearing indium zinc slag was researched extensively, such as pressure acid leaching, high temperature evaporation, solvent extraction method[l-7], acid leaching method has the advantages of high leaching rate, which can be separated hydrochloric acid, sulfuric acid and silicon fluoride acid systems. Solvent extraction method has the advantages of low production cost, fast reaction speed, high enrichment ratio, and simple operation."

Jan 1, 2013

By Steve R. La Brooy

Techniques for dealing with copper-gold ores are reviewed. Cyanide has little selectivity of gold over copper, and depending on the reactivity of the copper minerals cut-off grades for gold recovery by direct cyanidation are generally below 0.5% copper for oxide ores and 1 % for sulfide ores. Non-cyanide gold leachants also tend to be reactive to copper. The cheapest option for sulfidic ores is to produce a flotation concentrate for smelting, while transition ores generally need a sulfidisation pre-treatment. The requirement for the concentrate to have a high enough copper grade to be acceptable to a smelter may compromise copper and gold recovery. This can lead to significant gold grades in the flotation tailing, and copper levels in the tailing that are too high for direct cyanidation to be able to recover the gold. Oxidised ores, flotation tailing or other material not amenable to flotation represent the greatest grey area for gold recovery. Copper removal by acid, alkaline or ferric pre-treatment is possible though not generally used. Cyanide pre-leaching to remove copper, followed by copper and cyanide recovery represents a potential option that has been installed at one Australian gold plant, where copper is recovered onto carbon, ahead of the slower leaching gold. Actual cyanide recovery depends on ore mineralogy, allowing for losses as cyanate, thiocyanate, carbonate and ferrocyanide. Alternative options for gold recovery following cyanide leaching include precipitation, ion exchange and solvent extraction of the gold. Ammonia-cyanide leaching may offer another option for more selective gold dissolution from flotation tailing and oxidised materials. A plant is currently under construction in Mauritania.

Jan 1, 1992

By Tony Treasure, Ian Ewart

The EMEW® cell has been developed to overcome a number of inherent limitations in conventional electrowinning technology, particularly the high cost and restricted process windows characteristic of conventional hardware. The EMEW technology has been widely demonstrated to achieve high performance for various metals under chemical conditions well outside the limits required for efficient operation of conventional cells. In particular application of the EMEW cell for recovery of silver offers significant operating and capital cost advantages over conventional Merrill Crowe technology used for cyanide based solutions. The cell also offers process advantages for direct silver recovery from nitric acid solutions. The performance of the EMEW® cell on silver cyanide solutions, producing high grade silver metal in a single step, is accomplished by providing a physical mechanism which presents metal ions to the cathode on a highly efficient and continuous basis. The simplicity of design and operation of the EMEW cell offers the following advantages for silver recovery from cyanide or nitrate based solutions: • High grade product in a single step. • Selective for silver over other metals in the electrolyte. • Wide operating concentration range (100,000 - 5ppm). • Ability of the cell to operated in a variety of acid or alkaline electrolytes. (Cyanide, Nitrate). • Simple liquor reticulation. • No pretreatment required - Clarification, deaeration or zinc dust. • High cmTent density and current efficiency compared to conventional electrowinning cell. • Modular design allows for flexible operation and production rate. • Pilot plant results using full scale cell result in accurate scale up design. • Easy/fast installation - cell banks are delivered pre configured with piping and wiring. • Enclosed cell minimizes corrosive vapor and liquid losses in the circuit.

Jan 1, 2000

By John W. Buch

"INTRODUCTION The Ruhr coal basin is estimated to cover an area of more than 1,000 square miles. Here, the total thickness of the coal bearing formation (Carboniferous) is 10,500 feet, and drilling-hole have revealed 92 coal beds with a total thickness of 262 feet. 6/ Beds pitch from 0 to 90 degrees and about 70 percent of the wartime production came from beds that pitched less than 30 decrees. 5/For example at the Minisiter Stein mine, there are 24 minable coal beds ranging from 80 centimeters. (2 ft., 7 1/2 in.) to 250 centimeters (8 2 1/2 in.). The vertical thickness of the measures is 1,000 meters (3,200 ft.), and at this mine the deposits are covered with 150 meters (500 ft.) of surface wash. The cross section (fig, 1) at Fritz mine; Hoesch, A.G., Essen, Ruhr, is characteristic, The mines have been developed and worked to vertical depths of 2,000 to 2,500 feet by vertical shafts; main-level intervals are 500 to 700 feet apart. Haulage roads are straight, driven in rock, and centered as nearly as practical between property boundaries. Levels are sectionalized by driving crosscuts at right angles to the main haulage road on 800- to 900-foot centers. The roads are the main transportation arteries for the use of trolley or Diesel locomotives. A plan of the sixth main level (fig. 2) at the Bruchstrasse mine; Gelsenkirchener A.G., Bochum, illustrates main-level development and,sectionalizing with crosscuts. The cross section in figure 3 is that of the fourth crosscut west at the same mine."

Oct 1, 1946

Steps were taken for a permanent organization of the scientific and technical employees of the Government at their mass meeting on May 8. This was the result of an informal meeting on Apr. 23 of thirty representative Government scientists and technical men who organized the preliminary committee and called the mass meeting. This subject has been widely discussed during the last year and was brought acutely to the fore by the work of the Joint Congressional Reclassification Commission, because that Commission has stated that it wished to deal with employees only through organizations. Rodney H. True of the Department of Agriculture was Acting Chairman. He pointed out that the principal advantages that were expected to be derived from such an organization were: (1) Improvement of conditions and facilities for more effective scientific and technical work; (2) adequate presentation of the needs. and results of such work to the public and to legislative and administrative officers; (3) -greater freedom in both official and non-official activities; (4) just and reasonable salaries based on service performed and the economic and social conditions which prevail; (5) greater public recognition of the aims and purposes of research; (6) advancement of science and technology as an essential element of national life. Three plans of organization were offered to the meeting, which covered the fundamental principles which could be utilized by these Government employees. The first plan would have permitted the new organization to work only through existing scientific organizations. This is the plan that scientific and technical Government employees in England have adopted and an outline of the English plan was read to the meeting.

Jan 6, 1919

By Eric G. Zahl, John P. Dunford, Hamid Maleki

Coal bumps are influenced by geologic conditions, the geometric design of coal mine excavations, and the sequence and rate of extraction. Researchers from private industry and government agencies around the world have studied mechanisms of violent failure and have identified individual factors that contribute to coal bumps. To develop predictive tools for assessing coal bump potential, the authors initiated a comprehensive study using information from 25 case studies undertaken in U.S. mines. Multiple linear regression and numerical modeling analyses of geological and mining conditions were used to identify the most significant factors contributing to stress bumps in coal mines. Twenty-five factors were considered initially, including mechanical properties of strata, stress fields, face and pillar factors of safety, joint spacings, mining methods, and stress gradients. In situ strength was estimated in 12 coal seams where uniaxial compressive strength exceeded 2,000 psi. Allowances were made for favorable local yielding characteristics of mine roof and floor in reducing damage severity. Pillar and face factors of safety were calculated using displacement-discontinuity methods for specific geometries. This work identified the most important variables contributing to coal bumps. These are (1) mechanical properties of strata, including local yield characteristics of a mine roof and floor, (2) gate pillar factors of safety, (3) roof beam thickness, joint spacing, and stiffness characteristics, which influence released energy,(4) stress gradients associated with the approach of mining to areas of higher stress concentrations, and (5) the mining method. By combining the strength of both analytical and statistical methods, new capabilities were developed for predicting coal bump potential and for building confidence intervals on expected damage.

Jan 5, 1999

By Zhang Huaiwei, Shi Xiaoyan, Li Xinlin, Sun Fei, Hong Xin

"The control of the slag properties has become very essential in improving the separation between the slag and the matte in the copper slag cleaning process. The goal of the present work is to characterize the copper converting slag through chemical analysis (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy detection (EDS) and thermal analysis (DSC). The majority of the identified elements were Fe, Cu, Si and 0. The XRD has presented compounds such as Fe2Si04, Si02, CuFe204, Fe304, and Cu. The main existence of copper element was the metallic copper due to the entrainment loss. Slight amounts of copper were existed as the CuFe204 in the slag. The density, viscosity, electric conductivity and the thermodynamic property of the molten copper converting slag were also investigated in the study.IntroductionCopper slag, which is produced during pyrometallurgical production of copper from ores, contains materials like iron, alumina, calcium oxide, silica etc. For every tonne of metal production about 2.2 ton of slag is generated [l]. The slags of copper converting process contain about 5% of copper and about 20% magnetite. The copper are present in the slags either as physically entrapped or in chemically dissolved [2-3]. The traditional slag cleaning method is electric furnace process including two steps, intensive slag reduction and quiet sedimentation. Although the process is suitable for the various copper slags, it is also with the higher energy consumption [ 4-7]. The slag characterization studies are the fundamental step in the definition of an appropriate recycling process for saving the energy consumption."

Jan 1, 2013

By Catherine T. Aimone-Martin, Susan G. Beattie

A series of small scale explosive tests were performed at a perlite mine near Socorro, New Mexico. The tests were designed to investigate the azimuthal or directional relationship between small scale geologic structures such as joints and the propagation of explosively-induced ground motions. Three shots were initiated within a single borehole located at ground zero at depths varying from 83 m (272 ft) to 10 m (32 ft). An array of three component velocity and acceleration transducers were placed in two concentric rings at distances of 20 m (66 ft) and 40 m (131 ft) surrounding the single hole at 7.5° , 15° , and 30° azimuths as measured from ground zero. Data from the transducers were then used to determine the average propagation velocity and waveform characteristics of the blast vibration through the rock mass at the various azimuths. The rock mass was mapped to determine the predominate joint orientations (strike and dip) and the average propagation velocities were correlated with this geologic information. The results showed that there is a correlation between the predominate joint orientation and ground motion amplitudes and velocity. The more predominate geologic structures allow the wave to follow along their strike thereby forming a planar path of least resistance and in turn, allowing higher velocities and amplitudes. Secondary joints or structures may act in concert with more prominent features to form a network of channels or paths along which the wave moves more freely than it may when traveling against the structures. The greatest azimuthal variations in velocity and amplitude was observed for the shallow shot at 10 m (32 ft) depth.

Jan 1, 1996

On an average of at least once a year there comes to the attention of the Institute Headquarters the activities of some individual who represents himself as a member of the Institute, and by a hard-luck story or other means secures loans or advances of money which are never returned. On one or two occasions the Institute has been able to secure the arrest and conviction of these frauds. Recently some individual has been operating in California and defrauded several members of the Institute. He is described as a man of 5 ft. 7 or 8 in. height, decidedly slim, and his weight is about 140 lb. His hair and mustache are gray, eyes blue or gray and he claims to be near-sighted. He is also said to have had a keen, furtive, "Hang-dog" look and claims to have been raised in Bethlehem, Pa. He speaks with a German accent. If a man answering this description presents himself before any members and claims to be a member of the Institute it will be to the good of the profession if he can be caught making fraudulent representations and placed where his ability to defraud will be under control. The most effective means of apprehending persons of this character is the very prompt notification to Institute Headquarters of any persons claiming to be members of the Institute in hard luck. If such persons are asked to supply their signature or photograph or both to be, forwarded to Institute Headquarters for identification this will serve as an excellent check on their operations. Reluctance to comply with such a request is in itself a suspicious circumstance.

Jan 9, 1919

Citigold Corporation operates the Warrior gold mine at Charters Towers, northern Queensland, mining narrow quartz veins (0.1 to 2 m wide) in granodiorite by long hole open stoping on levels 15 m apart. Access is by decline and cross-cuts with on-ore development drives. The mineralisation comprises Palaeozoic mesothermal quartz veins containing gold, pyrite, sphalerite and galena, hosted by the Ordovician age Towers Hill Granite. The gold grain size is variable from 1 to 500 ¦m with 1 m face samples up to 800 ppm Au, and average run-of-mine grades of 10 to 14 ppm. Despite the spectacular gold tenor, little visible gold is present. Gold grades are highly variable presenting challenges in ore reserve estimation. Tonnages are discounted by 70 per cent to allow for the low payabilities (30 to 50 per cent) of the veins. Estimation techniques allow high confidence in overall global grade estimates but poor reliability on a local scale (25 m). Kriging ranges as low as 5 - 8 m means that obtaining a Proved Ore Reserve by diamond drilling is not economically feasible, and broad-scale mine planning decisions are made at the Inferred Mineral Resource stage and mine design work at the Probable Ore Reserve stage. Proved Ore Reserves can only be estimated after underground development has proceeded through the mineralised body with levels at 15 m vertical spacing sampled at 2 - 3 m intervals along the level. However, reconciliations between actual gold produced and earlier resource estimates produce workable results. A further three mines are scheduled to be developed underneath the city of Charters Towers.

Jan 1, 2008

By R. V. Ramani, B. K. Belle

The increased effectiveness of a two-phase spray system (TPSS) over a single-phase spray system (SPSS) for dust suppression is reported in several laboratory studies. The dust collection efficiencies of SPSS and TPSS were studied in a model experimental longwall gallery facility at Pittsburgh Research Laboratory at NIOSH (USA). The experimental design consisted of two factors: pressure, and airflow. Each factor had three levels. SPSS experiments were conducted at only one pressure (1035 kPa) which is nearly 1.5 times higher than the highest air and water pressure for TPSS experiments. The results of the study are presented in this paper. While it appears that TPSS performed better than SPSS, the data is not sufficiently conclusive on this aspect. The differing spray characteristics of the chosen TPSS and SPSS nozzles did not allow a direct comparison of the two systems. In the TPSS arrangement, considerably greater turbulence in airflow is created around the shearer; it is likely that at least in the immediate vicinity of the tailgate drum, there is a roll back of the dust/mist cloud into the walkway. Therefore, positioning of the personnel upwind of the tailgate drum is necessary to avoid high dust exposures. The rate of decrease in concentration with TPSS is higher than that with SPSS. This may be due to the greater atomization of the water. The test set-up did not allow the study of conditions when coal is cut from tail to head where the potential for personal exposure is high. Changes in the experimental design are necessary to overcome some of the reasons expected for the inconclusive results.

By J. Hanna, H. R. Gonzalez

Discussion by N.L. Hargett Dear Dr. Hanna: As discussed in our phone conversation, we are enclosing a suggested revision to the paper, "Application of Bentonitic Clays in Suspension Fertilizer Formulations," published in MINERAL & METALLURGICAL PROCESSING, May 1990. The revision will replace the second paragraph in the article. The reason for the revision is that suspensions have decreased in market share since 1984 and at present comprise an estimated 25% to 30% of fluid mixtures. This represents 6% to 7% of all fluids and only 2% to 3% percent of all fertilizers. Based on national surveys conducted by the Association of American Plant Food Control Officials (AAPFCO), suspensions comprised an estimated 25% of all fluid mixtures in 1974, 33% in 1976, 35% in 1980, 40% in 1984, and 36% in 1988. Revision to "Application of Bentonitic Clays in Suspension Fertilizer Formulations." Suspension fertilizers are an important segment of the fertilizer industry in the United States. Suspensions allow higher concentrations of nutrients (N, P2O5, K2O) than clear liquid solution fertilizers. K20 content of solutions is limited to about 10%, while suspensions can contain more than 30% K2O. Suspensions can tolerate greater variations in temperature than solutions. In suspensions, if crystallization occurs, the crystals can remain suspended in a clay jell instead of settling as they would in solutions. Solubility is not a limiting factor in suspensions, since complete solubility of phosphate is not required. This allows a wider range of phosphate materials to be used. Also, materials commonly used in formulating suspensions are less expensive and more widely available than those for clear liquids (Getsiner et al., 1984).

Jan 1, 1992

By Lijuan Li, Xin Xia, Junjun Huang, Qijie Zhai, Xiang Jiang

"Some experiments with different temperatures (1173, 1223, and l273K) and different annealing times (3, 4, 5, 6min) were carried out on cold-rolled plate of Fe-36Ni invar alloy. The microstructure and the mechanical properties were observed and tested respectively, and the fracture morphology was observed by SEM. The results show that with increasing of the temperature and the annealing time, the austenite grains gradually grow up accompanied by a small amount of annealing twin crystals, meanwhile, its plasticity and toughness are improved, and it is typical ductile fracture under the condition of tensile failure. After annealed at l223K, the invar alloy has better comprehensive properties than that at the other annealing temperatures, and the grains size is more uniform. Furthermore, when the annealing time is 4min, the invar alloy has the best comprehensive properties.IntroductionAs we known, most metals and alloys expand with increasing temperature. More than one hundred years ago (in 1897), Guillaume observed that Fe-Ni alloy with face-centered cubic (fcc) crystal structure, consisting of36%Ni, showing a very small thermal expansion coefficient below the ferro-to-paramagnetic transition, the thermal expansion coefficient around room temperature( <2 X 1O-6K-1 compared to most metallic materials which have a thermal expansion coefficient of 10-20 X 1O-6K-1) [1,2]. Since then, the subject has attracted many researchers, and various alloys with low thermal expansion coefficients have been developed. These alloys, generally known as ""invar alloys"", are in demand where dimensional changes due to variation in temperature must be minimized and where high stability is required [3, 4]."

Jan 1, 2012

By E. B. Swanson

Crude oil production in Iraq during 1932 was maintained at slightly higher levels than in 1931, but the output continued to be restricted to the requirements of local consumers. The Iraq Petroleum Co., representing British, American and French interests, which has been operating within its concession east of the Tigris River since 1926, began drilling operations on Apr. 5, 1927, and completed its first well at Baba Gurgur on Oct. 14, 1927, to which area the company has since confined its drilling activities. Relatively small quantities of oil have been produced annually, but the products have been utilized in company operations and have not been offered on the Iraq market. The Khanaqin Oil Co., which has its field of operation at Naft Khana in the so-called Transferred Territories, has been supplying the Iraq market with petroleum products from Iraq wells since March 12, 1927. The output of the Khanaqin Oil Co. refinery, at Alwand, during the past three fiscal years ending March 31, has been as follows: (In Barrels of 42 Gallons Each) 1930 1931 11931 Gasoline................................. 102,940 104,571 118,012 Kerosene................................ 104,010 108,112 111,624 Fuel oil...........................1 286,9001 332,142 354,244 503,850 544,825 583,880 The Iraq Petroleum Co. has a small topping plant, with a capacity of about 150 bbl. a day, used in the manufacture of petroleum products for the company&apos;s own needs. During the 1932 fiscal year, the production was 3918 bbl. of gasoline and 2235 bbl. of kerosene, as compared with 8157 bbl. of gasoline and 6308 bbl. of kerosene during the preceding fiscal year.

Jan 1, 1933

By Steve Kral

The Fourth International Symposium on Hydrometallurgy was organized to give those in the minerals processing field an opportunity to discuss current topics of interest in the broad field of hydrometallurgy. Held in Salt Lake City, UT Aug. 1-5, 1993, this fourth symposium also paid tribute to Milton E. Wadsworth for his many contributions in this area over the past 40 years. The science of hydrometallurgy has made great strides since the last symposium was held 10 years ago. The use of electrochemical principles and techniques has produced encouraging results. For example, the application of in situ electrode spectroscopy has helped to understand the mechanisms operating in hydrometallurgical processes. Sophisticated computer models have been developed to handle the thermodynamic properties of concentrated electrolytes. However, it is up to the hydrometallurgist to continuing working on bridging the gap between theory and practice. The successful application of solvent extraction-electrowinning (SXEW) is one illustration of the successful transfer of technology. Its widespread use in the United States during the 1980s played a significant role in the revival of the domestic copper industry. Currently, electrowon copper accounts for about 30% of total US production. Impressive developments in precious metals recovery have also occurred. Since the last symposium, carbon-in-pulp (CIP) and heap leaching have become widely used in gold recovery. And recovery of refractory precious metals ores and concentrates by pres¬sure oxidation and bio-oxidation have made significant advances. In all these examples, hydrometallurgy has played a significant role in the recovery of minerals and metals from primary sources. In addition, considerable attention has been focused on the treatment and recovery of values from secondary sources.

Jan 1, 1994