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By Al Romphf

Managing blasting-induced air overpressure levels is a key compliance requirement for most blasting operations. Regression analysis, plotting overpressure amplitude vs cube root scaled distance, will often present a level of scatter which should be considered unacceptable. Relying solely on regression-based predictions can lead to overly conservative restrictions that may negatively impact other key performance indicators. Improved methods are needed for accurate overpressure prediction. The Heelan-Blair wavelet has been shown to closely resemble the overpressure waveshape produced when a single charge is fired under typical confinement conditions. The amplitude of a single-hole overpressure wave is influenced by factors such as proximity to the receiver, charge mass, orientation, and confinement both at the collar and face. Additional factors, including timing sequence, barrier effects, wind direction and velocity, must also be considered. The linear superposition method, commonly applied for ground vibration prediction, can be adapted for air overpressure modelling. In blast design software, this approach can consider all relevant parameters and environmental interactions. Given the uniform nature of air compared to rock, linear superposition using realistic elemental wavelets may replace the need to fire a signature hole. Data from 38 single-hole blasts conducted at quarries and mines throughout North America were used to develop and calibrate a linear superposition model. This model reasonably reproduces air overpressure results from full-scale production blasts, offering a practical approach to overpressure compliance and prediction.

Jan 26, 2026

By Bora Derin

This work deals with the recovery of valuable metals from the ancient copper smelting slags located in Küre-Turkey. In this process, copper and cobalt were recovered in metallic form and/or as their compounds, whereas iron was recovered as magnetic oxide or pigment. Abrasive grit material was produced using reduced final slag. The process stages involved carbothermal reduction in a DC arc furnace, granulation, leaching, chemical precipitation, selective sulfidizing roasting and product preparations. In this paper, the process stages were described as theoretically and experimentally whereas slag and products were characterized in detail.

Jan 1, 2003

By V. I. Lakshmanan

The growing concerns on process efficiency, escalating operating and capital costs along with environmental and social concerns of using conventional technology for extracting gold and titanium dioxide demand an in-depth understanding of the fundamentals and a broader understanding of the various process steps involved. This will allow development of efficient process flowsheet for product recovery and compliance with regulatory guidelines. This paper will discuss our recent developments in mineral processing and hydrometallurgical technologies to recover gold and titanium dioxide from a wide range of feed materials including ores, concentrates and tailings.

Sep 1, 2012

By D. A. Phillips

A procedure for designing an optimum pit to yield maximum profit is described. The volume in which a possible pit is considered is divided into discrete blocks, each of which is assigned an economic value equivalent to its worth as a block of mineable material. The profitability of a pit can then be generated by summing the blocks within the pit. The optimizing procedure starts at the surface level and proceeds downwards level by level, to obtain the optimum pit at each level. The method makes use of the fact that an optimum pit at a particular level must be completely contained in any optimum pit at a lower level. Procedures for generating block costs, and pits with various slope angles under the restriction of complete block removal are considered briefly. The main description is of the theory of the method and the computer program based on this. The method is applicable to any type of mineral deposit, the only requirement being that the orebody should be represented accurately by a block model.

Jan 1, 2014

By C. Bryce

Rhenium is primarily recovered as a by-product from molybdenum roasting circuits. However, rhenium is also present in copper heap leach solutions at very low concentrations and represents a potential new rhenium source. Freeport-McMoRan Copper & Gold has developed a new process using carbon adsorption followed by ion exchange or solvent extraction to concentrate rhenium from less than 1 ppm to 15 g/L. The product is compatible as a feed to an existing rhenium processing plant. A pilot plant operated at Freeport-McMoRan?s Sierrita mine has demonstrated the technical and financial feasibility of this new process.

Feb 23, 2014

"3.1. IntroductionAmong the six platinum-group elements (POE), four have identical cubic symmetry, two identical hexagonal symmetry (Table 3.1). Despite crystallographic differences, there is a clear relationship expressed in the chemistries of the POE: they tend to be mutually soluble in one another and can frequently substitute for one another in compounds with other elements. This chapter consolidates the data on phase relations of the POE and the compounds they form with elements selected for their known or potentially important mineralogical significance- As, Bi, Cu, Fe, Hg, In, Ni, Pb, S, Sb, Se, Sn and Te-together with selected data for the occurrence of POE in certain elements such as Au and Ag, and compounds such as FeS. Resources used to compile the data are those available from the chemical, mineralogical and metallurgical literature. First each element is discussed, with composition limits of solid solutions drawn from binary phase diagrams. Single element data are followed by a discussion of the relevant binary systems and a tabulation of data for binary compounds found in those systems (Table 3.2). Tables and diagrams for the ternary and quaternary systems for which information is available follow, and finally the very limited information on the solubility of POE in mineralogically important elements and compounds is presented.The chemical, mineralogical and metallurgical literature on the unary and binary systems is extensive and widely scattered in many languages and publications; fortunately, most of the data needed to compile this chapter can be found in reliable compendia. The most useful and most recent of these works is by Moffatt (1979), because it provides a ready index to all material relating to binary systems listed in previous compendia; furthermore, the Moffatt compendium will reportably be kept up to date by annual supplements."

Jan 1, 1979

By X. T. Feng, Y. H. Hatzor, Y. Tal, G. Yagoda-Biran

"When studying jointed rock mass deformation around underground openings it is of great importance to model correctly the excavation sequence during the numerical simulation. This is because for effective arching mechanism to develop in the roof minute block displacements must take place and some of the available discontinuities shear strength must be mobilized. If from the beginning of the simulation the underground opening already exists in the numerical model, block displacements into the excavation space will initiate and develop from time zero, before the initial stresses in the model have attained their actual initial level in the field. These initial block displacements are therefore artificial and exist only in the numerical model, not in the physical reality, and may lead to erroneous assessment of the stability of the designed structure, typically on the conservative side. We have introduced sequence excavation capabilities both in the numerical manifold (NMM) and the discontinuous deformation analysis (DDA) methods and show here the advantages of this modification using three different case studies, each illuminating a different aspect of this enhancement.We begin with the 25 meter deep 2000 year old underground Zedekiah limestone quarry below the old city of Jerusalem, Israel, which is still standing today unsupported with a free span of 40 m. We show that when the opening exists from the beginning of the numerical simulation the required friction angle for roof stability is 25 degrees, whereas when the opening is removed after all stresses and displacements in the model have been stabilized the required friction angle for stability is only 15 degrees.We then model the excavation sequence of a tunnel model representing a 2500 meter deep research tunnel in the Jinping hydroelectric project, China, in order to determine the in situ stress field at this depth by a grid search inversion of displacement data obtained using the sliding micrometer technology in the course of tunnel excavation. Thus we are able to constrain the in situ stress field at these depths where standard in situ stress measurement procedures are extremely difficult to execute properly.Finally, we use sequence excavation modeling capability to find the total height of the expected loosening zone around tunnels excavated through columnar jointed basalts which pose a great engineering challenge because of the characteristic dense network of slender prismatic blocks that transect the opening at a steep inclination. We use MPBX data obtained during excavation of a deep tunnel through such a rock mass to validate our numerical results and show that application of standard empirical guidelines for dimensioning rock bolt reinforcement in such rock masses may in fact result in very un-conservative design because existing empirical approaches typically ignore the anisotropic nature of the structure of such rock masses which, as we show, plays a very significant role in determination of the extent, shape, and geometry of the loosening zone around the opening."

Jan 1, 2015

By Edward W. Parker

I. INTRODUCTION. AT the Seventy-sixth meeting of the Institute, held in New York, N. Y., February, 1899, I presented a, paper on this subject entitled, Coal-Cutting Machinery,' which has become somewhat out of date, in view of the decade's development in this feature of the coal-minim industry. It should be explained that the present paper is limited to the use of mining-machines in bituminous mines. Practically all of the anthracite mined is ?shot from the solid," no undercutting being done. Anthracite-mining is therefore not considered in the statistics or other references. The statistical record as compiled by the United States Geological Survey shows that in 1898, the year preceding the presentation of my former paper, there were 32,413,144 short tons of coal undercut by the use of machines. In 1907 the machine-mined coal-product amounted to 138,547,823 short tons. In sympathy with the general decrease in coal-production during 1908, the output of machine-mined coal decreased to 123,183,334 short tons, but the proportion of machine-mined coal to the total output, nevertheless, showed an increase, from 35.1 per cent in 1907 to 37 per cent in 1908. In 1898 only 19.5 per cent. of the total product was undercut by the use of machines. The number of undercutting-machines in use in the bituminous mines of the United States has increased from 2,622 in 1898 to 11,144 in 1907, and to 11,569 in 1908. The total production of bituminous coal in the United States in 1908 was almost exactly double that of 1898, while the machine- * Published by permission of the Director of the U. S. Geological Survey. 1 Trans.. xxix.. 400 to 4,59 (1899).

Sep 1, 1910

By Tetsuya Uda

Our recent achievements of rare earth separation technique[1,2] and new process idea for rare earth magnet recycling[3] are reviewed, (1) Binary chloride mixtures of rare earths were separated by a new selective reduction-vacuum distillation process. According to our experimental results, apparent separation factors were 8.1 for the Pr-Nd chloride mixture and 570 for the Nd-Sm chloride mixture. These values are much higher than conventional solvent extraction methods. (2) A study of recycling process of magnet sludge was carried out. The rare earths in the neodymium magnet sludge were extracted by chlorination with FeCI2, An activated carbon was used as a de-oxidation reagent Metallic iron in the sludge was not chlorinated because the iron monochloride is not stable, The extracted rare earth chlorides were easily separated from Fe-alloy and the excess of FeCh by vacuum distillation, 96 % of neodymium and 94 % of dysprosium in the sludge were extraeted into chloride phase, By the vacuum distillation, a mixture of neodymium and dysprosium trichlorides of 99.2 % purity was recovered, On the other hand, the rare earth chlorides can be converted to the corresponding oxides by a pyrohydrolysis reaction accompanied by a formation of HCl gas, The HCI gas can chlorinate metallic iron to FeCh, Therefore, a new recycling process for rare earth magnet waste can be realized as a chlorine circulation type process. During the process, only carbon and water are consumed and there are no toxic pollutants, Moreover, the obtained rare earth oxide can be directly used as raw material in the conventional oxide electrolysis process,

Jan 1, 2003

By C Li, K McDonald an, T Nicholson, C Brown

The relative reactivities of chars prepared from different coal samples at temperatures in the range 500 to 1150¦C were determined by measuring the rates of metallisation of a standard ilmenite concentrate. The results have been interpreted in relation to different measured physical and chemical properties of the chars. Char reactivities were found to correlate with the maximum specific surface area (SSA) of the chars, obtained from plots of SSA versus temperature. Weathering of coal samples gave higher reactivities which correlated with higher SSAs. Experiments using recycled chars showed that the high internal SSAs developed during earlier reduction reactions provide no benefit in terms of increased metallisations. The important role of char hydrogen contents in controlling low temperature metallisation rates was demonstrated. Chars prepared from different rank coals had the same hydrogen content when prepared at the same temperature. Ilmenite metallisation rates had a linear dependence on the hydrogen content of the chars. Large differences in the slopes of the metallisation versus H2 content curves for different chars were interpreted in terms of SSA variations and catalysis of the gas reactions by dispersed metallic iron particles in the chars. A simple test based on magnetic separation of the char was shown to give an indication of enhanced reactivity due to contained metallic iron.

Jan 1, 2001

By Bodnaras G. E, Sceresini P. A

The Filblast Cyanidation Process incorporates the advantages of intense high shear mixing, high dissolved oxygen concentration and high pressure to achieve extremely rapid gold dissolution rates. This is made possible by the unique design of the Filblast gas shear reactor. The reactor is a rugged and compact in-line device. The outer casing is protected by a polyurethane coating and the internal parts are of wear resistant polymer. The largest unit built to-date has overall dimensions of 1200 mm length by 300 mm diameter and has a capacity of 150 dry tonnes per hour at 40 - 45 per cent solids. Service life at this throughput is at least three months. The process may further be applied to high temperature leaching of refractory gold ores or other metals. Wear resistant metal or ceramic materials would be employed for this duty. Four mines are currently employing the Filblast Process for treating a variety of ore types ranging from highly reactive, almost impossible to treat, pyrrhotite/arsenopyrite to deeply weathered clay ore which forms a highly viscous pulp. The effect of shear thinning has resulted in improved adsorption kinetics resulting in higher carbon loading and reduced soluble gold loss. Total tonnage treated is approximately four million. Operating costs which include leasing and maintenance charges for the Filblast and pump power costs are about 16 cents per tonne. This is equivalent to about ten per cent of savings. Laboratory scale units having capacities up to 30 litres/min are available for test work but laboratory testing techniques so far developed do not accurately reflect the oxygen and cyanide savings which have been achieved in the plant.

Jan 1, 1994

By A. D. MacPhail

The Highland Valley Copper partnership was formed in July 1986 and was the logical result of a mine with a large ore reserve but no adequate mill, and a mine with a large, modem mill but dwindling ore reserves. The original partners -Cominco and Lornex -were joined in January 1988 by Highmont Mining Co. which contributed a two-line concentrator. During 1988/1989, the Highmont mill was moved 7.5 km to adjoin the Lornex mill, forming what is now called the Highland mill, with a current nominal capacity of 130 000 tonnes per day. The mine is located 220 km northeast of Vancouver, British Columbia and is close to four communities in which personnel make their home: Logan Lake, Merritt, Ashcroft, and Kamloops. The map in Figure 1 2.2 shows the general area. Kamloops is a major service centre and is serviced by two railways, two major roads and a regional airport.

Jan 1, 1993

The Highlands Region of Papua New Guinea has 3 major national highways. The locations of these national highways are shown in Figure 1. The Highlands Highway begins at Lae City on the coast and passes through the Highlands towns of Goroka, Kundiawa and Mt Hagen. It terminates at Togoba approximately 10km out of Mt Hagen town. The Enga Highway begins at Togoba and passes through the towns of Wapenamanda, Wabag and Laiagam. It terminates at the giant Porgera Gold Mine. The Southern Highlands Highway also begins at Togoba and passes through the major towns of Mendi, and Tari. It terminates at Koroba station, near the Hides Gas Field. Two separate Feeder roads intersecting the main highway service both the Kutubu Oil Project and the Hides Gas Field. These national Highways play a very important role in the development of Papua New Guinea. Goods and services are delivered to the bulk of the population of the Highlands Region using these highways. Heavy machinery and equipment for the mining and petroleum projects of Porgera, Hides and Kutubu are transported using these roads.

Jan 1, 1997

Jan 1, 1880

By Sadao Maruyama

INTRODUCTION Since the big discovery of Kuroko deposits in Kosaka mine, Akita Pref., northeastern Japan in 1959, major Japanese mining companies have been engaged in extensive exploration for the deposits expending large amounts of money. Above all their exploration activities have been particularly fruitful in discovering new deposits in northern Akita Pref. It is estimated that the total ore reserves newly found in the area are at least 50 million tons. Kuroko deposits are the most important ore source of copper, lead and zinc in Japan and have been mined since last century in the said area. Kuroko (black ore) is fine, compact aggregates with sphalerite , glena and barite as principal constituents and chalco- pyrite, pyrite and tetrahedrite as subsequent constituents. The name Kuroko comes from its appearance. It is not rare that total grade of copper, lead and zinc reaches 20 - 30% and the gold and silver content is also fairly good. Accordingly the unit value of the ore is much higher than the ore from other types of deposits. Besides the Kuroko ore, the Kuroko deposits consists of Ohko (yellow ore, massive cupriferous pyritic ore), Keikoh (silicious ore, cupriferous network ore) and gypsum ore. This type of deposit is considered to be not only an important source of base metal but also a source of gypsum and barite. Although the importance of this type of deposit had been commonly recognized, sub-surface nature of the occurrence hampered exploration work. In recent years the improved exploration techniques and increased knowledge of the Kuroko deposits have met with remarkable success in the location of new deposits. This outburst of exploration and dis-

Jan 1, 1970

By H. C. Rickaby

Introduction The township of Swayze, from which the Swayze gold area derives its name, is in the Sudbury mining division, approximately 150 miles northwest of Sudbury. The gold area may be regarded as situated at the southwest corner of a triangular area whose northeast and southeast corners are at Porcupine and Shiningtree, respectively, and whose sides are between 70 miles and 90 miles in length. On a geological map, it would be found that belts of Keewatin greenstones and sediments form the sides of this triangle, and that they surround a large granite mass. Prior to the summer of 1931 the Swayze corner of this triangle had probably been less prospected than the other parts and comparatively little was known of it from the standpoint of gold mining possibilities. The extensive belts of iron formation to the south and west of Swayze received some attention about the year 1909, and during the years 1927 and 1928 some prospecting was done in the townships of Greenlaw and Cunningham, south of Swayze, but chiefly for base-metals- copper, zinc, and lead. In the summer of 1931 a very promising discovery of gold-bearing quartz was made by J. G. and J. L. Kenty, working for the Brett-Trethewey Mines, Ltd., in association with Northern Canada Mining Corporation, and Northland Prospectors, Ltd., and this property, now known as the Kenty Gold Mines, Ltd., has been actively developed with very encouraging results. Following this discovery a6d during the summer of 1932 much prospecting took place in the area, as a result of which a number of other discoveries of gold were made, chiefly to the west of the original find. They are distributed over a wide area, which includes the townships of Rollo, Raney, Swayze, Denyes, Halcrow, and Greenlaw.

Jan 1, 1933

By Alexandre Dolabella Resende

O estudo do padrão de fluxo do aço no molde de lingotamento contínuo é de grande importância para a siderurgia, uma vez que permite compreender como as variáveis de processo afetam a qualidade do aço produzido. Existem diversas técnicas, numéricas ou experimentais, utilizadas para realizar esses estudos. Este trabalho apresenta um estudo de simulação numérica, que tem como objetivo avaliar a influência da fração de argônio injetada no sistema no padrão de fluxo do aço no molde de lingotamento de placas. As condições de processo simuladas foram obtidas de diversas máquinas de lingotamento, com diferentes vazões de aço e argônio injetado. Os resultados numéricos foram validados através de um método experimental denominado “Nail Board”. Após a realização do estudo, foram constatadas consideráveis alterações do padrão de fluxo devido à variação da fração volumétrica do argônio injetado no sistema.

Aug 17, 2017

By The Staff

"IntroductionThis paper lists typical liner performance data for various grinding mills at the Noranda, Waite-Amulet, Pamour, and Hallnor mines, and concludes with a comparison of these data, based on wear per square foot of lined mill shell area. Flow-sheets for each of these plants will be found in the reference cited.General InformationTwenty-eight ball-mills and one rod-mill are used by the Noranda organization for grinding ore. These mills, which are shown in general outline in Plate IV, are all of the overflow type and have a cylindrical shell attached to dished heads.Most of them are serviced by hand-operated cranes and none by power cranes. During re-lining, portable tugger hoists are employed to lift the liners and, frequently, to install them in place.The mills vary in length and diameter and the ratio of end liner area to breast liner -area consequently ranges from 1. 6.75 in a 5 ft. by 14 ft. mill, to 1:2.28 in an 8 ft. by 8 ft. mill."

Jan 1, 1950

By R. Burkhard

Recovery of metals from complex mixed wastes is a challenging task of modem material and waste management strategies. Thermal methods are an important tool in this respect. Plasma turned out to be particularly useful for treatment of complex or toxic wastes and residuals. In order to study plasma processes at reasonable costs, a pilot plasma plant has been used and wastes like ~pent Raney-Nickel catalysts, copper and ah.:lminum drosses, and. other metal containing wastes were investigated. The paper summarizes the most significant findings

Jan 1, 1995

By Leonardo Carneiro Andrade

O desenvolvimento de materiais renováveis e biodegradáveis é uma vertente que almeja a diminuição dos custos e dos impactos ambientais. Nesse âmbito, o presente trabalho visa o desenvolvimento de novos materiais, fabricados com fibras vegetais e que possam substituir outros que são derivados do petróleo. Fibras vegetais foram utilizadas e devidamente modificadas por mercerização e acetilação com o intuito de produzir materiais com compatibilidade química. Foram obtidos, nesse trabalho, compósitos de polietileno reciclado reforçados com fibras de sisal[1]. Utilizamos a ferramenta estatística denominada distribuição de Weibull, para prever as falhas mecânicas dos sistemas estudados. Foi possível observarmos que o compósito resultante teve uma melhora relativa em suas propriedades mecânicas, o que pôde ser comprovado por meio dos ensaios de tração. A distribuição de Weibull foi uma ferramenta que produziu resultados de acordo com os esperados, comprovando a melhoria de propriedades mecânicas do material.

Oct 30, 2017