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By G. J. Kipouros, N. Dadvand

"In recent years coatings of alloys have been produced for a wide range of applications including many for wire bonding application. The main characteristic of the baths of electroless plating is the presence of sodium hypophosphite as a reducing agent and also as the supplier of phosphorus. In the electroplating of alloys the Watts bath is predominantly used. This presentation compares the two techniques, electroless plating and electroplating, and discusses the possibilities of cross utilization of sodium hypophosphite in an attempt to formulate baths that eliminate the waste disposal issue related to some components.INTRODUCTIONThe importance of surface characteristics and the linkage of surface coating process to surface characterization has given rise to the evolution of surface engineering. Not only the surface preparation and morphology has become very important to the coating technology but also the knowledge of surface area exposed to the process of coating or corrosion is absolutely essential in ascertaining the behaviour of coatings and their adherence to the substrate. The above concepts are not unknown to researchers involved in the protection of surfaces, particularly metallic, from corrosion and/or erosion corrosion. However, the complexity of the surface defects, roughness, porosity, interconnected porosity and other related factors have contributed to the uncertainty of the true surface area versus the nominal surface area. Therefore critical parameters such as current density and chemical surface intensity although have been studied extensively at the atomistic level by carefully prepared surfaces are very difficult to be determined at the practical scale required during the coating processes.The most pronounced case calling for an understanding the relationship between the surface area and the effective protection is the coating of surfaces of items produced by compression or consolidation of powdery materials. With the advent of nanomaterials and the additive manufacturing through 3D metal printing this issue is becoming more important. Certain experience in this field come from the accumulated knowledge resulted from the attempts to characterize the electrochemical behaviour of powder metallurgy metals and alloys. Powder metallurgy has been a well-established process for half a century on basic metals such as iron, copper and their alloys. Recently the development of powder metallurgy process for aluminum, titanium and attempts to develop powder metallurgy processes for magnesium and its alloys has brought to light another important issue that of the development of coatings on difficult to plate reactive metals such as aluminum and magnesium. Despite of many successes in the development of powder metallurgy alloys the exact characterization of the corrosion behaviour of the coatings and the substrates is difficult to determine because of the unknown morphology of the exposed area i.e. the exact morphology and area of the exposed surface (Samal, 2007)."

Jan 1, 2016

The effect of long term exposure of full size bolts to corrosive environments is presented. A special test rig was used to test four bolts under different loading conditions. Four, X-grade identical profile bolts, each of 21.7 mm core diameters (23.7 mm full diameter) were subjected to prolonged corrosion testing using acid sulphate water. The pH value of the circulated water varied between 3.4 and 4.3. The corrosion exposure test period lasted three and half years. Two bolts were axially loaded to 10 and 20 tonnes force respectively, the third bolt was subjected to a 360 Nm torsion load and the fourth bolt was left unstressed to act as a reference bolt. After the test period ended, the bolts were stripped of their corroded coatings and weighted for weight loss. The diameter of each bolt was subsequently measured, and the loaded bolt samples were first tested non-destructively for tensile cracks and then tested for tensile failure. No cracks were found on post corrosion bolts tested non-destructively. The failure strength reduction on all four post-corroded bolts was significant, varying between 21% and 39%. The onset of corrosion was not confined to the targeted mid-section length of the bolt, however, the severest corrosion occurred at the anchored ends of the bolts.

Aug 1, 2013

By A. F. Beck

Abstract Canada has opened up a geological province in ?Western Canada which offers a new .stimulus to oil exploration geophysics. The problems of instrumental technique, interpretation, and logistics involved in the exploration of this new territory are presented in this paper and some of the efforts being undertaken to overcome them are discussed. The scope of this programme, its possible trend and extent, especially when viewed .against the background of the exploration effort in the United States, is touched upon. Introduction The science of earth physics was first applied to the search for oil on this continent some twenty-five years ago when torsion balance and refraction seismic methods were initiated in the Gulf Coast area of the United States. Since that time advances in the various branches of the science have been sporadic as new fields for their use opened up in the search for deep salt domes as well as less well-defined geological structures; in the application to well logging as part of the exploitation of petroleum; and in underwater surveys, aerial surveys, etc. In the present paper, attention has been concentrated only on the Western Canada plains area because of the recent remarkable growth of geophysics as an oil finding technique in this region. The other prospective oil areas of the West Coast and the Eastern Provinces of Canada are at present of minor importance, although they will undoubtedly receive increasing consideration in the future as accessibility to markets becomes a major factor and more improved geophysical and geological techniques are developed. A vast province in Canada, covering some 655,000 square miles of prospective oil territory (approximately one-half of the prospective oil area in the United States), has provided the new sphere of activity for geophysics (see Figures 1 and 2). Included in this area are immense inaccessible, uninhabited frozen regions which pose a new problem in logistics and operational techniques.

Jan 1, 1950

By D. MOORE, A. REINSBAKKEN, A. J. Sinclair

The Gypo quartz vein lies near Oliver, British Columbia, and was quarried between 1955 and 1968 for decorative chips. The vein is one of many quartz veins hosted by the Late Jurassic Oliver Plutonic Complex, specifically by the porphyritic quartz monzonite phase of the pluton. The vein has a known length of 155m and a thickness of 46m. It strikes east-west and dips at 60 degrees to the south. Mineralogy is predominantly quartz with minor pyrite, muscovite, fluorite, calcite, apatite and manganese; trace amounts of chalcopyrite, pyrrh otite, marcasite and molybdenite also are present. Quartz in the vein is zoned. A thin grey quartz zone found near the margins of the vein fades gradually into white quartz, which comprises over 95% of the vein. Late-stage boxworks cut earlier mineralization, particularly fluorite, which occurs as pods in a zone fairly close to the hanging wall. Sulphide minerals are found in a centrally located zone in the quartz vein. The hanging wall of the Gypo veins is altered only slightly, but thefootwall is altered extensively to a greisen of muscovite and grey quartz. Evidence suggests that early in rhe vein development, the adjoining country rock was feldspathized. As grey quartz and muscovite was deposited, a period of intensive greisenization and fracturing occurred which so weakened the rock that a central block of greisenized country rock foundered. This provided the open space in which the vein was deposited.

Jan 1, 1984

By N. W. Martison, J. E. Hawley

"The Moulton Hill deposit is in the Eastern Townships of Quebec, 3 miles northeast of Sherbrooke. It is complex, both structurally and mineralogically, consisting of a narrow, irregular, mineralized zone that has been traced for a length of 600 feet, and in places to a depth of 1,000 feet, containing copper, lead, and zinc sulphides with a low content of gold and silver. It lies in a series of highly schistose micaceous rocks, believed to be of Ordovician age, but the mineralization is probably post-Lower Devonian. New details of the structure of the ore have become available since it was first described (1) , and as these show some striking peculiarities a further discussion is here merited .As detailed elsewhere, the deposit was discovered in 1942 as a result of regional geological studies followed by the application of electrical geophysical methods.Actual production began in July, 1944, and ceased in June, 1945. During the period July, 1944 to June, 1945, 75,643 tons were milled§, yielding the following:"

Jan 1, 1954

By J. C. Folinsbee, D. R. Derry

"The Property of Opemiska Copper Mines (Quebec) Ltd. is in Levy Township, Chibougamau district, west of Chibougamau and south of Opemiska Lake. The original find was made in 1929 by the late Leo Springer and associates of Prospectors Airways Ltd., following observation from the air of an area of dark rocks in newly burned-over country. Work on the ground discovered three veins of high-grade chalcopyrite in gabbro (No. l, No. 2, and ""North"") and, after several seasons of trenching and diamond drilling, financed by Ventures Ltd., a shaft was sunk in 1936. This work indicated about 280,000 tons of six per cent copper ore to a depth of 500 feet. During this period, the senior author carried out a reconnaissance geological survey over the whole property and surrounding claims, which showed that the veins were in the gabbro portion of a large composite basic sill that had been folded with the enclosing lavas. Owing to the low price of copper and lack of transport work was suspended and the property remained dormant until 1951.In that year the company was re-financed, the property prepared for production, and further exploratory drilling undertaken. The drilling, based on structural indications, located a new vein of which the only previous evidence had been some irregular stringers. This vein, No. 3, was traced by drilling for a length of 2,000 feet and the indicated reserves were thereby increased to about one million tons. An additional vein, No. 4, was intersected in several holes.With this encouragement, plans for production were confirmed, and operations commenced' at the beginning of 1954 on a scale of about 400 tons a day, concentrates being shipped by truck to St. Felicien and thence by rail to Noranda. In the first year of operation concentrates were re-covered carrying 14,047,210 pounds of copper, 76,714 ounces of silver, and 6,259 ounces of gold. The operation is under the direction of J. P. Millenbach, General Manager, with J. M. Thompson as Assistant General Manager and F. G. Cooke as General Superintendent on the property."

Jan 1, 1949

By T. Tsutsumi, S. Kukino

"During the diametrical compression test, the tensile stress generated near the loading plate is influenced by the contact area between the loading plates and specimen. However, very few studies have determined the contact area. Theoretical or analytical models have shown that for an orthotropic material (i.e., with material properties that differ along each of three mutually orthogonal twofold axes), the maximum tensile stress is generated at the center of disk when the angle of the principal material direction to the loading direction is close to ?/4. The maximum value is almost constant, regardless of the contact area. Conversely, the maximum tensile stress is generated near the loading plate when the angle between the principal material direction and loading direction is small. The maximum value decreases as the contact area increases. Therefore, in the latter case, the influence of the contact area on tensile strength measurement of is significant.In previous studies, the distribution of stresses applied on the loading plate is assumed to be a uniform load. In reality, the applied stress is highest at the center of loading plate and seems to decrease with distance from center. The applied load disappears at the edge of loading plates. In this study, in order to satisfy this boundary condition on the loading plate, the cosine curve is adopted as the distribution of load applied on the loading plates in a theoretical model of the diametrical compression test. Furthermore, the elastic solution using boundary conditions shown in this study is used to obtain the tensile stress distributions on the loading axis for an orthotropic circular plane. These distributions are compared with empirical results obtained under uniform loading with a loading plate or concentrated loading in previous studies."

Jan 1, 2015

By Ruan Chi, Zhenyue Zhang, Zhengyan He

In order to understand what governs the leaching of exchangeable rare earth (RE) and impurities and enhance the RE leaching process, the effects of the concentration of ammonium sulfate, pH and leaching temperature on the migration of RE and aluminum (Al) during the leaching of weathered crust elution-deposited rare earth ore was studied. The elution curves for ammonium ion (NH4 +) were also studied to reduce the consumption of the leaching agent. It was found that a high concentration of leaching agent can enhance the leaching process of RE and Al, reduce the breakthrough volume of NH4 + and more rapidly obtain the equilibrium of NH4 +. However, excessive leaching agent can both increase the cost and the burden on the environment. There is almost no variation on the elution curves of RE and Al in the pH range of 4-8 and control of the pH of the leaching agent can be omitted. It is better for the leaching work to be done in summer since higher temperatures can enhance the RE leaching process and improve the use ratio of ammonium. Using 0.1 mol/L ammonium sulfate for leaching 250 g RE ore, 95.42% RE extraction can be obtained when the volume of leachate is 102.6 mL. At this moment, only 18.17% of NH4 + is used to exchange RE and 49.22% of NH4 + is left in the leachate that can be reused as leaching agent by replenishing ammonium sulfate. The results of our studies can provide theoretical guidance for high efficiency and low consumption exploitation of RE ores.

Jan 1, 2016

By M. Hozayen, Q. Ni, E. S. Radwan, P. Nawrocki, A. Jebbouri

"A major geomechanical study was conducted for one of the UAE onshore oil fields with the purpose of studying reservoir rock properties and stress distribution, based on which a 3D coupled reservoir geomechanical model was built. This model was later used for wellbore stability analysis and for analyzing the effect of fractures on future reservoir production performance, including fracture deformation and permeability evolution occurring due to reservoir depletion and resulting changes in local stress field. The subject of this study was a complex fractured Upper Cretaceous carbonate reservoir characterized by high degree of heterogeneity, both vertically and laterally. Wellbore instability related drilling problems were encountered while drilling the wells in this field. The problems were mainly in drilling the horizontal wells, including breakouts and mud losses. Experimental results of laboratory tests used in this study are summarized in Part I of this paper whereas wellbore stability analysis and formulation of a3D geomechanical model that was built for that purpose is summarized herein.A 3D geomechanical reservoir model was developed, which included natural fractures. The mechanical properties of the reservoir rock, such as Young’s modulus, Poisson’s ratio, UCS, friction angle and tensile strength were populated based on the correlations established in Part I of this paper and the developed model was then used to simulate the 3D mechanical-property distribution and the evolution of the in situ stresses in the field due to depletion from 1983 to present-day. Based on the full field model, mud weight cubes were developed to predict the safe mud weight windows in different drilling directions. In addition, well stability prediction for two planned wells was performed using a 3D near-borehole model. Firstly, the computed stress state and mechanical properties simulated in the full field model were extracted along the well trajectory of an existing horizontal well which was drilled recently and then, a3D near-borehole model was constructed along the well trajectory. The wellbore stability analysis along the well trajectory, including stress state, strain distribution and displacements, was performed to identify the instability events along the well trajectory. It has been seen that the presence of natural fractures is closely related to the recorded borehole instability incidents. The computed plastic strains which indicate the wellbore failure were consistent with the recorded wellbore instability events in the FMI image logs, what provide further verification of the developed model. Then, this 3D near-borehole model was applied to two planned horizontal wells and the wellbore stability analysis for the two wells was carried out.The results showed that drilling vertically in the reservoir is safer than drilling horizontally. However, the drilling mud weight window in the vertical direction is narrow, being as narrow as 18.7 pcf or 0.299 sg locally. Drilling horizontally is less stable towards the maximum far field stress direction than towards the minimum far field stress direction. The mud weight cubes were used to identify the optimal well placement and well trajectory. For planned well trajectories, this technology can also be used to determine the optimal mud weight."

Jan 1, 2015

By Frederick Biery

Outline ? Project Challenges ? Results from 100 recent projects ? What factors are driving the best and worst projects ? A look at recent mining projects ? Conclusions

May 1, 2009

By J. Xie

In underground coal mining, the potential for an outburst of coal and gas is considered to be one of the major hazards. As such, considerable emphasis is given to understanding and preventing such events. A number of indices are used in the prediction of the outburst in a coal mine. The main indices include initial gas desorption rate, gas pressure, gas content, coal strength, gas flowrate from a borehole drilled in a coal seam, and combinations of the above. Some of these indices are considered to be inadequate, inappropriate or impractical for some coal seam conditions, such as those with soft and friable coal. The Huainan Mining Group (Huainan) in China and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia have been jointly developing gas content based technologies to predict the risk of the outbursts. One of the major progressive achievements is a new method for determination of outburst gas content threshold values. The method utilizes empirical analyses, numerical modeling, and seam-specific knowledge . This paper describes the method and its application for the #11 Seam at Guqiao mine, Huainan.

Aug 1, 2013

By Alan E. Gallie

FOR many years the Witwatersrand has been the leading gold mining r camp in the world and, to a Canadian mining student, could not fail to be of overwhelming interest. The vast scale upon which the operations are conducted, the enormous production accomplished, and the perfection of the operative technique, have all so forcibly impressed themselves on his memory that it is difficult to select any one feature as more outstanding than another. For the purposes of this paper, however, the author has selected the very first feature of mine operation with which he came in contact, namely, shaft sinking, as it reflects, quite as well as any other, the spirit of mining in South Africa. Early mining in Johannesburg was by open cuts or trenches, dug along the outcrops of the reefs. The ore was thrown from bench to bench to the surface. As the depth increased, rock was hoisted by bullocks. In 1887, the first shafts were sunk and true underground work began. At the same time, boreholes were put down to test the continuity of the reefs at depth. The first was at the Village Main reef. It cut the South reef at 517 feet and the Main reef leader at 581 feet. The Main reef leader assayed eleven penny-weights. Subsequent boreholes proved the reefs down to thousands of feet. Many companies secured deep-level claims as a direct result of the information obtained from the early holes. These companies then held land on which there was no readily available ore. In order to get to their pay rock, vertical shafts through the upper strata were necessary. Shareholders were impatient, and shafts had to be sunk as speedily as possible. The old methods of shaft sinking were investigated, new methods developed, and soon all records were being broken. In the last thirty-five years, the record has been slowly advanced, and last summer it was again broken to stand at 430 feet in a 31-day month. During the period from 1915 to 1935 inclusive, in the Witwatersrand district, 96 miles of shafts were sunk. Today, with the advance in the price of gold and the increase in the mining area, there are over twenty-five major shaft-sinking operations being carried on.

Jan 1, 1937

By Tim Bekhuys

Equator Principles ? Applies to projects > $10 million ? Voluntary agreement between 58+ EPFIs ? Categorized projects based on environmental risk, consequences ? Requirements for EA, EMP, use of safeguard policies, consultation ? IFC Performance Standards on Social and Environmental Sustainability ? Apply if the project is in a low or lower-middle income country ? Low-middle income countries defined by the World Bank Development Indicators Database

May 1, 2008

By Edward R. T. Tiekink

Metal complexes continue to find therapeutic applications for the treatment of a wide variety of human ailments. Amongst these, gold(I) thiolates are used to treat rheutmatoid arthritis but, usually in combination with other treatment or as a last resort. New therapeutic uses of gold, both as gold(I) and gold(III), are being sought, including against cancer, the focus of the present contribution. It will be demonstrated that certain gold(I) complexes show exciting cytotoxicity profiles, rivalling those of cisplatin and standard chemotherapeutic agents. More importantly, anti-tumour activity is demonstrated in vivo, albeit in a mouse model. The presentation will give a brief overview of ?metals in medicine? with a focus on gold and will summarise some recent advances in the development of goldbased anti-tumour agents.

Oct 1, 2003

By W. Grell

"In this paper, two methods of standardizing mill language are proposed; one is based on metric units and the other on English units. Tentative procedures for chemical and screen analysis based on published methods are proposed.Standard procedures for determining work index, and for leaching, flotation, and classification tests are outlined.Objects of Standardization:(1) to improve communication -(a) among gold metallurgists(b) with other branches of mineral dressing(c) with mineral dressing in other countries(d) with general scientific procedure(2) to improve mill control by -(a) standard methods of analysis (i)(ii)(iii)(b) standard methods of calcula tiort(c) standard accounting proceduresin the plantin the mill laboratoryin the assay office(3) to improve mill test work and investigationAreas of Standardization(1) Nomenclature or terminology(2) Measuring techniques(3) Test procedures(4) Accounting procedures"

Jan 1, 1966

By Stuart M. Jones

This paper is derived from a document that compiles autogenous and semi-autogenous mill installations worldwide, through the end of 2010. Updates have been solicited from all major mill manufacturers and most have responded. A review of AG/SAG mills sold to date and in the last five years indicates that the AG/SAG mill market is very healthy and the trend is larger diameter mills with high diameter-to-length ratios. Ring motors (gearless) are the preferred drives for large mills even though the power transmitted through a gear drive is expected to near 11,000 kW per pinion in the near future.

Aug 1, 2010

By Robert B. Parsons

"Canadian investment abroad has been the focus of considerable attention in recent years. Canadian mining companies have been heavy investors in Latin America and are taking a hard look at Central Asia and the Pacific Rim. This international flow of capital is not one-way however. Foreign mining companies continue to make substantial investments in Canada's mining industry. This month. Tax Notes addresses some of the main Canadian income tax implications of foreign investment in Canada.Foreign Investment in CanadaThere are two basic forms of foreign investment in a Canadian company: share capital and debt. The following comments deal with each of these investments separately. It is appreciated that the relevant tax legislation is, as always, quite complex, and that the notes that follow are intended only to serve as a guide. This article should not be relied on as a substitute for professional advice."

Jan 1, 1994

By Yongfeng Jia, Shaofeng Wang, Danni Zhang

Arsenic in mineral processing solutions and effluents is commonly removed and immobilized via iron(III)-arsenatecoprecipitation. The effect of re-crystallization of 2-line ferrihydrite on the long-term stability of iron(III)-arsenate coprecipitate is still not fully understood. This work investigated the redistribution of arsenic and iron during 2-line ferrihydrite transformation at different pHs and temperatures over time. X-ray diffraction (XRD), transmission electron microscopy (TEM) and chemical extraction were employed to characterize the crystallinity of the iron oxyhydroxides. Results showed that the amount of arsenic released into solution during aging increased significantly with increasing media pH.

Jan 1, 2014

By Hongyan Qu, Lihui Zheng

"Horizontal wells in coal seams, Qinshui basin, China are prone to wellbore instability problems induced by drilling, completion and production operations due to the presence of natural cleat network, anisotropy with regard to permeability, brittleness and mechanically weak property of the coal rock. The mechanism of wellbore instability in coal seams is very different from that in conventional formations, the traditional wellbore stability study methods therefore, are not proper for wellbore stability analysis in coal.In this study, the mechanism and controlling of wellbore stability of coal seams in the Qinshui basin was investigated through theoretical modeling, laboratory experiment and field operation. Firstly, a new physical model of wellbore stability for highly-cleated coalbed was proposed, considering the combined effect of mechanical mechanism and reservoir characteristics, specifically, taking the effect of reservoir pore pressure in the vicinity of the wellbore on the wellbore stability into account. Then experiments on the triaxial stress evaluation were conducted at laboratory where rock mechanical parameters such as Poisson's ratio, Young's modulus, compressive strength, tensile strength, angle of internal friction and cohesion ability were measured respectively. The in situ stress at different depths in four wells of Zheng 1-303, Zheng 1-308, Zheng 1-309, and Zheng 1-310 in the Zhengzhuang were calculated, and the collapse pressure and formation breakdown pressure were predicted through the theoretical model we developed. Finally, by comparing the maximum collapse pressure and minimum breakdown pressure of the four wells in the coal as well as in the roof and floor of the coal seams, the fluid weight window for safe drilling in each coal seams was determined, and appropriate approaches against anti-sloughing in coal seams, Qinshui basin were applied in the field operation.The wellbore stability was found not only related to the wellbore pressure, but also affected by the pressure in the reservoir through the theoretical model. The fluid weight window for safe drilling in each coal seams varies with the coefficient of wellbore stability in the model. The laboratory experiment results indicate that the roof and floor of 3 # coal in Qinshui basin has high breaking strength, high heterogeneity, and are easy to collapse and breakdown. In addition, the whole rock mineral analysis shows that 3 # coal in the Duanshi block has high clay content, resulting in the phenomenon of hydration swelling as clay encountered water, and leading to unstable coal and extreme large drilling uncertainties. Due to the effect of the unstable rock mechanical properties of the roof and floor formation on the wellbore stabilizing, drilling parameters, drilling fluid performance and BHA were optimized during the drilling process according to the formation properties, rock mechanical properties and drilling techniques in the field operation."

Jan 1, 2015

By Larry Urbanoski

"This paper describes the application of a radioisotopic energy dispersive X-ray aY1alyser to complete on-stream analysis in a base metal concentrator.The major components of the system are outlined and some description of the application, operating experiences and benefits are provided.IntroductionThe ma1n intent of this paper is to describe the on-stream analysis system in operation at the Geco concentrator. X-ray analysis systems installed in Canadian concentrators to-date may be broadly classified as wavelength dispersive analysers whereas the installation described herein is an energy dispersive x-ray analysis system. Energy dispersive x-ray analysis techniques may utilize radioactive sources to provide primary x-rays for excitation of elements and separate the secondary x-rays on the basis of energy levels. In contrast wavelength dispersive analysers apply high voltage x-ray tubes to provide primary x-rays and utilize crystals to disperse and thereby separate x-rays generated by bombardment of the sample."

Jan 1, 1978