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By G. Q. Liu

"The application of oxygen-enriched cyanidation to three Canadian gold ore samples has been investigated. The results showed that the use of oxygen can improve gold dissolution kinetics, reduce grinding time, and lower cyanide and lime consumptions. To obtain the same gold extraction, the required cyanide leaching time was reduced from 48 hours in slurry containing 8 ppm O2 to 12 - 24 hours in 20 ppm O2 slurry. Reagent consumptions were reduced by 23 - 37% for cyanide and by 35 - 54% for lime. There was little advantage to further increasing the dissolved oxygen to 32 ppm from 20 ppm. Gold extraction from the +200 mesh fraction improved 4 - 14% in oxygen-enriched slurry. A general kinetic model derived from the cyanidation of three ore samples can be described by the following equation: <equation>where E is the gold extraction (%) at time t (hours), EI is the ultimate gold extraction (%) , and &apos;P and k are constants depending on cyanide concentration, level of dissolved oxygen, and the characteristics of the ore samples. Comparative studies of conventional carbon adsorption and carbon adsorption in oxygen-enriched slurry have also demonstrated that oxygen enrichment resulted in more favourable conditions for gold adsorption."

Jan 1, 1995

By J. E. Rowland

NIOCALITE is a new mineral species which has been identified in rock from the Oka district, Quebec. It occurs as prismatic crystals up to l 0 mm. in length and I mm. in width, in coarse, white, crystalline calcite with associated apatite, diopside, biotite, pyrochlore, and niobian perovskite. The crystals of niocalite are light yellow in col-our and have a vitreous lustre. The optical properties of niocalite (I) are as follows: Biaxial negative -2V = 56° a = 1.700, [ ] = 1.730 Birefringence y -a = 0.030 Optic orientation: X = b, Z/\c 12°, Y , /\a = 32° The specific gravity is 3.32 and the hardness is approximately 6 (Mohs scale). A detailed analysis performed on 2.4 gm. of hand-picked material reveals that niocalite is essentially a calcium niobium silicate. Table I gives the result of the analysis. Crystals of niocalite, apparently suitable for X-ray diffraction work, were selected, and single crystal photographs were obtained using both Weissenberg and Precession cameras. Initial difficulties were encountered in interpreting these films, and in correlating the crystal data with the optical data. The in-consistencies were explained by the fact that every grain examined was twinned to some extent.

Jan 1, 1957

By Lyall J. Lichty

THE property of New Calumet Mines, Limited, is on Calumet island, in the Ottawa river, about sixty-six miles northwest of Ottawa. Lead and zinc orebodies were discovered here in 1893. A gravity concentration plant was built in 1912 but was not a success metallurgically, and the plant was later destroyed by fire. A programme of diamond drilling on the property, started in 1937 and continuing to 1942, indicated ore reserves amounting to 1,300,000 tons averaging 2.75 per cent lead, 8.82 per cent zinc, and 0.041 oz. gold and 6.24 oz. silver per ton( l ). These orebodies have been developed underground by cross-cutting and drifting from a three-compartment vertical shaft, sunk to a depth of 745 feet. &apos;The ore is a contact metamorphic deposit occurring in rocks of the Grenville series, on or near the contact between biotite gneiss and an overlying calcareous amphibolite(2,3). It consists chiefly of iron-bearing sphalerite, galena, pyrrhotite, pyrite, and minor amounts of chalcopyriteand argentite. The gangue minerals closely associated with the ore are calcite, quartz, and various lime-silicate minerals.

Jan 1, 1945

By G. Song

This paper reports the anodizing voltage, gas evolution and sparking behaviors of an anodized coating formed on AZ91D in a silicate containing solution. According to their responses to an anodizing current, a four-stage anodizing mechanism is proposed. At the same time, the formed coating is characterized in terms of its microstructure, composition, thickness and corrosion performance. It was found that deposition of MgSiO3, Mg(OH)2 and MgO as well as dehydration of Mg(OH)2 are involved in the anodising process; the vigorous gas evolution accompanied by intensive sparking and the corresponding negative anodising efficiency in the later stage of the anodising process are closely associated with thermal decomposition of water due to the high temperature resulting from the intense sparking on the surface of the anodized alloy; the thickness, porosity, and composition of the anodised coating on a magnesium alloy depend on the final anodising cell voltage; and the corrosion resistance of a thick but porous coating containing more silicates appears to be more corrosion resistant than a thin but compact coating containing less silicates.

Jan 1, 2006

By Tedd E. Lister, Andre Anderko, Peiming Wang

Mobile electronic devices such as smart phones and tablets are a significant source of valuable metals that should be recycled. Value metals in phones are gold, palladium, silver, copper, cobalt and nickel. Devices now contain increasing amounts of rare earth elements (REE). Effective recycling schemes should include the recovery of these critical materials. Targeted recycling of items containing more of the less available critical materials could address their future criticality. This presentation will describe an electro-hydrometallurgy approach to efficient recycling of metals from scrap mobile electronics. The electrorecycling (ER) process generates oxidizing agents at an anode while reducing dissolved metals at the cathode. Development of the process involved generation of E vs pH diagrams, complemented with metals dissolution experiments used to assess the effectiveness of various solution chemistries. Although several schemes were envisioned, a two stage process has been the focus of work: 1) initial dissolution of Cu, Sn, Ag and magnet materials using Fe+3 generated in acidic sulfate and 2) final dissolution of Pd and Au using Cl2 generated in an HCl solution. Results from laboratory work will be discussed.

Jan 1, 2014

By K. V. Konigsmann

"The mill at Mattagami Lake Mines treats 3,850 tons per day. The mill feed is a heavy sulphide ore. It is composed ofPyrite & Pyrrhotite - 40%Marmatite - 17%Chalcopyrite - 2%Magnetite - 10%Talc and other Silicates - 31%The sulphides are intimately associated with each other and often finely disseminated throughout the siliceous gangue. An abundance of middling particles exist in the circuit and a delicate balance has to be maintained between concentrate grades and metal recoveries.The metal content of the mill feed fluctuates between 0.4 to 0.7% for copper and 6 to 13% for zinc.The flow sheet of the concentrator is shown in Figure 1.Eight sample streams have been selected for on-stream analysis, namely1. Copper Concentrate 2. Copper Cln Tailings 3. Copper Tailings 4. Zinc Concentrate5. Zinc Rgh Concentrate6. Zinc Cln Tailings7. Zinc Rgh Tailings8. Flotation TailingsThe mill feed is not being analysed. Only a very coarse sample could be obtained which would be difficult to pump, and the fluctuations in the copper content are too small in absolute terms to have much of a bearing on circuit operations."

Jan 1, 1969

By V. I. Lakshmanan

Rare earth elements and yttrium (REEs+Y) are being used in the making of hybrid electric cars, catalytic converters, wind power generators, LEDs, hard disc drives, flat panel displays, and portable electronics. Currently China produces more than 95% of REEs+Y, which has made REEs+Y a critical strategic resource. Process Research ORTECH Inc. (PRO) has developed the innovative mixed-chloride (HCl+MgCl2) solvent extraction processes for recovery of REEs+Y from their ores. The HCl leaching system provides the opportunity to regenerate the acid, while the presence of MgCl2 in the lixiviant enhances the activity of the hydrogen ion by orders of magnitude, making the lixiviant very aggressive and resulting in high recoveries of REEs+Y. Solvent extraction steps are used for separation and purification of REEs+Y from other value metals or impurities including iron, zirconium, hafnium, uranium, thorium, niobium, tantalum and titanium. Direct individual separation of REEs+Y in a mixed chloride system allows avoiding the additional process steps of precipitation and dissolution in HCl. The resulting process has a simplified flow sheet that is closed-loop and environmentally friendly.

Jan 1, 2014

By Selvia Tourn, Liliana Castro

"Abstract - Argentina, a large country with an important agriculture industry, needs an ever-increasing amount of phosphorus and potassium, as essential elements for plant growth. Current requirements are met from imports, but potential resources exist in Argentina. For example, several phosphatic occurrences are known in paleo-marine basins, the most significant of which are in Tertiary units in Patagonia. In addition, two types of potassium deposits are also known in Argentina: evaporite deposits in the Neuquén Basin at depths of 750 m to 1500 m contain 22 to 25 wt% K2O equivalent; and glauconitic sandstone containing about 6 wt% K2O has been identified in Patagonia.Several experiments were undertaken to test unprocessed phosphate rocks as slow-release, direct-application fertilizers, with good results. In addition, it is proposed that direct application of glauconitic sands would provide an efficient and economic alternative source of potassium. Tests with glauconite samples are still in progress. The existence of both phosphate and glauconitic rocks in Patagonia suggests that development of an extractive industry for these materials would not only help Argentina approach self-sufficiency in fertilizer usage, but also assist in the socio-economic development of this region."

Jan 1, 2003

By C. Langer

Although the existence of precious metals, particularly those of the platinum group, in the nickel ores in the Sudbury district has been known for a good many years- almost as long as the ore deposits themselves- the Mond Nickel Company were the first to effect their recovery on a commercial scale. The precious metals values of the different Sudbury ores vary considerably, and are generally higher in the copper-rich ores. These values are so very small that a direct determination in the ores gives quite unreliable results. This is not surprising if one considers that some of the ores contain on1y one unit of total precious metals in about two million units of ore, and that this one unit will consist of seven different metals, each with a different chemical behaviour. It is only after the ores have been smelted to a Bessemer matte containing about 80 per cent combined copper and nickel that the precious metals content can be determined with some degree of certainty. From the figures thus obtained, the precious metals content of the ores can be calculated, provided the tonnage of ore used to produce one ton of matte is known. The recovery of these minute quantities of precious metals out of ?such a large amount of gangue and sulphides of iron, copper, and nickel seems at first glance a commercial and technical impossibility. Nevertheless, science has found a way to conquer all the difficulties, and quite substantial quantities of the precious metals contained in the Sudbury nickel-copper ores have been regu1arly recovered for many years by the Mond Nickel Company.

Jan 1, 1927

By Yong Kang, Bingyuan Yan, Dandan Zheng, Xiaochuan Wang, Dengfeng Su, Dongyang Li

"According to the characteristics of rock mass and the directional cutting technology of water jet, a new idea of light shock controlled blasting with water jet slotting was put forward. Based on the fracture mechanics theory and the stress wave theory, the mechanism of damping with water jet slotting was analyzed. On the basis of the above, the evolution law of the pressure wave and displacement field during the blasting were simulated by FEM software ANSYS/LS-DYNA. The result shows that: the oriented slot plays a good role in orientation during the blasting, and makes the energy generated by gas released by the explosives gather at the tip of the oriented slot, which makes it easier for the main crack to expand along the oriented slot and indirectly reduce the stress effect on the protected object. Meanwhile, the energy of the seismic wave is reduced while transmitting through damping slot. Finally, compared with the normal blasting with damping ditch, the maximum acceleration is reduced by 15.62%, the maximum velocity is reduced by 52.99%, and the maximum displacement is reduced by 68.32%. INTRODUCTIONIn recent years, with increasing demand for energy and space, an increasing number of underground projects have been under construction. Drilling-blasting method, as a traditional main method for rock excavation, is still an indispensable means in the engineering construction. As is known, blasting vibration will cause the deformation and unstable of the existing building structures, so how to reduce the influence on the existing building structures caused by the blasting vibration has become the focus. Traditional shock absorption measures mainly include three kinds: the first one is pre-splitting blasting, the second measure is to change the parameter of explosive filling, and the last one is to excavate damping ditch between the protected object and blastholes. However, engineering practices show that: the protected rock may be damaged in the process of pre-splitting crack construction by blasting, the second measure is difficult in operating, and the third measure is troubled by large work quantity (Song Guangming, 1999; Lou Jianwu, 2004; Lou Jianwu, 2005; Li Xibing et al., 2008)."

Jan 1, 2015

By Ch. Enkhbold

Underground mining of minerals is becoming an increasingly complicated technological and ecological problem. It can be explained both by worsening of geological conditions of mining and by a specific character of mining industry, which, in contrast to processing branches of industry, intrudes into one of principal components of the nature ? the Earth&apos;s interior. At a traditional organization of mining industry, the entire volume of the produced rock mass is brought to the Earth&apos;s surface, where valuable components are extracted. This entails not only power over expenditure for long-distance transfer (especially in the vertical direction) of the waste rock forming a part of the original mineral, but also the formation of huge volumes of worked-out spaces. The latter leads (nature cannot stand emptiness!) to an irreversible development of geomechanical processes of shifting of overlying rock masses resulting in an irreparable damage of all surface structures located on the territory undermined by deep mining. Owing to their high productivity combined with low power consumption and instrumental compactness, novel bifunctional technological processes of minerals dressing successfully solve the problem of rock mass processing in underground conditions with subsequent operative disposal of final tailings of such underground dressing in the worked-out space. Besides, an integration of two processes into one is achieved, for example, a decrease in the rock mass coarseness with a simultaneous precise separation of valuable and waste components.

Aug 1, 2013

By John Hartlen

"The 19th century was an ""age of gold"" and Nova Scotia experienced its share of early gold rushes. Gold mining activity in the province was focussed into three ""rushes"" which occurred, approximately, in the 1860s, 1890s and 1930s; a total recovery of 1.1 million oz. Au has been recorded. The purpose of this note is simply to chronicle the technical development of gold mining and processing in the province and to comment briefly on the recently renewed interest in this precious metal. The first public discovery of gold in Nova Scotia was made by a farmer in 1860 at Old Tangier or Mooseland, and this find sparked the province&apos;s first gold rush. The mining and milling methods of the 1860s were ingenious. Initially, arrastras, crude stone-hewn grinding mills, drawn by men, mules or horses, were widely used. Nova Scotia&apos;s first conventional stamp mill was installed at Mooseland by 1862; it was comprised of four wooden stamps and is believed to have been imported from Scotland. One of the largest waterwheels of the 1860s, reportedly 16 feet in diameter and 8 feet wide with a SO-horsepower rating, was used in the Renfrew Gold District to drive gold stamps. Steam power was also employed, and many of the engines were of native construction, as was the unit at Waverley&apos;s Lake Major Company, which had a piston 1 foot in diameter by 12 feet long and was connected to a 16-ftdiameter flywheel."

Jan 1, 1999

By J. M. Harrison

"The Nor-Acme gold mine is near the shore of Snow lake, northern Manitoba, about 75 miles east of Flin Flon. The claims that form the nucleus of the present property were staked in 1927 by C. R. Parres, but it was not until 1941 that diamond drilling disclosed the potentialities of the deposit. In that year a large-scale drilling programme was begun under the direction of F. Ebbutt, of the Howe Sound Exploration and Development Company. Two orebodies were outlined containing about 5,000,000 tons of ore assaying $5.25 in gold per ton. In August, 1945, construction of the mining plant was begun.All information and interpretations contained in the following brief description of the deposit were obtained from surface mapping.GEOLOGYThe ore lies at the contact between a coarse, basic, pyroclastic rock, which is the hanging-wall, and grey, acidic lavas and sediments, which form the footwall. These rocks are cut by irregular basic intrusions that vary in composition from diorite to hornblendite, and by small acidic dykes . Tourmaline is locally common in the hanging-wall rock near the ore.The ore occurs in brecciated, silicified, and ·slightly carbonatized rock. Arsenopyrite is the main sulphide and the gold is associated with it. Pyrrhotite is locally abundant and minor pyrite, chalcopyrite, sphalerite, galena, and cubanite have been noted. Two orebodies are known, the Dick and the Toots. The Toots, which is much the smaller of the two, is about 1,000 feet west of the Dick."

Jan 1, 1954

By Lihong

A series of Fe2O3-elimination experiments were conducted on feldspar samples from Tangshan Stone?powder Plant. These experimental methods include scrubbing desliming, flotation,rod milling and high gradient magnetic separation. Some technical factors of feldspar concentration and a new technological flow?sheet of ceramics raw material concentration were put forward.

May 1, 2003

By E. M. Córdoba

The effect of the Fe3+ lFe2+ redox couple on the chemical and biological dissolution of chalcopyrite was studied. All the tests were carried out in stirred flasks with 100 mL of a ferric/ferrous sulphate solution, in the absence or in the presence of bacteria (iron- or sulphur-oxidizing) and at low (35 DC) and high (68DC) temperature. The initial redox potential was controlled between 300 and 600 m V Ag/ AgCI and silver was used as chemical catalyst. The results showed that the oxidizing action of ferric ion on the chalcopyrite was controlled, in all cases, by nucleation and precipitation of jarosites on unreacted particles. The tendency of Fe3+lFe2+ solutions towards equilibrium favours the activities of both ions to be equal. Consequently, the dissolution rate was faster at relatively low redox potentials (between 400 and 500 mY) than at high values (600 mY). In this sense, the presence of ferrous ion in the system is a key factor to control hydrolysis and precipitation of ferric ion. Unlike jarosite, the elemental sulphur produced during dissolution of chalcopyrite was porous and did not act as a diffusion barrier.

Jan 1, 2007

By K. Murase

Potentiostatic electrodeposition behavior of dendritic copper from acidic copper(I) chloride (cuprous chloride) baths containing sodium chloride and sodium bromide was investigated. The morphology, or appearance, of copper dendrite and the sodium content in the dendrite as an impurity were both influenced by deposition potential (0 to ?150 mV vs. SHE) and bath temperature (R.T. to 60 C), while the current efficiency for the deposition was 99% or more irrespective of the deposition conditions examined. The bath pH did not affect the deposition behavior in the pH range of 0 to 2. Bath temperature was found to be the most important factor influencing the deposition current. The current density of the dendrite deposition on a titanium cathode was lower than that onto a copper cathode with the same substrate surface area. The reproducibility of the current for the dendrite deposition was poorer when an as-polished titanium cathode was used, although it was improved by surface treatment of the cathode with an HF-HNO3-H3PO4 solution before electrodeposition. The deposition behaviors were discussed with the potential-pH diagram of the Cu-Cl-H2O system.

Jan 1, 2007

By D. P. Fenton

The Phelps Dodge El Paso Rod Mill produces approximately 2.4 million pounds per day of copper rod from a casting and rolling operation. The newly formed rod is treated to remove mill scale and oxides using a sulfuric acid and hydrogen peroxide solution which is bled periodically when the copper concentration reaches 30-35 g/L. The bleed solution is heated to 75° C to destroy the residual peroxide. Copper is then recovered in a 270 cell EMEW electrowinning plant. Clean acid is also regenerated in the EMEW plant and is returned to the rod cleaning circuit. The EMEW plant commissioned in January 2006, has two operators and replaces a copper sulfate plant with fourteen operators. The EMEW plant has a capacity of 1700 kg/day of cathode copper at 2.1 kWh/kg copper deposited. The electrowinning plant operates in closed circuit with the rod mill returning up to 2600 kg/day of sulfuric acid resulting in zero discharge. Use of dimensionally stable anodes (DSA®) ensures that the acid quality is maintained in the closed loop operation. The operating conditions, performance and plant experience of the EMEW copper and acid recovery plant are discussed.

Jan 1, 2007

By J. A. Muñoz

In this work, short and long-term tests were performed using different massive mineral sulfide specimens (chalcopyrite, pyrite, sphalerite, galena, covellite and chalcocite) of museum grade and quartz of analytical grade in an acid medium containing silver ions. After attack, the samples were observed by SEM and products characterized by EDS. Parallel, massive specimens of pyrite (FeS2) and chalcopyrite (CuFeS2) were embedded in an epoxy resin, either electrically isolated or in electrical contact, and treated with silver ions in the presence of bacteria. Finally, massive chalcopyrite and pyrite electrodes were subjected to electrochemical measurements in an acid medium under different experimental conditions (addition of silver ions and inoculation). The results showed that silver deposition takes place preferentially on specific mineral surfaces: chalcopyrite, galena, covellite and chalcocite. The chemical reaction of silver ions with pyrite and sphalerite was negligible at low silver concentration (8 ppm). But sphalerite reacted with silver ions at higher silver concentration (100 ppm). In a mixture of chalcopyrite and pyrite, silver was deposited on the former surface creating new cathodic sites which sped up the electrochemical reactions of chalcopyrite dissolution.

Jan 1, 2007

By Denis Blackburn

La Direction générale du développement de l?Industrie minérale (DGDIM) du ministère des Ressources naturelles et de la Faune (MRNF) du Québec tient un inventaire de toute l?activité minière sur le territoire. Cet inventaire s?est enrichi, au cours des dernières années, d?un grand nombre de projets dédiés au fer ou à des substances qui y sont associées (titane, vanadium, phosphate). Actuellement, cinq régions du Québec sont principalement touchées par la recrudescence de projets dédiés au fer : Fermont, Schefferville, Baie d?Ungava, Baie-James et Chibougamau. Fermont et Schefferville sont les régions les plus actives. Les infrastructures en place, telles que les routes, les chemins de fer, les ports, les lignes électriques et les municipalités, ont atteint, dans certains cas, leur capacité et de nouvelles infrastructures devront être construites pour satisfaire les besoins. À la Baie-James et sur le flanc ouest de la Baie d?Ungava, des projets d?exploration sont aussi en cours. Le manque d?infrastructure pourrait peser lourd sur le développement de projets miniers dans ces régions. Enfin, dans le secteur Chibougamau/Matagami et à quelques sites ailleurs au Québec, des projets d?exploration qui visent le vanadium, le titane ou le phosphate pourraient aussi fournir comme produit secondaire des concentrés de fer. Tous les projets, décrits dans cet article, sont situés sur le territoire du Plan Nord du gouvernement du Québec.

May 1, 2011

By S. Fahland, P. Vogel

"The Gorleben salt dome has been investigated since 1979 for its suitability as a repository for the disposal of high-level radioactive wastes. The geoscientific surface exploration was followed by underground exploration of the site beginning in 1983: underground excavation work included the sinking of two shafts from 1986 to 1994, the excavation of the infrastructure area and of drifts located in the first exploration area EB1 within the following years. The exploration was interrupted for ten years from 2000 to 2010 as part of a moratorium. After the expiry of the moratorium in March 2010, the geoscientific underground exploration at the Gorleben site was resumed. The investigations were interrupted again in autumn 2012 due to a political decision. The exploration programme included extensive geoscientific investigations: geological exploration, geophysical investigations, mining exploration and mining observation, laboratory tests, in-situ geotechnical measurements, geological modelling and numerical model calculations. To analyse and interpret the results of the in-situ measurements and mining observation geomechanical, thermal and thermo-mechanical model calculations were carried out. One of the main elements of the in-situ geotechnical investigations were high-resolution geothermal measurements performed in boreholes used for geological exploration and geotechnical tests.The geothermal measurements are used to evaluate several geotechnical findings, e. g. drift closure, rock deformation, stress change, and are completed by thermal model calculations to analyse and interpret the results of in-situ measurements and mining observation. The model calculations have been carried out using the special purpose JIFE code. To consider the whole exploration mine with the adjoining host rock as well as the successive excavation of drifts and boreholes in detail a three-dimensional finite-element model was developed. The model calculations are used to analyse the cooling-off of the surrounding rock of the drifts caused by ventilation. The cooling-off of the surrounding rock is an ongoing process affecting the results of further geotechnical measurements in the near field of the drifts. To predict a realistic time and space dependent distribution of the temperature field of the host rock within the exploration area which is influenced by ventilation thermal model calculations are necessary. Comparing the calculated temperature field with the in-situ determined rock mass temperature field within the exploration area EB 1 the results show a sufficient agreement. Furthermore there is very good correspondence, both qualitatively and quantitatively, between the experimental and the calculated findings regarding the temperature profiles including the effects of excavation and ventilation of the drifts."

Jan 1, 2015