Search Documents

By A. Bascetin

The mining industry in Turkey has been developing in the last 10 years. Mine wastes and tailings have thus been increasing, depending on the rising production rates. There are many problems related to accidents that occur in tailings damps. In this study, the applicability of the surface paste disposal (SPD) method for a Pb-Zn mine in western Turkey was examined. Density was 3.084 and specific surface area was 0.899 m2/g. The mill tailings have very low plasticity and show characteristics of clays and silts in terms of the Unified Soil Classification System. The particle size distribution of the tailings was 39.2% particles finer than 20 µm. The results of this study showed that the physical and chemical properties of mill tailings make them suitable for SPD.

Aug 1, 2013

By M. Gagné, F. E. Goodwin

The mining industry represents a significant investment in infrastructure of which steel plays a key role. Many structures in a mine are made of steel including shaft structures (buntons, station steelwork and headgear); stope structures (roof supports, pipe hangers); haulageway structures (ore transfer stations, electrical stubbies); and surface structures (plant buildings, tank supports, pipe gantries, conveyor belts, stacks, stockpile structures, stairways and railings). Maintenance of structural components can often be difficult because of the environment, including those where corrosive fumes persist, or limited access, such as in shafts where access is limited, or to short maintenance shifts or where limited working space is available. Thus a cost-efficient, long-lasting and maintenance-free protection system for steel should be specified. Galvanizing provides the required high-quality, long-term corrosion protection to steel. Galvanizing provides protection in two ways, first as a physical barrier to corrosion and secondly by means of cathodic or sacrificial protection that is unique to zinc. The dual nature of corrosion protection provided by galvanizing significantly extends the service life of steel even in the most challenging environments. The unique corrosion protection properties provided by galvanized steel will be highlighted with global mining application case studies.

Jan 1, 2015

By M. Knot

Fans delivered to the Russian Federation, and eventually to countries of the former U.S.S.R., for mine ventilation must meet the legislative requirements of local jurisdictions. This paper presents a discussion of these legislative requirements and presents examples of fan equipment designed to meet the requirements. The legislative obligations discussed include four (4) separate requirements, including: ?Technical design requirements ? The Federal Agency for Technical Regulation and Metrology is responsible to issue a GOST R certification declaring conformance to the requirements ?Operational requirements ? A ?License for Application? must be obtained prior to operation ?Explosion risk requirements ? If the area of operation includes potential for explosion a special certificate must be obtained ?Technical condition requirements ? Market segments within the mining industry require special conditions that must be satisfied Examples of fans designed specifically for use in the Russian Federation are also discussed and examples provided. Designs for fan volume flow control will be highlighted.

Aug 1, 2013

By G. T. Lapidus, R. M. Luna-Sánchez

In the present study, a series of cyanidation experiments were performed on a bulk sulfide concentrate which contained silver in four distinct phases, to determine its extraction rate, varying the oxygen concentration. The results showed that three of the four phases were refractory, aguilarite (Ag,iSeS) being the only leachable phase, and that the effect of the oxidant concentration is minimal. Mathematical simulations were performed, adjusting only the Damkohler number to adequately fit the experimental data. This model, and the mechanism implied, was compared with that found for acanthite (Ag2S) in a previous study, and the differences between the two discussed.

Jan 1, 2005

By W. W. Cummings

The Mineral King Mine, owned and operated by Sheep Creek Mines is located in the Purcell mountain range of southeastern British Columbia. Production of lead and zinc concentrates commenced in 1954 some 60 years after the initial discovery. Low cost mining methods have been employed to extract 16,0C'O tons of ore monthly from large ore bodies formed by replacement in limestone. Extensive areas in the limestone are yet to be explored and success in the search for new ore bodies is anticipated.

Jan 1, 1960

By Zhang. L.

Ordered intermetallic PtSb had been synthesized by arc-melted and then sintering treatment. The electro-oxidation of formic acid on PtSb was investigated at room temperature by cyclic voltammetry and chronoamperometry. The results are compared to those at a polycrystalline platinum electrode surface. It was found that PtSb intermetallic was catalytically more active than pure platinum according to the onset potential and current density. XRD and XPS technologies had been used to investigate the crystal structure and electron effect. We think formic acid decomposition on PtSb favors the reactive intermediate route and is not very much affected by the CO intermediate as compared to Pt.

Jan 1, 2005

By A. J. Antony Chettupuzha

During a construction project, it is important to ensure that accurate and pertinent knowledge is delivered on time to appropriate personnel. The criticality of documents exchanged or referred to by various parties, evolves over the course of the project lifecycle. Determining the criticality of documents at different stages of the project can aid companies with managing the flow of information in an organized manner, while providing for the detection of potentially disruptive, erroneous material that could result in delays and costs. Therefore, it is crucial to determine documents which have the potential to disrupt a process (by virtue of being incorrect versions etc.) so that they may be isolated or prevented from entering or interfering with the active flow of information in a project, while also ensuring standard revisions of documents are recognized and accessed accordingly. Electronic Product and Process Management [EPPM] systems provide the capability to establish and map information flow between different parties in a construction project. Analyzing an EPPM system may yield information about the criticality of certain documents within an activity, as well as isolate characteristics peculiar to documents which can assist in risk mitigation. We propose methodology that identifies such critical documents.

Aug 1, 2013

By H. B. Farnam

"THE IRON ORE Company of Canada has been using do-it-yourself type explosives for three years. During the last 12 months we have used over 10 million pounds of ammonium nitrate-fuel oil explosives and either purchased or formulated one million pounds of slurried explosives.W e have been moving approximately one million cubic yards of stripping and ore per month and we expect our production rate to in-crease. Eighty per cent of our strip-ping and ore is soft enough to be blasted successfully with ammonium nitrate-fuel oil mixtures. Twenty per cent of our material is extremely hard and requires an explosive having greater strength than an AN-fuel oil mixture.W e had been using canned am-monium nitrate base explosives and TNT pellets to give maximum bottom loading density to fracture hard rock. As AN -fuel oil became widely used, it was apparent that other types of explosives could be formulated to fit our blasting requirements. Dr. M. A. Cook of the University of Utah was consulted regarding new explosives and together we developed the blasting slurries.Figure 1 shows a general view of one of our hard rock pits. The foot wall is on the right-hand side and this material is called iron forma-Figure 1.-General view of hard rock pitstion by our Company but is called 'Taconite by the operators on the Mesabi Range. This material runs 35 to 45 per cent iron and many pieces are hard enough to scratch glass. The formation is tilted at an angle of 55 degrees as can be seen in Figure 3.The bedding planes of this rock are about 24 to 36 inches apart and if the material is not well broken or fragmented, large chunks or slabs must be handled by the shovels which reduces shovel capacity and efficiency and increases maintenance costs."

Jan 1, 1960

By M. S. King

"A simple method is proposed for determining the long-term deformation behaviour of evaporites. The theory developed can be tested by measuring the change in diameter as a function of time of a vertical mine shaft opposite evaporite strata. Ultimate shaft closures predicted by the theory agree well with those calculated with the very much more complex theory of Serata (1968), provided that sufficiently high octahedral shear strengths are used in the former.An analysis of measurements made in an isolated opening in a Saskatchewan potash mine shows that the octahedral shear strength of the surrounding potash and halite was approximately 500 psi several years after the opening was mined. This value is less than that deter-mined experimentally for halite by Serata. The same data indicate, furthermore, that the in-situ octahedral shear strength is decreasing slowly with time.The current controversy regarding the actual deformation of evaporites will only be resolved by the cooperation of potash producing companies in releasing data on the long-term deformation of their mine shafts."

Jan 1, 1971

By Cummings. J. B., R. Haworth

"THE OPERATION of the Potash Company of America, Ltd., at its plant near Saskatoon, Saskatchewan, is the result of many years of exploratory and development work, culminating in the construction of a shaft, milling, concentrating and other facilities necessary to the production of potash in a marketable form.The possibility that potash existed in •commercial quantities in Saskatchewan was first indicated in 1943, although it was not until mid-1946, when Bata Petroleums penetrated a potash bed at its Verbata No. 2 well near Unity that substantial in-ter.est was developed in the possible exploitation of this important mineral product.The Potash Company of America, which is the largest producer of pot-ash in the Carlsbad, New Mexico area, a district that has been sup-plying about 90 per cent of the North American potash demand, be-came interested in the Saskatchewan deposits •at an early stage. Its engineers made an intensive study of the western Saskatchewan area in 1947 and continued their review of operating problems throughout the next three years.""Potash"" is the commonly used general term applied to the minerals of potassium, of which there are several. The most common mineral forms in which it is produced are potassium chloride and potassium sulphate. The potash content of potassium compounds is ordinarily ex-pressed in terms of potassium oxide (K20) equivalent."

Jan 1, 1960

By Gaston Gendreau

CETTE PRÉSENTATION traitera des différentes phases des opérations de la mine du Mont-Wright depuis ses débuts jusqu'à présent. A une brève description de la géologie du gisement, suivra un exposé des méthodes d'exploitation de la mine et du genre d'équipement utilize.

Jan 1, 1977

By Louise Grondin

Laronde Mine has been working for a number of years to identify substances that could contribute to process water toxicity and to find an effective way of removing these contaminants from the water. Initial studies have identified ammonia, nitrite, cyanide, thiocyanate, cyanate, dissolved organic carbon, copper and zinc as potential toxicants. Bench-scale tests were carried out with Lakefield Research to find a water treatment process that could effectively remove the suspected toxicants. Nine treatment processes were evaluated: 1) granular activated carbon (GAC) filtration followed by zeolite, 2) zeolite filtration followed by GAC filtration, 3) aeration followed by GAC filtration, 4) multi-stage GAC filtration, 5) chlorination followed by dechlorination, 6) addition of clay based polymer, 7) treatment with peroxide and ultra-violet light, 8) bulk addition of GAC and zeolite powder, 9) treatment with bacteria. This article presents a summary of the test results and of the problems associated with the evaluation of technologies for the treatment of toxicity.

Nov 1, 2002

By C. Arson

"Optimizing hydraulic fracture injection parameters in order to maximize hydrocarbon extraction and to avoid extensive borehole spalling is still an open issue. In this paper, the Differential Stress Induced Damage (DSID) model is employed to simulate the anisotropic damage distribution around pressurized boreholes drilled in fractured shale. The loading path is purely mechanical: excavation and fluid injection are simulated by stress relaxation followed by pressurization. We investigate the effect of pre-existing fracture orientation, in-situ stress and injection pressure on the propagation of anisotropic damage during pressurization. Finite Element results indicate that (1) damage initiates and develops when the ratio of two in-situ stress component deviates from 1, and the magnitude of damage is proportional to this stress deviation; (2) For a given in-situ stress field, damage initiates for a certain threshold of injection pressure, and the damage zone extends as the injection pressure increases; (3) A pre-existing fracture only affects the damage zone locally; the orientation of that fracture does not affect the damaged zone, which is controlled by in situ stress and injection pressure.INTRODUCTIONHydraulic fracturing is used to increase shale permeability and to enhance hydrocarbon extraction. In order to maximize the extraction ratio and to avoid wellbore spalling and clogging during fluid injection, the parameters related to injection for each particular site need to be optimized. Therefore, it is necessary to clearly understand how shale responses upon excavation and pressurization.It is well known that breakouts grow in the direction of minimum compression and that plastic deformation around wellbores tends to arrest breakouts (Zoback et al., 1985). Laboratory acoustic emission tests revealed that fractures propagate along the direction of maximum compression stress, and fractures (breakouts) are surrounded by the Excavation Damaged Zone (EDZ), in which rock properties are weakened by the presence of micro cracks (Eberhardt et al., 1999; Martino et al., 2004). The anisotropy from orientated foliations and cracks may influence the development and propagation of fractures and breakouts (Everitt et al., 2004). Sonic televiewer logs proved that during hydraulic fracturing, fluid injection further alters the stress distribution (Evans et al., 2005). Shale natural fabric strongly affects the evolution of the EDZ around boreholes."

Jan 1, 2015

By Hong Zhong, Shuai Wang, Fangxu Li, Guangyi Liu

"The flotation performances and adsorption mechanisms of a-hydroxyoctyl phosphinic acid (HPA) to malachite, cassiterite and wolframite were investigated by micro-flotation tests and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that compared with styrene phosphonic acid (SPA), diphosphonic acid (DPA), benzohydroxamic acid (BHA) and salicylhydroxamic acid (SHA), HPA exhibited excellent collecting power to the three oxide ores. In addition, HPA showed superior selectivity against hematite, tourmaline, feldspar and quartz. The results of XPS analysis demonstrated that HPA reacts with active species (M) on metal oxide by formation of P-O-M or P-M bonds.INTRODUCTIONIn mineral processing, flotation has been the main process for separation and recovery of valuable minerals from complex ores (Mei, 2013; Zhou, 2014). One of the key requirements in flotation process is to increase selectively the surface hydrophobicity of the targeted minerals by surfactant (known as collector in flotation) adsorption so that these mineral particles can preferably attach air bubbles in a slurry or pulp (Bai, 2004; Hankins, 2004). To anchor a solid surface selectively, special functional group are designed to adjust the interaction between the surfactant and the active sites of solid surfaces (Wu, 2006; Huang, 2014).Organic phosphorous compounds have strong affinity toward metals or metal oxides because they form more stable metal complexes than metal carboxylates (Pazik, 2001; Zheng, 1998). In mineral engineering, phosphorous compounds have been exploited as metal extractants and flotation collectors (Alguacil, 2002; Sun, 2008). Ni (2012) and Zhang (1998) introduced diphosphonic acid (DPA) as an effective collector for flotation of fersmite and niobite. Liu (1999) found styryl phosphonic acid (SPA) was a superior collector for flotation recovery of finely disseminated rutile ores. Gruner and Bilsing (1992) thought SPA was one of the best collectors for flotation recovery of cassiterite which could obtain a high-grade concentrates of more than 40% with high recovery values. Bulatovic (1999) investigated the flotation performances of phosphoric acid ester (PAE) to perovskite, ilmenite and rutile and found that PAE was an impactful collector for selective flotation of titanium minerals from complex ores in the presence of petroleum sulfate. However, a-hydroxyoctyl phosphinic acid (HPA) as a flotation collector for recovery of titanium ores were hardly reported in the previous literatures."

Jan 1, 2016

By Yun-Jie Wei

Seismic areas were in the eastern margin of the Qinghai-Tibet plain, whose structures were complicated, mainly composed of Maowen fault, Yingxiu fault and Pengxian-guanxian fault. The rapid rise of the Qinghai-Tibet plain led the crustal material of the eastern edge to move to the southeast along the faults on a large scale since the late Cenozoic; Minshan block structure and Long Men Mountain tectonic zone represented the strong nappe thrust movement as the east boundary of Chuanqing slip block; the stress was accumulating when squeezed, which to a certain extent resulted in breakdown of the crust, and earthquakes. The shock speed, high-energy accumulation, and the reversed dextrorotation of the earthquake fault characteristics et al. happened, which caused the development of secondary geological disastersts. According to on-site investigation, the typical geological disasters had thrust rock collapse, the instability deposit, the revival of potential debris flow et al. whose genetic model had been analysed.

May 1, 2009

By A. Panteleyev, C. S. Ney, R. J. Cathro, A. Sutherland Brown

The general distribution of metal deposits in the Canadian Cordillera can be related to its tectonic evolution. The Canadian Cordillera is naturally divisible into five longitudinal tectonic belts within which rocks are broadly similar in type, age and history. From west to east they are the Insular, Coast Crystalline, Intermontane, Omineca and Eastern Marginal belts. Seven classes of metal deposits in the Canadian Cordillera are defined and their characteristics described. These classes are skarn, porphyry, massive sulphide, stratiform, magmatic, copper in basic lavas, and vein deposits. Maps showing the distribution of medal and metal-group concentrations serve to illustrate the relations in space and time between mineralization and geologic evolution.

Jan 1, 1971

By D. M. Maijer, S. L. Cockcroft, A. B. Phillion, P. Fan, C. Reilly

"A numerical model has been developed to study macrosegregation associated with liquid feeding in the Low Pressure Die Casting of A356 aluminum alloy wheels. The model of the wheel casting process has been implemented within the commercial CFD software package, FLUENT, using a User Defined Function (subroutine) to account for Si rejection based on the Scheil approximation. The model has been validated against temperature and microstructural data taken from a commercially cast wheel. The amount of segregation in the wheel has been shown to be significant in a couple of key areas. The implications of accounting for segregation include an improved ability to predict shrinkage porosity, fatigue performance and potentially also hydrogen porosity.INTRODUCTION The aluminum alloy A356 is widely used in the automotive and aerospace industries for various components. Examples include automotive wheels, automotive suspension components and airframe castings. Focusing on automotive wheels, Low-Pressure Die Cast (LPDC) A356 wheels offer significant design freedom and are far more aesthetically appealing to consumers than conventional stamped steel wheels. A356 wheels now dominate the market, appearing in all but the entry level offerings of the OEM manufacturers. However, they are typically over-designed to allow for the various casting related defects that degrade their mechanical performance. Thus, their potential to save weight has not been fully realized. Wheel manufacturers are under constant pressure to ensure their products meet strict mechanical requirements (ductility, fatigue, vibration), tight geometric tolerances and high aesthetic quality. The mechanical properties of the final product are determined by the microstructure – e.g. SDAS – and the defect population (porosity and oxides). Depending on their size and location, both porosity and oxides, can act as crack initiation sites reducing fatigue life (Caton, 2001; Jordan, 2010; Wu, 2015). There are a number of examples appearing in the literature (Atwood, 2000; Carlson, 2007; Lee, 2001; Yao, 2011) of numerical models that have focused on hydrogen-based pore formation that have demonstrated an ability to predict porosity formation and pore size distributions in geometrically simple castings. These models assume that the local gas species diffusion through the liquid metal to the pores is the rate-controlling factor of pore growth. Another common source of porosity is liquid encapsulation (Dantzig, 2009). As the pressure within the isolated liquid drops, pores form first due to the pressure dropping below the equilibrium partial pressure of hydrogen in solution and then second grow substantially as the pressure continues to drop falling below the vapour pressure of Al. One factor that can affect both mechanisms of pore formation is species macrosegregation, which has received comparatively little attention in die-casting."

Jan 1, 2017

By J. Trojacek

A large-scale development in exploration and production of uranium ores in the Czech Republic was done in the 2nd half of the 20th century. Many uranium deposits were discovered in the territory of the Czech Republic. Over a period of 50 years approximately, 110 000 tons of uranium in concentrate were produced. Different mining methods were developed and used. One of the most considerable deposits in the Czech Republic is the site Hamr na Jezere ? Straz pod Ralskem where both mining methods ? the underground mining and the acidic in-situ leaching ? were used. The extensive production of uranium led to widespread environmental impacts and contamination of groundwaters. Over the period of ?chemical? leaching of uranium (ca. 32 years), a total of more than 4 million tons of sulphuric acid and other chemicals have been injected into the ground. Most of the products (approximately 99.5 %) of the acids reactions with the rocks are located in the Cenomanian aquifer. The contamination of Cenomanian aquifer covers an area larger than 27 km2. The influenced volume of groundwater is more than 380 million m3. The total amount of dissolved SO4 2- is about 3.6 million tons. Approximately 0.5 % of the contamination is located in the Turonian aquifer. After 1990, a large-scale environmental program was established and the Czech government decided to liquidate the ISL Mine and start the remediation in 1996. The remediation consists of contaminated groundwater pumping, removing of the contaminants and discharging or reinjection of treated water. The objectives of the remedial activities are the followings : to restore the aquifer to a condition guaranteeing continuing usability of Turonian water of Northern Bohemia Cretaceous, to decommission boreholes and surface installations and to incorporate the surface of leaching fields into the ecosystems taking into account regional systems of ecological stability and urban plans. Nowadays four main remedial technological installations for reaching of these aims are used - the ?Station for Acid Solutions Liquidation No. One?, the ?Mother liquor reprocessing? station, the ?Neutralization and Decontamination Station NDS 6? and the ?Neutralization and Decontamination Station NDS 10?. Total capacity of this complex is sufficient to reach the target values of remedial parameters in 2037. The remediation action consists of: pumping of residual solution to the surface, separating uranium from the solution and reprocessing contaminants into commercially usable or ecologically storable products. It is expected that the amount of withdrawn contaminants will vary from 80 000 to 120 000 tons per year. Total costs of all remediation activities are expected to be in excess of 1.5 billion EUR.

Aug 1, 2013

By R. Khanna, K. Hyun Ko, A. J. Berkovich, J. Hook

"The co-pyrolysis of synthetic polymer polyethylene terephthalate (PET) and agricultural wastes (naturally occurring polymer-macadamia nut shell) was investigated in the temperature range 473K to 1273K using a horizontal furnace with an aim to understand their thermal degradation under isothermal conditions. In-depth characterization of pyrolysis residues was carried out using x-ray diffraction (XRD) and solid state nuclear magnetic resonance (NMR) for carbon structure, and through determination of the concentration of unpaired electrons using electron paramagnetic resonance (EPR). In previous studies, it has been found that PET thermally decomposes ~ 650K-700K, releasing (~80 wt % of initial weight) gaseous products due to random chain scission. In the case of macadamia nut shell, three types of byproduct can be obtained from pyrolysis: char, tar and gaseous products. In the co-pyrolysis of macadamia nut shell with PET in 50-50 wt% ratio, total product weight ratio could be modified with the addition of PET acting as a hydrogen source. This is because a recombination of thermal cracking products of cellulose could be suppressed by hydrogen from PET, which will later lead to an enhancement of tar formation. In addition, pyrolysis around 673K is sufficient for bond cleavage to occur in cellulose and lignin leading to the formation of negatively charged activated carbon with high surface area, providing bonding sites for volatiles evolving from PET. Therefore the co-pyrolysis may be able to enhance the product yield (tar/char/solid carbon residue) along with a reduction in the release of gaseous products. During the co-pyrolysis, temperature was found to have a significant influence on the kinetics of thermal degradation and solid residual by-products after co-pyrolysis.INTRODUCTIONPlastics are being used worldwide in a wide range of applications in the modern society; their usage has resulted in increasingly a massive waste problem. The production of most synthetic plastics requires hydrocarbons that are produced from petrochemicals derived from fossil oil and natural gas, a non-renewable source (Speight 2011). Currently, plastic manufacture utilizes ~4% of world oil and gas production, and it is expected to drive further increases in petroleum demand by 1-2% due to their large volume of manufacture (Hopewell, Dvorak et al. 2009). Landfilling and incineration of plastic waste are the two main routes to plastic waste management (Encinar and González 2008). In Australia, only 10% of waste plastics were recycled in 2006 (White and Hyde 2011). This means that large amount of fossil fuels from plastics has either been simply burned for energy recovery or buried in the ground. There is an urgent need for developing alternative avenues for recycling waste plastics. Our group at UNSW has carried out extensive research on the recycling of waste polymers as carbon resource in steelmaking including slag foaming and carbon dissolution from waste plastics into liquid steel at 1600°C; the effect of basic plastic characteristics such as chemical composition, structure, bonding network etc. was examined (Sahajwalla, Rahman et al. 2009)"

Jan 1, 2012

By Cindy Schiewek

Industrial injury occurrences are an ongoing concern for Mine Operators. Along with the personal suffering of injured workers comes an increase in compensation and productivity costs. Growing recognition of repetitive stress and bodily injuries, accompanied by recent studies, validates the assumption that a relationship exists between ergonomic injuries and machine design. Intuitively, there is a belief that an ergonomically designed machine will reduce repetitive stress injuries through design and education however; quantifying this belief has been a challenge for Mine Operators. Sandvik Tamrock has undertaken a project aimed at developing a business model to assist in quantifying the benefits of ergonomic intervention. This model focuses on distinguishing and quantifying this method of intervention to allow for a better evaluation of the machine. For simplicity, the project initially focused on the Face Drill Jumbos. The target of the project was three fold: !" Recognition of the cost drivers for compensation; ergonomic injuries !" Identification of the relationship between ergonomic machine design, and the decrease of the negative effects associated with the cost drivers !" Systematic prioritization for ?prevention by design? The project findings substantiate the expected reduction in injuries and compensation claims. Based on all ergonomic intervention studies conducted, each case showed a reduction in compensation cost; through prevention by design, one can reduce the amount of potential risk. The paper addresses the resources and methodology used, along with the findings and its relevance to the issues that face the Mining industry.

May 1, 2003