Search Documents

By G. Danko, C. Lu

"High temperature and humidity at the working negatively affect safety and health in deep and hot underground mines. It is necessary to predict during design the dynamic changes in temperature with heat and moisture emitted into the mine ventilation-thermal-humidity (VTH) system from various sources such as auto-compression, wall of strata, mining equipment and workers. Currently available mine ventilation and climate models are either furnished with a simplified, step-change-type (SCT) model for thermal solver (such as in Climsim, VnetPC, Minevent, MFire, etc), or with more advanced models to account for the “thermal history effect” (also known as thermal flywheel effect), such as in Ventsim and MULTIFLUX. The goal is to quantify the modelling error caused by the lack of variable thermal history component in the SCT model. Two models are compared: one with and one without the thermal history component in long, single airway examples with long-term climate simulations for 20 years assuming an input air temperature with daily variation. The examples illustrate the magnitude and the time-lag phase of the variation of the modelling errors with space, time and model conditions. Large errors are shown in the order of +14°C and –7°C errors, persistent for long time periods, up to 20 days in one example.INTRODUCTIONIt is important to predict the heat and humidity distributions during the design of hot and humid underground mines for the safety and health of the workers. The feasibility of extracting a rich deposit in great depth may depend on the extent of ventilation and mine climatization for maintaining an acceptable working environment. The cost of ventilation and cooling may be substantial, up to 40–50% of the total energy cost of mining (Clausen, 2017). The accuracy of model solution is important in view of the low profit margin in mine feasibility for deep and hot mines. Safety and health of the miners, the primary concerns, are therefore inherently connected to finding ever better solutions in simulation methods and ventilation control techniques."

Jan 1, 2019

By N. Dahata

B206 aluminum?copper alloy has a potential for wider use in the automotive industry due to its light weight and relatively superior mechanical properties as compared to aluminum-silicon alloys. The possibility of casting this alloy via Lost Foam Casting (LFC) has not been investigated in detail. Therefore, the effects of foam types (T170B standard untreated EPS and T175-brominated EPS), coating types (Styro Shield 5553 and Styro Shield 5554), copper level (4.5 wt % and 5.0 wt %) and titanium levels (0.5 wt % and 0.25 wt %) were related to fillability, microstructure and microporosity. The metal velocity in T175 EPS pattern was higher than that in T170B EPS pattern. For T175 EPS pattern, the total solidification time was 3% higher and the loss of temperature for decomposition of EPS was lower than those in the case of T170B EPS pattern. The grain size, porosity level and maximum pore size were quantified using Light Optical Microscopy (LOM) and image analysis. The casting with T175 EPS pattern showed larger grain size relative to that with T170B EPS pattern. The porosity level and the maximum pore size decreased significantly when the titanium level was increased from 0.05 wt % to 0.25 wt %.

Jan 1, 2007

By G. H. Faye

The prospect of obtaining high-grade concentrates from Canadian pyrochlore ores is rather unlikely, and experimental beneficiation pro-cesses ?appear to have yielded products in the range of 3 to 20 per cent N'b205? A possible solution of the problem is to find an economical chemical method for recovering high-purity Nb2?05 from such concentrates. A technically feasible but economically unproved process is outlined in this paper, in which the concentrate is decomposed by an acid attack and the oxides of niobium and tantalum are isolated and then separated by liquid-liquid extraction. The solution of the ore is adjusted to 7 M HF-5 M HNO3 and the niobium and tantalum are extracted from this solution with methyl isobutyl ketone. The mixed oxides of niobium and tantalum are recovered from the oxdanic phase and dissolved in 0.5 M HF-1.0 M HNO3. Tantalum is extracted preferentially from this solution with methyl isobutyl ketone, leaving niobium in the aqueous phase. By the use of this process it is possible to produce niobium pentoxide and tantalum pentoxi.de in 99.5 per cent purity with a recovery of approximately 95 'per cent, under lab-oratory conditions.

Jan 1, 1957

By Edouard Masengo

A long dyke will be constructed in a lake with rockfill placed by end dumping method. Its crest will be at elevation 521.5 m compared to the nominal lake level at 520 m. In the first portion, its height will vary from 1.5 m on a 35.1 m thick tailings layer to 18.3 m on about 0.5 m of tailings. In the second portion, the dyke will be built on native silty clay and will vary from 18.3 to 15.2 m in height. The tailings consist in stratified layers of fine-grained soils showing lateral and vertical segregation. The tailings are compressible and may develop excess pore water pressure on loading. The tailings overlie a thin layer of relatively soft native silty clay. The till beneath the silty clay is considered incompressible compared to the material above. After construction, as the tailings and silty clay consolidate, pore water pressures will dissipate and dyke stability will improve. Since dyke stability will increase with time, the primary concern is its stability during construction. As a result of construction activities, three potential modes of failure were identified and recommendations were provided regarding the measures that should be undertaken to increase dyke stability during construction.

May 1, 2003

By Jamal Asfahani

Abstract - Natural gamma ray well logging, an effective tool in geophysical prospecting, is used to investigate the radioactive and phosphatic layers in the Khneifiss mine in Syria. The interpretation of the gamma ray measurements, using numerical methods of analysis developed previously and applied successfully in some phosphatic areas in Syria, make it possible to define precisely the phosphate thickness from place to place in the study area. This technique has been successfully applied while studying seven boreholes in the area. Sixty-three core samples from phosphatic layers in the boreholes have been analyzed, using gamma ray spectrometry for the determination of P2O5 , U, Th, and K. Good correlation between P2O5 content and U concentration has been found. The total count gamma logs correlate reasonably well with the U core analysis, suggesting that radioactive equilibrium exists in the U decay series. These gamma logs can be therefore used effectively to quantitatively map the distribution of P2O5 and U. The characteristics of both subsurface phosphatic sand and phosphatic rocks have been investigated and outlined using a statistical approach. The affinity of uranium to some trace elements such as V, Sr, Cu, and Ni has been verified using correlation matrices of these elements.

Jan 1, 2002

By W. J. Kuit

Since closure in 1968, the Wedge Mine, situated adjacent to the Nepisiguit River in New Brunswick, has been flooding with acidic water containing toxic levels of heavy metals. Cominco Ltd. has undertaken a series of pollution control measures to mitigate the threat posed to the river quality. Included has been a successful treatment campaign in 1976 which discharged in excess of 30 million gallons of high-quality effluent from the accumulated volume of mine water. The sources of contamination have been identified as actively leaching waste dumps. A comprehensive program of permanent corrective measures has been prepared which will culminate in mine backfilling. Once completed, the unacceptable burden of water treatment in perpetuity at a non-producing property will be removed.

Jan 1, 1977

By J. Stiksma, R. Kalanchey, M. J. Collins, G. Owusu, R. Raudsepp, K. R. Buban, L. A. Barta, I. M. Masters

This paper describes the results of testwork for the treatment of Ambatovy laterite ore by a pressure acid leach process, with recovery of the soluble nickel and cobalt values as mixed sulphide intermediate by precipitation with hydrogen sulphide, and subsequent refining of the mixed sulphide to nickel and cobalt metals. These process development studies were carried out primarily in 2004, as part of a bankable feasibility study for the Ambatovy Nickel Project. The Ambatovy orebody is located in Madagascar. The mini pilot plant testwork was carried out in the Dynatec metallurgical laboratory in Fort Saskatchewan, Alberta. The results of the testwork were very encouraging, including nickel and cobalt extractions in the range of 95.5% to 97.0%, and 94.0% to 97.0%, respectively, in the ore leach step with sulphuric acid. High recoveries of nickel and cobalt were achieved throughout the remaining process steps, yielding separate nickel and cobalt metal powders with better than acceptable purity.

Jan 1, 2005

By Jose Alberto Gonzalez, Said Sharif Mahboob, Jeffrey L. Shepherd

"During the industrial electrowinning of zinc, uneven growth can cause short-circuits and make the deposits more sensitive to the presence of impurities that can significantly impact current efficiency. To produce levelled zinc deposits, additives such as glue, licorice and sodium silicate are often added to the electrolyte. Even in the presence of additives, uneven zinc growth still takes place because of the combination of hydrodynamic and electrolysis conditions in the cell house. Recent advancements in imaging spectroscopy and scaling analysis have opened an avenue to further study the effects of additives on zinc growth morphology. In this study, Atomic Force Microscopy (AFM) and scaling analysis have been used to monitor zinc growth characteristics including roughness, periodicity, aspect ratios and growth mechanisms as a function of electrolyte composition as well as deposition time. Zinc was electrodeposited from an industrial electrolyte containing a host of additives onto an aluminum cathode with a platinum wire serving as the anode. AFM images of the samples were collected to obtain 3D topographical information on which scaling analysis was performed to extract details on root-mean-squared (rms) roughness, periodicity (grain size), aspect ratio of surface features and growth mechanism. This analysis provided information on the mechanism by which the previously mentioned variables can impact short term growth and also provided a prediction of expected growth at long deposition times.INTRODUCTIONElectrowinning is one of the final stages in the industrial production of zinc metal. It is during this process where dissolved zinc ions undergo electro-reduction from an acidic electrolyte onto an aluminum cathode and are later recovered by stripping the zinc metal from the substrate. However, due to the nature of zinc growth as well as the various operating conditions, zinc deposition may occur unevenly, sometimes causing short-circuits that can cause electrode damage and reduced zinc production."

Jan 1, 2016

By T. Patching

"THE FOLLOWING notes on coal mining in the Edmonton city area are based, in the main, on scattered reports and accounts as little coal mining has been done in this area for about 20 years and few people are left who were involved in what was at one time an important industry of northern Alberta. Although coal mining is not likely to be permitted in the city area itself in the future, a record of this work is warranted to indicate the ·conditions and problems that may be encountered if underground mining again is proposed in the district in the same geological formations and in similar strata. Coal mining in the Edmonton area developed with the influx of settlers in the latter part of the nineteenth century and the first part of the present century. Probably local coal was used by the Fort's blacksmith as early as 1841, and the early settlers probably were 'gopherholing' into the outcrops along the river banks by the 1870s. The first report of commercial coal mining was in 1880 when a contract was let by the Hudson's Bay Company for the provision of 300 tons. As the population in the city and northern parts of the province grew, many new mines were opened along the river and in the district, and coal was even shipped by barge to points in Saskatchewan(1 ,2) By 1909 the Department of Public Works reported that 'Edmonton stands as the second largest domestic coal producing centre in the province'. It continued to hold this position until 1942. From about 1912 to 1951 annual production from mines in the city and surrounding district ranged between 0.38 and 0.65 million tons, depending on weather, wars and strikes. Production began to decline in 1951 because of the increasing availability and consumption of natural gas which was piped into the city and then provided to other towns and rural areas in the northern part of the province. Taylor noted that between 1880 and March 1970, when the last mine within the city area closed, the total of mines and prospects within the Edmonton city area rose to 153. Most of them were small; not more than 20 produced more than a quarter of a million tonnes during their entire life, and only three produced a million tonnes or more. As described by Taylor ""within the city district workings extend discontinuously from the apex of a narrow triangle near Groat Bridge to the base of the triangle in the Clover Bar area"". The larger mines were in this latter area. Approximate locations of the old mine workings in the city are shown in Taylor's atlas. A number of other coal mines were worked in the Rabbit Hill, Big Island, St. Albert, Namao, Cardiff and Morinville districts around the city."

Jan 1, 1985

By F. H. Samuel, J. E. Gruzleski, S. Valtierra, H. W. Doty, F. J. Tavitas-Medrano

319-type cast Al-Si-Cu-Mg alloys are commercially important due to their popular use in automotive applications. Artificial aging heat treatments are commonly performed in these alloys to achieve precipitation hardening and, therefore, improve their mechanical properties. The present work was carried out to investigate the effect of conventional (at a constant temperature, as specified by the standard T6 heat treatment regime), and non-conventional multi-temperature and interrupted aging cycles on the hardness, tensile and impact properties of two 319-type alloys (with and without Sr+ Mg additions). The results show that certain multi-temperature aging cycles have a more favourable effect in improving some mechanical properties than conventional cycles.

Jan 1, 2006

By C. A. Young, H-H. Huang, L. G. Twidwell

Equilibrium calculational software programs can be effectively utilized to model important parameters in aqueous and aqueous/solid systems, e.g., activity or concentration, solubility, temperature, solution pH, solution potential, and ligand complexation. In this regard, the calculational program ST ABCAL will be demonstrated. Illustrative examples for the creation of diagrams such as potential-pH, and activity or concentration-pH will be presented to demonstrate the fundamentals in real hydrometallurgical systems. Speciation, titration and mixing will be used to simulate or predict operational processes. Berkeley Pit water from a flooded abandoned copper open-pit mine will be used to illustrate the modeling process. According to analytical results the water contains about 20 important constituents. In addition to measured potential and dissolved oxygen, there are two distinctive oxidation/reduction couples. Concentration and other experimental parameters are seldom matched to each other and 12 different conditions have been identified. Water for each condition must be speciated in order to find the best-fit model. The STABCAL program will be used for the modeling calculations and the implication of the water chemistry to defining treatment opportunities will be discussed.

Jan 1, 2005

By Francis Breton, Daniel Larouche, Pierre Heugue, Rémi Martinez

"Nowadays, in order to fit environmental restrictions, automotive markets are demanding cast aluminum alloys working at high temperature (180–300°C). New generations of alloys are required for higher strength components in engine downsizing or start-stop systems which lead to higher loading and higher specific power and stretch current materials to their limits. Recently, transition metals, such as zirconium and vanadium, have been added as alloying elements into an AlSi7Cu3.5Mg0.1 alloy to improve physical, mechanical, thermodynamic properties with the aim of increasing service life of parts. In such alloys, the best mechanical properties are associated with the formation of precipitates through an optimum heat treatment sequence, including: solutionizing, quenching and artificial aging. This study is focused on the modified AlSi7Cu3.5Mg0.1 cast alloy with Mn, Zr and V additions for high temperature application. The characterization of the cast alloy in this study, firstly, helps to evaluate and understand its performance both chemically and structurally according to their physical state: as-cast or as-quenched. Comparison of precipitation kinetics between a binary Al-3.5%wt.Cu alloy and the AlSi7Cu3.5Mg0.1 (Mn, Zr, V) alloy has been characterized by differential scanning calorimetry, TEM observations and micro-hardness testing. The Kissinger analysis was applied to extract activation energies from non-isothermal DSC runs conducted at different stationary heating rates. The study focuses on the impact of the chemical composition such as Si content on the kinetics parameters.INTRODUCTION Pure metal Aluminum shows poor mechanical properties and its malleability is high, that is why alloying elements are added to the mixture before casting to improve physical, mechanical and thermodynamic properties (Javidani, 2015); such as Silicon (Si) for casting properties (castability, cold crack capability, wear resistance, shrinkage behavior), Magnesium (Mg) and Copper (Cu) to generate precipitation hardening systems. Aluminum hypoeutectic alloys (<12% Silicon) with Cu, Mg additions used in the automotive industry for manufacturing mechanical parts (Larouche & Javidani, 2014) are mostly subject, after casting, to precipitation hardening heat treatment (Mohamed & Samuel, 2012) according to specifications and associated standards. The best mechanical properties are associated with the formation of precipitates through an optimum heat treatment sequence, generally including: solutionizing, water quenching and artificial aging (Manente & Timelli, 2011). Hypoeutectic aluminum-copper alloy with amount of Cu around 1 to 4.5wt% is an elementary case for precipitation in heat treatable aluminum alloys. Researchers essentially focused their work on the full precipitation sequence of binary Al-Cu alloy during aging which is presented below."

Jan 1, 2018

By D. W. Rogers

Several commercial polyacrylamide flocculants most widely used in Western Canadian mineral processing plants have been analyzed chemically and compared in standardized settling tests as aids to thickening and clarification. Data are included for both dry and liquid-type flocculants. Percentages of active ingredients in these commercial products varied Widely. Performances were compared on the basis of: equal additions of active ingredients, nearly equal molecular weights and nearly equal degrees of ionic character. Based on zone settling velocities and supernatant clarities of siliceous slurries coagulated by lime additions, dry flocculants proved more economical than liquid flocculants. Using these same two criteria, the most highly anionic were more effective than either weakly anionic or non ionic polyacrylamide- type flocculants.

Jan 1, 1978

By Yongteng Dong, John P. Quinn, Bradford Wesstrom, Guikuan Yue

With increasingly low-grade copper ores being mined, it is difficult to handle growing concentrations of As, Sb, Bi and/or Fe in the whole flowsheet, especially during copper electrorefining. To better elucidate the effects of those impurities on the quality of cathode deposit and/or current efficiency, a detailed speciation study of the electrolyte under industrial conditions is required to quantitatively describe their distribution in the solution, thereby facilitating their effective control and removal. In the present study, a thermodynamic model of complicated iron-arsenic-copper-sulfuric acid electrolyte under industrial conditions was developed. The main species of those elements involved in the electrolyte were first identified, and their thermodynamic data were collected and critically assessed. Those data were then used to estimate the activity coefficients of species, and to calculate the equilibrium constants from 25°C to 70°C. The developed model provides a mathematical tool that is capable of quantifying the concentrations of free ions and complexes in terms of temperature and solution composition. Finally, oxidation-reduction potential measurements were employed to validate the model. INTRODUCTION In copper electrorefining, impurities like arsenic, antimony, bismuth and/or iron can partially dissolve in the electrolyte and accumulate gradually, and eventually cause problems such as bad cathode deposit (co-deposition with copper or mechanical inclusion from the floating slime), lower current efficiency, etc., which eventually increases the operating costs. The presence of impurities may substantially reduce properties of copper products such as conductivity, corrosion resistance, mechanical properties, and leads to more energy consumption (Schlesinger et al., 2011; Jafari et al., 2017). To remove these impurities, various methods have already been proposed and applied in industrial copper production, such as solvent extraction, ion exchange, chemical precipitation, absorption by activated carbon, etc. (Cunningham et al., 1997; Navarro et al., 1999; Toyabe et al., 1987). In addition, adding reducing agents such as sulfur dioxide and trivalent arsenic could also precipitate arsenic, antimony and bismuth from copper electrolyte, by changing the distribution of impurities with various valence (Braun et al., 1976; Xiao et al., 2007). The disadvantages of those methods include high energy consumption, serious contamination, lower selectivity and efficiency, and so on.

Jan 1, 2019

By H. Hejny

Given the current status of political discussion in Europe about raw materials issues, the sustainable development of the extractive industry and the reduction of its environmental and societal footprint are among the key topics in this discussion. In this context, the European Commission approved the EO-MINERS project (Earth Observation for Monitoring and Observing Environmental and Societal Impacts of Mineral Resources Exploration and Exploitation). The overall aim of EO-MINERS is to bring into play EO-based methods and tools to facilitate and improve interaction between the mineral extractive industry, authorities, and the society in view of its sustainable development while improving its societal acceptability. Developing generic, standardised and reliable EO-based products to monitor the environmental and societal footprint of mining projects is the way chosen by EO-MINERS to improve this interaction, along with the organisation of tripartite meetings gathering all relevant stakeholders. The project uses existing EO knowledge and carries out new developments on three demonstration sites (Sokolov lignite mining area, Czech Republic, Witbank coal field, South Africa, Makmal gold mine, Kyrgyzstan) to further evaluate and demonstrate the capabilities of integrated EObased methods and tools in monitoring the environmental and societal footprints of the extractive industry during all phases of a mining project, from the exploration to the exploitation and closure stages. It contributes providing reliable and objective information about affected ecosystems, populations and societies, to serve as a basis for a sound ?trialogue? between corporate stakeholders, governmental organisations and societal stakeholders. The project already developed a set of consolidated indicators based upon previous knowledge about mining-related issues along with interviews of national, regional, and local stakeholders. These indicators reflect known environmental and societal issues at mining sites as well as the interest of various relevant stakeholder groups. The process described in the EO-MINERS project ? policy assessment > indicator identification > choice of suitable EO tools able to serve monitoring task > monitoring by EO tools > making available objective information for fair dialogue among stakeholders ? is generally applicable to all stages of a mining project. The key to success will be the right choice of indicators addressing the problem and subsequently the right choice of suitable EO tools and finally the willingness of all stakeholders to find a common solution. To this end, the EO-MINERS project organises site-specific ?trialogue? workshops at each demonstrations site, which aim to provide relevant information in adequate quality to the stakeholders as common ground for discussions. Local stakeholders, including mining companies, regulatory bodies, and community representatives are invited to participate in these workshops where the relevance of the developed EO-based products to environmental and societal impact assessment will be discussed. The presentation will discuss results obtained during these trialogue workshops, as well as the success and difficulties and reluctances encountered. The project will further indicate ways and means how the EO products and other project results may be used for monitoring purposes in all phases of a mine.

Aug 1, 2013

By F. P. Hassani, M. Hefni, M. F. Kermani

"This study is part of large and an ongoing investigation into the development of a light-weight and highly fluid mine fill for various applications in mining and civil operations. Foam mine fill is the new material proposed for backfilling mines, and is fabricated by mixing stable foam into a mixture of tailings, binders, and water. This paper investigates the effects of both binder dosage and the amount of foam used upon the mechanical and physical properties of foam fill, mainly in regards to compressive strength, porosity and density.Samples were prepared using tailings from a copper mine as the inert material, Normal Portland Cement as the main binding agent, and a foaming agent with a foam generator. Samples were cured for 7, 14 and 28 days and were then subjected to unconfined compressive strength (UCS) testing. Select samples were subjected to mercury intrusion porosimetry, so as to study the microstructural properties. An empirical model was then developed, using a response surface methodology to establish a relationship between the investigated parameters. INTRODUCTION AND BACKGROUNDThe disposal of mine tailings is a significant issue in the mining industry, particularly as mine production increases. Many mines re-use mine tailings for backfilling, which is a method for reducing environmental exposure to tailings, maintaining underground stability, and increasing ore recovery (Benzaazoua, Belem & Bussière, 2002).This paper introduces a new type of backfill called ‘foam mine fill’. This proposed backfill material is similar to cellular concrete, as air bubbles are entrained in cement or lime mortar, resulting in a cellular structure (Narayanan & Ramamurthy, 2000). Air voids can occupy up to 70% of the volume of concrete, which makes it light- weight, and thus can be used for a wide range of civil applications, including backfilling (Tarasov et al. 2010; Panesar, 2013). Unlike cellular concrete, the incorporation of air bubbles into a mixture of tailings, binder and water makes foam fill a potential new backfilling material. Furthermore, a preliminary investigation on foam fill samples found that pulp densities should be optimized before adding the foam, in order to produce consistent samples without foam segregation or losses (Hefni et al., 2014)."

Jan 1, 2015

By H. Salamanca

HighService has developed different equipment using wireless technology and machine vision systems that were specially designed to allow 1) the online determination of the SAG mills liner&apos;s service life, 2) the automatic detection of a missing dipper tooth in mineral extraction shovels, 3) the reduction of accident risk potential in the mineral transportation within the mine, and 4) the reduction of collision risk potential between shovels and wheel dozers during mineral extraction. For the development of all these systems at HighService, extensive research has been done in radio frequency and image processing fields. The integration of both technologies with the expert knowledge of the company on the typical harsh environment conditions of the mining industry has led to the development of heavy duty equipment that tolerate the extreme mechanical requirements of SAG mills and electrical mining shovels.

Jan 1, 2007

By R. C. Gegg

The property of MacLeod-Cockshutt Gold Mines, Limited, is in the Little Long Lac area of the Thunder Bay Mining Division, Ontario, about four miles south of the Canadian National railway station of Geraldton. The town of Geraldton is about 170 miles east of Port Arthur and 22 miles west of Long Lac, which is on the main line of the Canadian National railway. The Trans-Canada highway passes through the property and during the winter season the road is maintained between Port Arthur and Long Lac. Electric power is supplied by the Hydro-Electric Commission of Ontario from their Cameron Falls plant and is distributed at 44,000 volts by a local transformer station. Early History The South orebody was discovered by diamond drilling in the spring of 1936. This is a porphyry contact orebody with major pyrite and minor arsenopyrite mineralization. Some gold is present in the &apos;free&apos; state, but for the most part it is locked in the pyrite, with little or none in the arsenopyrite. Preliminary test work was based on comparing straight cyanidation with bulk flotation and cyanidation of the concentrates. The overall results by the two methods were found similar, but for economic reasons the flotation-cyanidation process was adopted. Before the mill came into operation, a new and entirely different type of orebody, consisting of massive sulphide lenses in banded iron formation, was discovered to the north of the existing workings. These bodies are an intricate mixture of pyrite and arsenopyrite, both carying gold.

Jan 1, 1949

By D H. Sharp

The Quebec Cartier Mining Company produces iron concentrate for twelve months of the year from Port Cartier. This J>Ort is designed to handle ship varying in size from 3,000 to 100,000 d.w.t., requiring 50 feet of water at low tide. The harbour was built on shore for reasons of economy and layout, after considering many more conventional offshore designs. It provides for heavy oil bunkering, tanker off-loading, a heavy lift derrick and freight handling, besides ship loading and mooring. The weather for the previous fifty years was studied to enable wind and wave conditions to be accurately assessed for design purposes, and to determine probable lost time due to adverse weather conditions through-out the year. The first ship to be loaded was 60,000 d.w.t.; the second, 20,000 d.w.t. The latter entered the harbour after dark, under its own power, following a tug through the partly dredged narrow entrance. Large ships use tug assistance. Ships may leave the loading berth with the other berths occupied.

Jan 1, 1963

By V. Evans

Mine lateral development advance rates currently average about 5 metres (16.5 ft.) per day. Granduc Tunnel hit 35.1 metres (115 ft.) on their best day, 12 km from the portal, single heading forty-three years ago. This Canadian mining record remains an excellent example of rapid drill and blast excavation with suggestions for improving current practice.

May 1, 2011