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By Tim J. Carew, Dennis C. Martin

"One approach to stabilization of rock slopes is to place a buttress at the toe of the slope to provide additional resisting forces and increase the length and strength properties along the failure surface. This paper describes the rock mechanics and mine planning aspects of incorporating a buttress of intact rock in the lower part of the slope as part of the slope design for the south wall of the final pit at Cassiar Mine. Stability analysis techniques and results are described. Analyses results have indicated that, in order to maintain steep over-all slopes in the final pit, a buttress of intact rock shoud be incorporated into the lower section of the slope until late in mine life. The effect of the buttress is to flatten the slope and reduce the slope height thereby improving slope stability. The mining plans would be such that the buttress would be mined out during the last four months of mining when the consequences of instability would be least severe.IntroductionThe concept of using a buttress to stabilize slopes has been used in mining and civil engineering construction in may locations (Richards and Stimpson, 1977). Most buttresses involve placement of coarse rock fill timber cribs or other material as a load at the toe of an already unstable slope to provide forces which resist failure by counteracting driving forces and increasing the length and strength of the failure path.This paper describes the geotechnical and mine planning aspects of incorporating a buttress of intact rock in the design of the south wall of Cassiar Mine. The effect of an intact rock buttress is to flatten the slope and reduce the slope height, thereby improving slope stability. No actual construction is required other than normal excavation of the slope. The ""mine plans would be such that the buttress would be mined out at the end of mine life when the impact of instability would be less severe and additional ore might possibly be recovered from the slopes. Mining of the buttress could induce instability at the very end of mine life at a time when maximum ore extraction has been achieved."

Jan 1, 1986

From 1999 to 2008 rock related accidents accounted for 75 fatalities, nearly 6,000 injuries and almost 14,000 incidents (Pappas and Mark, 2011). Clearly this shows that rock related safety on coal mines remains a serious issue and more effort is needed to address this hazard. This paper reviews support design considerations and monitoring needed to improve rock related safety in room and pillar coal mines in the USA. From the present study design considerations continue to evolve and improvements in technology and a better understanding of failure mechanisms and methods to prevent these failures from occurring are in place. At first glance, the design of safe and efficient underground openings appears simple until the designer begins to realize the complexities and variability of geometries, geology, loading and stress influences, support designs and other factors such as corrosion and economics. Ultimately the goal of all designs is to ensure that it can be completed safely, last for the duration of the design life and it is economically feasible.

Aug 1, 2013

By M. Honarmand, Z. Moezifar, H. Ranjbar

Abstract - The Sar Cheshmeh area covers an area of 640 km2, and is located in the southern part of the Iranian Volcanic-Sedimentary Belt. ETM+ images have been used for alteration mapping. The Crosta method was found useful for enhancing exposed areas containing hydroxyl and iron oxide minerals. However, field checking has shown that this method is not able to identify all the known areas of hydrothermal alteration. Many of these altered areas are also not clearly resolved in the geophysical data. In order to improve resolution of such areas, integration of remote sensing and geophysical data may be helpful. The Darrehzar Cu deposit was chosen as a control area. The data have been divided into two sets: explanatory and target variables. The explanatory data are Landsat hydroxyl and iron oxide images and airborne geophysical data (K, U, and Th total counts, and total magnetics). The target variables are rock geochemistry and ground geophysics. Data analysis and integration of geophysical and remote sensing data were performed using directed principal components. This technique is found to be useful for the delineation of hydrothermally altered areas with more confidence.

Jan 1, 2002

By Brian Hall

For some years, the mining industry has been consistently delivering returns below the market average. One of the causes is a disconnect between what is perceived to drive value creation by many industry analysts and senior corporate executives, and what actually drives the intrinsic value of mining operations. The perverse effect is that strategies that should increase value are perceived to have the potential to drive share prices down, and vice versa. This paper challenges common perceptions of what drives a mining company?s value. Anecdotal evidence suggests that the key drivers of value in the market, and hence in many boardrooms, are such things as increasing the reserves and production rate, and reducing unit operating cost. However, while the quoted reserves may satisfy ore reserves reporting code requirements to be economic, this does not imply that they are optimal. Often, a proportion of the quoted reserve reduces the potential value of the operation. Metal price increases, increased production rates, and operating cost reductions are all seen as conditions or actions that can improve value, and lead to cutoff grade reductions, thereby increasing ore reserves. However, modern cutoff theory and studies conducted by the author and his colleagues show clearly that, while breakeven cutoff grades will fall in these circumstances, optimum cutoffs may be much less volatile, and may even increase. Results from case studies indicate that value is maximised by right-sizing, not maximising, the production capacities, and by optimising the cutoff strategy. Values of many existing underground mining operations can be increased significantly by a substantial cutoff grade increase. Also, an increase in downside risk, and hence reduced returns, can occur using typical life-of-mine planning strategies if prices received are lower than predicted. Since this is often the case, low industry returns may be a direct result of typical strategic mine planning processes. Relatively simple cost-effective techniques are available to provide senior decision makers with information needed to assess the tradeoffs between their many conflicting corporate goals, and the balance between risk and reward. Often this information is not being generated at all. If it is, decisions affecting the value of the company are occurring by default at relatively low levels within the hierarchy, with senior executives apparently unaware of them or their potential impact. The paper concludes that without a re-evaluation of the way mining projects are valued, to demand proven value optimisation from mining plans by boards and mining analysts, the industry will continue to deliver below average returns.

May 1, 2003

By L. C. Galloway, G. L. Tiley

"Mine hoist brakes must meet the following statutory performance criteria:- There should be two independent braking systems; at least one should act directly on the hoist drum.-If one brake fail s, the others should be able to retard and stop the hoist safely before the descending conveyance, carrying the rated load, reaches any obstruction.- When all brakes apply, decelerations should not be so violent that men travelling in the conveyance are injured.- The brakes shall not overheat and fade during an emergency stop.This paper discusses design principles and capacities of caliper and disc type brakes, when applied to double drum and friction hoists of equivalent capacity.IntroductionThis paper is about the brakes that are used on mine hoists; their functions, especially in emergencies, typical design, and how they are operated, controlled, tested, and adjusted.There are two basic types of mine hoists:1. Drum hoists, where the ropes are attached to, and coil on drums. The simplest system has only one drum. Most such hoists, however, have two drums, attached to a common shaft. Ropes are wound on each drum in opposite directions, so that when one conveyance is being raised, the other is lowered. The conveynaces may travel in vertical or inclined shafts. In the latter case, the hoist s are referred to as slope hoists.2. Friction hoist s, where the headropes are not attached to the wheel, but are in contact with it for an angle of lap of, typically, between 180 and 195 degree s. Forces are transmitted from the hoist wheel to the head ropes by friction.The lower ends of the conveyances are connected to balance ropes , approximately the same weight per foot as the headropes."

Jan 1, 1986

By D. M. Hausen

"Refractoriness in Carlin-type gold ores results mostly from fine locking of gold in pyrite, locking in various gangue phases, notably quartz, and a ""preg robbing"" condition attributed to organic carbon. All three conditions may occur in any given deposit, including Newmont &apos;s Carlin and Gold Quarry deposits in Nevada, where types of ref ractoriness occur locally in minor amounts.Measurements of specific gravity, water absorption and screen size distributions of gold in alteration rock types from Gold Quarry show transitional changes from siliceous cherts through decreasingly silicified and increasingly argillized siltstones.Low permeability of siliceous ores contributes to ""size dependent"" refractoriness in cyanidation test work. Colligative physical and chemical measurements demonstrate that silicified cherty ores are difficult to grind, poorly permeable, and less amenable to cyanidation. Refractoriness in pad or column leaching of coarsely crushed siliceous siltstones and cherts is shown to correlate with interrelated measurable mineralogic and physical parameters.IntroductionMetallurgical treatment of variably amenable and refractory types of gold ore may be guided by both analytical and mineralogic data on the interlocking of gold (microscopic an d sub- microscopic) in assorted gangue/sulphide phases. Most oxidized ores from the Carlin gold mine, north of Carlin, Nevada, are amenable to direct cyanidation. The permeability of most oxidized ores from Carlin coupled with the fine size of the gold < 1.5 um) yields rapid extractions and high recovery without fine grinding.Small portions of the Carlin ore body, and also the nearby Maggie Creek and Gold Quarry orebodies, are less amenable to cyanidation, and are classified as refractory. Refractory conditions may be attributed mostly to the association or interlocking of gold with pyrite and /or microcrystalline quartz or chert, and also by the adsorption of leached gold by deleterious forms of carbon, termed ""preg-robbing"" carbon. Each of these conditions are described and defined, with emphasis on a form of silica-locking, which has been referred to as "" size dependent"" refractoriness."

Jan 1, 1985

By G. R. Webber, P. J. Whittaker

"A multielement (Au, Cu, Pb, Zn, Ni, c-, Ag, As, Hg, Co, and S) geochemical rock sampling survey was carried out in 1977 in the Munro Township area of Ontario to assess the application of rock geochemistry for gold exploration in the region. Detailed sampling with analysis for gold and arsenic was done in 1986 in the immediate vicinity of the Croesus Mine.Samples of quartz veins and rock formations were taken in regional traverses and in more detail near old showings, prospect pits, and trenches. Quartz, graywacke, carbonate rock, and rhyolite contain the highest concentrations of gold for samples taken away from the old workings. Ultramafic rocks and gabbro have uniformly low gold. Basalt samples have slightly higher geometric means, but individual samples contain high gold concentrations. Multielement highs are mostly in mineralized quartz samples. Gold distribution is independent of other elements in most other rock types. Samples near old showings possess elevated concentrations of gold indicating that prospecting for individual mineral deposits by bedrock sampling is feasible. Concentrations of gold greater than 100 ppb are mostly within 30 m of old workings. Those samples which contain greater than 1000 ppb Au were obtained from quartz veins, basalt, graywacke, and rhyolite.High concentrations of gold were not notably concentrated near the Contact Fault although some anomalous samples came from near and on both sides of the fault. Arsenic concentrations are elevated near the Contact Fault. Detailed sampling near the Croesus Mine suggests that gold was introduced with faulting, alteration and quartz veining. Gold and arsenic have been added to the wallrock in the vicinity of the main veins."

Jan 1, 1989

By George H. Bodfish

This paper begins with a short history of air compressors, emphasizing their "roots" in the mining industry. It then describes the types of compressors available, including reciprocal, the various rotary positive-displacement compressors, and the centrifugal. The advantages and disadvantages of selecting a certain type of compressor over another are enumerated, considering customer requirements and operating costs, among other factors. Guidelines to operation and maintenance are discussed, including installation, monitoring and maintenance procedures. Finally, the paper addresses itself to future trends, with special attention being given to the system concept, the increasing use of rotary compressors, power consumption, reliability, packaging and noise attenuation.

Jan 1, 1978

By J. L. Llanca

The New Level Mine project (NLMP), the planned underground expansion of the El Teniente mine in Rancagua, Chile, is expected to reach a daily extraction rate of 137 to 180 ktpd upon achieving full capacity. Production is planned to start in the year 2017 and the current plan is to meet that target through two development phases, from the year 2012 to 2014 and from the year 2015 to 2017. To achieve the 2012 to 2014 underground development schedule, the ventilation requirements have been estimated in the range of 189 m3/s (400 kcfm), and cannot be made available without significant modifications to the current system of El Teniente. As a result, a certain number of alternatives were explored to find a solution to this shortfall, for example, adding raises to generate parallel airways and installing fans to reinforce the current ventilation system. From the alternatives studied, the installation of a second main fan (system) in parallel to an existing one was identified as the best solution, and selected for implementation, however the location was not ideal and there were concerns as to the operation of both fans once the second fan was installed. This paper presents the study used to estimate the operational points of both the current and the new fan, and to justify the parallel installation of the additional main fan. An additional computational fluid dynamics study was undertaken to validate the operational point, given the particular geometry of the fan?s location and placement, to guarantee a stable operation of the fans. Finally, the protocols arising out of this work for starting the fans, and operating them in parallel to avoid generating a stall condition and damaging the investment are discussed.

Aug 1, 2013

By M. Kawata, T. Amano, T. Miyamoto, K. Shibayama

"The High Pressure Acid Leach (HPAL) plant of Taganito HPAL Nickel Corporation (THPAL), located in Taganito, Philippines, with a nameplate capacity of 30,000 Ni-t/year started commercial operation on October 2013. The plant load was smoothly ramped up and it achieved monthly production equivalent to 33,000 Ni-t/year in 2016. Partial improvement of the plant capacity for the achievement of 36,000 Ni-t/year, as evaluated from the current operation progress of each system is planned for 2017. In this paper, aside from presenting the progress of the plant ramp-up, research and development activities such as the reduction of nickel loss and the improvement of filtration capacity which was achieved by particle size control of ZnS precipitates in the Zinc Removal system are also discussed.INTRODUCTION Taganito HPAL Plant Project History of THPAL Taganito HPAL Nickel Corporation (THPAL) was incorporated in August 2008, as a joint venture of three (3) companies, namely Mitsui Corporation with 15% share, Nickel Asia Corporation (NAC) with 10% share and Sumitomo Metal Mining Corporation (SMM) with a controlling stake of 75%. Aside from its capital share, NAC’s Taganito Mining Corporation (TMC) supplies the ore for the HPAL plant located in Taganito, Claver, Mindanao, Philippines. The objective of THPAL is to produce 30,000 MT of nickel and 2,600 MT of cobalt as mixed (Ni/Co) sulfide by treating nickel laterite ore in the Philippines and exporting to Japan as raw material for SMM’s Niihama Nickel Refinery (NNR) for the next 30 years. In other words, 1.15 wt% of nickel in ore is refined to 99.99 wt% nickel in electrolytic nickel. The mixed (Ni/Co) sulfide is shipped to NNR and SMM provides the technology and management personnel to THPAL plant as well as sulfuric acid which is the main reagent for HPAL process. Figure 1 shows the location of THPAL and current relationship between the stake holders.The Characteristics of THPAL Plant In terms of plant design, a 2-train system is applied for the HPAL circuit considering the reliability of the process, facility and avoidance of whole plant shutdown due to HPAL troubles. The technical data, operation know-how and improvements gained from the successful operation of Coral Bay Nickel Corporation (CBNC) which was established in April 2002 were reflected in THPAL’s plant design. As for the H2S plant, a more economical design was considered which is different from CBNC."

Jan 1, 2017

By Bhawani Singh, Mahendra Singh, N. K. C Samadhiya

"Inherently anisotropic rocks occur in abundance at many rock engineering project sites in Himalayan region. These rocks pose difficulty in analysis and design due to their direction dependent strength behaviour. Moreover the strength varies in a non-linear manner with confining pressure. Mohr- Coulomb strength criterion is widely used by geotechnical engineers for defining strength of rocks subjected to given confining pressure. However, the conventional Mohr-Coulomb (MC) criterion suffers from the limitation that the strength is treated to be linearly dependent on confining pressure. In the present article, the MC criterion has been modified by incorporating non-linear term while retaining the original parameters c and ?. The non-linearity with confining stress level has been imbibed through critical state concept (Barton, 1976). The criterion has been applied to a triaxial test data base comprising of more than 1140 triaxial tests conducted world-wide on anisotropic rocks. Statistical evaluation of the goodness of fit of the proposed criterion to the data-base has been carried out. Further the predictive capabilities have been evaluated by determining the error in estimation of triaxial strength if only few triaxial test data are available for determining the criterion parameters. The data base has also been back-analysed to assess the critical confining pressure for anisotropic rocks. Statistically the critical confining pressure, for the present criterion, may be taken nearly equal to 1.25?cmax, where ?cmax is the maximum value of the UCS out of all orientations of planes of anisotropy. It is concluded that reasonably good estimates of the anisotropic strength are possible through the proposed criterion.INTRODUCTIONMany rocks encountered in Himalayan region like shale, slate, schist and phyllite are inherently anisotropic and exhibit direction dependency in their strength behaviour. In addition, the strength of the rock also depends on the confining pressure and, the strength response is non-linear especially when the confining pressure may vary over large range. Conventionally, Mohr-Coulomb criterion is the most widely used criterion for rocks. However, the limitation of this criterion in its present form is that the strength is treated to be linearly dependent on the confining pressure. The present study attempts to address the following two main objectives: i) Include nonlinear response in the Mohr-Coulomb criterion while retaining parameters c and In their original form; and ii) consider anisotropic response of the rock for a given confining pressure. A nonlinear strength criterion, which uses shear strength parameters c and as per Mohr-Coulomb criterion, has been suggested based on critical state concept for rocks."

Jan 1, 2015

By M. D. Johnson, R. K. Bezys

"The majority of Ontario&apos;s limestone and dolostone production comes from a few Paleozoic carbonate units. In eastern and central Ontario, Ordovician rock units, which are the main sources for production, include the Oxford, Gull River, Bobcaygeon, Verulam, and Lindsay Formations. They are predominantly utilized for aggregate and cement manufacturing, with the Bobcaygeon Formation being used as a source of building stone. Along the Niagara Escarpment, the Silurian Lockport, Amabel, and Guelph Formations are sources for the limestone industry. The largest tonnage of rock extracted by the industry comes from these Silurian units, especially the Lockport and Amabel Formations. These units are used primarily for aggregate, although they are also a source for lime. In southwestern Ontario, the Silurian Bertie Formation and Devonian strata, represented by the Bois Blanc Formation, Onondaga Formation, Detroit River Group, and Dundee Formation, contribute to Ontario&apos;s production of lime, cement production and crushed stone. The Detroit River Group (Lucas and Amherstburg Formations) is the main source of the lime and cement produced in the province.Northern areas, which may become significant sources for the industry, include Manitoulin Island, the Lake Timiskaming area, and the James Bay Lowland. IntroductionThe Engineering and Terrain Geology Section of the Ontario Geological Survey has undertaken a geological inventory of all active and abandoned limestone and dolostone quarries in Ontario. This geological study, combined with a commercial study of active quarries carried out by the consulting firm of Derry, Michener, Booth and Wahl, will provide an up-to-date report on the industry in the province and will be published by the Aggregate Resources Section of the Ministry of Natural Resources. This report will follow the format and style of D.F. Hewitt&apos;s Ontario Department of Mines Industrial Mineral Reports and Circulars (Hewitt, 1960, I964a, 1964b, 1964c; Hewitt and Vos, 1972). Examinations of the quarries were carried out by geologists in the Paleozoic I Mesozoic Geology Subsection of the Engineering and Terrain Geology Section, and include, in addition to the authors, R,R. Wolf, V.A . Mazur, and D.K. Armstrong in the summer of 1986."

Jan 1, 1988

By M. D. Johnson, R. K. Bezys

"The majority of Ontario&apos;s limestone and dolostone production comes from a few Paleozoic carbonate units. In eastern and central Ontario, Ordovician rock units, which are the main sources for production, include the Oxford, Gull River, Bobcaygeon, Verulam, and Lindsay Formations. They are predominantly utilized for aggregate and cement manufacturing, with the Bobcaygeon Formation being used as a source of building stone. Along the Niagara Escarpment, the Silurian Lockport, A mabel, and Guelph Formations are sources for the limestone industry. The largest tonnage of rock extracted by the industry comes f rom these Silurian units, especially the Lockport and Amabel Formations. These units are used primarily for aggregate, although they are also a source for lime. In southwestern Ontario, the Silurian Bertie Formation and Devonian strata, represented by the Bois Blanc Formation, Onondaga Formation, Detroit River Group, and Dundee Formation, contribute to Ontario&apos;s production of lime, cement production and crushed stone. The Detroit River Group (Lucas and Amherstburg Formations) is the main source of the lime and cement produced in the province.Northern areas, which may become significant sources for the industry, include Manitoulin Island, the Lake Timiskaming area, and the James Bay Lowland. IntroductionThe Engineering and Terrain Geology Section of the Ontario Geological Survey has undertaken a geological inventory of all active and abandoned limestone and dolostone quarries in Ontario. This geological study, combined with a commercial study of active quarries carried out by the consulting firm of Derry, Michener, Booth and Wahl, will provide an up-to-date report on the industry in the province and will be published by the Aggregate Resources Section of the Ministry of Natural Resources. This report will follow the format and style of D.F. Hewitt&apos;s Ontario Department of Mines Industrial Mineral Reports and Circulars (Hewitt, 1960, I964a, 1964b, 1964c; Hewitt and Vos, 1972). Examinations of the quarries were carried out by geologists in the Paleozoic I Mesozoic Geology Subsection of the Engineering and Terrain Geology Section, and include, in addition to the authors, R,R. Wolf, V.A . Mazur, and D.K. Armstrong in the summer of 1986."

Jan 1, 1988

By J. Kochhar, Robert G. Cooper

"The Cape Breton Development Corporation is a federal Crown corporation which was formed in 1968. Initially, the Corporation had two divisions - the Industrial Development Division, whose purpose was to stimulate Cape Breton Island&apos;s economy, and the Coal Division with a mandate to phase out the operating coal mines. However, that strategy changed in the early 1970s with the Middle East oil crisis. As a result of that crisis, Nova Scotia Power Corporation adopted an ""off oil"" policy. Today, approximately 700/0 of Nova Scotia power needs are met by generation of electricity from coal. Therefore, since the early 1970s, emphasis has been on the rehabilitation of the Cape Breton coal mining business with the opening of three new mines.Today, Devco is solely a coal mining company which employs 3300 people.Physical DescriptionThe mines operate in the Sydney coal field which is located on the eastern tip of Cape Breton. The Corporation leases the deposit from the province of Nova Scotia and its leases cover all coal from the outcrop to the 4000 ft depth. The seams outcrop along the shoreline and dip beneath the ocean floor at dips varying between 5% and 100%.There are eleven seams, of which three - the Harbour, Phalen, and Hub - have been extensively mined."

Jan 1, 1990

By S. J. Cook

Copper, a world commodity, and the first metal used by man, played a great part in the beginnings of modern civilization, which rests so dependently on the utilization of metals. Then, long after the close of the so-called &apos;bronze age,&apos; when iron and steel had attained great prominence as the world&apos;s most important metals, the practical application of electricity to industry and commerce, for the improvement of every phase of man&apos;s multitudinous activities, gave a new impetus to the production of copper. Improved metallurgical practice made it possible to work low-grade properties at a profit. Research disclosed many new uses for copper. The metal, now produced from the mines of the world in the proportion of about one pound to every 50 tons of pig iron, has attained an importance which rivals that of iron and steel in the commerce and daily life of every nation. New fields of copper-bearing ore have been discovered in Canada in recent years. Established mines in the United States and Chile are producing on a great scale. Africa looms up as one of the great question marks in the future of copper. Whereas, a few years ago, the end of the world?s resources was predicted as being in sight, the evidence now available seems to show that the copper production of the world is likely not only to continue, but to increase for a long time yet to come. Canada&apos;s future in copper is a great subject; in the present paper only a few of the most outstanding factors affecting Canada&apos;s destiny in this large field may be noted, but if consideration of the points raised herein serves to focus attention on the magnificent possibilities of Canada as a producer of copper, the preparation of the paper will be more than justified.

Jan 1, 1928

By W. P. Clement, M. C. Bell

"PT International Nickel Indonesia, a subsidiary of Inco Limited, mines and processes nickel laterite ores for the supply of nickel matte, primarily to the Japanese market. It has large ore reserves and a substantial portion of its energy requirement is supplied from its own hydro-electric plant. Since the early 1980s, the company has increased its production level and has dramatically reduced its unit costs. Projects are in progress to further decrease costs and recently a major expansion - 31% increase in nominal capacity - has been undertaken, consistent with marketing opportunity in Japan. The expansion project, which has a low capital cost per unit of production, is outlined in this paper.IntroductionPT Inco is a fully integrated mining and smelting facility located in Indonesia on the island of Sulawesi, and is based on a very large, world class nickel laterite orebody located 60 km inland from the Gulf of Bone. Construction of a single furnace line plant started in 1973. Complete supporting infrastructure of townsite, hospital, schools, shopping centres, road systems, and an airport, all had to be built. Prior to completing the first phase, the decision to expand the plant to a three kiln-furnace line was made. A major factor in the decision was the ability to develop the hydroelectric potential of the nearby Larona River. This involved construction of a 30 m high dam, and a 7 km surface canal to the generating station. The penstocks drop 150m to three 55 Mw turbines. The power generated is sufficient to supply the entire electrical load for the complete smelting complex and town site. The unique capability to supply the high smelting energy requirements for a lateritic nickel ore by fully captive hydro power, has, over the past decade insulated PT Inco from the large upward swings in oil prices suffered by other lateritic nickel producers.Wet ore is first partially dried to 20% moisture in two co-currently fired rotary driers, screened on an internal trommel, and delivered to two dry ore storage buildings. The partially dried ore is calcined at 750°C and partially reduced in three large 100 m by 5.5 m kilns. Reduction is accomplished by lancing bunker C oil onto the ore bed at the discharge end of the kiln. The kilns are equipped with five air pipes with onboard blowers to gradually bum the combustible gases generated by the lance oil. The kilns were also originally equipped with two side burners to supply additional heat close to the feed end of the kiln. Calcined ore is transferred by 20 ton refractory lined containers to the furnace feed bins at the top of the smelter. Smelting is carried out in three 18 m diameter furnaces powered by 45 Mw transformers. Slag is skimmed at 1550°C through water cooled breast plates and removed to the slag dump by Haulmaster Carriers. Matte of 25% Ni, 1O% S, 65% Fe is tapped at 1350°C into the converter aisle. The iron is slagged in converters to produce a nickel sulphide matte at 80% Ni. Three rotary Kaldo converters were initially installed. The product matte is granulated, dried, and shipped in returnable rubber bags to Japan. Most of the matte is fluid-bed roasted to nickel oxide and then directly reduced in a second reducing fluid bed reactor at our facilities in Japan.The smelting complex was designed to smelt two million tonnes of dry ore per year, equivalent to 34 000 tonne nickel production at an ore grade of 2% Ni. The cost of the entire project including working capital was $900 million."

Jan 1, 1990

By C. H. Lee, T. T. Wang

"Exampling of the tunneling task in the Tsengwen Reservoir Transbasin Diversion (TRTD) in southern Taiwan, this study investigates the application of the Drilling Survey System (DRISS) in both Drilling and Blasting (D&B)- and Tunnel Boring Machine (TBM)-excavated sections. In the D&B section, a nonlinear relationship exists between drilling energy and uniaxial compressive strength of rock mass, in which a reasonable coefficient of determination can be analyzed statistically. Additionally, the DRISS accurately predicted an unfavorable section with a valuable position. The magnitude of uniaxial compressive strength back calculated using DRISS data also matches those acquired from geological investigations with different approaches. Study results indicate that the DRISS is an effective tool for fore-probing of both D&B- and TBM-excavated tunnels. INTRODUCTIONModern advancements in geological and geophysical investigations, and drilling techniques, have provided valuable information for detecting and interpreting geological conditions of rock tunnels with a resolution of several to ten of meters (Brückl et al., 2001, 2008, Lorang et al., 2005). Nevertheless, construction risks remain considerable during tunnel excavation, especially when a tunnel was excavated by a Tunnel Boring Machine (TBM). Predictions of the local fault, shear zone, and other minor geological features, which may cause moderate collapse or excessive deformation of rocks surrounding the tunnel, before tunnel excavation is highly desirable for high-quality tunnel construction and economically efficient project management.Rather than conventional geophysical prospection methodologies, which always favor large-scale investigation with moderate precision, this study focuses on the drilling method probing ahead of a tunnel. The goal of such an investigation is not only to prevent catastrophic collapse, but also to provide quantitative or semi-quantitative information for estimation of the mechanical parameters of rock mass.For the tunneling task in the Tsengwen Reservoir Transbasin Diversion (TRTD) in southern Taiwan, a drilling survey system is adopted for fore probing. Data collected from both drilling and blasting (D&B) and TBM-excavated sections are analyzed statistically and discussed. The applications of the Drilling Survey System (DRISS) are addressed accordingly."

Jan 1, 2015

By J. R. Foster

Investigations into the effect of a variety of acid digestions on common rock-forming minerals demonstrated a considerable variation in the proportion of the total metal extracted. A similar situation applies to the analysis of a number of common rock types. In addition, grain-size variation has an effect on the amount extracted by certain digestions. This work indicates that considerable care needs to be given to selecting an appropriate acid digestion capable of determining metal held in particular components of a sample. By using partial extraction techniques, the identification of certain patterns of metal distribution, undetectable by normal methods involving total metal analysis, may be achieved.

Jan 1, 1973

By Nabeel Khan

Annual oil production from the Canadian Oil Sands in Northern Alberta has been rising for several decades, and more ore and overburden are excavated each year from an increasing number of open pit mines. Overburden meeting certain specifications will be used to dam tailings and fill open pits, but the remaining material must be stored in overburden storage structures (OBSS). Well-designed overburden storage structures are more stable and cost less in the short- and long-term. The purpose of this paper is to explore OBSS designs that will be stable yet economical in the short- and long-term. The geological background of the site is briefly discussed, including the effect of each of the main geologic layers (recently deposited till and muskeg, Clearwater Formation clay shales, McMurray Formation oil sands, and the Devonian limestone) on the slope stability of the OBSS. Cost is considered in the analysis when balancing between minimizing costs (steeper slopes) and acceptable factors of safety (flatter slopes), all the while considering the financial consequences of failure. Potential failure planes are identified and probabilistic analysis is conducted on the critical failure surface. The variations in the factor of safety caused by varying pore water pressure, friction angle, and cohesion, are plotted and discussed.

Jun 1, 2012

The teaching of geophysics in Canada at the present time presents a variety of approaches to the subject, and the different paths adopted imply, in turn, an uncertainty in the minds of some educators as to the role this science is to play in the future progress of geology, and a hesitancy to commit themselves to foster its development. The pedagogical attitudes vary from a whole-hearted acknowledgment that the science of geophysics is fundamental to the understanding of terrestrial phenomena (including, of course, geological processes) to a hesitant immersion of the toe to test the water&apos;s temperature (which is, of course, essentially a geophysical experiment) before deciding whether or not the time is ripe for total immersion. The present discussion has been organized in the hope that it will help to clarify the roads to geophysics and assist educators in making a more understanding choice of the best paths for them to follow, according to their particular requirements and objectives. Before proceeding further, however, it is necessary to define the term geophysics and circumscribe the field it covers. In the first place, it should be emphasized that geophysics is NOT confined to the art of geophysical prospecting. The popularization of geophysics has unfortunately engendered a general misconception of the word, and consequently a tendency to ignore the wider meaning of the term. Etymologically, geophysics means the physics of the earth. It is so understood by the International Union of Geodesy and Geophysics and the various geophysical societies which adhere thereto. To them, geophysical prospecting is but a very small field indeed, which they consider had best be left to engineering and prospecting organizations.

Jan 1, 1951