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The geologists at the Zinc Mine in Broken Hill have developed a method of logging core using portable MS-DOS computers and LOTUS 123. The computer based logging system has almost halved both the time and cost to produce a completed log. The system is fast, flexible, easy and pleasant to use.

Jan 1, 1990

By Pingchao Ke, Zhihong Liu

"To overcome the problem that scoroditeis not stable in neutral and alkaline solutions, we proposed and investigated a synthesis method of scorodite coated in-situ with hydrated ferric oxide in the Fe(II)-As(V)-H2O system at the initial Fe(III)/As(V) molar ratios larger than 1.0.The synthesis was carried out at 90?,pH 1.5 under atmospheric pressure. During the synthesis, oxygen gas was conducted and bubbled into the system to oxidize Fe(II) ions into Fe(III)ions, and Na2CO3aqueous solution as neutralizing agent was added controllably into the system for keeping the pH constant at 1.5. In this study, three samples of scorodite were synthesized at the controlled initial Fe(II)/As(V) molar ratios of 1.0, 2.0 and 3.0, respectively. The characterizations of the samples by HRTEM, TEM/EDX, and chemical composition indicated that the particle surfaces of scorodite synthesized at the initial Fe(II)/As(V) molar ratio of 2.0 and 3.0 were coated in situ by a film of hydrated ferric oxide with the thickness of several nanometers, while the sample synthesized at the initial Fe(II)/As(V) molar ratio of 1.0 was uncoated scorodite. The TCLP and long-term leaching for the toxicity characteristic of the samples showed that scorodite coated in situ with hydrated ferric oxide was stable in a wide pH range from 3.0 to 10.0, with the arsenic concentrations in the leaching solutions less than 1.0mg/L. Nevertheless, uncoated scorodite was unstable under the conditions from weak acidity to alkalinity, with the arsenic concentrations in the leaching solutions larger than 5.0 mg/L.INTRODUCTIONArsenic pollution is a challenge for environment and health and has been an important issue for scientists (Hopkin, 1989).Arsenicis commonly associated with ores or concentrates of nonferrous metals, mainly as independent arsenic bearing minerals such as arsenopyrite (FeAsS), tennantite(Cu12As4S13), enargite (Cu3AsS4), cobaltite (CoAsS), and gersdorffite (NiAsS), realgar (As2S2), orpiment(As2S3), etc.(Matschullat, 2000; Mandal & Suzuki, 2002; Long & Peng, 2012). In the nonferrous metallurgical processes, arsenic is enriched mainly in such arsenic bearing materials as various flue dusts, residues, and anode slimes, which results in the accumulation of arsenic in the system owing to the circulation of those arsenic-bearing materials back to the system and the pollution to the environment (Harris, et al, 2003).In addition, the utilization of arsenic is limited and has been decreasing owing to its toxicity and carcinogenicity. Therefore, arsenic has to be removed from those arsenic-bearing materials and discarded safely (Dutrizac & Jambor, 1988; Monhemius & Swash, 1999; Drahota & Fillippi, 2009).In this case, how to immobilize arsenic has become a difficult problem which must be solved. Among the methods of immobilizing arsenic which have been proposed and investigated, immobilizing arsenic into a stable mineral to fix it, has been realized as a promising method and becomes a research focus(Dutrizac et al, 1987; Dutrizac & Jambor, 1988; Demopoulos et al, 1995; Fujita et al, 2008a; 2008b).Scorodite has been known as one of the best minerals for immobilizing arsenic, owing to its high stability under weak acidic condition, the arsenic content as high as 32wt%,and good crystallinity benefiting the separation of solid to liquid(Daivid et al, 1999; Zhu & Merkel, 2001). Scorodite can be synthesized from arsenic containing solutions under both hydrothermal and atmospheric conditions, and a lot of work has been done on the synthesis of scorodite and its leaching stability characterization (Filippou & Demopoulos, 1999; Gomez et al, 2011).Two plants for the immobilization of arsenic as scorodite have been putin to operation in Chile and Japan, respectively (Filippou & Demopoulos, 1999; Amir et al, 2016)."

Jan 1, 2017

Jan 1, 1937

By H. -L. Heikkilä, E. Peuraniemi

"Boliden Harjavalta Oy has a long tradition in the Finnish metal industry starting from the 1930's. The Smelter consists of copper and nickel flash smelting lines. Off-gases are captured in the acid plant to produce sulfur products. During the early years of production, the surrounding environment suffered from high SO2 and dust emissions. The first acid plant started in 1947, a few years after commissioning of the smelter. The flash smelting method was developed and commissioned in 1949. This created the basis for today’s environmentally sound metal production. Recent air emission reductions are related to treating lean ventilation and granulation gases. Emissions from the stacks are monitored with continuous measurement devices. SO2 and PM10 concentrations are also measured from the residential area and reported online in cooperation with Harjavalta community and other local industry.INTRODUCTIONProductionBoliden Harjavalta Oy smelts copper and nickel concentrates and refines copper in the western part of Finland. The copper concentrates come from external copper mines mainly in South America and Europe. Concentrates are unloaded at the Pori harbor and transported to Harjavalta by train from a distance of about 60 km. Boliden Harjavalta Oy has operations in Harjavalta and Pori. The smelter in Harjavalta produces copper anodes that are transported via railway to the copper refinery in Pori. The anodes are electro-refined into copper cathodes and by-products like Se, Ag, Au and Pt/Pd concentrate. In the Harjavalta smelter SO2 containing gases are delivered to a sulphuric acid plant where sulphuric acid and liquid sulphur dioxide are produced.Our nickel smelter smelts nickel concentrates on a tolling basis to produce nickel matte for customer needs. SO2 containing off-gases are delivered to the sulphuric acid plant for sulphur capture and modification into products.All our operations are certified according to the Quality, Environmental and Occupational Health and Safety Standards ISO 9001, ISO 14001 and OHSAS 18001. Boliden Harjavalta Oy was the first company in Finland operating in the metal and technology industry to be certified according to the Energy Management Standard EN 16001, currently this certification is done according to ISO 50001."

Jan 1, 2012

A static equilibrium mathematical model of the lead,flotation circuit at The Zinc Corporation Limited is developed to permit the feasibility of applying computer control techniques to be studied. The model is based on the relationship between the cumulative recovery of a mineral species R from n flotation cells or assemblies in a unit given asR = M(1-(1 - p)?)where M is the maximum possible: recovery and p is the probability of flotation for the particular mineral.The verification of this relationship by data from pilot plant cell-to-cell and plant open flow flotation units shows that these systems behave as if the probability p is constant for each cell or assembly of anyone unit. It is also concluded from this study that mineral recovery is independent of the head assay. Two consequences of this probability relationship, are demonstrated.1. The total recovery from an open flow unit is enhanced by increasing the number of flotation assemblies but maintaining a constant flotation time and total air addition.2. The rougher and scavenger capacity required to recover a bulk lead-zinc concentrate is approximately half that used for selective flotation.The static equilibrium model is derived by solving a series, of mass balance equations which incorporate the recovery-probability relationship for each type of flotation unit. It is used to calculate the complete metallurgy of the circuit for any arrangement of cells knowing only the plant feed assays and the probabilities of flotation for the three mineral types, galena, marmatite, and gangue for rougher, scavenger, and cleaner flotation. The high degree of prediction obtained is demonstrated by comparison with plant results.Pulp flowrate is the principal variable affecting the accuracy of the present model. Work is in progress to establish this effect and permit the derivation of a dynamic model. Even so, the static model is valuable in its present form for the analysis and design of circuits, and optimisation studies using computer services have been conducted.

Jan 1, 1964

By Miguel Barron

Recently, a new lance design for BOF steelmaking has been proposed in the literature. This lance, in addition to six peripheral inclined supersonic nozzles, contains a vertical centered nozzle whose oxygen flow is independent from the main oxygen supply. The above authors affirm that their lance maximizes the droplet generation without causing spitting. In this work, the performance of a lance with four peripheral nozzles and one vertical centered nozzle is numerically modeled by means of Computational Fluid Dynamics software. Transient two dimensional computer simulations were carried out considering two phases, namely molten steel and gaseous oxygen. Numerical results confirm that bath agitation and droplet generation are enhanced as a result of the vertical centered nozzle, however a proper performance of this lance, related to a conventional one, strongly depends on the Mach number of the oxygen jets and the lance height.

Jan 1, 2008

By M. H. Haycock

Introduction The property of Rouyn Merger Gold Mines, Limited, is in Rouyn and Joannès townships, Western Quebec, seven miles east of the town of Rouyn. Traversing it is the east-west trending Cadillac-Bouzan fault. Diamond drilling in 1944 and 1945 along a shear zone south of the fault indicated an ore deposit lying at the contact between sedimentary and volcanic rocks and dipping approximately 60° to the northwest. In the summer of 1945 it was decided to sink a shaft to investigate the indicated ore zone. In the immediate vicinity of the deposit, bed-rock is overlain by clay beds, in some places as much as 70 feet thick. Consequently, possible shaft sites were limited to those locations where overburden would not be excessive. The most favourable site was about 125 feet to the south of the ore zone as projected vertically from bed-rock to the surface. Accordingly, it was decided to sink the shaft at this point, with an inclination of 60° N. W., paralleling the dip of the ore zone.

Jan 1, 1948

By Valcana Stoyanova

The distribution pattern, abundance variations and types of polymetallic nodules and associated megabenthic communities in area covers more than 60 000 km2 laid out in the eastern Clarion-Clipperton Zone (CCZ) is presented. Our observations are based on data from 158 boxcore stations collected during the cruise of the Interoceanmetal (IOM) in 2004 on board of RV Yuzhmorgeologiya. Although those polymetallic nodules for two decades been subject to prospecting and exploration studies carried out by IOM, the knowledge of megabenthic communities and their distribution pattern within nodule field was extremely limited. With purpose to evaluate the relationship between polymetallic nodules and associated benthic megafauna, an comparison analyze was carried out in respect to their composition, types, abundance across the studied area owing into account the local particular feature of bottom topography. It is suggested that the nodule-bearing seafloor supported more diverse fauna (higher number of morphotypes) than the nodule-free areas. Moreover, based on correlation between types of nodules and associated faunal morphotypes frequency the apparent relationship is considered. The most abundant megafaunal taxa (between 68 ? 92%) is essentially associated with the occurrence of the diagenetically growth nodules type (D-type and its D1-subtype); the role of the H and HD nodule-types was variable. In respect to the bottom topography, the highest diversity in the structure of megafaunal communities was recorded in the gently undulating plains and on the horst slopes, thus the highest nodule abundance occur on the topographic slopes.

Jan 1, 2008

Bioleaching of Weathered Saprolite - Heavy Metal Adaptation Mechanisms of Aspergillus foetidus Nickel laterite ores remain important to the future supply of Ni and Co as they contain the bulk of known nickel and cobalt reserves (80 per cent and 90 - 95 per cent respectively). Current commercial extractions of Ni and Co from nickel laterite ores are energy intensive and operational costs are high. Microbial leaching of oxide ores has the potential to offer a much needed step-change in the technology for processing laterite ores. Biological leaching of low-grade nickel laterite is based on a non-traditional leaching of oxide minerals using heterotrophic micro-organisms. The organisms solubilise metals by excreting organic acids; these acids then form complexes with heavy metals. Optimisation of the process in in-situ application, however, has been hampered by the toxicity of the heavy metals that are being leached by the organisms. Our recent study has shown that organisms are able to develop tolerance towards heavy metals by adaptation. This study examined the extracellular metal detoxification mechanisms of A. foetidus in 0.2 per cent (wt/v) to 0.7 per cent (wt/v) of weathered saprolite ore. To support our analysis, FTIR, CHNS and microscopy were used to confirm the participation of specific functional groups in the extracellular detoxification process.

Sep 13, 2010

By A. M. Alfantazi, R. R. Moskalyk

Over the years, improvements have been made in the recovery of nonferrous metals, including improvements in the areas of mineral processing, pyrometallurgy and hydrometallurgy to extract cobalt as a byproduct from host minerals containing mainly nickel, copper and associated precious metals. At present, the technological emphasis is on solvent extraction coupled with electrowinning (SX-EW) for lateritic sources of supply within the Southern Hemisphere, such as in Australia and New Caledonia. Although sulfide-bearing ores, such as those found in Canada and Russia, will serve as a viable long-term source for cobalt, a ubiquitous metal, the future trend is anticipated to be in the implementation of compact and efficient SX-EW facilities that apply state-of-the -art innovation with environmental compliance This paper serves to collate the known practices for the recovery of market-grade cobalt by means of electrowinning from either an aqueous sulfate medium or chloride medium after upstream leaching, solvent-extraction and solution-purification procedures. For completeness, other commercial production techniques for the recovery of cobalt as a sulfide or oxide product are included in the summary of current cobalt processing practices.

Jan 1, 2000

By W. R. Phibbs

The blast furnace of the Columbia Steel Corpn., at Ironton, Utah, was put in blast April 30, 1024, and its operation has presented some interesting problems. The coke for the furnace is furnished by 33 Koppers Becker type ovens of 15 tons capacity each. The coal is shipped from the company's mine at Columbia, Utah, which is approximately 123 miles from Ironton, and is probably the highest volatile coal that is being coked for blast furnace use in this country. The analysis of the coal is: PeR Cent. Moisture................................................. 3.90 Volatile.................................................. 39.00 Fixed carbon............................................ 51.10 Ash............................................... 6.00 Sulfur................................................. 1.07 The analysis of the coke is: PeR Cent. Volatile.................................................. 0.55 Fixed carbon............................................. 89.70 Ash...................................................... 9.75 Sulfur................................................... 1.05 The coke is light and of a fingery construction, but is very fast burning. A screen test of the coke as loaded into the skip tubs at the furnace shows the following: Per Cent. On 2 in.................................................. 17.90 On 11/2 in................................................ 41.78 On 1 in.................................................. 27.80 Through 1 in............................................. 12.52 The by-product yields are as follows: Gas................................. 11,000 cu. ft. per ton of coal Sulfate............................... 30 Ib. per ton of coal Tar.................................. 12.65 gal. per ton of coal Motor fuel........................... 3.00 gal. per ton of coal Average B. t. u. in gas................. 567

By T. J. Otto, C. Musingwini

"The objective of any mining company is to sustainably maximize the net present value (NPV) throughout the life-of-mine (LOM). The expected NPV over the LOM is calculated based on a mine plan, yet the actual value realized by the mining company depends greatly on the level of intertemporal execution against the mine plan. Consequently, a major key performance indicator (KPI) that is often overlooked in open pit mining, due to a greater focus on temporal KPIs, is the degree of spatial compliance to the mine plan. Such focus sometimes leads to short-term actions being detrimental to long-term plans. In this paper we describe the development and implementation of a spatial mine-to-plan compliance reconciliation approach for an open pit mine. Application to a case study open pit iron ore mine in South Africa indicated a significant improvement in the spatial mine-to-plan compliance, from 69% to 94% over a three-year period from 2014 to 2016. These results indicate that implementation of the proposed spatial mine-to-plan compliance reconciliation approach can contribute positively to improving the level of spatial execution and assists in improving the alignment between short-term, medium-term, and LOM plans.IntroductionThe objective of any mining company is to maximize the net present value (NPV) throughout the life of mine (LOM). However, this objective needs to be fulfilled in a sustainable manner that considers the needs of various stakeholders, including employees, shareholders, and local communities where the mines operate. The expected NPV is calculated using a mine plan as a basis. Mine planning broadly involves identifying a strategy to exploit the mineral resource in a way that maximizes value at an acceptable level of risk throughout the LOM (Tholana and Neingo, 2016).The mine planning process is a well-recognized component in the mining value chain of an open pit mine. Figure 1 reflects the relative position of mine planning within a typical open-pit mining value chain from the mineral resource to the market"

Mar 1, 2019

By Feng Tianran, Lu Shijie, Shen Zhengchang, Han Zhibin, Tan Ming

"As a kind of non-metallic material, high-purify quartz sand has been widely used in many fields. Flotation is a popular way to process quartz sand. But it is in difficult position for flotation to get high-purify quartz product due to large amount of coarse particles contained in the feed. In this paper, a design principle of special flotation cell for high-purify quartz sand has been put forward base on ore property analysis and laboratory test, and the pilot scale special flotation cell has been developed to meet the requirement of the quartz sand flotation process. The special flotation cell for high-purify quartz sand is featured by middle positioned impeller, false bottom and draft tube, which could decrease the rising distance of mineralized bubble and strengthen the circulation capacity of the lower part of the flotation cell. Hydrodynamic study indicates that high air dispersion degree and strong lower slurry circulation could be produced by pilot scale special flotation cell, which is helpful to create a suitable hydrodynamic environment for quartz sand processing.INTRODUCTIONNatural quartz is a non-metallic mineral, which is widely used as raw material in multiple industry process (Shifu, 2006). High purity quartz, especially containing more than 99.9% silicon dioxide, is characterized by high temperature resistance, small thermal expansion coefficient, highly insulating and so on. The demand of high purity quartz has been rising along with social and economic development, now high purity quartz is widely used in the field of photovoltaic industry, electronic information, communications and aerospace industry.Quartz is a kind of main rocking-forming minerals in the nature. There are seven genetic types, such as natural crystal, quartz sandstone, quartzite, vein quartz, konilite, natural siliceous sand, granite quartz (Baolei, Shuilin, & Dianchao, 2012). The natural crystal is primarily used as raw material to refine high purity quartz, but it is not available for two reasons. On the one hand, the natural crystal is extremely expensive and poor in resources reserves, which can not satisfy the need of large-scale industrial production. On the other hand, the chemical component of natural crystal is instability, it may lead to low stable product performance in large industrial applications, and it is also difficult to achieve raw materials standardization. Therefore, there are a lot of studies to search for other technological methods to obtain high purity quartz from other genetic quartz types."

Jan 1, 2016

By B Clemen, D Gordon, F Cesnik, P Griffin

In March 2002 Newcrest Mining Ltd commissioned a 4 Mtpa gold-copper concentrator at its Cadia Valley Operations in New South Wales. This paper presents the design and construction considerations, commissioning and ramp up issues related to start up of the concentrator as well as current performance and future expansion plans. Commissioning of the plant was the culmination of six years of project planning, from discovery of the resource during the Cadia Hill drill out campaign in November 1996 to project implementation and plant operation. Current resource estimates stand at around 50 Mt with an average grade of 2.4 g/t gold and 0.8 per cent copper. At current processing rates the project life is expected to exceed ten years. The processing plant comprises a 9.75 m (32 ft) diameter Fully Autogenous (AG) mill, a single 6.7 m (22 ft) diameter ball mill, pebble crushers, gravity gold recovery circuit and flotation plant. Upgrades to the existing infrastructure and manning requirements at Cadia will be discussed as well as the resultant impacts on operating costs for the operation. The processing plant was expected to deliver 290 000 ounces of gold and 30 000 tonnes of copper in concentrate in its first full year of operation and progress against that goal will be presented.

Jan 1, 2003

By Ihor A. Kunasz

Introduction Lithium minerals occur predominantly in pegmatites which contain mineral assemblages derived from the crystallization of postmagmatic fluids or from the metasomatic action by residual pegmatitic fluids. They have been the traditional sources of raw materials for ceramic and chemical industries. With the discovery of Searles Lake, brines became new sources of lithium. Indeed, the 1960s may well be referred to as the "brine decade" because several brine bodies of significant economic importance were discovered. In the United States, the brines of Clayton Valley, Nevada, are presently exploited by Foote Mineral Co. The brines of the Great Salt Lake of Utah, the Smackover formation, and the Imperial Valley geothermal field, have been defined as important resources of lithium. In South America, new occurrences have been identified in Bolivia and Argentina. At the Salar de Atacama, Chile, new production capacity is scheduled for 1984. Following the termination of the AEC purchase program in 1959, several companies such as Maywood Chemical Co., American Lithium Chemicals, and Quebec Lithium Corp. were forced to close their operations. Nevertheless, with the development of new applications in glass ceramics, air conditioning systems, synthetic rubber, and metallurgy (aluminum potlines), the lithium industry grew steadily, and with the potential application of lithium metal in batteries and nuclear reactors, a healthy growth can be foreseen. New products and new applications are likely to stimulate exploration for expanded, reserves as well as the search for new sources from which lithium could be extracted economically. Geochemistry of Lithium Lithium is the third element in the periodic table. It is the lightest of all the metals, having an atomic weight of 6.938, an ionic radius of 0.68Å and a charge of +1. The geochemistry of lithium has been extensively studied and has been summarized by Rankama and Sahama (1950), Goldschmidt (1937), and Hortsman (1957). The distribution of lithium in igneous rocks is controlled by its size and its charge, and by the (MgO+FeO) / Li2O ratio. In the early stages of crystallization of a magma, that ratio is very large. Consequently, both magnesium and iron are removed by ferromagnesian minerals in preference to lithium which is then concentrated in the residual magma. This results in an enrichment of lithium in silicic rocks and pegmatites (Strock, 1936). Pegmatites are coarse-grained igneous rocks formed by the crystallization of postmagmatic fluids. Minerals within pegmatites may also form by metasomatism (Jahns, 1955). Genetically, the pegmatites are associated with neighboring intrusives. Mineralogically, granitic pegmatites contain feldspar, quartz, and mica as the main constituents and a variety of exotic elements such as lithium, beryllium, tantalum, tin, and cesium, which may or may not occur in economically significant concentrations. Detailed studies by numerous investigators (Cameron et al., 1949, 1954; Hanley et al., 1950; Jahns, 1953, 1955; Page et al., 1953) indicate that pegmatites often exhibit an internal zonal arrangement, with each zone containing a specific suite of minerals. The lithium minerals are usually found in the intermediate zones, and although as many as 13 zones have been recognized by Cameron, et al. (1949), a complete zonal arrangement is rarely found. Zoning of pegmatite bodies has also been observed on a regional basis. The regionally zoned pegmatite sequences exhibit mineral assemblages and complexity according to their re-

Jan 1, 1983

By P. W. Bridgman

IT is characteristic of most scientific investigators that they are not satisfied with the discovery of new facts, no matter how curious or unexpected, but that along with the factual discovery there is a constant effort to understand It appears that. one's interest in, and satisfaction with, the discovery of an array of news experimental facts is enormously increased if one has at the same time a theory or hypothesis guiding one's expectation of what sort of new experimental discovery may lie around the corner Conversely, as a theoretical physicist one's satisfaction with his theory is greatly enhanced if along with the development of the theory can go the discovery of new experimental facts, confirming or perhaps modifying the theory as it grows Of course, there have been long and stretches in the history of physics in which new data of unquestioned ultimate importance ham e piled up, without much inspiration or illumination in the way of understanding For 50 years spectroscopy had such an and history, but how irksome this was felt to be is plainly shown by the almost audible relief that greeted the first success by Bohr in injecting understanding into the situation, and by the fresh rush of experimenters into this field when the prospect of understanding had once been offered The investigations in the field of high pressure, which have occupied me for a long time,1 until the last few years have been in very much the Same sort of situation as spectroscopy before the advent of Bohr A great many kids, of data were collected for a great many solid and liquid substances, and there could be no question of the importance of these data, because the uniform change of dimensions produced by hydrostatic pressure is perhaps the simplest conceivable type of alteration to which a body can be subjected But except for a few isolated flashes, there was no theoretical illumination, so that it had to be to a large extent the enthusiasm of the collector that kept me going However, within the last few years the wave-mechanics theory of solids has progressed so rapidly that

Jan 1, 1938

"This contribution is concerned with adaptive processing decisions, where the process parameters are optimally adapted to the varying properties of the material input stream. Our starting point is the geometallurgical paradigm that the varying properties of the input stream are considered known e.g. from a geometallurgical model of the mined ore body, and optimal processing parameters are computed from them, by finding the parameter seaming optimal in a computer simulation.This approach however has to work with a lot of uncertainties: The prediction of the geometallurgical ore parameters can only be done with some geostatistical uncertainty. The parameters themselves are only proxies for true ore properties. Model prediction can differ relevantly from actual process results, due to model simplifications. Due to these uncertainties the computed processing choices can turn out to be inferior to simple non-adaptive processing. In this contribution we focus on the uncertainty of the ore properties and analyse this effect systematically, by modelling this uncertainty effect mathematically and in computer simulations. The most important findings are:(a) Processing choices not taking into account the uncertainty sometimes even perform worse than simple non-adaptive processing, for the sole reason of ignoring the uncertainty effect.(b) Ore properties, not adequately reflected in the ore description, might require different approaches, in which the observed processing behaviour feeds back into process control.(c) Bayesian decision theory allows computing optimal processing choices combining the information from the mine (geostatistical predictions) and from the process feedback. These choices give much more robust choices and do not suffer from the drawbacks described for the simple approach we started from.These new approaches can substantially improve the performance of adaptive processing in existing plants."

Jan 1, 2016

Expect Labrador Iron Ore Shipments by 1954 Iron ore shipments from the Quebec-Labrador area are a "definite expectation" by late summer, 1954, according to William H. Durrell, general manager of the Iron Ore Company of Canada. About $120 million have been invested in the project, with a total of $200 million expected to be reached before a ton of ore is shipped, Mr. Durrell said. According to the general manager approximately 418 million tons of open pit highgrade ore have been proven in the project. Deposits lie several hundred miles north of the mouth of the St. Lawrence River in territory which was without transportation of any kind. Construction of a railroad from Seven Islands to Knob Lake, about 360 miles, is an important part of the development plan. The railroad will be the first to adopt complete roller bearing applications. Construction is on schedule with 215 miles of the route graded. Completion involves two tunnels through rock, one of almost half mile length, a 700-ft bridge and several smaller spans.

Jan 3, 1953

By Harold J. Schock

This paper describes an experimental method for the monitoring of diesel-generated exhaust gas pollutants in a dead-ended drift for the purpose of assessing the effect of control approaches. Experiments were conducted to determine the relative merits of these ventilation configurations: no auxiliary ventilation, induction ventilation at the entrance to the drift, and ventilation of the dead-ended drift with positive displacement tubing. The drift used in this experimental work was approximately 105 ft. (32.0 mf long and slightly downsloping, with an average height and width of 8 ft. (2.4 m) and 28 ft. (8.5 m1 , respectively. The data were gathered for assessing these ventilation methods and for gathering data to support a computer model of the dispersion and mixing processes. For this drift, it was found that ventilation with positive displacement tubing provided the best removal of diesel-generated pollutants. Induction ventilation appeared to be the least effective of the three methods examined. A comparison was also made between personal monitoring and area monitoring. Results of this analysis showed that in regions of high concentration gradients, it was not possible to get good agreement between point sampling and personal monitoring. In well-mixed areas, good agreement between the two methods of monitoring was obtained.

Jan 1, 1980

By J. T. Kline

This paper will present a review of the underground leaching of remnant copper mineralization left as a result of the block cave mining operation at the Lakeshore Mine in Casa Grande, Arizona.

Jan 1, 1985