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By Fabio Terzi

In this investigation some preliminary results are reported about the electrochemical oxidation of CO using goldbased encapsulated nanoparticles grafted on conducting substrate. The investigation has been planned in four steps: 1. production of Au(111) substrate and modification with self assembled monolayers; 2. synthesis and embedding of nanoparticles; 3. grafting of encapsulated nanoparticles on electrode substrates; 4. investigation of CO electroxidation on the modified electrode. The systems were characterized by means of various techniques (spectroscopic, microscopic, and electrochemical methods), obtaining information about SAM's structure and morphology, size and composition of nanoparticles and electrochemical behavior of modified electrodes.

Oct 1, 2003

By Peter Middendorp, David J. Tara, Gerald E. Verbeek, Jan Fischer

"For pile driving simulation the model used must be accurate for the entire process, i.e. from the start of pile driving until the pile has reached its target depth. Of the various model components (hammer, pile and soil), the soil is the most difficult to characterize accurately. This is well known, but the aspect that is not as well understood (and therefore commonly misapplied) is the fact that the soil properties and thus the soil parameters do not remain constant during the pile driving process. Furthermore, this phenomenon of soil fatigue, mainly for skin friction, as a continual change of soil resistance during pile installation, is not implemented into all commonly applied pile driving simulation software and could therefore not be taken into consideration. In this paper the effect of soil fatigue will be described by numerous research results, showing that this effect will occur regardless. Different methods to consider the change of soil resistance during pile installation will be presented, some applying soil fatigue while others merely reduce soil resistances. Using currently available wave equation software that can take soil fatigue into consideration, the importance of doing so will be shown on the basis of the back calculation of a monopile installed offshore in Germany.THEORY BEHIND SOIL FATIGUESkin friction and toe resistanceTo simulate pile installation as accurately as possible, detailed geotechnical knowledge about the mechanical behavior of the soil surrounding the pile is necessary during each step of the installation process. Therefore, to ensure ""geo-mechanical correctness"" of a pile driving simulation, the shaft friction and the toe resistance have to be recalculated at each penetration level. For the skin friction parameters this is especially important since they change significantly during pile installation because of soil fatigue. Depending on the pile and soil type, the toe resistance can experience changes as well due to soil fatigue during to pile driving. However, in this paper the toe resistance values were kept constant over the entire penetration depth.In general, the unit skin friction can be derived from measured values (CPT, qs) or calculated as a function of the horizontal effective stresses dh acting perpendicular to the pile wall of a vertically driven pile. The horizontal stresses can then be converted into the unit skin friction qs using the Mohr-Coulomb failure criterion:"

Jan 1, 2017

By T. R. Ellis

"In August 2013, the Appraisal Practices Board of the U.S. Appraisal Foundation issued its “APB Valuation Advisory #4 - Identifying Comparable Properties,” which contains analysis and examples that may suggest a broader meaning of the term “comparable properties” than is current convention in real property value appraisal in the United States and internationally. The advisory is directed at the appraisal of real property of all kinds, including interests in mineral properties, as indicated by the inclusion of two mineral property appraisal papers in the appendix that lists suggestions for further reading.This paper firstly reviews as background the historical meaning of a comparable property, with its perceived constraints, against real-world examples of transacted mineral properties that are adjusted to subject properties to provide market value indications. The advisory’s findings are then examined and evaluated as to whether they may influence and benefit the work of mineral property appraisers, particularly in situations where their sales comparison analyses may be challenged. The conclusion is that the combination of constraints that the advisory’s findings specify for use of the term “comparable” will for mineral properties be met infrequently or rarely. As a result, mineral property appraisers are advised to avoid using the terms comparable or “comp” when referring to transactions of mineral properties that they analyze to derive data for appraising the value of their subject mineral properties. IntroductionA mineral property appraiser rarely finds a sale of a mineral property that meets the literal meaning of the term “comparable sale,” by being directly comparable to the subject property of the appraisal in all factors of significance in the determination of the value of the property interest being appraised. Real estate appraisers have long used a more liberal interpretation of the meaning of comparable sale and its commonly used abbreviation, “comp.” Real estate appraisers compare sales to their subject property on the basis of price per hectare or acre of land and price per square meter or square foot of building floor area. Adjustments totaling to within the range of +30 to -30 percent from the sale property to the subject, before factoring in the property area, have generally been viewed as appropriate for the sale to be considered a comparable sale."

May 1, 2016

By Christoph Zschiesche

Managing complex material streams within a lead smelting/reduction process has a long history at Aurubis. After modernization of the secondary lead smelter in 1991, Aurubis operates an electric furnace and a Peirce Smith converter to process complex secondary materials. This process links the copper and the lead metallurgy allowing Aurubis to properly combine primary and secondary process lines to optimize the processing of complex raw materials and smelter intermediates. However, combination of copper and lead metallurgy processing requires a continuous evaluation as raw material quality and composition varies. This paper describes Aurubis lead smelter processing and provides some fundamental considerations to optimize the lead processing, in particular with aspects related to speiss formation

By M. Manrique

Various pyrometallurgical methods for treating Ilmenite and Zircon concentrates are reviewed. Laboratory experiments, using a thermal plasma reactor, have been performed to evaluate: the conversion of ilmenite to TiC or TiC-Fe and the conversion of zircon to ZrC or ZrC-SiC. Results are examined and possible processing routes are identified.

Jan 1, 1996

By Causey J. Douglas

In 1988, at the request of the Bureau of land Management, the U.S. Bureau of Mines studied part of the 13,460-acre Owyhee Breaks Wilderness Study Area (OR-003-059) in order to evaluate its identified mineral resources. The study area is in Malheur County, OR, about 27 miles northwest of Jordan Valley. No mineral resources were identified in the study area during this investigation. There is an occurrence of jasper along Birch Creek and an associated occurrence of zeolite in some tuffs. In the northern part of the study area is an occurrence of bentonitic clay containing less than 40,000 tons. Much of the area is covered by landslide blocks, colluvium, earthflow deposits, and talus, composed of Tertiary-age volcanic rocks. The upper plateaus are capped by Tertiary-age basalt.

Jan 1, 1989

By G. B. Hudson

Previous papers (1, 2) pertaining to the treatment of uranium-bearing ores were concerned with the flotation of the radioactive minerals. In this investigation, the application of flotation to the removal of acid-consuming minerals from uranium ores was considered. Two pitchblende-bearing ores, which, because of the presence if dolomite were abnormally high acid consumers, were studied. In both in-stances commercial reagents of widely varying fatty acid composition proved satisfactory as flotation col-lectors, particularly at a pH of 10.5, for the carbonate minerals. From an economic viewpoint, however, Neo-Fat 42-12 was favoured. A mixture of sodium tripolyphosphate and citric acid was an effective depressant for the pitchblende in the ores. The tailings remaining after the removal of the dolomite by flotation contained, in one case, 88.5 per cent of the uranium in the original sample, and, in the other, 93.8 per cent. Analyses conducted on these tailings and on the original ores showed that

Jan 1, 1963

By E. McCullough, S. Gaillard

"Diesel particulate matter (DPM) has been regulated by the U.S. Mine Safety and Health Administration since 2002 in underground metal and nonmetal mines. To demonstrate regulatory compliance, DPM samples must be collected and later analyzed by the U.S. National Institute for Occupational Safety and Health (NIOSH) 5040 standard method, but the FLIR Airtec DPM monitor can serve as a complementary engineering tool. The monitor is a handheld instrument that offers near-real-time measurements of elemental carbon (EC), which is a primary constituent of DPM. As part of an ongoing field study, the monitor was used to survey EC in an underground stone mine. This effort was aimed at determining spatial and temporal DPM variations in several key locations. The results of prolonged area monitoring—that is, lasting several hours — revealed that DPM concentrations were diluted substantially as air moved away from the primary production zone, but that concentrations could vary quite a bit in a single location from day to day and between seasons. DPM concentrations were generally lower in winter than in summer, which is consistent with increased natural ventilation airflows during winter. Using a modified sampling cassette, an attempt was also made to sensitize the Airtec monitor to allow for “spot-checking” of EC concentrations — that is, measurements made in several minutes. Preliminary field data showed that the sensitive cassette performed well in terms of providing accurate data that could be useful for rapid assessment of DPM. IntroductionDiesel particulate matter (DPM) is the solid fraction of the exhaust emissions from a diesel engine. It largely consists of elemental carbon (EC) and organic carbon (OC) (Birch, 2003). The World Health Organization International Agency for Research on Cancer classified diesel exhaust, including DPM, as a carcinogen (World Health Organization, 2012). It is believed to cause and/or exacerbate respiratory illness upon inhalation, deposition and retention in lung tissue. Because DPM exists in both the micro- and nanoparticulate ranges, it can bypass typical autoimmune defense mechanisms that keep larger particles out of the respiratory system (Ristovski et al., 2012)."

Dec 1, 2016

By Sandra K. Zacharias

Brass, a deliberate alloy of copper and zinc, has been known since before Roman times. There are two main methods of making brass: (1) Cementation or calamine process - crushed zinc ore (calamine, ZnC03 , or calcined calamine, ZnO), is mixed with charcoal and small pieces of metallic copper and heated to about 900°C in a closed crucible, (2) Alloying - metallic copper and zinc are melted together in a reverberatory furnace. According to most modern authorities (e.g. Smith and Forbes 1955), the calamine process was the only one used in western Europe prior to the 18th century. At that time, the alloying technique began to take over, because metallic zinc was successfully produced on a large scale for the first time. Previously, this had been a problem because zinc vapourizes at 906°C or about the same temperature at which it can be reduced from its ore. Thus, some means had to be devised to collect and condense the zinc vapour (Tylecote 1976). Metallic zinc was known, however, earlier than the 18th century A.O. Several early finds have been made, including a rolled sheet of metallic zinc found in excavations at the Athens Agora dating to the 3rd to 2nd century B. C. (Farnsworth et al. 1949). The Chinese were producing zinc by at least the 10th century A. D. and, by the 17th century, Chinese zinc ingots were being imported into Europe by the Dutch East India Company (Needham 1974). Metallic zinc is also mentioned in several European documentary sources from the 16th century (e.g. Paracelsus, Agricola). This study traces the changes in Western brass making methods from Classical to Renaissance times by examining documentary and archaeological evidence.

Jan 1, 1999

By A. Liem, R. L. Johnson, C. Sturgess, E. Kuzub

New challenges in mineral processing arise as high-grade ores become less available and the mining industry is forced to exploit lower grade ores. One of the challenges in beneficiating lower grade ores is the liberation of mineral particles while maintaining control over material management. Lower grade ores need fine grinding to free valuable minerals, but finely divided particles can cause severe problems, such as dustiness and flowability, in subsequent stages of material management. There are at least two approaches that can be taken to resolve this dilemma, both of which relate to particle size enlargement. First, the application of a dust suppressant can be used to control that aspect of material management. The optimal choice of dust suppressant agent depends on effectiveness and cost, both of which can be strongly influenced by the selection of application method. Second, agglomeration combining small particles into larger units-can reduce dust and improve the flow characteristics of the material at the same time. There are several mechanisms that can be employed to agglomerate mineral materials. Although agglomeration adds a new processing step, it is often cost effective. This paper describes these two approaches and their respective challenges, as they relate to a mined ore. We report on modified or newly developed procedures for characterizing mineral ores with respect to material management. On the same material, we use agglomeration processing to capture fines within larger particles and show how dustiness and other aspects of material handling are affected. We conclude by discussing their specific application in accordance with the mineral properties and processing needs.

Jan 1, 2004

By Nick Hazen

Many successful actions are required to bring a profitable extractive metallurgical operation into production. Competent process development performed within the project development schedule increases the chances of obtaining project financing and decreases the risk of engineering design errors being built into the commercial plant. The general sequence of steps in process development is well known: technology review, desktop studies, scoping studies, prefeasibility, and so on, with an increasing requirement for experimental evidence as the studies advance. This paper suggests principles for guiding process development work so that the efforts stay on track toward a smooth startup and a profitable commercial operation. It emphasizes closely aligning the research with the corporate goals of the mining company management, understanding the mineralogy and variability in the deposit, and guiding by flowsheet and material balance. Examples of hydrometallurgical process development leading to the early use of solvent extraction in the mining industry are given.

Jan 1, 2014

By M. Bai

The influence of mining on the hydro-geomechanical environment is greatly constrained by alternating mining geometries. The limiting magnitudes of surface subsidence and groundwater flow over the mining area, as a result of geometry changes, can be reasonably predicted through a coupled finite-element model introduced in this paper. Verification of the model has been tested using real and conceptual case studies which reveal that changes in strata conductivities are strongly related to the strata deformation induced by mining. The greatest modification of hydraulic conductivities occurs within the caving or severely fractured zones. The study indicates that narrowing the panel face width will substantially reduce both the intensity and extent of mining damage to the overlying strata, limit surface subsidence and constrain the change in hydraulic conductivity to a reduced scale and smaller extent, particularly as mining depth increases.

Jan 1, 1993

By J. T. I. Poijärvi

Outokumpu Harjavalta Metals Oy operates copper and nickel smelters, three sulphuric acid plants and nickel refinery at Harjavalta and copper refinery and precious metal plant at Pori. The by-products of these plants are presented in this paper. The by-products of the smelters include products from slag cleaning of flash smelting furnaces and converters, flue dusts and smelter off-gases. Weak acid and sludges from cleaning of smelter off-gases and acids are the by-products of the acid plants. The by-products out of the copper refinery are crystallized metal sulphates and sludges from electrolyte purification, on which a co-production process of the copper tankhouse is based. The main by-products of the precious metals plant are products from anode slime treatment and platinum metal group concentrates in the recovery of precious metals. Sludges from nickel matte leaching and precipitates from solution purification are the by-products of the nickel refinery. The formation, treatment and processing as well as the research work done for the utilization instead of dumping of the by-products in the production of copper and nickel will also be discussed in this paper.

Jan 1, 1995

By Kotaro Ogura

"The electrolysis process in which CO2 is selectively reduced to C2H4 at a three-phase(gas/solution/metal) interface on a copper-mesh electrode has been developed in a concentrated solution of potassium halide. At open-circuit potential, CO2 is captured on the electrode by being inserted into the double-layer consisting of halide anions specifically adsorbed and potassium cations which are located in the Helmholtz inner and outer layers, respectively. CO2 thus activated is subjected to the electrochemical reduction. In the early stage of reduction, CO2 is converted to formate radicals that are adsorbed on the electrode by taking the place of halide anions. The reductive coupling of these radicals results in the formation of intermediates such as -CH2C(O)- and CH2=CH-, and C2H4 is finally produced. The catalytic activity of the electrode process involving the insertion of CO2 into the double layer is not deteriorated at all during the electrolysis, and the continuous reduction of CO2 to C2H4 is possible with the addition of inorganic acid under the assistance of natural energy.Carbon dioxide is a serious pollutant released from fossil fuel power station, internal combustion and many industrial operations. The easy release of CO2 to the air has caused the global warming, and the technique which intends to curtail CO2 by pushing it back into the ground has been suggested. However, this problem should be greatly mitigated if CO2 can be converted to innocuous substances. Especially, the reuse of CO2 as fuels and chemicals is extremely effective not only for the mitigation of the global warming but also against the depletion of the fossil fuel reserves. Several processes for converting CO2 to valuable compounds have been proposed including hydrogenation over heterogeneous catalyst at high temperature and electrochemical and photochemical reduction. In the conversion and cutback processes of CO2, however, it is of importance that the process is feasible under mild conditions, because the secondary generation of CO2 is feared if high energy is required and supplied with a fossil fuel. In this meaning, the electrochemical reduction of CO2 taking place at room temperature, which is similar to photosynthesis, is promising. From the practical point of view, it is further necessary that the conversion rate is high enough and the product is satisfactorily valuable."

Jan 1, 2008

By C. C. Clark, D. J. Benton, J. B. Seymour, L. A. Martin

"The U.S. National Institute for Occupational Safety and Health (NIOSH) is conducting research on jackleg use and related accidents in underground metal mines. This paper provides an analysis and overview of jackleg drill usage, accidents, operational characteristics and alternatives, based on information from injury reports, legacy research, stakeholder input and published literature. The results indicate that jackleg drills are involved in more groundfall accidents in underground metal mines than any other drill, and jackleg-drill-related injuries are most prevalent at the face in the course of installing initial ground support. Practical mechanized alternatives to jackleg drills for drilling and bolting under incomplete support in narrow underground openings have not yet been realized. Small, versatile mechanized bolting equipment needs to be developed to address jackleg-drill-related accidents and improve safety at mines where jackleg drills are being used. IntroductionJackleg drill is a generic name for a handheld, rotary, percussion rock drill equipped with an attached reaction leg to provide stability and thrust (Fig. 1). All of the drill and leg controls are located near the operator’s handle at the rear of the head portion of the drill. Jackleg drills are classified according to the bore size of their pneumatic pistons, which normally range from 6.03 to 8.26 cm (2.375 to 3.25 in.) (Kurt, 1982; Clark, 2012). Jackleg drills typically weigh 46.7 kg (103 lb), but the weight can approach 54.4 kg (120 lb) after being fitted for operation with drill steel and air and water hoses (McKibbin and Clark, 2001). In underground mines, jackleg drills are commonly used to drill 3.8-cm (1.5-in.) diameter holes up to 1.83 m (6 ft) deep in rock."

Aug 1, 2016

By John T. Berry, Robert D. Pehlke, Michael J. Beffel

"Pattern making and metal casting organizations are currently adopting CAD/CAM systems and implementing this technology in design and production. Al though significant progress has been reported, these systems generally are based on two or two and one half dimensional analyses. Very few are based on solid geometric modelers.The present paper emphasizes the need for solid geometric modeling of the casting and rigging system and linkage with a solidification simulator. The nature of some of the technological challenges which have slowed this development are discussed, including accurate description of complex surfaces and their intersections and the bridging of computer encoded information with NC technologies and with FEM-based simulators for stress and thermal analyses. A recently prepared modular-structured FEM simulation code implemented on a micro computer is described.Construction of a solid geometric model of the casting and rigging and validation of the combination for optimum characteristics of soundness, quality and yield by solidification simulation are I inked as key elements in the foundry of the future. Data base support for this CAD/CAM system is rapidly being developed throughout the world.INTRODUCTIONThe simulation of shaped casting solidification using the digital computer, goes back to at least the early nineteen-sixties when Forsund (1) in Denmark applied the technique to the problems of casting surface quality.Prior to that time, the work of Paschkis and co-workers using the analog computer ranges back to the nineteen-forties, when work sponsored by the AFS Heat Transfer Committee at Columbia University revealed many hitherto unknown or only partly anticipated aspects of casting solidification (2).Three reviews of the various historical aspects of simulation should be referenced. Firstly, the AFS monograph by one of the present writers (RDP) and his colleagues - describing background and later work, again sponsored by the AFS Heat Transfer Committee at the University of Michigan (3). Secondly, a review prepared by Durham and Berry (4) which discusses broad aspects of casting solidification simulation. Thirdly, a review by Erickson (5) which contains an excellent bibliography to 1980. In addition to these papers, the publications lists of the CADCAST project* and the proceedings of the two Engineering Foundation Conferences of Casting and Welding Modeling, published by ASME, are also most notable (6) •"

Jan 1, 1986

By J Jasper, L Koroznikova, J Begelhole

This paper outlines a comparison of heavy liquid and heavy suspension separation methods for iron ore characterisation.As part of Arrium MiningÆs program to improve its knowledge of ore types being processed in its two hematite ore beneficiation plants (OBP), metallurgical evaluation of hematite feed for the upgrading process has become a major focus.Iron ore deposits almost always contain more than one valuable (and relatively dense) iron mineral. Iron ores are found with a range of iron contents, giving rise to density variations.At present the industry relies on heavy liquid separation techniques for the evaluation of iron ore samples arising from exploration, mining or metallurgical processes. There are only a few high-density liquids available, which are both high-cost and highly toxic.Low-toxicity solutions that can be utilised at relative densities up to 3.0 have been developed. However, highly-toxic organic liquids are required presently to achieve relative densities beyond 3.0.Bromoform which has a specific gravity (SG) of 2.89, and diiodomethane (SG 3.31) are commonly used; both present significant health and safety hazards.æClericiÆs solutionÆ (mixtures of thallium formate and thallium malonate) provide liquids having specific gravities between 4.0 and 5.0. ClericiÆs solution is highly toxic and testing is currently conducted by a limited number of laboratories worldwide.An alternative to ClericiÆs solution and organic liquids is a low-toxicity, high-SG, suspension technique, which has been demonstrated successfully for heavy mineral sands. This heavy suspension method employs mixtures of fine tungsten carbide particles in lithium heteropolytungstate (LST) solutions.Heavy liquid separation is not commonly used as part of routine iron ore feed characterisation due to the expensive, toxic and time consuming nature of the technique. Our results show that the heavy suspensions method can achieve low-cost, low-toxic separation and are outlined and results compared with results using ClericiÆs solution presented.Heavy suspension technique provides a theoretical/absolute separation of a particular sample. By placing an iron ore sample in a suspension of a particular density, it produces two products: a sink fraction and a float fraction. As iron oxides-hydroxyoxides are denser than the gangue minerals associated with the ore, particles that have high iron content will sink and the particles with gangue association will float. This process is repeated over several densities, thus also enabling separation of the constituent iron ore phases. A theoretical grade and a theoretical mass recovery can be calculated. With these calculations, a grade-mass recovery curve can be constructed for any element that is of interest.This type of characterisation can be used to either prepare OBP feed-piles of known processing characteristics, or to benchmark the performance of the process against what can be theoretically achieved on a continuous basis.CITATION:Begelhole, J, Jasper, J and Koroznikova, L, 2013. Application of the heavy suspension technique for ore beneficiation plant feed characterisation from the Southern Middleback Ranges, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 269-278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By M. Rafieazad, P. Fathi, X. Duan, M. Mohammadi, A. M. Nasiri

"Direct metal laser sintering (DMLS) is a metal additive manufacturing technology that creates highly complex components by fusing metal powder into a solid part. In this study, the impact of surface roughness on corrosion resistivity of AlSi10Mg_200C alloy manufactured through DMLS was investigated. The as-printed DMLS-AlSi10Mg _200C alloy was subjected to various surface finishing processes including grinding and sandblasting. The corrosion performance of the surfaces was then evaluated using potentiodynamic polarization testing and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution to mimic seawater environment. Surface characterization and corrosion morphology of the samples were assessed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy. The results of this study show that the surface finishing process and the resultant surface roughness has a significant impact on the corrosion resistivity of the DMLS-AlSi10Mg_200C alloy in the seawater environment.INTRODUCTION Direct Metal Laser Sintering (DMLS), also known as Selective Laser Melting (SLM) (Sames, List, Pannala, Dehoff, & Babu, 2016), Laser Beam Melting (LBM), or Laser Metal Fusion (LMF) (Herzog, Seyda, Wycisk, & Emmelmann, 2016), is an additive manufacturing process that utilizes a precise, high-power laser to micro-join powdered metals and alloys layer by layer to form almost fully dense and functional components in three dimensions from the 3D computer-aided design (CAD) data. Complex geometries not possible with conventional manufacturing processes can be readily manufactured with high accuracy using the DMLS process with no need to time-consuming tooling."

Jan 1, 2018

By C. Carrasco

"Over the last 30 years the average grade of mined ore bodies has significantly decreased while the proportion of waste removal has in many cases more than doubled. This has been identified as prime reason of a major increase in energy consumption and decrease in productivity across mining operation. Metal coarse preconcentration of ROM feed grades by size rejects low grade gangue/waste material in the size range of 10-100 mm prior to grinding, typically before primary crushing. This relies on propensity of metal to preferentially deport in the fine size fractions after breakage. Metal preconcentration by size has the potential to increase energy efficiency and therefore improve mining productivity on unit of metal basis. Results of an extensive belt cut sampling campaign conducted at a major Australian Au-Cu mine operation show that for some samples between 90% of Au and 80% of Cu is in 40% of the mass at -50 mm fraction. This indicates that low grade coarse material can be removed from the circuit, doubling feed grade at half of the tonnage and therefore improve energy efficiency per unit metal produced. This response, however presents significant variability in the same order as other processing attributes such as impact hardness and flotation recovery. This has led to development of geometallurgical laboratory tests using blast hole chips and drill core facilitating mapping and population of coarse metal preconcentration signatures in long term resources and short term production models. Preferential Cu deportment by size at drilling scale can be recognised, however scales up factors are required to transform laboratory results to production responses. At 50 % of mass the drilling products underestimate the belt cut responses by 20-30 %. Bulk sampling campaign with blast hole and drill core samples spatially related was also conducted to investigate in more detail the difference between production scale and drilling scale preconcentration responses."

Jan 1, 2014

By Westwater, J. S.

The Mather mine of The Negaunee Mine Co. embraces nearly all of Sections 1 and 2, T47N, R27W. within the limits of the cities of Negaunee and Ishpeming on the Marquette iron range of Michigan's Upper Peninsula. Operations of the Negaunee Mine Co., the stock of which is jointly owned by Bethlehem Steel Co. and The Cleveland-Cliffs Iron Co., are under the direction of the latter company. The opening of the Mather mine was described by C. W. A1len. Mather "A" shaft was completed to an initial depth of 2352 ft in early 1943. The shaft capacity of over one million tons yearly is in prospect of being realized by orderly development and mining, and sinking of the second or "B" shaft then started in accordance with previous planning. Mather " B, " also a vertical shaft, was designed as a twin to Mather "A" shaft and the sinking technique developed at Mather "A" was utilized in "B" shaft operation.

Jan 1, 1949