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By V Yadi

Geostatistics has been widely used for more than four decades as a powerful tool in ore resource/reserve estimates and grade control. This method has gradually replaced the conventional method such as polygon and cross-section for grade estimation by more mathematical techniques such as kriging. The advances in geostatistical understanding and the availability of appropriate software packages have given much more contribution in speed and high accuracy during production. However, in many cases, these techniques are sometime applied without support with a good thorough understanding of the geological controls on metal distribution. To produce the result close to actual, the geological control in interpretation and appropriate geostatistical task is a must. Geological logging was described in the core must be consistent with the level plan produced by commercial modelling software used as a guide for grade control during production. Experience gained through evaluation of the Central I deposit resulted that the most effective systems continue to be based on geostatistical methods of resource estimation. Computer applications modelling software packages are necessarily as the core of an efficient in undertaking these assignments. They contribute to make a valued to data management and are becoming increasingly effective during processing. The latter role is particularly important to check the actual versus estimated values where will significantly to improve personnel to have a confident with their knowledge combined with experience and complete their jobs satisfy.

Aug 22, 2011

By Weiran Zuo, Jinsheng Guo, Chun Yu, Jinyu Zhan, Bao Guo

High-precision prediction of the target minerals’ content in the feed and concentrate products is vitally important for the efficient beneficiation of mineral resources. Visible and near-infrared (NIR) spectroscopy provides a cost-effective way for online measurement of the mineral content in an industrial process. In this investigation, simulated specimens consisting of five different types of minerals that are present in the copper oxide ore, malachite, quartz, calcite, hematite, and chlorite were prepared with a variety of malachite contents, and the mixed specimens were analyzed by a visible-NIR spectrometer in an integral sphere mode. The reflectance spectrum is used as input and the malachite content as output to build the prediction model. The obtained data was modeled by support vector machines (SVM), and a Grey Wolf Optimization (GWO) is proposed with the goal of improving the prediction accuracy. The GWO algorithm has been applied to adaptively search for the best combination of featured values. After cyclic comparison, the optimal penalty factors c and g can be quickly and accurately selected. The experimental results show that the SVM model established by the GWO algorithm has a better fitting effect and smaller prediction error, compared with other models.

Aug 3, 2023

By D. Harrington

In this period of generally increasing taxes of various kinds, one hears less complaint by mining companies about the high cost of workmen's accident compensation than was the case a few years ago, the reason perhaps being that other and more pressing phases of the tax problem now over shadow the heavy expenditures for compensation premiums which a few years ago were considered a severe burden on the mining industry. Nevertheless, the financial expenditures of the mining industry in higher compensation benefits and hospitalization or in higher premium rates, or both, instead of being less have actually increased in many States in the past year. In the spring of 1937, proposals for increased benefits to injured employees in compensation, hospitalization, or medical aid were actively before legislatures in California, Connecticut, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Massachusetts, Michigan, Minnesota, New Mexico, Oregon, Pennsylvania, South Carolina, Texas, Utah, Washington, Wyoming, and possibly other States. In some cases, the proposed increases in benefits were so much greater than expenditures for similar items in the past that premium rates per $100 of payroll would almost certainly rise sharply. At this same time, occupational-disease-compensation coverage also was under consideration by legislatures in Arkansas, California, Delaware, Idaho, Indiana, Kansas, Massachusetts, Michigan, Minnesota, Montana, Nebraska, New Jersey, Ohio, Pennsylvania, Tennessee, Utah, and Washington. Sooner or later (and probably within the next few years) occupational-disease compensation will be accorded practically as wide recognition as accident compensation receives at present, and, unquestionably, mining in all of its branches will be affected more or less drastically. Hence, the present outlook is that the mining industry, in company with practically all other industrial activities, will be confronted by materially higher compensation costs than those of the past or the present, to which rather violent exception has been taken, at least in some States and at some times.

Jan 1, 1938

By Pedro E. Rengifo

Splicing methods have undergone considerable developments over the last 2Oyears. Continuous conveyor belt service is dependent entirely on the strength and life of the splice to hold the two ends together. Ultimately, belting performance is dependent on the quality, efficiency, and technique of the splicer. As customers demand better belting performance and running tensions increase, the need for splices that perform as efficiently as the belting has increased also. Higher dynamic belt constructions have also dictated the need for "new"sp1icing techniques. Regardless of the belt type used or spliced, one item that is most necessary with all belt types is the quality of the workmanship and standardized splicing methods that employ all of the necessary elements required to ensure reliable field service. This paper will explore the use of Goodyear-issued internal standards for field splicing following the constraints of quality and efficiency for fabric and steel cord reinforced belting. Also included are the 10 most common mistakes made by splicers, Goodyear-issued Field Quality Assurance Standards, and check lists for end users to adhere to the manufacturers' requirements for splicing including materials and specifications for conveyor belt splicing and repairs.

Jan 1, 2004

By J. H. E. Jeffes, K. T. Jacob

The activity coefficients of oxygen in liquid Pb-Sn alloys have been measured between 550 and 1100°C by use of solid oxide galvanic cells: Pt, Ni-NiO | Zr02 Solid electrolyte | O (Pb + Sn), Cermet, Pt; and Pt, Fe-FeO | Zr02 Solid electrolyte | 0(Pb + Sn), Cermet, Pt. Alcock and Richardson's quasi-chemical equation, with the coordination number of atoms set to 2, is found to predict successfully the activity coefficients of oxygen in these alloys. The relative partial molar enthalpy and entropy of oxygen at 1 atom per cent in the alloys have been calculated from the variation of the activity coefficient with temperature. The addition of Sn to an unsaturated solution of O in Pb is shown to decrease significantly both the partial molar enthalpy and entropy of O. As the measurements were restricted to a narrow range between 750 and 1100°C in Pb-rich alloys, however, the pronounced variation of the partial molar enthalpy of O with temperature at constant alloy composition predicted by the quasi-chemical model could not be verified.

Dec 1, 1971

By Martin J. Gavin

"Before discussing oil shales it may be well to consider briefly the conditions surrounding the petroleum industry in the United States, because these largely explain why so much interest is being manifested in oil shales. The United States is not only the greatest producer of petroleum in the world, its output amounting to about 65 per cent of the world's total production; but is also the world's greatest consumer, using more petroleum than it produces within its own borders. For the past four or five years it has been necessary to import oil at a continually increasing rate to make up the deficit between domestic production and domestic consumption. Experts who have made a close study of the future supply and demand for, crude petroleum are satisfied that under present production practice and with the development of possible undeveloped productive areas, the gap between domestic consumption and production will steadily .increase.As possible solutions for the impending domestic shortage of oil, various expedients are receiving attention. These may be grouped under three heads, as follows:(1) Temporary measures, such as curtailment of consumption, development of more efficient methods of production, and more efficient utilization of supplies of petroleum still available. It is unlikely that there will be any great curtailment in consumption of petroleum in the United States; rather, consumption will continue to increase unless a real shortage of oil actually forces curtailment of consumption. The other two possibilities mentioned deserve, and are resolving, serious thought. Much experimental work along these lines, some of which has already yielded excellent results, is being done. Obviously, however, any of these remedies are temporary ones only, so far as regards domestic production of petroleum."

Oct 1, 1920

By Jacob Schoder

This is one of a series of papers published by the Bureau of Mines on mining and milling methods and costs. The Tennessee-Schuylkill Corporation, Chloride, Ariz., mines and mills a lead-zinc ore containing gold, silver, and a small amount of copper. The mill products are lead and zinc concentrates that are shipped to smelters. The company was the second largest producer of lead and zinc in Arizona in 1937 and was seventh in gold production. Operations discussed are those being conducted at the mine in October 1938 and are representative of the complete operating period from 1936 to date.

Jan 1, 1939

By J. Pereyra, M. DeMarco

"INTRODUCTION It can be vital that bolted joints holding subassemblies together remain secure. Bolts should resist the loosening effects of vibrations and dynamic loads yet need to be easily removable during maintenance. When a threaded fastener is subjected to vibration, the rapid movement causes a lowering of friction against the threads and a subsequent loss of preload. The loss of preload allows the fastener to vibrate loose and possibly fall out. As the diameter of fasteners increase desired preload becomes increasingly more difficult to achieve. Input torque requirements for achieving proper bolt preload is exponentially related to any given fasteners diameter. This means that specialized tooling or bolting practices are usually required to attempt the tightening of fasteners to reach their required preload. Traditional methods can cause problems with joint integrity and do not provide consistent bolt load across the bolted surface. BOLTED CONNECTIONS A failed critical bolted joint can lead to high maintenance costs, machine downtime, and risk to worker safety. Control of the clamp load in a bolted joint is vital. However, when faced with a problem joint, it is not surprising that the design engineer will not have an answer if asked about the clamp load. Torque calculations must always be based on the existing conditions that often are vague. Unless all parameters are correct, the calculation will be unreliable. Examples of parameters are: • Thread condition of the fasteners • Hardness of contact surface • Material (steel, aluminium, copper, etc.) • Extra friction from a locking fastener • Extra friction from an adhesive • Lubricant on the thread • Type of bolt head (flanged, regular or serrated) • Surface coating of the bolt • New or reused fastener During tightening, bolts are subjected to both tensile and torsional stress. The total stress in a bolt can be calculated using the formula: Total stress = vsx2 + 3txy2 In order to maximize the desired tensile stress (sx) it is vital to minimize the torsional stress (txy). Tensile stress (clamp load) is achieved when the bolt is axially elongated. Unwanted torsional stress (twisting) in bolts arises during tightening due to thread friction. High thread friction increases torsional stress and causes yielding at lower clamp load levels than normal. A lubricant is necessary to minimize the malign torsional stress. However, many commonly used bolt-locking systems are based on increased thread friction (deformed nuts, adhesives, etc). To minimize thread friction and concurrently safely secure the joint has often incorrectly been considered impossible. The use of locking systems that increase thread friction is the single most common reason why the full capacity of bolted joints is not utilized. The following example illustrates the problem."

Jan 1, 2015

By A N. Danoucaras, S E. Goater, D Hearne, A M. Bansuan

It is globally recognised that existing and emerging mining activities should be conducted in a æsustainableÆ manner for the entire life of mine. Many companies annually publish corporate sustainability reports to demonstrate their actions in accordance with international expectations. This concept of sustainable mining practices also applies to mine water management, with influences often extending beyond site operations, affecting surrounding catchments and community users. This paper explores differences in conceptual and operational terms of æsustainableÆ mine water management within the Philippines. Outcomes of a review of corporate sustainability reports, governance documentation, research programs, and stakeholder knowledge acquired through action-research workshops are presented. The paper aims to inform and support future capacity building exercises delivered by the International Mining for Development Centre (IM4DC), with outcomes tailored to government officials and policy makers of developing countries. The project is funded by IM4DC, which is working with AusAID to identify needs and develop capacity with regard to mining for development; specifically, issues pertaining to governance and regulation, social and environmental sustainability, and operational effectiveness in developing countries.CITATION:Bansuan, A M, Goater, S E, Danoucaras, A N and Hearne, D, 2012. Integrated sustainable water management in mining for development in the Philippines, in Proceedings International Mine Management 2012, pp 205-226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By G. Morin, G. Marin, M. C. Parr, J. Carignan

"Investment casting offers many advantages for the near net shape production of complex geometries, however, molten titanium reacts with most of the refractories used in investment casting shelling systems, which leads to the formation of an oxygen contaminated surface layer. This layer, called alpha case, is 0.1 to 0.6 millimeters in thickness according to the casting section size and must be removed either by mechanical or chemical milling processes. Alpha case removal processes affect casting tolerances and may contaminate the part intended for medical applications (e.g. embedding of abrasive grit media in the alloy). A shelling system based on an yttria prime slurry has been developed and was found to almost suppress the mold metal reaction. Yttria is an expensive refractory, but slurry life was found acceptable for small castings using a closed container and flow coating process instead of conventional pattern dipping. Alpha case depth has been determined for Ti6Al4V by metallographic techniques and microhardness measurements on different step block casting cross sections. Alumina and yttria second prime stuccos were evaluated in this study. The shelling system minimizes finishing operations in the production of casting for medical applications.INTRODUCTIONTitanium investment castings have been in the commercial market since the beginning of the titanium era in the mid 50’s. Investment casting is a cost effective way to produce complex parts for medical, aerospace and chemical processes applications. Investment casting of titanium is difficult due to the high reactivity of titanium with air and refractories used for shell mold building especially for the face coat. Melting is done under vacuum and no shelling system has been proven effective to suppress the mold-metal reaction yet. The main issue with the mold-metal reaction is the formation of an oxygen enriched zone at the surface of the castings named alpha case (Frueh et al., 1997; Kim, 2002; Saha, 1986). The alpha case is brittle, reduce the fatigue life in service of the parts and must be removed by chemical milling.For industrial purposes, calcia partially stabilized zirconia based slurries have become widely used in titanium investment casting for primary coats due to a combination of limited metal shell reaction. Calcia stabilized zirconia slurries have an acceptable shelf life and offer an interesting production window. Our experience shows that a resulting alpha case depth is 280 micrometers for a casting section of 6.35 mm in thickness is typical with such a shelling system (Morin, 2013)."

Jan 1, 2016

By A. D. Marcy

The Midnite Mine is an inactive, hard-rock uranium mine in Stevens County, WA. Oxidation of sulfide-containing minerals, primarily pyrite, in the ore body produces large quantities of acidic water. An interception system installed by the mining company limits the discharge of contaminated water from the mine. The U.S. Bureau of Indian Affairs (BIA) and the U.S. Bureau of Land Management (BLM) have been actively involved in planning remediation of the disturbed areas. To assist in remediation, the U.S. Bureau of Mines (USBM) initiated research to determine water quality and to define ground water flow characteristics. USBM personnel designed a monitoring network, supervised installation of sampling wells, and collected and analyzed water samples. This Report of Investigations describes interpretation of data collected between December 1989 and April 1992. The computer program WATEQ4F was used to identify aqueous species distribution and to calculate potential solid phase controls of solubility. To assist in interpretation of changes in water quality between sampling locations and to develop models describing proposed flow paths, the computer program BALANCE was used. Using output from these programs and field observations, a description of the chemistry along proposed ground water flow paths at the mine is presented.

Jan 1, 2010

By Zay Jeffries

From the title of this chapter the reader could expect an attempt to out- line the anticipated shape of things to come, mineralwise. We have no crystal ball and if we possessed one we could claim no expertness in its use. In the first place no one can tell the future status of man. No one has any way of knowing to what extent peace will prevail, nor to what extent changes may occur in national sovereignties or forms of government or in international relationships. So future man is an uncertainty. Nor can we predict new developments that may result in significant changes in man's status or in the mineral industry or both. If, for example, this chapter had been written in the middle 1930's, nearly everything that has happened since in the fields of atomic energy and space technology would have been missed. Yet what vast changes these I have made in the status of man! Also the changes in the mineral industry have been important. A writer would have been bold indeed had he prophesied that uranium would play such an important role. But we need not confine our foggy vision to these fields. The steep rise in the use of aluminum, titanium, and germanium reflects the unpredictable in what may be thought of as the more normal pursuits. This should not discourage one from using the past and currently observable trends as bases for limited predictions. To do this, however, it is desirable to make certain assumptions about man's status without pretense that these assumptions have a high probability of fulfillment: 1. Only minor changes will occur in the geographical boundaries of the nations of the world. 2. World War III will not take place in the near future. 3. As a consequence of (2), man will not destroy himself by wanton use of atomic weapons. 4. Disarmament will take place, if at all, gradually rather than all at one time. Under the above assumptions the world will enjoy a period of relative peace even though the status may be one of an armed truce. The assump-

Jan 1, 1964

By K Ehrig, C Lower, V Liebezeit, M Smith, E Macmillan

"Minerals, minerals, minerals. Elements occur in the earth as minerals. If local physical, chemical and structural conditions are conducive to concentrating these minerals to sufficiently high abundances in the earth’s crust, a mineral deposit will form. If technology is available to extract metals from the minerals economically, then you have a mineral resource that will be mined and processed. Determining which minerals are present and quantifying their abundances, textural characteristics (grain size and shape) and how they are intergrown with each other is the realm of the mineralogist. Geologists use this mineralogical data to understand how the mineral deposit formed, how to find high-grade zones within the deposit and where to find other mineral deposits. Metallurgists use this data to design, operate and optimise processing facilities to extract metals from the minerals. The types, quantity and precision/resolution of the mineralogical data required by geologists and metallurgists are different, but are not mutually exclusive of each other. Fortunately, measurement technology is available that is relatively rapid, high volume and low cost, thus enabling ore and gangue mineral characterisation at a historically unprecedented scale of a mineral resource.CITATION:Ehrig, K, Liebezeit, V, Smith, M, Macmillan, E and Lower, C, 2014. Geologists and the value chain – how material characterisation by modern mineralogy can optimise design and operation of processing facilities, in Proceedings Ninth International Mining Geology Conference 2014, pp 5–14 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By Martial P. Corriveau

The preparation of coal is essentially the same for export as it is for the domestic market. The big difference, I would say, is that, while coal for certain domestic uses (utilities, for instance) need not always be of the highest quality, as long as it is uniform, the buyer of coal for export invariably demands a well-prepared, top-quality product. And he is willing to pay for it, as long as he knows what he is buying. This is where quality control enters the picture. The day is long past since the export market was the dumping ground for coals which could not be sold on the domestic market. Today, the export buyer wants American coals not so much for a price but for the necessity of blending the American coals with foreign coals to achieve the desired chemical and/or physical characteristics, To blend intelligently, he must know in detail what are the qualities of the coals to be blended. Sampling and chemical analysis facilities at the piers provide the information on the coals exported, These facilities are maintained for the export buyer by independent laboratories; however, in one instance, the buyer operates his own laboratory. With very few exceptions, and Clinchfield?s Moss No. 3 mid-volatile coal is one, cargoes shipped overseas are loaded as blends of two or more coals. Up to now, foreign requirements have not been too clearly defined; therefore, shippers must be prepared to blend mixtures of the desired combination. Successful blending requires an accurate knowledge of the coals shipped. And this makes it necessary for the coal producer to maintain his own control laboratory.

Jan 1, 1959

By Martti E. Maliniemi

The Svappavaara mine is located 47 km southeast of Kiruna C. The ore deposit now being worked, Leveäniemi, belongs to Luossavaara- Kiirunavaara AB (LKAB) and is the company's, and also Sweden's, third biggest mine after Kiirunavaara and Malmberget. The distance by rail to the Norwegian port of Narvik is 214 km and to Lulei on the Gulf of Bothnia 340 km (Fig. 1). The village of Svappavaara has about 800 inhabitants. The climate is arctic in character. The temperature during the months of December to February is about -20º to -35ºC, and the ground is covered by a blanket of snow for about eight months of the year. The brief, intensive summer often arrives with startling speed, bringing both sunshine and warmth. HISTORICAL BACKGROUND Mining operations took place in Svappavaara as far back as 300 years ago. During the period 1655-1684, copper ore was taken from the deposit called Gruvberget in the vicinity of the village. The total production of raw copper was probably about 1,045 tons. During the 18th and 19th centuries, several attempts were made to extract iron ore from the numerous deposits found within the district. These brave attempts, however, were foiled by the high phosphorus contents and the enormous transport difficulties. The present-day mine fields in Leveäniemi were discovered in 1897. At that time, it was difficult to determine the size and value of the deposit because of the thickness of the soil cover (3 to 15 m) and the

Jan 1, 1969

By C. R. Dale

IT IS the purpose of this paper to point out a number of the most common causes of crooked holes; to outline methods of drilling and straightening which to my personal knowledge have proved successful in numerous cases; to describe some of the characteristics of holes which, though not crooked in an exaggerated sense, may still cause serious mechanical trouble if not recognized and properly remedied; and to define clearly the part of oil-well surveying in the concerted effort operators generally are making to keep their wells straight from spudding to completion

Jan 1, 1931

By F. E. Joyce

The Bureau of Mines studied copper-nickel minerals (mainly sulfides) of the Duluth Gabbro Complex in north-eastern Minnesota to determine their response to selective high-temperature sulfatization techniques. The gabbro, containing 0.44 percent copper and 0.13 percent nickel, was ground to minus 325 mesh and sulfatized in a heated, rotating, stainless steel bench-scale retort. Tests demonstrated that over 95 percent of the copper and 80 percent of the nickel can be converted to water-soluble sulfates, depending upon the roasting conditions employed. Yield equations were developed using regression analysis for predicting the extraction of copper and nickel between the temperature limits of 520° to 670° C, the roasting time limits of 3 to 7 hours, and S02 limits of 10 to 40 percent in S02-air mixtures.

Jan 1, 1971

By E. J. Karges

The use of pulverized coal for generating power and performing industrial processes has made an important contribution to our industrial economy during the past half century. Actually, the burning of coal in powdered form is a subject that has held the attention of engineers for a century or longer. Its widespread use, however, is comparatively recent, As early as 1866 patents were granted to Messrs. Whelpley and Storer for a method of feeding pulverized coal into a furnace as an auxiliary to the grate fuel. In the many tests made during the subsequent years with various kinds of apparatus, the experimenters were handicapped in not getting the coal fine enough to obtain complete combustion and to prevent excessive formation of slag.

Jan 1, 1965

By A. C. Hnatyshyn

INTRODUCTION THOSE concerned with coal mining operations in Alberta have been asked repeatedly the same question, "Why is mechanization in Alberta proceeding so slowly as to lag far behind the mines in the United States?" This question is often asked in such a manner as to indicate that a severe reprimand is overdue to the mining engineers of this Province for their apparent indifference to the problem of improving their mining operations by increased mechanization. To the average person, unacquainted with mining conditions and problems, mechanization appears to be simply a matter of introducing equipment to load coal underground and, once this is done, substantial economies in operating costs will automatically follow. Invariably, those who have followed this simple reasoning have found, to their regret, that such is not the case and that effective mechanization involves something more than the mere process of introducing loading equipment into a mine. To be effective, any programme of mechanization must take into consideration all operations incidental to the mining, transportation, and handling of the coal from the working face to the tipple, and must utilize equipment which can be best adapted to any peculiar condition or circumstance prevailing in the mine concerned. In the use of such equipment, the net and final result should be an improvement in operating costs of sufficient magnitude to at least return to the operator, over a specific period of years or during the expected life of that equipment, all his investment plus a fair return on that investment.

Jan 1, 1951

By I. Ruiz Bustinza, L. F. Verdeja, Daniel Sbarbaro, R. Parra, J. Mochón

The oxidation of sulfides is a complex process involving gaseous products and intermediate species given rise to emission and absorption spectra which carry out important information about the reaction process. This information could be used for on line monitoring of pyrometallurgical reactor if the appropriate sensors were available. We present in this paper an analysis of the concept that has been successfully applied in iron and steel making industry, as well on fuel combustion control, where the spectra measurement gives the possibility for online monitoring and automatic control of high temperature processes. This concept has not been widely applied in the nonferrous pyrometallurgical primary production. The design of new sensors is discussed from the analysis of spectra measurements during flash combustion of copper concentrates at laboratory scale.

Jan 1, 2015