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By A. L. Mular

Introduction The cost of grinding may be divided into a fixed equipment cost portion and an operating cost portion. The fixed equipment cost is the amount of money required to purchase the grinding mill itself. This amount may be kept separate from the installation cost which, often, is taken as a percentage of the fixed equipment cost. A good average is 43%; therefore a $100,000 ball mill would cost approxi¬mately $143,000 installed. Operating costs are variable and paid per unit time for power, liner replacement, grinding charge replenishment, labor, and mainte¬nance including major parts replacement. Such costs depend on the geographical location and will vary with the cost of labor. Operating costs are difficult to estimate. Most mining companies consider such information proprietary. This section provides a means to obtain an estimate of the equip¬ment cost of a grinding mill with a rated accuracy of±l0%. Compara¬ble methods to determine operating costs are not available. Such costs are presented in table form with suggestions for updating them. Esti¬mating the cost of liners and steel replacement is possible as described in a later section. Capital Costs of Grinding Mills Grinding mill costs have been related,124 by means of equations and corresponding graphs, to the nominal horsepower requirements of mills. All graphs are based on a Marshall and Stevens cost index for Mining and Milling of 300, where a cost index is a ratio used to estimate current prices of equipment from obsolete prices. Where (Cost Index Now) Cost Now = (Cost Then) (Cost Index Then) (I) For example, the cost of an autogenous mill that requires a 3000¬hp motor is estimated as $500,000 (Fig. 95). This was the estimated price when the M&S (Marshall and Stevens, Mining and Milling) cost index had a value of 300. If the index is currently at 400, then the estimated current price of the autogenous mill is: Cost Now = ($500,000) (400) (300) = $667,000 Most professional journals will publish current values of cost indices at least once a month. In subsequent pages, each graph of grinding mill cost vs. mill horsepower has an associated graph of capacity vs. horsepower along with a table that relates mill size to horsepower. The associated graph and the table must be used with caution, since both apply to an average ore under average conditions. Example calculations showing how graphs should be used are shown in the following. It should be stressed that the cost data incorporated herein ex¬cludes the cost of pumps, motors, lines, and classifiers, unless other¬wise stated. Costs are not direct quotes; they are the averages of quotes supplied by manufacturers and analyzed by means of regression analysis. Example 1. Calculate the power required to grind 100 tons of dry solids per hour (in a closed circuit with a classifier) when the

Jan 1, 1985

By William E. Foreman

Editor's Note: For purposes of uniformity throughout this book, Coal Preparation, 5th Edition, the editors have advocated the use of the U.S.A. Sieve Series of testing sieves (see Table 6-2) as the testing sieves of modem choice. The adoption and use of the U.S.A. Sieve Series and its forerunner, the Tyler Standard Screen Scale, has for over seventy-five years introduced uniformity into reports; has simplified the comparison of results; and has provided control for operation of modem coal preparation circuits. While a full explanation of the differences, and more importantly the similarities of these two measuring systems cannot be stated here, it is felt that a brief clarification of terms is in order. The difference between the U.S.A. Sieve Series and the Tyler Standard Screen Scale Sieve Series is the identification method. Tyler Screen Scale sieves are identified by mesh designation with the width of opening varying by the square root of two, or 1.414 times the width of opening in the previous sieve. The U.S.A. Sieves are identified by openings in millimeters or microns and also arbitrary numbers which do not necessarily mean the mesh count; this series uses width of opening variations in the order of approximately the ratio of the fourth root of two, or 1.189. Tyler Standard Screen Scale and U.S.A. Sieves can be used interchangeably, and to avoid confusion the nameplate of all Tyler Screen Scale sieves show the U.S.A. Number, while all U.S.A. Sieves show Tyler Screen Scale mesh equivalent numbers on the nameplate. INTRODUCTION Sizing is the process of separating mixed mineral particles into groups of particles all of the same size, or into groups in which all particles range between definite maximum and minimum sizes. This chapter applies the modem mechanical screen and the liquid-solid cyclone (hydrocyclone) to the process of sizing solid particles as applied to coal preparation. Screening is a mechanical process that separates particles by size. Modem coal preparation is made possible by efficient sizing. Sizing of coal is defined in terms of the opening through which an individual particle will or will not pass, or as two openings, the larger of which passes the particle and the smaller of which retains the particle. Screening accomplishes sizing by passing coal of a wide range of sizes through a series of screens, each of a decreasing size. The individual screen discharges are then directed into different screen products for subsequent sale or processing. Screening in modem preparation plants is done for the following reasons: 1. Removal of fine coal before a size reduction step. 2. Size separation of the coal into a coarse and fine fraction for sized products or for processing in coarse and fine coal circuits. 3. Recovery of heavy media from heavy media coal cleaning circuits.

Jan 1, 1991

By Liming Yuan, James Rowland, Lihong Zhou, RICK THOMAS, DAVOOD BAHRAMI

Continuous monitoring of carbon monoxide and other fire-related parameters by means of an atmospheric monitoring system (AMS) is used in the mining industry for early fire detection. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) have developed a direct method to calculate the fire heat release rate (HRR) when a mine fire is close to the AMS sensors, but this method is only applicable to the case where a fire occurs in AMS-monitored airways. This paper presents an improved method for determining the fire HRR using AMS sensor data at any location downstream of the fire. The method was validated using a full-scale diesel fire test conducted in the Safety Research Coal Mine at NIOSH’s Pittsburgh Mining Research Division.

By C. Sykes, E. Turner, M. Wyart-Remy

This paper follows that of the Milos Conf, 2002 and examines the collection and reporting of SDIs in the industrial minerals industry in Europe. It compares the characteristics of the GRI Reporting Guidelines, with its Metals and Mining Sector Supplement with those of the EU DG Enterprise Scheme, launched in 2001. The particular issue of SME's and companies which are not publicly traded is examined. The pros and cons of participating in such schemes is a central theme of the paper. The paper concludes that there and many business benefits for these companies in participating and submitting their data. The European Commission Scheme is strongly recommended for companies in the sector which are SME's and not-publicly traded as well as large firms who are listed on European Stock Exchanges.

Jan 1, 2005

By F. Block, K. Kohli

Outcrop barrier pillars serve to keep mine personnel and the public safe from sudden uncontrolled flows of water accumulated in active and abandoned underground mine workings. When an outcrop barrier fails, the result is an outbreak of water to the surface and is termed as blowout. Mine blowouts are associated with above-drainage mines and can occur through the coal outcrop and sealed portals. A blowout is often catastrophic, a threat to the people on the surface living or working in the path of a potentially large flood. In addition, blowouts can destroy homes, cause landslides and severe erosion and release pollution and acid mine drainage. This paper provides guidance on the planning, design, evaluation and inspection of barriers to address the problem of mine blowouts associated with above-drainage coal mines.

Jan 1, 2007

By J. L. Yordan, J. Kortmeyer, I. Yildirim

Talc is used to remove stickies from pulp during paper recycling processes. It is well known that the interaction is controlled by the surface chemistry at the talc/water, sticky/water and talc/sticky interfaces. If the interfacial tensions are known, one can calculate the free energies of interaction and hence predict whether the stickies can be removed by talc. In the present work, the surface tensions of several different talc samples were determined using the acid/base theory. The information was then used to determine appropriate interfacial tensions, which in turn were used to determine the free energy of interaction between talc and stickies. It was found that the calculated free energies are much more negative than those between the stickies and other minerals such as calcium carbonate, bentonite clay and kaolin clays.

Jan 1, 2002

By G. Karahalios

Industrial minerals have always enjoyed an important share in the technological growth of any country in the world. Today, extraction and trading of industrial minerals has expanded, but is also subject to stricter environmental guidelines. This paper presents the current status as well as the growth potential in the exploitation of industrial minerals in the countries of the south eastern European region, i.e. Albania, Bosnia-Herzegovina, Bulgaria, Croatia, F.Y.R.O.M., Greece, Italy, Serbia and Montenegro, Slovenia and Turkey. More specifically, annual production figures per country are presented for1992-1998. These figures are compared to each other and, where applicable, to world production figures. Trading of industrial minerals from these countries to Europe and the world and its effect to the local economies is also evaluated were such data is available.

Jan 1, 2000

By C. F. Bonney

Spherical or oil agglomeration has been recognised for many years as a possible process for the recovery of mineraVmetal values. BP has investigated the potential of spherical agglomeration for a number of minerals as have other workers. Testwork has also been carried out by both BP and others on the selective agglomeration of fine coal. The spherical agglomeration of both minerals and coal depends on the use of an immiscible liquid e.g. a hydrocarbon which is added to a suspension of the solids in water. On agitation the oil is distributed over oleophilic/hydrophobic surfaces and particle impact allows inter-particle liquid bridges to form causing agglomeration. It is also possible to enhance the oleophilicity of the material to be recovered by the use of collectors similar to those used in froth flotation.

Jan 1, 1998

By D. L. Petersen, C. R. Nelson, B. K. Nelson, B. D. Wagener

The Lafayette Bluff tunnel, currently under construction for the Minnesota Department of Transportation (MnDOT), will be among the widest highway tunnels in the United States. The 199-meter tunnel is being constructed in a closely jointed, variably weathered diabase rock mass. Cover above the tunnel crown ranges from 4 meters to 27 meters, and is less than the tunnel excavated width of 18.3 meters for about 60 percent of its length. These factors dictated special support and lining design, limitations on excavation sizes and required sequences for support installation. Tunnel excavation is by controlled blasting, with multiple top headings and bench. Rock support and lining consists of external portal beams, rockbolts and reinforced shotcrete. A final concrete lining provides structural support for the rock mass and the membrane waterproofing system.

Jan 1, 1991

By E. M. J. A. Pallone, F. N. Cunha, W. S. Resende, R. M. Stoll, R. C. Bradt

Utilization of the magnesium aluminate spinel in refractor' applications is briefly reviewed. The synthesis of a magnesia aluminate spinet aggregate from natural raw materials is considered in terms of the crystal chemistry of the spinet structure and expected impurities. Principles for the formation of this spinet refractory aggregate from different natural raw materials are presented. The basic concepts were then applied to the reaction of a bauxitic clay with a natural magnesite. This combination of raw materials has the potential to produce a low-cost refractor' aggregate that is a composite of spinel and forsterite. Experimental results are reported to produce a spinel refractor.' aggregate containing a small amount of forsterite. It possesses low apparent porosity and high bulk density suitable for industrial refractor' applications, including steelmaking, aluminum and copper foundries and cement production.

Jan 1, 2002

By E. A. Metz

Work related pulmonary diseases are in the top TEN causes of occupational disability and death in the United States. Likewise, it also ranks high inmost of the other industrial countries. It is difficult to know the true occurrence of occupational lung disease because of poor documentation. This is especially true when one examines workers’ compensation claims. Most frequently, silica and asbestos are paramount in our discussion of work related pulmonary disease. Little consideration is given to other “dust-related” diseases, irritant reactions, reactive airway responses, and hypersensitivity reactions. The major classification of occupational lung diseases will be discussed. This includes both acute and chronic disease that arises in the work place, especially, the mining industry. It’s more important to make an accurate evaluation and diagnosis for the prevention of disease among other workers.

Jan 1, 2000

By J. M. Barker

The concept of global-market access through transportation efficiency is a concept whose time has come. The basis of this approach is customer satisfaction—the higher the better. But beyond what seems almost too logical is the question of how to achieve this market access. All industrial mineral exporters face stiff competition. Factors include proximity of competitive industrial minerals and substitutes, pricing pressure, political and cultural differences, currency fluctuations, communication problems, trade finance restrictions, and transportation imbalances. The following discussion will focus on transportation activities in global competitiveness, but the producer with the larger offering of services will often make the sale, not necessarily the low-cost producer (Cook, 2002). Some key concepts for global-market access are “the market concept,” just-in-time delivery, quality retention, and global customer service.

Jan 1, 2003

By H. H. Hughes, J. G. Dunn, P. G. Fernandez, H. G. Linge

Dissolved Arsenic (As) is stabilised primarily as As(III) and As(V) and enters ground water streams from sources such as the increasing metallurgical processing of As - containing ores [1]. As(III) is more toxic than As(V) and is less effectively removed from solution by oxide precipitation. Even for dilute As(III) solutions, skin contact or ingestion can cause dermatitis or cancer and there are stringent effluent control standards in place for As containing effluent from mining operations [2]. Chemtronics (Perth, Australia) has manufactured a compact digital voltamme­ter, based on anodic stripping voltammetry (ASV) and suitable for use in the laboratory or field. In this paper we demonstrate the utility of this equipment for measuring As(III) concentration with a detection limit of ca. 10 ppb.

Jan 1, 1995

By John D. Batty

With the emergence ofbiooxidation as a viable process for the pre treatment of refractory gold ores, so have the number of publica­tions on this topic increased dramatically. To a novice in the field of biooxidation, the infonnation presented is often confusing and sometimes even incorrect. Infonnation has also been published that is misleading in that it highlights a particular feature of a process that is either totally irrelevant or of no consequence to the ultimate goal viz. achieving the maximum economical gold recovery. To assist a potential user of biooxidation in evaluating the available published infonnation some guidelines or considera­tions for some of the more important aspects are given, as well as some extracts from publications that demonstrate the manner in which information has been presented.

Jan 1, 1996

By John W. Greene

ennec?tt's Bameys Canyon Mine personnel developed an mnovahve process to extract gold from a small (1.8 million tons) sulfide ore zone in an oxidized ore body located at the Bameys Canyon Mine. This approach consists of extracting the sulfides from the ore via flotation, shipping the concentrate to Kennecott's new smelter, and mixing the flotation tailings with the oxide ore, agglomerating the mixture, and stacking the resultin tailings/oxide ore combination on the heaps. Conventional heap leaching technology is utilized to recover the gold from the mixed materials. Overall, the total gold recovery from the sulfide ore is esti­mated to be 90%. This approximation is based on a smelter gold recovery of 98% from the concentrate and an 88% recovery from the tailings during heap leaching

Jan 1, 1996

By H. G. Linge

The Australian gold industry currently contributes some $4bpa to the national economy [l]. Some 40% of the total gold is produced in the region centred on Kalgoorlie known as the Eastern Goldfields of Western Australia. This region is the largest single centre of production with an output of some 100 tpa of gold [2]. In the Eastern Goldfields, refractory arseno­pyritic gold ore is an increasingly significant source of gold, feeding several operations utilizing bio-oxidation as the pre­carbon in pulp/leach (CIP/L) treatment process [1]. This paper desribes an alternative pre-CIP/L treatment option for use in the Eastern Goldfields based on the chlorination of arsenopyrite by chlor-alkali technology [3] using the salt resources available from saline water present in abundance in the region.

Jan 1, 1995

The feasibility of exploiting a mineral deposit by developing a surface mine is closely related to the environmental protection and land reclamation costs. This issue has utmost importance for West Macedonia Lignite Centre (WMLC) of Greece, where there is still a lot of interest for opening of new mines and for further development of the existing open-pits. The decision-making process in these cases can be based on a decision tree that takes into consideration the various cost components of environmental management, the alternative solutions, the environmental permits and the cost reports of environmental management actions carried out so far. Moreover, the mine planning procedure is affected indirectly by numerous uncertain environmental and socioeconomic parameters, such as the delays caused by the bureaucratic procedures and the settlement of arguments in the Court.

Jan 1, 2006

By Didem Maral

Olivine is a name of a mineral group that has a chemical formula of: (Mg, Fe), SiO4. The most important rock for the olivine group minerals is dunite, which can contain olivine up to 95-99%. Dunite can be obtained from chrome enrichment as a by-product. As a result of alteration of the olivine group minerals, several kinds of different minerals can occur. Main consumption areas of olivine are steel and iron industry. Also olivine is used in not only casting and refractory industries but also production of radiator, ballast material and abrasive. North of Bursa-Orhaneli has got more than 5 billion tons reserves in ultrabasic massifs. M.T.A found that olivine has got high quality of using in refractory and casting industry.

Jan 1, 2005

By Fathi Habashi

THE MOST important arsenic minerals are shown in Table 6-1. The recovery of arsenic from arsenic sulfides is treated in Chapter Four. Arsenical ores may be either leached directly, or first smelted to volatilize as much arsenic and sulfur as possible, and the resulting product, called speiss, is then leached. A speiss is mainly a complex mixture of metal arsenides, but its [Table 6-1. Arsenic minerals. Arsenides Niccolite NiS Smaltite CoAs2 Skutterudite CoAs3 Sulfarsenides Cobaltite CoAsS Enargite CuaAsS4 Arsenopyrite FeAsS Arsenic sulfides Realgar As4S4 Orpiment As2S3] composition varies widely, depending on the type of ore treated. A speiss usually contains 15-35% arsenic. Methods of leaching are describedd in the following paragraphs.

Jan 1, 1970

Acid Mine Drainage (AMD) is the most serious environmental problem facing the Canadian Mineral Industry today. Acid Mine Drainage results from oxidation of sulphide minerals (e.g. pyrite or pyrrhotite) contained in mine waste or mine tailings. It is characterised by acid effluents rich in heavy metals that are released into the environment. A new acid remediation technology is presented in this paper by which metallurgical residues from the aluminium extraction industry are used to construct permeable reactive barriers (PRB) to treat acid mine effluents. It describes column tests performed to simulate a PRB using Bauxsol?, a chemically and physically treated bauxite refinery residue, as a reactive material. This experimentation shows promising results for the Bauxsol? PRB method in neutralizing pH and removing metals from acidic mine effluents.

Jan 1, 2006