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By A. A. Dor

Recent developments in the design of concentration plants have reflected the increased recognition that has been given to the economic and metallurgical advantages of autogenous grinding. This has manifested itself in the increasing adoption of primary auto genous grinding in iron ore 'beneficiation plants in North America. Table 1 lists eleven major iron ore beneficiation plants which have either been put in operation since 1961 or are under construction at present. Seven out of these eleven plants have adopted primary autogenous grinding. Four of them have coarse grinding mills (8 to 14 mesh) and three have fine grinding primary circuits (48 to 65 mesh). Their nominal capacity totals 26. 2 million ltpy of concentrates or pellets, representing very nearly 75% of the aggregate capacity 135. 3 million ltpy) of the eleven concentrators listed. For a long time there was a tendency to consider that primary autogenous grinding was only applicable to suitable coarse grained ores, However, extensive testing of a very wide variety of ores, and actual operating performance in several commercial plants, seem to have established beyond reasonable doubt, that the majority of mineral ores which the beneficiation engineer may be called upon to process can be ground autogenously. The basis for the selection of autogenous or conventional grinding mills, becomes principally economic and depends on the liberation characteristics of the ores under consideration and their relative hardness and grindability.

Jan 1, 1965

By Constantine C. Popoff

This report reviews and analyzes, by a simple analytical and logical reasoning, the conventional methods of reserve computations of mineral deposits described in various domestic and foreign publications. It brings together, formulates, and evaluates the principles underlying interpretation of exploration data; and ties such principles to the proposed classification of methods. The material is discussed in sufficient detail to allow general application.

Jan 1, 1966

By A. L. Holley

THIS process is performed in the Pernot puddling furnace; it removes from 75 to 80 per cent. of the phosphorus, most of the sulphur, and practically all the silicon, from crude iron, in from five to eight minutes. It has been in regular use since March, 1877, and has prod uced over seventeen thousand tons of washed metal for the open-hearth furnace. During two years, nearly all, and lately, all the open-hearth steel produced in these works has been made from about 5 tons of washed pig and 2 tons of scrap per open-hearth furnace heat. There are 12 open-hearth furnaces, of which 4 to 9 are running, according to the state of orders. A large amount of highly phosphoric iron from France and Belgium has been also washed and then puddled for parties who have taken, or are expected to take, licenses. The washing of pig for puddling, however, is not a practice at Krupp's works, because pure pigs are nearly as cheap as impure ones. The author and his assistant, Mr. Laureau, spent, during the last month, three days at Krupp's works, examining this process. They copied out of the office books characteristic analyses and physical tests, some of which are given herewith. They also brought hone many samples of pig, cleaned metal, puddle bar, and steel, which they saw treated. Analyses of some of these samples appear in Table IV. As there are no blast furnaces at Essen, the iron is melted in two Bessemer cupolas with fore-hearths; they melt 12g pounds of iron with 1 pound of coke. The metal is run by a spout from the fore-hearth into an opening at the side of the main door of the washing-furnace. The Washing furnace.-This is a regenerative gas furnace. It has a Pernot revolving-hearth of 12 feet external diameter and 3 feet depth. (See Plate.) The four regenerator chambers have 780 cubic feet capacity, which is about the same as the average regenerator capacity of open-hearth steel furnaces of equal tonnage. The lining is 13 inches thick on the sides and 9 inches on the bottom, thus giving a hearth 9 feet 10 inches by 2 feet 3 inches deep. The lining is composed of lumps of highly refractory ores

Jan 1, 1880

By A. L. Holley

This process is performed in the Pernot puddling furnace; it removes from 75 to 80 pel. cent. of the phosphorus, most of the sulphur, and practically all the silicon, from crude iron, in from five to eight minutes. It has been in regular use since March, 1877, and has produced over seventeen thousand tons of mashed metal for the openhearth furnace. During two years, nearly all, and lately, all the open-hearth steel produced in these works has been made from about 5 tons of washed pig and 2 tons of scrap per open-hearth furnace heat. There arc 12 open-hearth furnaces, of which 4 to 9 are running, according to the state of orders. A large amount of highly phosphoric iron from France and Belgium has been also washed and then puddled for parties who have taken, or are expected to take, licenses. The mashing of pig for puddling, however, is not a practice at Krupp's works, because pore pigs are nearly as cheap as impure ones. The author and his assistant, Mr. Laureau, spent, during the last month, three days at Krupp's works, examining this process. They copied out of the office books characteristic analyses and physical tests, some of which are given berewith. They also brought home many samples of pig, cleaned metal, puddle bar, and steel, which they saw treated. Analyses of some of these samples appear in Table IV. As there are no blast furnaces at Essen, the iron is melted in two Bessemer cupolas with fore-hearths; they melt 124 pounds of iron with 1 pound of coke. The metal is run by a spout from the forehearth into an opening at the side of the main door of the washingfurnace. The The washing-furnace.—This is a regenerative gas furnace. It has a Pernot revolving-hearth of 12 feet external diameter and 3 feet depth. (See Plate.) The four regenerator chambers hare 780 cubic feet capacity, which is about the same as the average regenerator capacity of open-hearth steel furnaces of equal tonnage. The lining is 13 inches thick on the sides and 9 inches on the bottom, thus giving a hearth 9 feet 10 inches by 2 feet 3 inches deep. The lining is composed of lumps of highly refractory ores

Jan 1, 1880

By RALPH BALTES, AMIR EHSAN KIANFAR, FABIAN UTH, ELISABETH CLAUSEN

As indoor positioning provides particular challenges due to the unavailability of GPS signals, various systems such as ultrawideband (UWB), radio frequency identification (RFID), ultrasound, and wireless local area network (WLAN) have been proposed in recent years. Some of these technologies are currently being marketed and some are still being developed. UWB technology allows for higher precision while also reducing power consumption. Hence, the underground automation and localization systems can use this technology for more accuracy and robustness. This article discusses new robust UWB modules used for underground positioning and collision avoidance with regard to human safety in underground mining operations.

Jul 31, 2020

By Charles Janin, HENNEN JENNINGS

Many articles have been written on the general principles and details of gold dredging, a but it is not possible within the limits of this paper to recapitulate them, and it is thus necessary to assume some knowledge of this literature by the readers of this paper. Although the purpose of this paper is to describe gold dredging in Montana, a brief mention of some early appliances used in New Zealand, Australia, and California may serve as a world-connecting link in our consideration of the development of gold dredging. DREDGES EARLY USED IN NEW ZEALAND, AUSTRALIA, AND CALIFORNIA. Spoon dredges operated by hand were tried in New Zealand on rich spots in the Clutha River with some success as early as 1865. A dredge of this kind is shown in Plate I, A. In 1870 a modification of the spoon, operated by steam and being thus a primitive steamshovel dredge, was worked in New Zealand. Steam-shovel dredging was attempted in California as early as 1888 and 1893, and with some success in later years. The elevator gold dredge with endless bucket chain was put into operation in New Zealand in 1882. Plate I, B, illustrates a type of this dredge operated by current wheels. Plate II, A, shows a steam-operated dredge of this class, also started in 1882. In 1897 R. H. Postlethwaite, connected with the Risdon Iron Works, San Francisco, introduced the dredging practice of New Zealand into California. The first dredge built sank in the turbulent current of the Yuba. The second at Oroville, owned and operated by W. P. Hammon, proved effective and was the start in California of successful gold dredging. Since then the growth of the golddredging industry in California has been so rapid that the gold output from dredges in that State exceeds that of all other States in the Union, and, in fact, of any other country of the world, the value of the gold produced in California by dredging from 1897 to the end of 1914 having been about $71,000,000.

Jan 1, 1916

By H. H. Fairfield

THE production and inspection of the materials of war involves thousands of observations. Logical action is generally based on the interpretation of many observations. The success of such action depends upon the accuracy of the observations and the soundness of the interpretation placed upon them. There are countless instances where the observer 'sees but perceives not'; that is, the significance of a group of observations is lost, due either to faulty interpretation or to no interpretation at all being placed on the results. This condition is being partly corrected in the United Kingdom and the United States (1) by the promotion of certain principles by Ordnance officials. The term Quality Control has been adopted to describe a system of studying and controlling industrial products by methods of handling observations. In these pages an attempt is made to outline in a non-technical manner some of the ideas used in the handling of observations. Of course the authenticity of the observations determines the worth of any decisions based on them. No matter how brilliant is the theory built on unreliable sampling, it is usually of little practical value. n some fields it is almost impossible to obtain observations free from bias. Let us suppose that observers of speed in miles per hour were available for judgment: (a) a bystander, (b) a motorcycle policeman, and (c) a motorist accused of speeding. The bystander might be unbiased but probably would be very inaccurate. The motorist is usually biased on the low side. The policeman is the only qualified observer and, if over-zealous, he might be biased on the high side. Conclusions drawn from large numbers of biased observations naturally would be of little value.

Jan 1, 1943

By R. Thomason

Thank you Dr Barcza, President of the South African Institute of Mining and Metallurgy, for inviting me to share our experiences in Australia as regards the competency movement and my Association?s experience in assisting engineers become managers. This is my second visit to South Africa, and I am struck by the similarities between our countries. This extends to the professional issues associated with engineering and competencies in particular. I propose to outline two exciting stories today. ? Development of competency standards for professional engineers in Australia. ? Development of a management programme which has assisted professional engineers regain positions of leadership in Australian industry and government. First of all I would like to outline the Association of Professional Engineers, Scientists and Managers, Australia(APESMA).

Jan 1, 1997

By FOSTER HEWElT

THE scope of this paper is the description of two districts in Peru in which deposits of vanadium have been found, and the consideration of much laboratory-work that I and others have done to determine the nature of these deposits. It is with regret that I present some of the data in a state of evident incompletion, particularly the analyses of a few of the minerals, which leaves some doubt as to whether the true nature of the minerals is understood. I make no apology, however, since in this case, as in many others referring to ore-deposits, conclusive opinions cannot be stated until a great amount of work has been done, and the deposit has been thoroughly exploited. I believe that the data and the tentative conclusions here presented indicate a unique and interesting condition which may assist others in work along similar lines; and further, what is of more practical importance, stimulate a search for a metal which, though long considered rare, is probably so merely because proper care has not been taken to recognize it. An excellent bibliography on the occurrence of vanadium in nature is given by F. W. Clarke in his paper, Data of Geo-chemistry;1 and in the preparation of this paper I have consulted many of the references contained in the Bibliography of the Chemistry of Vanadium, by M. Moissan.2 A brief review of the subject having special reference to the metallurgy of vanadium is contained in the small book by P.. Nicolardot.3 One of these vanadium-deposits has already been briefly

Mar 1, 1909

By D. Prince, G. Nollet

"Since 1994, Aur Ressources has operated Louvicourt mine, a zinc and copper mine close to Val d’Or, at a rate of 4300 t/d. Ever since the start-up of the plant, management has encouraged innovative approaches in reliability. The first of three papers will discuss the vibration monitoring program in place. The program will be described and two examples will be given: detection of a rolling bearing defect on a pinion driving the ball mill and identification of wear on the bearings of the flotation cells. Figures on the return on investment and the costs of a monitoring program will also be given.The second article will discuss the lubrication aspect. Since the establishment of a good monitoring and oil analyses, Louvicourt mine decreased its oil consumption by more than 38 000 L/yr. In addition, the company set up an oil regeneration system that restores the original properties of oil.The third article will cover the management aspect. Work organization as well as the management philosophy enabling the employes to push predictive technology to higher levels will be examined in detail. The key elements which made it possible for Louvicourt mine to position itself among world-class companies in the organization of maintenance will be discussed."

Jan 1, 2002

By F. Dahl, P. Raleigh, J. Holzhauser, B. Nilsen

Tunnel excavation using tunnel boring machines (TBMs), has become increasingly common in recent years, despite the fact that precise evaluation of certain risks have not kept pace with the use of these machines. One of the risks easily overlooked by Engineer and Contractor alike are the effects of abrasive ground on the costs and schedule of a given project. The impacts of worn and damaged TBM cutter heads have been observed on hundreds of tunnel projects around the world. It would appear that a reliable prognosis of the abrasiveness of soils on a project would be of great importance for designers, clients and contractors alike. Several well acknowledged test and prognosis methods already exist for rock, however there is only very limited knowledge available to describe the abrasiveness of soil and its impact on soft ground TBMs. This paper will examine approaches to this problem and suggest a new approach based on a current project undergoing design.

Jan 1, 2007

By Michael F. Dunn

Since crushing of rock to a smaller size is an integral part of almost any mining and quarrying operation, a study was carried out to identify and develop improved techniques for alleviating a major cause of accidents and work stoppages arising when an oversize luck or boulder lodges in the throat of the crusher. The configurations and operations of various crusher types is described, sources of boulders in the mining operation, and a detailed review is made of mining, quarrying, and construction regulations for all states, Canada, and the Federal Government for applicable provisions. Representative mines were visited and other operations contacted for their boulder handling techniques where it was found that blasting techniques used included mudcapping, bombs, and blockholing, often done very crudely and inefficiently with poor practices and various mechanical systems were used such is hooks of, overhead cranes, impact hammers, and grapplers. Safety analyses of all methods pointed out the hazards associated with blasting in the open and the dangers of entering a crusher. Boulder blasting can be done in a safer fashion if a planned step-by-step procedure is followed, and inherently safer blasting products such as exploding bridge wire blasting caps and improved blockholing techniques. In general, though, the installation of a suitable mechanical system such as an impact breaker will prove safer and cost effective even in a smaller mine or quarry.

Jan 1, 1981

By M. Hesham El Naggar, Yasser Abdelghany

"ABSTRACT: The axial and lateral monotonic and cyclic behavior of helical pile foundations was investigated and new innovative helical screw systems suitable for seismic loadings were developed and patented. More than one hundred full scale field load tests were conducted on instrumented helical screw piles installed in cohesive soil. The piles included: plain helical screw piles (P-HSP); grouted (G-HSPs); fiber reinforced polymer FRP-G-HSPs; and reinforced grouted RG-HSPs. The RG-HSP piles axial capacity was more than twice that for P-HSP, with minimal reduction after cyclic loading, and their lateral capacity was more than 3 times the P-HSPs capacity. A 3-D finite element model was established. The results of 3-D finite element modeling were used to establish the load transfer mechanism and a design methodology for the considered piles.INTRODUCTION AND LITERATURE REVIEWHelical (screw) anchors have been utilized in tension loading and have gained popularity for bearing load applications. Helical piles represent an overall cost effective alternative to conventional piles for new construction and repair applications. The helical piles speed and ease of installation, less noise during installation added advantage with regards to their efficiency and reliability for underpinning including re-support and reconstruction of distressed and damaged foundations for either stabilization or rehabilitation. The “square shaft” SS175 pile is a segmented deep foundation system with helical steel bearing plates (helices) welded to a central steel shaft. Load is transferred from the shaft to the surrounding soil through these bearing plates. Segments or sections are joined with bolted couplings. Practically installed depth is limited only by soil resistance and economics. A helical bearing plate or helix is one pitch of a screw thread. All helices regardless of their diameter have a standard 75 mm pitch (Figure.1). The performance of single helical anchors and group action were studied experimentally and theoretically by several researchers, the researches focuses on the installation torque and uplift resistance. Some researches focus on the load carrying capacity with little pile response to cyclic loading effects or to instrumented full scale field testing. Helical piles axial compressive or lateral loading still is not well characterized and needs more analyses and their seismic performance was not investigated. For such this research was initiated to investigate the helical piles monotonic and cyclic performances under axial and lateral loadings to consider their usage in different applications in seismic zones. Among the several researchers, Clemence (1983); Mooney et al. (1985) conducted field and laboratory testing; Hoyt (1989), Hoyt et al. (1995), and Ghaly and Clemence (1998) conducted theoretical and experimental testing, Puri and Vijay (1984), Huang et al. (1995), Perko (2000), and Pack (2000) conducted theoretical analyses. Rao and Prasad (1993), Prasad and Rao (1994), conducted experimental testing; Vickars and Clemence (2000) studied the performance of helical piles with grouted shafts."

Jan 1, 2014

By M. Ralchenko, C. Samson, M. Svilans, C. Walsh

"Through-the-Earth (TTE) radio has been proposed as a means of emergency communications in mines. The propagation of a TTE radio signal depends chiefly on the subsurface conductivity distribution. Robust forward models of signal propagation can be computed based on a realistic conductivity estimate. These models can be used, for example, to optimize frequency, estimate signal range, identify zones of anomalously strong or weak signals, or to optimize the position of the above-ground TTE radio unit. A method was developed to determine the conductivity distribution of a mine overburden using TTE radio transmission data. At multiple locations in an underground test mine, we recorded a wideband electromagnetic signal, spanning a frequency range of approximately 500 to 8,500 Hz, transmitted from a vertical magnetic dipole at the surface. Using a finite-difference time-domain forward modeling code, a layered Earth conductivity model that accounts for topography was fitted to the observed data, which minimizes the difference between the calculated and observed attenuations for each transmitter-receiver pair, for each frequency of interest. Introduction and objectiveThrough-the-Earth (TTE) radio has been proposed for emergency underground communications. The most common type of TTE radio is based on the transmission and reception of signals by electromagnetic induction. These signals are in the extremely low to very low frequency range — in practice, between 400 and 9,000 Hz. This technology was historically developed for mine safety, although recently other applications have been suggested, such as communications in civilian infrastructure like high-rise buildings or tunnels, in the military, and even for wireless detonation and activation. In a coal mine, which is a setting of particular importance for TTE radio due to the higher risk of accidents, day-to-day communications can be done through a wired link. High-frequency line-ofsight systems, whose signals cannot penetrate rock, are also used for communications from nonfixed points. Another option is a leaky feeder system, which is a permutation of a line-ofsight system and a wired link, where a partially shielded coaxial cable allows the signal to “leak” (Delogne, 1982). In an incident such as a mine collapse or explosion, a TTE radio system can still provide a communication link, as wired systems can be severed, and line-ofsight systems cannot penetrate through collapsed portions of the mine, or to the surface (Forooshani et al., 2013; Yarkan et al., 2009)."

Jan 7, 2018

By S. K. Kawatra, J. A. Halt

"Low-grade iron ores are finely ground and processed to recover iron-bearing minerals. However, the iron-rich powder is too fine to be used directly in blast furnaces and most direct reduction furnaces, and must be agglomerated or pelletized into a usable product called “pellets.” Bentonite clay has traditionally been used as a binder to make iron ore concentrate pellets, but it is expensive and contaminates the pellets. Organic binders may be a viable alternative to bentonite clay. This manuscript reviews organic materials that have been used to make iron ore concentrate pellets. Included are discussions on the development of organic binders, common pros and cons to organic binder use, organic binder structure and its effects on agglomeration, and additives to organic binders.IntroductionIron ore agglomeration turns finely disseminated, low-grade iron ores into a usable product, called pellets. During pellet production, fine-grained, iron-rich minerals are liberated from low-grade ores, concentrated, and agglomerated into round balls that are thermally hardened or cold-bonded to form pellets. Pellets are then transported to blast furnaces or direct reduction operations where they are used to produce iron; iron is further refined and shaped into the wide variety of steel-based industrial and consumer products in use today.Over the years, pellet production has become increasingly more prevalent with the increased exploitation of low-grade iron ores and increased iron and steel consumption around the world. In 2010, world iron ore pellet production was 388 Mt. It could be argued that the current pellet production process has been enabled by the use of binders – practical experience has shown that it would be nearly impossible to agglomerate iron ore concentrates using rotary drums and discs without using a binder."

Jan 1, 2015

By Jean-François Dorion

La corrosivité des environnements miniers souterrains est un phénomène peu étudié au Canada. En plus de détériorer les systèmes de soutènement, la corrosion s?attaque aussi à divers installations et équipements souterrains. Cette étude, débutée en janvier 2007, est l?établissement d?une banque de données afin de caractériser les environnements miniers souterrains selon leur potentiel de corrosivité pour les systèmes de support de terrains. Pour ce faire, cinq (5) mines ont été sélectionnées afin de comparer les environnements : Laronde, Géant-Dormant, Niobec, Mouska et Doyon. À chacune des mines, trois (3) endroits ont été étudiés. Les résultats préliminaires démontrent une grande variabilité des conditions d?une mine à l?autre ainsi qu?à l?intérieur même d?une mine. La minéralogie des roches et du gisement influence la composition des eaux souterraines et la présence des sulfures joue un rôle important sur l?agressivité de l?eau et de l?air des mines de l?étude. Afin de déterminer le potentiel de corrosivité, plusieurs paramètres doivent être considérés et la mine doit être zonée selon l?agressivité des endroits.

Feb 1, 2008

By Scott W. Hazen, Richard F. Link, George S. Koch

The Mi Vida mine , Big Indian district , San Juan County , Utah , is in an ore deposit of uranium and vanadium minerals disseminated in certain sedimentary beds of the Triassic Chinle formation . Statistical analysis of assays of samples taken from the ore body affords an estimate of the grade of the ore body and provides a prediction about the direction of best mineralization beyond the sampled area . The basic data analyzed are assay results for uranium ( Uз Og ) , vanadium (V₂O ) , and lime (CaO ) from 225 channel samples cut at 79 sample points . Through the use of appropriate statistical methods , particularly regression analysis , the grade of ore may be estimated more precisely than by conventional means , and the most favorable direction to extend the mine may be predicted . Frequency distributions of assay residuals for uranium , vanadium , and lime are compared to frequency distributions of assays without regard to trend . Correlations among these variables are obtained and interpreted . The statistical methods employed illustrate certain techniques that may be used to analyze assay data from ore deposits in general .

Jan 1, 1964

By L. V. Chugaev, Y. M. Shneerson, P. V. Zaytsev, I. V. Fomenko, M. A. Pleshkov

"Pressure oxidation (POX) is one of the most common and reliable methods of processing gold-bearing sulfide concentrates. However, when processing concentrates that contain natural carbonaceous matter, substantial gold losses occur due to autoclave preg-robbing. The latter involves formation of gold chloride complexes under typical POX conditions (high temperatures, high acidity and high ORP) and subsequent sorption of these complexes by carbonaceous matter. Naturally, chloride ion plays a significant role in the process of autoclave preg-robbing; its concentration in POX solution has a well-marked effect on subsequent gold recovery during cyanidation of POX residue. The previous research done by SRC Hydrometallurgy showed that autoclave preg-robbing of gold could be significantly inhibited by the addition of mercury(II) compounds to POX slurry. The positive effect of mercury(II) was well pronounced both at high (>20 mg/L) and low (<5 mg/L) Cl concentrations in POX solution. The successful bench-scale laboratory testing was followed by pilot plant trials at Ore Test Facility in Blagoveshchensk, Russia. The present paper provides the results of these trials. The bench-scale testing results were verified; the optimum oxidizing parameters and reagent dosage were specified. The behavior of mercury (II) at POX pilot plant was found to be in good consistency with industrial practice described in the literature.INTRODUCTION Pressure oxidation (POX) is one of the most common, reliable, and commercially proven methods of processing gold-bearing sulfide ores and concentrates. However, when processing double refractory materials that contain natural carbonaceous matter, POX technology advantages are compromised by autoclave preg-robbing of gold. The latter occurs when natural organic carbon and soluble halides are both present in autoclave feed. Strongly oxidizing conditions of POX (high temperature, oxidation-reduction potential or ORP, and acidity) favor formation of gold-halide (mostly, gold-chloride) complexes, which tend to bond with carbonaceous matter. The exact nature and mechanism of this bonding is unknown, but as the result of this, cyanide is unable to leach gold from POX residue and the precious metal is lost to the tails (Axenov et al., 2014; Dimov, Chryssoulis, & Sodhi, 2003; Fomenko, Zaytsev, Pleshkov, Chugaev, & Shneerson, 2013)."

Jan 1, 2017

Resolution Copper Mining LLC (RCML) is currently in a Pre-feasibility study evaluating a large and deep copper and molybdenum deposit in the historic mining district east of Superior, Arizona. Work scheduled for the next several years includes dewatering the existing shut-down mine (the Magma Mine) and sinking an exploratory shaft to 2,130 meters (7,000 feet) below the surface. To dewater the Magma Mine and sink the exploratory shaft, RCML must extract and manage about 2 billion gallons of accumulated mine water inventory, as well as about 300 million gallons per year of new inflow. In order to conserve a valuable water resource in a desert environment, RCML worked with the New Magma Irrigation and Drainage District (NMIDD) to provide treated mine water to blend with and supplement the NMIDD?s water supply to approximately 2,000 hectares (5,000 acres) of farmland located east of Phoenix. A 44 km (27-mile) pipeline was needed to convey the treated water. It was essential that a treatment system be used which could reliably meet irrigation water quality goals, produce a non-scaling effluent to maintain pipeline flow capacity, and generate a dense sludge minimizing disposal cost and volume. This paper describes the resulting mine water treatment and recovery system (MWTS) and how the system has performed against objectives.

Jan 1, 2011

By Daniel M. Flanagan

"Editor’s note: Each year, Mining Engineering features an industrial minerals review. Several people put in a fair amount of time in developing the material for this issue, all the while doing their own jobs. Thank you to the industrial minerals annual review editor, to the Industrial Minerals & Aggregates Division technical committee chair and vice chairs, and to the authors of the individual commodity profiles. Jim Norman, member SME, of Tetra Tech, is the industrial minerals annual review editor.Joe Garska, member SME, of Imerys, is chair of the Industrial Minerals &Aggregates Division’s Technical Committee.The technical committee vice chairs include:• Hyunjung Kim, member SME, of Chonbuk National University, agricultural materials.• Xihui Lin, member SME, of Kemira, ceramics and refractory materials.• Nikhil Gupta, member SME, of Virginia Tech, chemical raw materials.• Adam Rodriquez, member SME, of Penn State, construction aggregates.• LeDeana Roberts, member SME, of Imerys, fillers and pigments.• Harsha Kolla, member SME, of ChemEOR, sorbents, filters and process aids.• Edgar Blanco, member SME, of FLSmidth, specialty minerals.Their help makes possible this July industrial minerals issue. On behalf of ME readers, the editors thank them.During the past 25 years, U.S. ball clay production (the quantity sold or used by domestic producers) increased from 788 kt (869,000 st) in 1990 to an alltime high of 1.31 Mt (1.44 million st) in 2003 (Fig. 1). Housing construction within the United States, a leading market for ball clay-based ceramics and sanitaryware, began to decline in 2005, which resulted in a considerable decrease in sales of ball clay that continued through the 2008-2009 economic recession. After bottoming out at 831 kt (916,000 st) in 2009, ball clay production steadily increased through 2015 (Fig. 1). Estimated sales in 2015 were 36 percent higher than those in 1990 and 18 percent lower than those in 2003.Four companies (H.C. Spinks Clay Co., Imerys S.A., Old Hickory Clay Co., and Unimin Corp.), mined ball clay in five states during 2015. An estimated 1.7 Mt (1.18 million st) of ball clay valued at an estimated $47.5 million was sold or used by U.S. producers, a 4-percent increase from 1.03 Mt (1.14 million st) valued at $45.2 million in 2014. Approximately 65 percent of total ball clay production was air-float, 25 percent was crude or shredded and 10 percent was water-slurried"

Jul 1, 2016