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By G. T. Adel, J. D. Miller, C. L. Lin

Washability analysis determines the maximum separation efficiency that can be achieved in the operation of coal preparation plants. Unfortunately, there are no on-line techniques for determining this most fundamental information. It now appears possible to determine coal washability on-line through the use of x-ray computed tomography (CT) analysis. This paper presents the results for the development of a CT-based, on-line coal washability analyzer. The development of appropriate hardware and software necessary to adapt a CT analyzer for use in determining coal washability is discussed. Testing of the analyzer using well-characterized coal samples is presented.

Jan 1, 2000

By David M. Mchaina, Allan E. Hall, Siegfried Rohr, J. D. Botsford

Incidents associated with secondary dust ignitions in the mining of massive sulphide ore deposits are of major concern in Canadian underground metal mines. During stope or development blasting, a highly concentrated cloud of sulfide dust is created and may be ignited, resulting a secondary explosion which releases a considerable volume of sulphur dioxide and possibly other sulphur gases. The consequent pressure, heat and toxic gases can result in loss of life, significant damage to equipment and loss of production. These losses are expensive and should be prevented. Explosions of this type have occurred at the H-W mine of Westmin Resources mainly in the development headings and cut and fill stapes. This paper presents the results of a study conducted at the H-W mine to compare dust sampling methods for explosivity tests. The associated benefits and pitfalls of each sampling technique are examined. The investigative work conducted to develop and test preventive and control methods against sulphide dust ignitions is also discussed. The techniques which will minimize the risk of sulphide dust ignition in metalliferous mines are outlined. A review of current preventive and control measures practised at the H-W mine is also presented.

Jan 1, 1989

By T. Lamond, J. O. Costello

Marble is a preferred surfacing material in up-scale buildings. Its use increased in the 1870's with rising national wealth and declined in the 1950's when synthetic materials for these applications were developed. Natural marble is now limited to high-end domestic and commercial structures. Cultured marble is a paste of white marble dust and polyester resin cured in molds yielding fixtures of specific finished dimensions. Dyes incorporated at different stages in the mixing cycle mimic shades and veining of natural marble. This paper discusses the filler requirements for cultured marble production and reviews new techniques to cut and finish natural marble.

Jan 1, 1999

By H. Hamza

Oil sand tailings are disposed of in large ponds in which MFT (Mature Fine Tailings, a stable suspension of fine particles in water) forms after many years of settling. Long-term storage of large volumes of MFT is costly to maintain and also poses an environmental liability. The Advanced Separation Technologies laboratory at CANMET Western Research Centre has worked closely with oil sand companies to eliminate MFT generation by applying paste technology to oil sand tailings. In this process the fine tailings are flocculated to produce a thickened material that has the potential to consolidate to a dry landscape, while warm water is recovered and recycled for reuse in the extraction process. This paper presents some results of an extensive technical program involving bench-scale tests for flocculant selection and continuous thickener pilot tests.

Jan 1, 2002

Ventilation network modeling in mine planning dates back at least three decades, but it is not widely accepted and/or practiced until the last decade, thanks to the advent of modern computers with their increase d speed and storage space. There are at least half a dozen such modeling software packages available on the market each with different features and acceptance. This paper compares five popular software packages,?? VnetPC Pro, MineVent, VentSIM Visual, VentGraph and MFIRE 3.0. A case study using Missouri S&T?s Experimental Mine is conducted to compare the five software packages in features, interface, output display and user-friendliness.

Jan 1, 2012

By S. Hamilton

Occurrences of boron-containing ores are relatively rare on a global basis. The first verifiable use of borax was in the 8th century by Arabian gold and silversmiths. Due to the rarity of the borate mineral occurrences, borates were originally traded at relatively high prices and were used for very specialized applications. Today, there are

Jan 1, 2006

By G. R. Struble, J. R. Marks, A. B. Brown

The center of mining at the Homestake gold mine in Lead, SD, is moving deeper every year. As a result, it has become necessary to upgrade the ventilation system. This paper describes the first phase of a scheduled two-phase upgrade - installation of a 2.2-MW (3000-hp) centrifugal fan. The higher pressure fan is required to route larger airflows into the deeper production levels. Selection of the fan began by specifying the necessary operating point to provide these larger airflows. Special site work had to be done on the surface to accommodate the new fan structure as well as underground to reroute airflows.

Jan 1, 1987

By H. I. Morrison, A. J. deVilliers, D. T. Wigle, H. Stocker

INTRODUCTION At the end of 1959, high levels of radioactivity attributed to radon and its daughter products were discovered in the fluorspar mines at St. Lawrence, Newfoundland. These levels were presumed to be the cause of an unusually high incidence of lung cancer among the fluorspar miners (deVilliers & Windish, 1964) (Parsons et al. 1964). The mining of fluorspar (calcium fluoride) began in 1933 as open pit operations but converted to standard underground mining procedures in 1936. During the second world war, production was greatly expanded as a result of increased demand for fluorspar used in the production of steel. Wet drilling was first introduced into general use in 1942. Ventilation was mainly by natural draft occasionally supplemented by small blowers. The amount of ventilation varied greatly between mines as well as over time. For example, one large mine, the Iron Springs mine, had only a single small raise to the surface some 600' from the central shaft. Other mines, such as the Director mine, had a number of raises to the surface and, as a result, had far better ventilation. Mines also varied by the amount of ground-water which seeped into them. In the early 1950's, an unusually large number of lung cancer cases were diagnosed among the fluorspar miners. As a result, in 1956 and 1957, J.P. Windish of Canada's Department of Health and Welfare tested for possible causative agents in the mines. Unfortunately, radon measurements were not conducted until 1959 and 1960 when Windish tested Director mine as did the A.D. Little company in 1960. As a result of the high radon levels found, mechanical ventilation was introduced and the concentration of radon dauthers fell, on the average to well below 1 WL. During this period, lung cancer cases continued to be diagnosed with 29 lung cancer deaths recorded by 1964 and 71 by 1971. As of July 1981, 105 lung cancer cases had been identified (Hollywood, 1981). Previous reports concerning the fluorspar miners have dealt in detail with the factors in the occupational environment and discussed occupational mortality patterns. The purpose of this paper is to review further the mortality experience with particular reference to lung cancer in relation to cumulated radiation exposure and to describe briefly our ongoing study of this group. METHODS Occupational histories were prepared for men who had been employed by the mining companies at St. Lawrence during the period 1933 to 1977. The histories were compiled from company records except for the period 1933 to 1936, records for which were lost in a fire; however, the occupational histories for this period were completed by searching census records and interviewing company officials, ex-employees and others. In addition, occupational and smoking histories were also obtained for some miners during a survey conducted in 1978. Occupational records included name and date of birth as well as the type, place and hours of work by year. For each year prior to 1960, hours of work were converted to working months (1 WM = 167 hours) and were multiplied by the estimated average radon daughter concentration in working levels (WL) to yield the annual radiation exposure in working level months (WLM). Pre-1960 radiation levels were estimated on the basis of the history of mining methods employed, ventilation history of the mine, type and place of work and conditions under which the first radiation measurements were made in 1959 and 1960 (deVilliers and Windish, 1964). During the period from 1960 to 1967, the average exposure was about 0.5 WL. Beginning in 1968, radiation levels were measured more frequently, and, beginning in 1969, daily exposures for each worker were recorded based on radiation levels in the place worked on a given day. Mortality data were obtained from medical certificates of death. In a small number of cases, medically certified death certificates were unavailable. In these cases, probable cause of death were obtained from forms completed by the local clergyman (returns of death), parish records, information obtained from interviews with family members of the deceased and/or hospital information, before assigning a cause of death. Data obtained from these sources were found in Tables 1, 2 and 4, cover the time period 1933 to 1971. Data in Table 3 as well as in Figures 1 through 3 cover deaths from 1933 to 1977, and includes only those miners for whom medical certificates of death were available. Two medically certified causes of death were changed from other causes to lung cancer on the basis of pathology reports.

Jan 1, 1981

There are bound to be changes with age, so I should not have been surprised or disappointed when what I had considered as high ad- ventures were much fewer and more widely scattered in the last 20 years of my long and active business life. But such adventures came until I was past 80 years of age and no one could expect more than this. Frequent visits to mines in this country and Canada and directorships in Bralorne and its subsidiaries, Homestake Mining Co., Bradley Mining Co., and the Bunker Hill Co.; and Copper Range Co. and its great new White Pine mine in Michigan, lasted far beyond the usual retirement age. The least happy part of my last two decades of active life was the death or sickness of many of my old friends. Hubert d'Autremont, whose friendship no one could replace, died suddenly in 1946. Henry Carlisle and Temple Bridgeman, for many years office associates, had heart attacks that cut down their activities far too soon. Many other less intimate friends died or became ill, but I knew that with advancing years such losses were inevitable. These memoirs would be endless if they covered all of the unusual work and associations I found in the last 20 years. So I must confine the rest of my recollections to expeditions that would have thrilled any engineer at any time. Masaro Mine, Mindanao, Philippines The first of the four "high adventures" came late in 1949, when I was 65 years old. For over a month I had been discussing reported rich lead-silver-copper properties in the Philippines with Thayer Lindsley and other officers of Panaminas. A competent and agreeable "Elderly" (not as old as I was) engineer named Ward Williams had talked with Thayer about high grade mines in a remote part of the

Jan 1, 1976

By John A. L. Campbell

Surface dependent processes, such as froth flotation and flocculation, are important or potentially important techniques for combating some of the current major problems in coal preparation. In order to correctly apply or imporve a surface dependent process, it is of paramount importance to understand the interfacial phenomenon, especially the double layer properties, exhibited by the solid. The specific objective of this research was to determine the properties of the bituminous coal/liquid interface by an electrokinetic method, streaming potential, and to relate the findings, wherever possible, to the existing unit operations of froth flotation and flocculation. The electrokinetic properties of both the whole coal and its lithotypes were investigated. As part of the total investigation, the role played in the double layer by the reagents commonly employed in the surface dependent process was also established (1). These data will be presented at a latter date.

Jan 1, 1969

By Robert A. Hains, William P. Balaz, K. Payne

Ceramics are usually used to line chutes, pipes, dust collectors, separators, cyclones or bins where abrasive or corrosive material is moving. Improvements in ceramic manufacturing methods and quality, use of other abrasion resistant materials in combination with Alumina ceramic, improved adhesives and installation methods allow the use of Alumina ceramic tile in applications with impact. This paper discusses the criteria to determine if ceramics can provide a cost effective alternative to other liners for abrasive material handling applications, design parameters for liner systems, system costs, and case histories. The goal will be to provide a practical guide for improving the performance of existing ceramic lined systems or determining if ceramics is a cost effective solution for your abrasive material handling applications.

Jan 1, 1996

By R. D. Lawrence

Suggestions have been made that the appraisal of mining assets using discounted cash flow techniques should be based solely on proven and probable reserves in reliance upon the widespread international recognition of uniform resource definitions. Following a review of general accepted valuation principles, a survey of the literature and, most importantly, a review of real transactions in the open market, it is clear that valuators should not be constrained by the growing acceptance of modern mineral resource codes. On the contrary, valuation practitioners should be encouraged to examine all classes of mineralization and, after making due allowance for risk, to utilize all mineral resources as a basis for determining fair market value.

Jan 1, 2000

By Henry A. Signore

The Appalachian coalfield, located in eastern Kentucky, Pennsylvania, Virginia and West Virginia, has been one of the most productive in the United States. Total production from the Appalachian coalfield during 1994 was 340.8 Mt (375.4 million st), or 37% of the 929 Mt (1 billion st) produced in the United States that year. This region contains various coal types from high- to mid-sulfur coal in Pennsylvania and northern West Virginia to low-sulfur, compliance steam coal and premium-grade metallurgical coal in eastern Kentucky, Virginia and southern West Virginia. The region's product is in high demand in domestic and export markets. Productivity continues to improve, resulting in the primary coal operators solidifying their market positions.

Jan 1, 1995

By C. W. Matthews

Introduction Screening is defined as a mechanical process which separates particles on the basis of their size and their acceptance or rejection by a screening surface. The key element in this method of particle sizing is obviously the screening surface, the medium that contains the apertures for the passage of the undersize material. This surface must be strong enough to support the weight of the material being screened, flexible enough to yield to the vibrating force applied to it, yet light enough to provide a reasonable ratio of open area to attain a practical through- put. To balance all of these factors is difficult enough. The problem is compounded, however, because screening media are made in a great variety of types, shapes, sizes, and materials of

Jan 1, 1985

By X. F. Wang, K. B. Fu

"We investigated experimentally and theoretically the adhesion behavior of Acidithiobacillus ferrooxidans (At.f6) to different copper sulfides. The adsorption experiment showed cell densities of 10.74 × 106, 8.06 × 106, 3 × 106, 4.24 × 106 and 2.35 × 106 cells/cm2, respectively, on the surfaces of djurleite, bornite, covellite and chalcopyrite. The order was: djurleite > bornite > covellite > chalcopyrite. The results indicate that A. ferrooxidans has high affinity to adhering to the surfaces of djurleite and bornite in the acidic region. But the thermodynamic approach predicts that there will be no attachment of At.f6 to the surfaces of bornite, covellite and chalcopyrite. This discrepancy is due to the inadequate description of electrostatic interactions. The DLVO approach shows attachment of At.f6 to the surfaces of djurleite, bornite and covellite, and repulsion between At.f6 and chalcopyrite. The DLVO approach can explain the differences of the adhesion of At.f6 to different copper sulfides.IntroductionThe bioleaching of low-grade copper sulfides is a developing technology, and has been applied successfully to the extraction of copper from secondary sulfide minerals (Watling, 2006; Pradhan et al., 2008; Akcil and Deveci, 2010). The bioleaching of chalcopyrite is still a major challenge (Bosecker, 1997; Brierley and Brierley, 2001; Ehrlich, 2004). A study conducted at Billiton Process Research showed the following preferential order of sulfide minerals leached by mesophilic cultures: chalcocite > bornite > cubanite > covellite > pyrite > enargite > carrolite >> chalcopyrite (Dew et al., 1999). The bacteria can solubilize the valuable metals from the orebodies by the oxidation of minerals. Bacterial adhesion plays a critical role in the bioleaching processes (Chen et al., 2008; Harneit et al., 2006). Generally, bacterial adhesion can be explained by surface thermodynamics and the extended DLVO theory, in which the adhesion energy between the bacteria and mineral is calculated as a function of the separation distance (Sharma, 1999; Bos et al., 1999; Sharma and Hanumantha Rao, 2002). These methods take into account Lifshitz-van der Waals interactions, electrostatic interactions and acid-base interactions (Busscher et al., 2010). These interactions are very well understood and formulated in mathematical equations. The most important inputs in these calculations are surface energy, surface charge, electron donation and electron acceptance on the bacterial cell surface and mineral."

Jan 1, 2015

The occlusion of unliberated gold particles in silicates and sulfides in crushed/milled ore dictates the recovery that can be expected. The grade of this occluded gold in cyanide leach residues shows a consistent, general relationship to the head grade of the ore, irrespective of mineralogy or geographical location. The residue grade almost invariably increases with the head grade, but not in proportion to it. This phenomenon appears to stem from the nature of the geological events originally responsible for creating the ore deposits. A statistically-based technique for determining the true head grade-tail grade relationship from gold plant operating data is described. The effect is illustrated with results from several worldwide gold milling operations analyzed over the last 35 years.

Jan 1, 2008

By R. Buisman, K. Reyneke, M. Fullam, J. V. Brown

Most mineral processes currently in use, such as flotation, spirals, gravity concentrators, etc., are only effective over a small range of sizes, hence the upstream need for technology to accurately classify fines by size. The Pansep’s design is revolutionary. Slurry is fed onto connected mesh sections that move without bending or vibration, in a circular motion. Both sides of the screen mesh are utilized, so Panseps are self-cleaning and has half the footprint of other mesh-type screens. Developed in South Africa in 1997, the Pansep has proved itself very effective as a wet fines screen to effectively classify fine mineral fractions from 50 to 2,000 micron (325 to 10 mesh).

Jan 1, 2001

By J. Manrique, B. Bustamante, P. Altamirano, J. Mendoza, J. Reyes

With no doubt, Peruvian mining potential is great as well as the energetic one. Unfortunately, this potential is threatened by social unrest. Several methods and strategies from different standpoints have been rehearsed with respect to unrest in Peru, however, the problem goes on without getting the right conflict interpretation and most of all, effective solutions are not achieved. The mining unrest dates from ancient times and has not always had the same stages nor the same demands. In the 20´s and 30´s, conflicts focused on workers’ rights and demands. In the 70´s, conflict focused on mines nationalization that were under foreign control. In the 80´s, conflicts took place because of requesting better wages, better working conditions, better mining profits distribution and more investment in communities that surround mining projects. It is very important to highlight those transversal demands such as land purchase, agricultural property, impacts and water reduction as well as pollution, impact on water systems and disappearance of springs have always been present over the historical period.

Mar 2, 2022

By D. M. Thayer

Laboratory and pilot plant investigations have indicated that copper recoveries of 50% can be achieved with fine grinding and flotation of a copper reverberatory furnace slag, Microscopic and microprobe studies indicate that the recoverable copper is in the form of matte, chalcocite, and metallic copper; the percentage of copper in particles appearing to be copper-free was from 0.23 - 0.54%.

Jan 1, 1969

By Mucella Ersoy, Nese Celebi

Management Information System (MIS), is a system using formalised procedures to provide management with appropriate information to make timely and effective decisions. Before developing MIS, first functions of the organisation should be defined and grouped into subsystems. After determining the information required and produced by each system and interaction between subsystems, the related data resources should be structured into a series of databases and files. In this study, the MIS developed for Soma Open Pit Mines, Turkey is described in this respect. First, analyses of the existing system including user requirements and scope of the system are given. Then the designed information system, its subsystems, interaction between subsystems and system structure are presented in detail.

Jan 1, 2002