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By K. S. Eric Forssberg, Lennart Ryk

The paper discusses coal utilisation in Sweden. All hard coals have to be imported from other countries. Peat from domestic sources is used as a complement. Environmental legislation and taxation on fuel and emissions are severe. This situation affects the procurement, preparation, handling and use of coal. The paper presents: • R&D projects concerning deep cleaning of thermal coal. • Handling and treatment of coal used in PFBC boilers and for blast furnace injection • Dust prevention for coal and peat briquettes. Procurement of coal emphasising quality and environmental issues.

Jan 1, 1995

Introduction The US mineral industry in 1983 participated in the recovery from the recent recession. Compared with 1982, the value of raw nonfuel mineral output rose 8% to $21.2 billion. The $218 billion worth of goods processed from this crude mineral output represented a 9% increase over 1982. Even in real terms, these figures reflect growth. Demand for nonfuel mineral materials, of course, depends on the overall state of the economy, which steadily improved each quarter in 1983. Of particular importance to the mineral industry were surges in key mineral-consuming sectors such as construction and automobile manufacturing. New housing starts rose one-third, to 1.7 million units, while automakers turned out about 35% more cars (6.8 million) and 25% more trucks (2.4 million) than in 1982. These are significant increases, even considering recent trends toward smaller, lighter vehicles, and multiple-unit housing. A comeback for the mineral industry, however, is bound to proceed unevenly, particularly at the beginning. Traditionally, the industry lags behind the rest of the economy during a recovery, and some mineral products respond to overall economic improvement more quickly than others. This pattern has been repeated many times and the industry is used to it. Mineral executives know it is best to be patient and cautious during the first stages of an economic upturn. Many experts say that it may take extraordinary toughness, patience, and caution this time around. Steel Improves Raw steel production - a major indicator of both material use and mineral production - rose 14% to 77 Mt (85 million st), stimulating a 7% rise in domestic iron ore production to 39 Mt (38 million It). Still, the iron ore industry operated at less than half capacity, with most major mines remaining closed for part of the year. Iron ore imports dropped 24% to 10 Mt (11 million st), so demand was partly met by withdrawals from stocks. Despite the increase in steel production for 1983, output remained far below levels of just a few years ago. For example, 1983 production was still 29% less than in 1981. Raw steelmaking capacity actually declined about 10% during the year to 122 Mt (135 million st). The industry continued to cite steel imports, especially those from developing nations, as a major cause of domestic capacity loss. As long as steel production remains weak, steelmaking metals suffer. Domestic producers of bulk ferroalloys of chromium, manganese, and silicon operated at about one-third capacity in 1983, with six of the 19 companies involved being closed all year. The US mined no manganese or chromium, and very little nickel, although the country's only nickel mine did resume production in November. Molybdenum production, at 13.6 t (15 st), was only about one-third as much as in 1982. The major molybdenum mines, Climax and Henderson in Colorado, remained closed all year. To meet demand, molybdenum stocks were halved to 19 t (21 st). Mine shipments of tungsten, another mineral tied to steel production, dropped 30% to 1.1 kt (1,200 st) of contained metal. One of the most positive responses to the general economic recovery came from the aluminum smelting industry. By the end of the year, it was operating at about 79% capacity, compared to 59% in January. Nevertheless, the 3.3 Mt (3.64 million st) of primary aluminum produced represented only a slight increase over 1982. Total bauxite imports were about 27% below 1982 levels. Production of magnesium metal rose 11% to 100 kt (110,000 st). But titanium was more typical of other

Jan 5, 1984

By M. C. Rockwell

There are about 1.8 Mt (2 million st) of discarded dolomitic-limestone tailings from the Gays River lead/zinc mining operation in Nova Scotia currently stockpiled in a tailings pond at the mill site. Neutralization effectiveness similar to an agricultural grade limestone and low contents of residual metals make the tailings a potential source of soil conditioner material for the local market. However, the fine particle size, 98% passing 147 pm (about 100 mesh), and a moisture content of 20% make their handling, shipping, and application to soils difficult. The tailings were agglomerated into small hard pellets with various amounts of soil nutrients, moisture content less than 13%, and pH values ranging from 6.5 to 8.7.

Jan 1, 1987

By J. Hindman, E. Moeller

Vermiculite is currently mined from shallow (less than 25 m or 80 ft) surface deposits throughout the world. The largest producers are Palabora Mining of Phalabowra, South Africa (ore stock is a phlogopitemica), Xinjiang Yuli Xinlong Vermiculite of Korla, China, and W.R. Grace of Enoree, SC (ore stock is a biotite mica). Smaller operations are in Australia, Brazil, Russia and Zimbabwe. They also produce vermiculite on a continuous basis but do not export any significant amounts of product to North America. Intermittent and poorly documented production on a minor scale is reported from Argentina, Egypt, India and Uganda. Worldwide vermiculite production in 2004 increased1.7 percent to 432.8 kt (477,000 st). North American production declined, while African and Chinese production continued to increase.

Jan 1, 2005

By A. M. Marabini, V. Alesse, Belardi. G.

An alternative flowsheet was designed for the flotation treatment of a complex sulfide ore from the Sotiel Mine in Spain. The ore contains 0.71% Cu, 2.24% Pb and 5.63% Zn. Two specially developed synthetic collectors, methyl-mercapto-benzoxazole (MMBO) and 6n-propoxy-mercapto-benzo-thiazole (PMBT), were examined. MMBO exerts a specific action on copper and zinc minerals after treatment with copper sulfate, and PMBT exerts a specific action on Pb minerals. Flotation operating variables (pH, frother type, frother quantity and feed particle size) were examined by means of rougher flotation tests to determine the optimum conditions for the new collectors. Once the optimum conditions were determined, a series of open flotation circuits were run on feeds of various particle sizes (obtained by different types of grinding). The objective was to obtain high-grade Cu and Zn concentrates. The results of the open-circuit tests demonstrated that a Cu concentrate grading from 18% to 23% Cu and a Zn concentrate grading from 40% to 48% Zn can be produced.

Jan 1, 1996

By Timothy J. L. Haley

The population of the Rhondda underwent a spectacular rise as energy requirements increased in the mid-nineteenth century. The rapid expansion in the demand for coal transformed the population from a few hundred sheep farmers in the eighteenth century, into a thriving coal-based economy of some 168,000 inhabitants in 1924. Cochrane (1958) put forward the idea that the differential migration of more healthy men from the Rhondda Fach during the period since the peak of population in 1924, had resulted in a respiratorily-impaired residual population. This idea was used to explain the reduced survival of miners & ex-miners aged 55-64 years from this valley as compared with a similar group from Leigh in England. Using the proportional hazards regression model of Cox (1972), a comparison is presented of the exact twenty-year mortality of migrant and non-migrant miners & ex-miners and non-miners from the Rhondda Fach. The analysis makes allowance for the pattern of migration throughout the twenty-year period and adjusts for the confounding influence of variables such as age, occupation, and category of Simple Pneumoconiosis. The results indicate that contrary to expectation, any effect of migration upon mortality is manifest only at higher ages. Furthermore, for these men, the migrants have worse survival than the non-migrants. Also, contrary to expectation in the light of work by the British Coal Board (Soutar et al, 1982) there is no evidence of increased mortality amongst men with category I simple pneumoconiosis. INTRODUCTION [The Background] In September 1950, the Medical Research Council's Pneumoconiosis Research Unit at Penarth in South Wales initiated a study of lung disease in the smaller of the two Rhondda Valleys - the Rhondda Fach. At that time, the primary interest was in assessing the possible role of pulmonary tuberculosis in the aetiology of the serious (complicated) form of coal-workers' pneumoconiosis, i.e. Progressive Massive Fibrosis. The Rhondda Fach is situated in South Wales, some 25 km north-west of Cardiff. It is a narrow winding river valley about 12 km long, and approximately 1 km wide. The name means Little Rhondda; there is a corresponding Big Rhondda - the Rhondda Fawr. Together, these valleys make-up most of the Rhondda Municipal Borough. Following the initial survey in 1950-51, there have been several follow-up studies of this population. In addition, amongst numerous other investigations to unravel the aetiology of coal-workers' pneumoconiosis, Medical Research Council teams studied various other (sample) population groups, particularly in the industrial areas of the adjacent Aberdare Valley, and in Staveley and Leigh in England. The agricultural areas of the Vale of Glamorgan in South Wales, and Annandale in Scotland were also studied.

Jan 1, 1993

By R. B. Coleman, T. P. McNulty

HISTORICAL PERSPECTIVE Environmental protection is not a newcomer to the minerals industry, there having been numerous examples dating from decades ago. Sometimes the awareness of a need for preservation or restoration derived from the ethics and principles of the engineers and management responsible for development and operation of a property. On the other hand, pressures to clean up industrial messes frequently were applied by special interests such as farming and ranching, recreational and conservational groups, and local governing bodies. Mineral industry environmental controls in this century have therefore been a patchwork of good intentions and bad, clean operations and dirty ones. The Hoboken siphon converter for converting copper matte while effectively capturing sulfur dioxide at a relatively high concentration was developed in Olen, Belgium in 1928, a full sixty years ago. The alternative was closure of the Hoboken smelter by Belgian government health officials who had become intolerant of sulfur dioxide emissions which were causing serious respiratory ailments in the river valley in which Olen is situated. As early as 1958, the Anaconda Company had a full-time botanist on its metallurgical research staff with the responsibility of learning how to vegetate the extensive tailings deposits at Anaconda, Montana. By that time, considerable progress had already been made in restoration of Silver Bow Creek, which at one time was “dead” for as far as 40 miles down- stream from the point of entry of acid mine drainage in Butte.

Jan 1, 1989

By Hooman Askari-Nasab, AHLAM MAREMI, EUGENE BEN-AWUAH

In oil sands mining, tailings are voluminous unwanted byproducts generated from extracting the desired mineral from the mined ore. Dyke construction and backfilling activities require well-managed techniques to facilitate progressive reclamation at the earliest opportunity. This directly affects the sustainability and profitability of the mining operation. This research introduces a goal programming framework that simultaneously optimizes the (1) production schedule with limited duration stockpiling and directional mining, (2) dyke construction schedule, (3) size, shape and location of tailing cells and (4) mining and processing production targets. The results show that in creating in-pit tailing-cell designs, decreasing the mining-cell volume and increasing the number of mining cells improves the net present value (NPV) of the operation due to increased operational flexibility.

By L. Korkiala-Tanttu, M. Rinne, Z. Song

Disposal of mine tailings has been recognized as an unavoidable burden of mining companies and local authorities. Conventional methods dispose mine tailings in a passive manner which hardly generates any value from them. On the other hand, growing local communities close to mines need more infrastructures which require great amounts of raw materials. In view of the above mentioned situation, a novel utilization of mine tailings is explored as alternative material for asphalt pavement, in order to extract more value from mine tailings and solve the high cost of pavement material. Inherent physical properties of the mine tailings were first investigated to find out their availability as pavement material. Then test specimens were made as mixture of the mine tailings and other pavement material to be tested in laboratory. The mine tailing materials presented a considerable potential as asphalt filler for low-volume roads. Furthermore, the limitat

Jan 1, 2011

By D. Moraetis

The present study examines the nutrients and micronutrients availability of uncultivated soils originated from different parent rocks. The study areas include four types of parent rocks with different geological origin, from acidic to ultramafic. The parent rock mineralogy and the nutrients available in soils are in strong relation-ship. Mineralogy, particle size distribution and chemical composition of the soil samples were studied jointly with the nutrient content of soil solution. High magnesium availability in soils of Anogia area is related with the alteration products of the ultramafic rocks. Potassium content of the soils exhibits no relation with the geology of the area. Micronutrients, iron and manganese, shows strong dependence to the bulk chemistry and mineralogy of the parent rock material. In contrast no interrelation detected between zinc and copper availability in soil and parent material.

Jan 1, 2006

By Wayne Taylor, Martyn Dawborn

Simulation modeling of portions of two platinum mines using General Purpose Simulation Software (GPSS/H™) is presented in this paper. Both mines, located in the Bushveld Igneous Complex PIC) of South Africa, exploit Merensky and UG2 reef horizons, which are processed separately and therefore handled individually from the stope face to surface, requiring duplication of storage arrangements and batch operation of transport facilities. The first simulation assignment concerns the upgrading of a shaft system operating exclusively on Merensky ore, to hoist UG2 ore and increase production. The second assignment comprises a simulation of rock flow from the stope face to surface by way of tramming, inclined conveying and vertical hoisting. Development ends and stope boxholes were modeled down to individual hoppers (cars) demonstrating the versatility of the GPSS/H™ language.

Jan 1, 2002

By A. D. Trujillo, R. D. Wunder

The Chino Mines Co., a Kennecott- Mitsubishi partnership, located in Hurley, NM, recently completed a $405 million modernization of its mine, concentrator, and smelter facilities. The mine/concentrator modernization commenced in 1980, and the smelter modernization began during 1982. Modernization of the mine and concentrator facilities involved increasing the mining rate from 98 kt/d (108,000 stpd) to 152.2 kt/d (167,800 stpd). Ore mining was designed to increase production from 20.2 kt/d (22,300 stpd) to 34 kt/d (37,500 stpd). A new concentrator was con- structed near the mine using semiautogenous grinding. The new smelter uses the INCO flash smelting process, increasing capacity by 40.8 kt/a (45,000 stpy) to 99.8 kt/a (110,000 stpy) of saleable copper.

Jan 1, 1988

By Jinrong (Patrick) Zhang

Improvement of conventional flotation efficiency, separation of carbonates from apatite, recovery of phosphate values from phosphatic clay and other ways of utilizing the clay, disposal of clay slurries and subsequent reclamation of the settling areas, and conservation of resources and energy remain major challenges in the beneficiation area for the phosphate industry. These problems have been actively investigated by the industry, government agencies, and research organizations for decades with modest success. However, some recent research activities have generated promising results and possible new technologies. The dominant position of the Crago process in phosphate beneficiation is being challenged by some of the single stage processing schemes. Heavy media separation enables one producer to process a portion of high carbonate ores. Separation of dolomite from apatite by reverse flotation of carbonates with phosphate depressants showed potential for industrial application. Consolidation of phosphatic clays in mine cuts using a modified "sandwich" process is being tested. Beneficiation in the acidulation plant or grinding at the mines may be considered in the future.

Jan 1, 1993

By D. L. Sober, D. Ince, T. V. Vasudevan

Separation of dolomite from Florida phosphates was achieved by first conditioning the feed with fatty acid at pH 10 followed by reconditioning at pH 4 or below, before flotation. Observed selectivity of this two-stage conditioning process was attributed to the amount as well as changes in the nature of adsorbed collector species upon reconditioning. In this paper, bench-scale flotation results of optimizing the major process parameters, such as reconditioning pH and collector dosage, for upgrading natural high dolomitic phosphate samples from Florida are discussed.

Jan 1, 1991

By K. G. Tan

Widely available silver and arsenic bearing concentrates can be smelted to produce a discardable slag, a base metal speiss, and a crude silver button which is easily separated from the other phases after solidification. This paper discusses the development of a novel process as an alternative to existing nitric acid leach methods for the production of high purity silver from the raw silver button. Direct electro-refining of the raw silver anode in a sulphate medium is integrated with downstream purification and recycling modules that are customized to allow efficient recovery of silver and saleable by­products. The test results, flowsheet alternatives and process details are presented and discussed in terms of overall technical feasibility, economical viability and environmental compliance considerations.

Jan 1, 1999

By J. K. Mokka, P. D. Rao, H. K. Lin

Extensive exploration has resulted in delineation of a massive sulfide district on the north flank of the east-central Alaska range. The district covers approximately 400 mi2 and contains numerous stratiform, transposed and some replacement type sulfide deposits ranging in size from less than 1 million st to 20 million st. Five types of ores were sampled for the study. Mineralogical analysis revealed that the minerals are too fine grained for conventional grinding and beneficiation. Hydrometallurgical studies were conducted using ferric chloride as a lixiviant. Ore microscopic studies as well as electron microprobe analyses of minerals in the raw samples and leach residues explained the low recoveries for certain elements as well as sources of impurities that need to be eliminated from the process streams.

Jan 1, 1992

By Drew F. Holbrook

Most of the siliceous rocks of the Arkansas Novaculite are novaculite, but they also include some chert, siliceous shale and, rarely, sandstone. Novaculite is defined as a homogeneous mostly white or light-colored rock, translucent on thin edges, with a dull to waxy Juster, and comprised almost entirely of microcrystalline quartz. The most plausible theory of origin for novaculite is that primary silica from submarine volcanism was picked up by organisms and deposited as amorphous silica, which was subsequently converted to microcrystalline quartz (novaculite) through diagenesis. The Arkansas Novaculite crops out over an east-west distance of 200 miles in the Ouachita Mountains of Arkansas and Oklahoma. Three divisions of the formation have been defined: a Lower Division, almost entirely massive light-colored novaculite; a Middle Division of interbedded dark chert and shale; and an Upper Division of massive calcareous novaculite. The Lower Division and most of the Middle Division are Devonian in age, and the remainder of the Middle Division and all of the Upper Division are Mississippian. The massive novaculites of the Upper and Lower Division attain their maximum development along the southern and central outcrop belts of the formation in Arkansas, and it is these rocks that are the source of current silica production. The calcareous novaculite of the Upper Division weathers readily to a light-colored, porous, less brittle rock, and in places to tripoli deposits. Currently tripoli is mined from a single deposit near. Hot Springs, Arkansas, and the rock is processed for highly specialized filler and abrasive applications. In the vicinity of Hot Springs, Arkansas, certain novaculite layers from the Lower Division with unique textural characteristics are quarried and processed into whetstones. Several small quarries produce this rock for two local and one out-of-state whetstone-fabricating plants. Chemical analyses of composite samples of novaculite from both the Upper and Lower Divisions taken at widely separated localities average 99 percent SiOz indicating a substantial resource of high-silica rock.

Jan 1, 1978

By T. R. Ellis

The vast majority of valuations produced for mineral properties using the net present value method provide an estimate of investment value or use value. Such an estimate can be a long way from the price that the property would actually sell for if placed on the market. Indicators from the market need to be used to validate or modify the net present value calculation if market value is being appraised. The comparable sales and replacement cost methods used in the appraisal of urban buildings generally fail when used in the appraisal of mineral properties. Other methods of sales analysis are introduced. Guidelines for what a minerals appraisal report should contain are presented.

Jan 1, 2002

By Charles Fisher

When considering the biodiversity of fauna endemic to hydrothermal vents or hydrocarbon seeps one must consider not only the numbers of unique species, but also the physiological diversity (and potential biochemical/physiological uniqueness) of the fauna. The deep ocean ridge system is home to some of most extreme animal habitats found on Earth. In addition to the high pressure, low temperature, and lack of light characterizing the deep-sea in general, hydrothermal-vent environments are characterized by toxic chemicals and temperatures that would be hostile to most other animal life. Perhaps even more challenging than the absolute levels of chemicals, dissolved gases, and temperature with which vent animals contend are the extreme gradients in time and space of all of these parameters. For example, temperatures around some vent animals can fluctuate from ice-water to hot-tub levels over seconds and can exceed 350°C only inches away. Specially adapted animals not only tolerate these conditions, they often thrive under them. As a result, the biomass of many deep ocean ridge ecosystems rivals that of coral reefs and tropical rain forests. In the Gulf of Mexico, hydrocarbon seepage through the sea floor driven by salt tectonics results in environments that are geologically very different from hydrothermal vents, but are geochemically similar enough that closely related animals are found in the two habitats. This includes seep mussels, clams, shrimp, worms, and other animals whose close relatives are found in hydrothermal vent environments. Although many aspects of the biology of the animals from the two environments are very similar, there are also significant differences in their life histories and physiologies that reflect the fundamental differences in the geology of their habitats.

Jan 1, 2008

By Jeong-Heum Kim, Jan M. Mutmansky

A number of solution methods for solving the nonlinear equations derived from mine ventilation networks use meshes selected from the network as the basis of the solution techniques. Mathematicians working in network theory have outlined several methods for speeding up the computations through mesh selection and ordering procedures. In the mine ventilation area, a fair amount of attention has been paid by ventilation specialists to procedures for choosing the meshes so that the computational effort is eased. However, little attention has been paid to mesh ordering methods. This paper outlines research into random mesh ordering procedures plus two non-random mesh ordering procedures and compares some results using these procedures within four solution algorithms.

Jan 1, 1993