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By Hans Breuer

The new regulations for the bituminous coal mining industry, issued by the mining authorities of the Federal Republic of Germany, are aimed at reducing to a feasible minimum any development of the coal workers pneumoconiosis (CWP) by lowering the admissible dust exposure of mine workers. Additional and improved measures of dust suppression and job assignment control *) are required for the purpose In this connection two basically different demands are placed on dust measurements: As far as dust suppression is concerned, the causes of dust development and the effectiveness of methods applied to reduce dust concentrations have to be identified, whereas with regard to the control of job assignment, the dust exposure of mine workers has to be depermined. Demands placed on dust measurements -- specifically for determining dust exposure -- are liable to become more severe since the threshold limit values were considerably reduced in these last years and since any additional dust suppression measures as well as a purposeful job assignment to certain mine workers are dependent on relevant measuring data. Therefore, research work has been carried out with the objective of measuring and evaluating, in terms of their effect (i. e. their incidence on the development of a CWP), size distribution, concentration, and specific noxiousness of any prevailing dust conditions.

Jan 1, 1980

By John J. Dran

In recent years, market rates of interest have risen well above their historical long-term average. Also during this period, the short-term variability of interest rates has been greater than in prior years. Interest rates have a significant effect on the operation of our economy. They influence the extractive industries in a number of ways. Their major long- range impact is on investment decisions - specifically the valuation of mineral deposits. An understanding of the factors that influence interest rates is important to the engineer or businessman who makes the investment decisions for the mining company. The effect of changes in the market rate of interest on the value of mineral reserves is critical to the future financial success of the mining enterprise. The most common simplification of the factors determining the level of interest rates is that they are a function of the demand for and the supply of money. While this is an oversimplification, most businessmen would be hard- pressed to provide a better explanation. The purpose of this paper is to explore certain fundamental economic aspects of interest rates and to examine their effect on the analysis of investment in mineral deposits.

Jan 1, 1975

By James M. Barker

Marketing is the linchpin of the industrial-mineral (IM) industry. Without markets and consumers for IM products, all other associated IM activities are superfluous. The simple existence of an IM deposit does not mean that it can be exploited. A dynamic interaction between exploration (geology), mining, processing, transport, marketing, sales, and consumers is required for profits. Geology dictates the existence of a deposit, but markets dictate its development, and transportation provides the connection. This is true to such an extent that marketing commonly is called the exploration phase of IMs. Marketing is strategic and includes long-range market-development and planning activities, whereas selling is tactical and more focused on day-to-day consumer interactions. Each will help the other when properly done. Many producers of IMs have failed because of inadequate marketing skill, information, and practice. Over many years at the Montana Bureau of Mines, the many developers seeking technical assistance to find an IM deposit, but who had no marketing plan, always failed. In contrast, the few who sought assistance first on marketing, with the IM deposit to be found later, always succeeded (Richard Berg, personal communication, 1998). Marketing has many facets helped by geologists who must be aware of what marketing is attempting to do. A geologist needs to understand many aspects of IMs: location (deposits, plants, consumers), processing (specifications), transportation (truck, rail, barge, ship), competition (local, regional, national, international), substitutes, pricing, and new developments and market forces of all kinds. Some needed skills are not taught formally to geologists, so well-rounded self-education and on-the-job training are the way a geologist normally enters into IM marketing. The IM geologist generally is associated with marketing either by helping to prepare a market study or by acting on the results of one. Preparing a market study is a two-part process. The first part is relatively simple but requires a time-consuming collation of data into an IM survey (mostly past-and present-oriented). The more difficult and much more important second part entails expanding the IM survey into a market evaluation (mainly future-oriented) that emphasizes forecasting, timing, location, and specific products. A market evaluation generally boils down to formulating the right questions to ask of the right persons. One very good question to ask is, "What could be the market for this specific IM?" while thinking for yourself without excessive recourse to gossip, rumors, promoters, developers, or (at times) IM experts. The evaluation must prove that market potential exists and suggests a marketing plan. Effective marketing is an ongoing process, with the initial marketing plan modified over time, using wide and continuous input to avoid tunnel vision. Industrial-mineral markets are based either on commodity (lower-priced, basic-processing) minerals or specialty (higher-priced, value-added) minerals. IM marketing methods are either product-driven (commodity minerals), a more traditional approach, or market-driven (specialty minerals), but these are neither mutually exclusive nor is one always better than the other. Focusing too much on specialty minerals can lead to problems. A blend of commodity products with specialty products commonly lowers risk and enhances long-term profits. The highest profits occur in specialty minerals at the cost of higher risk and complexity and require intelligent marketing, versatile technical services, and creative research and development. Industrial minerals are best served by an industrial-marketing approach rather than a consumer approach. Modern industrial marketing emphasizes the consumer using the "marketing concept." The marketing concept focuses all management and operational activities on total consumer management and satisfaction similar to the total quality management approaches to excellence.

Jan 1, 1999

By Byron R. Berger

Disseminated Au-As-Hg mineralization is localized along the Getchell Fault system at the Getchell Mine in north-central Nevada. Replacement ore bodies occur in Cambrian carbonaceous limestone and limy shale beds. Cretaceous granodiorite, dacite porphyry, and andesite porphyry dikes parallel the fault zone and are spatially associated with the mineralization. Hydrothermal alteration and mineralization occur continuously along 4-5 km of the fault system, and extend more than 1 km down-dip. Alteration consists primarily of removal of carbonate and deposition of quartz, pyrite, and carbonaceous material. Marcasite, sericite, kaolinite, calcite, barite, and fluorite are common. Gold content reaches more than 43 ppm in parts of the altered zones and averaged 9.3 ppm in the mined ore bodies. For the mineralized zones as a whole arsenic averages 0.28%, and occurs primarily as realgar, orpiment, and arsenopyrite. Mercury (22 ppm) is finely disseminated and mercury-bearing minerals are seldom recognizeable. Accessory mineralization includes antimony (100 ppm), copper (47 ppm) , lead (18 ppm) , molybdenum (10 ppm) , tungsten (16 ppm) , and zinc (50 ppm) . Geologic field studies and K-Ar dating suggest that the mineralization is related to a hydrothermal system produced by the granodiorite and related dikes.

Jan 1, 1975

By T. A. E. Breen

A new high intensity grinding technology has been developed and is now being commercialized by Hicom International of Australia. This has led to the development and manufacture of Hicom 120 grinding mills which are now being sold internationally for a range of mining industry applications. The first commercial process application has been for the diamond sector, where the ability of the mill to remove host kimberlite rock by attritioning, with no damage to the thereby liberated diamonds, is seen to be a most beneficial attribute. There are, however, many other mineral industry applications for this mill.

Jan 1, 1999

By Mark Van Dyke, Ted Klemetti, Jake Beale, Zoheir Khademian, Joe Wickline

In 2016, a 3.7-ML magnitude event caused by mining activity occurred at a longwall mine in southwestern Virginia which was recorded by the United States Geological Survey (USGS) and felt by local residents. The event was the largest of its kind since a global mine design change by the operator was instituted in 2008 following three large events in 2005, 2006 and 2007 (3.4, 4.3, and 3.4, respectively). Two of the three pre-2008 events (2005 and 2007) damaged ventilation controls in the mine which fueled a mine fire. In 2016 the mine’s management requested researchers from the National Institute for Occupational Safety and Health (NIOSH) to access geological data and determine what parameters could possibly lead to events of a magnitude of 1.0 ML or greater. Evaluation of 2,152 geological data points and modeling revealed three major geological factors in common with the majority

By Glenn Melchert, Paul Eger, Jon Wagner, Dave Antonson, John Folman

Current approaches to reclaiming acid generating tailings include permanent water cover or encapsulation with various synthetic liners and/or clay. Although these methods can be effective, some ongoing maintenance will be required in perpetuity to ensure that water levels are adequately maintained or that the integrity of any capping system is protected. The successful creation of wetlands in tailings basins offers the possibility of creating a stable environment for the tailings with minimal maintenance. Acid-generating tailings from a massive zinc sulfide deposit in Winston Lake, Ontario, were placed in small cylindrical tanks to examine the feasibility and effectiveness of creating wetlands and mitigating acid and metal release. Two uncovered controls were established in addition to the five treatments, which were done in duplicate. Each wetland tank was 117 cm in diameter and contained 6 1 cm of tailings. Treatments included 61 cm cover of wetland soil, 61 cm of glacial till, 61 cm of tailings, and two tanks with 71 cm of water. One of the water covers included the aquatic macrophytes: Elodea canadensis, Potamegeton sp., and Ceratophyllum demersum. Cattails (Typha latifolia) were planted in the plots with substrate cover, and the initial water level was set at ten centimeters. The pH within the tailings in the treated tanks generally ranged between 6.0 and 6.5 and zinc concentration ranged from 0.02 to 0.1 mg/L. The drainage from the controls had an average pH of 3.3, and 7,700 mg/L of zinc.

Jan 1, 2000

By H. Dho

The role of sodium silicate in the anionic flotation of a Florida phosphate ore was investigated using laboratory continuous flotation tests, frothability tests and SEM observations. In the absence of sodium silicate, Ca++ promoted the unwanted activation of quartz by forming calcium bearing precipitates. The addition of sodium silicate enhanced the flotation efficiency through: (1) the removal of impurity minerals and calcium-bearing. precipitates from quartz surfaces by dispersion, (2) drier and more persistent froths stabilized by oily droplets containing calcium silicate precipitates, and (3) higher specific flotation rates of phosphate relative to quartz, leading to faster flotation rates and increased selectivity of separation.

Jan 1, 1990

By M. Niec

Poland lies at the junction of three geologic provinces: the East European Precambrian platform, the Middle European Paleozoic platform, and the Alpine orogenic belt comprising the Carpathian Mountains. However most of the rocks that contain mineral deposits and many of the recently explored and mined deposits are commonly hidden under thick overburden, sometimes up to over 500 m thick. The discovery of these mineral deposits was due to the combination of geologists talents for inference and the keen interpretation of geophysical data ultimately tested by drilling. Examples of such use of the state-of-the-art geology include the following: 1. Sedimentologic and paleogeographic reconstructions led to the discovery of 8.8 Gt of bituminous coal under 500 m of Jurassic and Cretaceous cover in the Lublin basin, 2. Tectonic and paleogeografic data suggested a potential for discovery of burried Upper Permian copper de-posits on the Foresudetic monocline; subsequent exploration discovered 75 Mt of copper and 0,17 Mt of silver, 3. Geological interpretation of gravity and magnetic da-ta combined with sedimentologic data and regional subsur-face geology resulted in the location of 1.3 Gt of Fe-Ti-V ore in the Precambrian basement of northeastern Poland under -500 m of cover 4. A combination of metallogenic theory and geological interpretation of regional geophysical mapping led to the discovery of Caledonian-Hercynian granites and grano-diorites with accompanying porphyry-type Mo-W-Cu ores below 300 m cover on the northeastern border of the Upper Silesian coal basin 5. Tectonic reconstructions based on gravity and seismic data combined with theory on the origin of native sulfur led to the discovery of 1.0 Gt of native sulfur under cover up to 300 m thick. Five deposits were found at the northern margin of the Carpathian Foredeep. The other deposits found include lignite, polyhalite, lead-zinc ores.

Jan 1, 1996

By Bo R. Arvidson

The strongest magnetic roll separator available on the market enhances certain industrial minerals purity to levels not reached previously. Exceptionally strong forces can also be utilized for processing relatively fine particles at feed rates several times greater than for prior art electromagnetic induced roll separators. Since the unique machine does not work with an air-gap, coarser particles than what has been considered practical can be separated at rates up to 20 tph per single machine unit and 40 tph for a double machine unit. Examples for all these three application areas will be given. While the roll separator can be used only for dry processing presently, the other new separator can be used for both wet and dry applications. It is a medium-intensity, high- gradient magnetic separator employing a filamentary matrix. It was primarily developed for recovery of weakly magnetic iron ore fines, but it is finding applications for cleaning of industrial minerals such as wollastonite, calcite, clay and talc. Its main advantage is a simple design resulting in a very lm cost machine both with regards to total capital investment and operation. A significant technical advantage exists also. The metallurgical performance is similar to conventional electromagnetic separators, while the cost per ton is about half of such separators.

Jan 1, 1985

By V. M. Johnston

The most abundant fuel resource in the U.S.A. is also the most under-utilized. Proven reserves of bituminous coal, sub-bituminous and lignite constitute from 60% to 90% of our total fossil fuel reserves -- dependent upon the parameters used by the analyst making the estimate. Despite this ample supply, bituminous coal provided only 20% of U. S. energy consumption in 1967 and 1968, this dropping to 17.57 in 1971 and 1972. By 1978, according to my projections, 16.7% of the Nation's mechanical energy will come from bituminous coal. However, our energy needs are growing at such a rate that the 20.6% provided by bituminous in 1967 equalled 480 million tons while the 16.7% of U. S. consumption visualized for 1978 will require nearly 650 million tons. In order to view coal's position with perspective in this developing energy crunch, it is necessary to examine the total energy situation. To this end, I have prepared a couple of tables which you should have before you. I chose this procedure rather than slides because I would need to utilize an entire wall to make the data visible to an audience. Therefore, I refer you to the long sheet entitled "U. S. Energy Consumption - Trillion Btu - 1967-1978." As you can see from the heading, I am confining my treatment of the problem to the intermediate term. In the long run, if we are willing to pay the cost, we can do a lot of things, including the complete conversion of coal into a sulfur-free fuel.

Jan 1, 1973

By K. Verghese

Neutron capture prompt gamma-ray analysis provides the best method for on-line analysis of the elemental composition of large volumes of bulk material. This paper summarizes the Monte Carlo models which simulate the radiation transport within two such analyzer systems; namely, the borehole configuration and the conveyor belt configuration. The models are useful in the design optimization of the analyzer systems, in minimizing the amount of experimental calibration data for calibrating these analyzers, and in investigating the detection sensitivity for different elements. The computational scheme in these models is made extremely efficient by the use of various powerful variance reduction methods and by efficient data management. Experimental verifications of the two models carried out in the laboratory indicate very good agreement with the Monte Carlo results.

Jan 1, 1984

By Walter R. Lawrence

Newmont Gold Company, formerly Carlin Gold Mining Company, is a publicly owned corporation, 95% owned by Newmont Mining Corporation. Newmont Gold Company has operated gold recovery operations North of Carlin, Nevada, since 1965. Development of the Gold Quarry ore body, 19 kilometers south of the original mine, resulted in the decision to construct gold recovery and ancillary facilities in what is referred to as the Southern Area. Plant No. 2, located 11 kilometers North of Carlin, Nevada, was designed to treat 6350 tonnes per day of oxidized gold bearing ore assaying 2.5 grams per tonne of Au at an average recovery of 87%. Flowsheet development conducted by Newmont personnel resulted in the decision to construct a carbon-in-pulp recovery circuit preceded by two-stage grinding, Detailed engineering was done at Toronto by Bechtel of Canada beginning on January 1, 1984. Actual construction began on March 1, 1984, and was completed in June, 1985. First feed was run on June 22, 1985.

Jan 1, 1987

By F. S. Knoll

The high tension process which separates materials based on relative differences in surface conductivity has been very successful in recovering non-ferrous metals from municipal waste. Aluminum is by far the largest constitutent of the total non-ferrous metal fraction; accounting for >95% in most localities. Wire and insulation mixtures from industrial wastes have been treated commercially for several years by a high tension process initially developed for use in the iron ore industry. The wire and insulation application was a forerunner of municipal waste dry treatment technology. In the past eighteen months the rotating-drum-type electrostatic separator has undergone extensive testing and development in order that the process might be efficiently adapted to the recovery of aluminum from municipal waste.

Jan 1, 1974

By M. S. Celik

Despite its importance in various diverse industries, research on beneficiation strategies of boron minerals has not received enough attention. Boron minerals are primarily upgraded by wet processing methods. However, severe environmental constrains have accelerated the development of dry processing techniques such as calcination. Interestingly, boron minerals, colemanite, ulexite and borax undergo respectively decrepitation (fragmentation), shrinkage and expansion upon heat treatment. Each mineral then requires a different beneficiation scheme. In this study, laboratory and pilot plant studies on calcination of boron minerals conducted in our laboratories are reviewed along with their implications in commercial operations.

Jan 1, 1997

By Robert L. Gamble

The world's largest fluidized bed steam generator located at Rivesville, West Virginia is currently undergoing initial operation. This unit is designed to generate 3708 kg/s (300,000 Ib/hr) equivalent to 30 MWe of superheated steam while firing coal in a fluidized bed of limestone. Coal was first fired in this unit in December, 1976 and start up operation is progressing.

Jan 1, 1977

By M. Z. Rashad

The purpose of this work is to determine the influence of sample length or size on the value of variance (Semi-variogram) to select the suitable length that is required to the geostatistical computations of ore evaluation. Three cases in Ghorabi Iron Ore were studied. The first one was on the iron fraction (Fe\) at which the semi-variogram gave an evidence to good continuity of the fraction in the ore. In this case, the length of sample has not important influence. The second case was for the Mn\ component of the same area where the semi-variogram has a nugget effect. The selected length for this case was 4 meters. The Cl fraction of the ore was the third case where the anisotropic phenomena was appeared and the suitable length is 3 meters.

Jan 1, 1992

By T. M. Gurr

In response to concerns voiced by local, state, and federal agencies and various environmental groups, the Central Florida Phosphate Industry and various governmental agencies have been investigating methods to accelerate the consolidation of waste clays generated during phosphate washing and beneficiation processes. The objectives of research efforts have been to reduce the storage volumes required for clay waste, accelerate reclamation and to return the land to approximate pre-mining topography. Government and industry research to accelerate waste clay consolidation has evolved two general methods: gravity thickening and chemical flocculation. Gardinier, Inc. one of the phosphate mining companies, evaluated the use of synthetic (polyacrylamide) flocculants as an alternate waste clay thickening method in response to mining conditions encountered at their Fort Meade Mine and the proposed North Hardee County extension of the Fort Meade mine (Figure 1). After considerable research and evaluation, the Alsthom-Atlantic Clariflux Super-flocculation method was chosen by Gardinier, Inc. as a method to seriously consider for use at their Fort Meade mine.

Jan 1, 1986

By G. Robert Guillet

Nepheline syenite is a light-colored feldspathic rock that is used primarily as an addition to the glass batch. It is also used in ceramics and as an industrial filler. Composed essentially of the soda and potash feldspars and nepheline, nepheline syenite contributes needed alkalis and alumina to the glass composition. And because it contains a higher proportion of these oxides per unit weight, it is a formidable competitor for feldspar in northeastern North America and parts of western Europe. Nepheline-bearing rocks are not uncommon on a world scale, but few are able to be beneficiated to a composition sufficiently low in iron to be used in the making of glass. Nepheline can only form in an environment deficient in silica. Hence free silica, as quartz, is always absent in the primary mineral assemblage. Biotite, hornblende and magnetite are usually present as minor accessory minerals, and zircon, garnet, muscovite, and apatite may be present as trace minerals. Nepheline syenite is produced for glass, ceramics, and filler markets by Unimin Canada Limited at Blue Mountain, in south- eastern Ontario. Unimin acquired the former Indusmin and IMC properties from Falconbridge Ltd. in 1990. Elkem Nefelin AIS commenced production of similar products from Stjernoy Island in northern Norway in 1961. Unimin acquired this company in 1992. Nepheline has also been a byproduct of apatite mining on the Kola Peninsula for many years, and in 1951 the production of alumina from nepheline was commenced in a plant near St. Petersburg (Leningrad). There are now four plants in the Russian Republic, two smaller ones based on nepheline tailings from apatite mining and two larger and more recent plants in central Siberia using other nepheline resources. All four of these plants are integrated complexes that produce alumina for the subsequent production of aluminum metal, sodium and potassium carbonates, and portland cement. Roofing granules are produced by the 3M Company from a nepheline rock in Arkansas. In 1980 and 1989, trial shipments of nepheline syenite were recorded from new sources in Brazil and western Turkey respectively. Recent interest is also recorded for deposits in China, Saudi Arabia, and British Columbia.

Jan 1, 1994

By R. P. Plasket, G. M. Dunn

The cobalt plant was successfully commissioned in mid-1983. It is located within the company's nickel - copper re finery situated in Springs, South Africa. Plant design, which began in 1981, made provision for the corrosive process environment, stringent environmental standards, and the latest noise abatement requirements. In addition, the process flowsheet for the primary recovery of the cobalt byproduct and the purging of six impurity metals (nickel, iron, copper, manganese, lead, and arsenic) was designed with simplicity as a primary objective. High purity cobalt powder has been produced since commissioning.

Jan 1, 1987