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By S. B. Kim, J. Hong, K. Park, W. Kim, H. Kim, Y. Han, J. Choi

"For the first time, the influence of stearyl trimethyl ammonium chloride (STAC) as a collector, on the flotation behavior of lepidolite (Uljin, South Korea) was systematically examined in Denver Sub-A cells. Flotation tests were carried out by varying amount of STAC (50–200 g/ton), feed size (-65, -100, -150, and -200 mesh), and solution pH. The impeller speed of 1000 rpm, flotation time of 10 min and AF-65 (a frother) of 250 mL/ton were invariably applied. In order to complement flotation experiments, zeta potential measurements and XRD analysis were conducted. XRD results showed that the ores were mainly composed of lepidolite, muscovite, quartz, calcite and albite. In addition, zeta potential results showed that isoelectric points were about 2.5, 2.3, and 9.7 for quartz, albite, and calcite, respectively, and lepidolite was determined to be less than 2. Overall, the results of 3-stage flotation showed that Li2O grade and recovery tended to increase with increasing STAC dosage and decreasing feed size. In addition, Li2O grade increased with decreasing pH. The results were explained by the extent of the interaction between STAC and each mineral.INTRODUCTION A great number of potential applications of lithium are being developed currently by the thermonuclear fusion power generation industry(1,2) as well as by the battery and fuel cell industry(3). Even though lithium is mainly consumed in the form of lithium metal and some lithium compounds, about 10% of total lithium production is consumed directly as mineral concentrates by the ceramic industry for the manufacture of special ceramics and mica based glass-ceramics(4). Granitic pegmatites normally contain feldspars, quartz, and mica in addition to lithium-bearing minerals such as spodumene (LiAl(SiO3)2), petalite (LiAlSi4O10), and lepidolite (KLi2Al(Al,Si)3O10(F,OH)2). The amount and grade of metallic minerals tend to gradually decrease and become lower, leading to the increase in the price of base metal or metallic compound(5). Accordingly, recent studies have been extensively devoted to developing the technique to improve the grade of metallic minerals from low grade metallic ores(6,7). Nevertheless, studies regarding the improvement of Li grade from lepidolite ores are very scarce. Lepidolite is a phyllosilicate mineral of the mica group and is often associated with other minerals such as calcite, muscovite, feldspar, and quartz, which need to be separated for lepidolite enrichment(8). Many studies have reported the flotation techniques for separating calcite, muscovite, feldspar, and/or quartz from various targeting minerals(9-11); however, there has been no attempt to investigate physico-chemical properties of lepidolite and its separation from such types of gangue minerals through flotation. Hence, in this study, for the first time, flotation has been carried out for the quaternary ammonium salts (stearyl trimethyl ammonium chloride (STAC, (CH3)3CH3(CH2)16NCl))-lepidolite system based on only the electrokinetic property of minerals that consist of lepidolite ores without adding any depressant to get an initial insight on its flotation behavior. The experimental variables that influence the lepidolite flotation such as amount of collectors, feed size and solution pH have been also examined."

Jan 1, 2015

By T. P. Meloy

Improvement of grade and recovery requires the use of optimum processing circuits. Critical to an optimum circuit is the set point for separation. With the introduction of the concept of circuit analysis (Meloy, 1982), it became possible to determine optimum circuits for a given task. No analysis, however, has yet been made as to the grade requirements of the larger circuits. Williams and Meloy (1982), reviewed the literature and concluded that, within the operating range, most unit operations involved in particle separation behave linearly. For the purposes of this analysis, linearity will be assumed. Grade, G, is defined as the weight of the coal mineral, C, that appears in the product, divided by the weight of the coal mineral plus the weight of the gangue mineral or waste mineral, Q, which appear in the product.

Jan 1, 1982

By J. J. Gusek

An 81 hectare (200 acre) tailings impoundment at a taconite operation in Wyoming that ceased operations in 1983 has been a source of blowing dust. The site qualified for reclamation under Wyoming's Abandoned Mine Land (AML) reclamation program. The ultimate reclamation construction included: incorporating commercially available organic amendments and fertilizers into a 300 mm (12 in) thick "cap" of a sterile clay loam cover material, lowering the water level in an adjacent flooded mine pit that was feeding uncontrolled seeps into the tailings basin, constructing a wide tailings pond spillway that allows flood control while minimizing seasonal water level fluctuations in the pond, and building rock berms and rock snow fences for wind erosion control and soil moisture preservation. Tree planting in the protective wind/snow shadows of rock berms and rock snow fences, and the plugging of a decant pipe are planned for future work.

Jan 1, 1998

By C. Roos

"Mining companies have included quantifying uncertainty, or at least risk, as a requirement of project justification for many years. However, many times this process lags behind the traditional mine planning process and the results are rarely used to improve the plan. Nearly every parameter used in a mine plan is an estimate and the mine planning engineer should recognize, and even embrace, the inherent uncertainty in those parameters and its effect on their forecast results. While many of the uncertainties are beyond the scope of the traditional mine plan (e.g. global market uncertainty, socio-political uncertainty, environmental uncertainty), some uncertainties can, and should, be included in the mine planning process.Many mining engineers have incorporated techniques such as Monte Carlo Simulation or Discrete Element Simulation to understand the range of productivity that can be expected for an operation, but most still rely upon one estimated model for what is likely the critical component of technical uncertainty, the geologic resource. Modern geostatistical methods can provide multiple orebody realizations to provide a thorough unbiased picture of the geologic uncertainty. However, most traditional mine planning techniques are not formulated to allow for multiple (100-200) realizations of each material quality/grade parameter.Commercial software companies and research groups are progressing with development of tools that can incorporate geologic uncertainty, and even optimize extraction plans in the uncertain environment. Unfortunately, this author believes that a significant number of mining operations will not be able to adopt these techniques due to the computational requirements of the advanced techniques and the costs associated with implementing proprietary software. In an attempt to encourage mining engineers to embrace the inherent uncertainty in their mine plans, this article presents a cost-effective alternative that can be developed in-house, at any mine, to schedule mid- to long-term mine plans while continuously monitoring the uncertainty in the results. The aim of this article is that by demonstrating the usefulness of such a system, mining companies will encourage engineers, geologists and geostatisticians to find ways to incorporate this powerful data into their processes and procedures."

Jan 8, 2017

By D. R. Spears

The U.S. Bureau of Mines has developed a Fast Air-injected hydrocyclone-Shallow Tank (FAST) flotation system. Conventional flotation cell kinetics are a compromise between two conflicting requirements, the need for an agitated zone for rapid bubble-particle collision, and a quiescent zone for bubble-pulp separation. The Bureau of Mines has designed a flotation system in which bubble-particle collision and bubble separation are carried out in two discreet unit operations. A bubble slurry was mixed with an ore slurry at a high rate in a modified air-injected hydrocyclone for rapid bubble-particle collision. The mixture was then fed into a unit specially designed for rapid separation of the bubbles from the pulp. A conventional flotation cell required 2.8 min to obtain 90 pet recovery at a 7-pct Cu rougher concentrate grade, whereas the FAST flotation system can obtain 85 pet recovery with a 13-pct Cu rougher concentrate grade in 0.28 min, and 92 pet recovery with a 7-pet Cu grade in 0.56 min. The Bureau's FAST flotation system is adaptable to a wider variety of flow sheets and could potentially allow for replacement of conventional flotation cells with smaller and faster units.

Jan 1, 1991

By A. Haghighat

The Missouri University of Science and Technology?s (Missouri S&T) Experimental Mine is a teaching and research facility which has been excavated in limestone by mining engineering students over almost 100 years. The mine is currently being extended to a second level. Available fans for ventilation are two surface fans of 24 kW and two underground booster fans of 12 kW. The design of a ventilation network in conjunction with multi surface fans and booster fans entails a complex procedure. Ventsim Visual software modeling has been used for network analysis to determine the optimum surface and booster fans locations, blade settings, and speeds. Both natural and mechanical induced ventilation pressures have been taken into account. Three working faces on each level have been designated as target points that minimum air quantities are required. The model has been calibrated against a pressure and quantity survey. Design of ductwork, door/stopping positions and different fans characteristics have been examined. The optimum flow rate at identified working faces, efficiency and minimum energy losses and annual network power cost determine the best scenario. The optimum design has been determined for the ventilation network for the next 100 years. The optimum flow rate across working faces is the key criterion selected.

Feb 23, 2014

By C. Opoku-Ware, M. Kukay, P. Conrad, F. Inkoom, R. Pal

Researchers at Montana Tech are investigating the potential for developing trees tolerable to degraded un-reclaimed mine site tailings and soils as a solution to re-establishing long-term tree growth on those sites. This project involves growing tree seedlings from seeds planted in the degraded mine tailings and soils in which they will eventually be planted. The outcome of the project is expected to lead to a successful solution for re-establishing tree growth in degraded tailings and soils in Butte, Montana with minimal post-planting human intervention. Work conducted on the project to date has shown successful growth of seedlings in degraded tailings and soils. INTRODUCTION In an effort to improve Butte Area One natural resources, this research project is working to help restore tree growth in the Butte Priority Soils Operable Unit Boundary (BPSOU) (Opoku-Ware, et al 2018). Research by Blicker, et al (2003) found that, the BPSOU, which is part of the Silver Bow Creek/Butte Area National Priorities List (Superfund) Site within and near Butte, Montana has multiple historic mining sites situated entirely within the urban setting of Butte. Mine wastes and mill tailings, accumulated from over 100 years of gold, silver, and especially copper mining are dispersed throughout Butte, posing health risks to human and environmental receptors. Stabilization of tailings sites is needed to control fugitive dust, prevent run-off of toxic material resulting in subsequent sediment deposition in streams, reducing the volume of water seepage through acidic and heavy metal contaminated material, and improving land productivity and aesthetic values (Watkin and Watkin, 1982). If successful, the project will help restore water quality and maintain stream flow in Silver Bow Creek where it flows through Butte Area One. Trees native to Butte are being grown to seedlings in a greenhouse located on Montana Tech’s campus which will be planted in degraded soils located within the BPSOU. Growing trees is expected to help restore vegetative ground cover within the watershed contributing to stream flow in Silver Bow Creek. The trees will prevent soil and tailings from eroding and being deposited in Silver Bow Creek where they could degrade water quality and choke stream flow. The project combines research with tree seedling growth to provide a resource for Butte that could produce thousands of tree seedlings each year adapted to the harsh climate, soil, and tailings conditions that exist in the BPSOU where they will grow. It is anticipated that the trees developed by the project will have the capability for long-term survival and growth because they will be germinated and grown into seedlings in the degraded soils and tailings collected from the BPSOU where they will be planted. Soils and tailings collected for the project have been evaluated to determine if they lack nutrients or contain substances potentially toxic to the long-term growth and survival of the trees. Toxic levels of metals, high concentrations of soluble salts, extremes in pH, nutrient deficiencies and imbalances, surface crusting, high bulk density, low infiltration rates, high surface temperatures, low cation exchange capacity, restricted microbial activity, low water retention, harsh climatic conditions and surface particle movement are some of the traits of mine tailings sites that restrict revegetation efforts (Barth, 1986).

Jan 1, 2019

By J. Bilant, B. Carlson, N. Gow

High Pressure Grinding Roll (HPGR) technology has been evaluated to replace tertiary cone crushing at Coeur Rochester operations (Coeur Rochester, Inc.) as an opportunity to improve silver recovery. In 2016 and 2017, onsite and third-party pilot programs were initiated to evaluate the impact of metallurgical recovery and heap leach performance of crushed product generated by an HPGR. In 2018, Forte Dynamics evaluated the HPGR laboratory metallurgical data from Coeur Rochester and all third parties to develop field-scale leach curves based on new crushing scenarios. The laboratory recovery test work data was consolidated and scaled to field conditions to determine projected heap leach performance. Based on the metallurgical testing conducted, the replacement of current tertiary cone crushers with HPGR technology has the potential to increase Coeur Rochester’s silver recovery rate by 8%, from 61% to 69%, and shorten the overall timing of silver recoveries from 20 years to just over two years. INTRODUCTION The Rochester mine, and associated valley fill heap leach facilities is an open-pit silver and gold mine located in Pershing County, Nevada, approximately 26 miles northeast of the city of Lovelock. In 2017, Rochester produced approximately 4.7M troy oz silver (Ag) and 51k troy oz gold (Au). Ore mined at Rochester is either fed directly to the primary X-Pit crusher, crushed at an in-pit crusher system, or placed directly onto a heap leach pad as run-of-mine (ROM). Both crushing circuits are comprised of three stages of crushing to produce a nominal 3/8” ore. Primary crushing consists of jaw crushing while secondary and tertiary crushing are composed of varying cone crushers. Historical recovery rates of crushed Rochester ore average 61.4% Ag and 95.9% Au over a period of 20 years [1]. These rates were derived from third party verification of in-house metallurgical test results, crusher production and heap leach production results from 1986 through 2004 in a private report for Rochester produced by KD Engineering Co., Inc. Recovery rates are regularly verified by compositing daily samples of ore delivered to each leach pad from the X-pit crusher, in-pit crusher, and/or ROM. A proportionate split of each sample is used to generate monthly composites for metallurgical analysis utilizing column leaching and bottle roll leaching. These tests are run in a manner analogous with production conditions and deliver test results that provide expected heap leach performance. As the Rochester oxide deposit has been mineralogically and metallurgically consistent, the gold and silver recovery trends have also been consistent over the life of the project. In 2016 and 2017, onsite and third-party pilot programs were initiated to evaluate the impact of HPGR technology to metallurgical recovery and heap leach performance of crushed product in an open circuit configuration, as a potential replacement for the currently in place tertiary cone crushers. During these years, HPGR was evaluated in three phases of test work.

Jan 1, 2019

By Norbert Patzelt, Johann Knecht

Future ore reserves of major gold producers in North America and elsewhere will consist of refractory gold ores. About 60 % of the current U.S. gold production is mined in Nevada. Several of the large gold operations in this state indicate that 40 to 90 % of their future ore feeds will contain refractory gold. To com­pound problems, average head grades for refractory U.S. gold ores had fallen from 8 - 9 g/mt to about 4 g/mt by 1991. In Latin America, 52 % of the gold operations will require milling for optimal recovery. Deeper reserves are, like in North America, refractory. Therefore a special treatment process is needed in order to allow for the gold ore to be leached downstream in a conven­tional cyanidation process for a high gold recovery. There are several options available for this oxidation process like treat­ment of the gold bearing ore in pressure oxidation, in a biooxi­dation or in a roasting plant depending on the reason for the refractoriness. If organic carbonaceous matters and sulfides are the prima­ry reasons for the refractoriness, whole ore roasting is a pre­ferred method for the treatment of this type of ore. Since dry ore is to feed to the roaster, a dry grinding mill is advantageous. For the dry grinding system, the moisture content and the ore char­acteristic is of importance. Those parameters decide the mode of the grinding system. For autoclave systems common wet grind­ing systems can be applied. This paper deals with technical aspects for dry grinding plants and gives an outlook on and pos­sibilities for new grinding systems.

Jan 1, 1996

By V. Carabias-Hütter, A. J. Basu

The paper aims at promoting sustainability assessment and reporting into practice using a globally acceptable set of guidelines and a common framework for internal and external reporting at a project/site level. Indicators are used for measuring performance, and this paper addresses development and implementation of performance indicators for sustainability assessment and reporting at local as well as global levels. The selection of a proper set of indicators is a challenging task. The indicators selected should provide the expected information for making right decisions. Relevant and credible sustainability reporting supported by a consistent performance indicator system can be the starting point for benchmarking environmental and social performance for the natural resources sector.

Jan 1, 2004

By K. P. Wang, Ta M. Li

The Chinese energy and mineral industries are readying themselves for a period of dynamic transition, unprecedented in the country's long and sometimes turbulent history. The transition comes as a result of the government's new program of "Four Modernizations" in its agricultural, defense, industry, and science and technology sectors. The announced program is generally considered by Western observers to be a moderate, pragmatic approach to get China on the road to industrial parity with Western nations by the year 2000. The game plan calls for integration with the West to beef up Chinese know-how and the purchase of foreign technology to supplement areas where China lacks the ability to do so itself. While the role of energy and minerals is not specifically mentioned in the program, it was made clear to ME that China realizes the basis of any sustained modernization program is tied closely to the health of its minerals sector. Various published reports have indicated the existence of an already vibrant energy and minerals sector with world rank production in coal, iron ore, tin, antimony, cement, pyrite, asbestos and tungsten to name just a few. For the most part, except for the export metals, the primary focus of China's production has been on fulfilling domestic needs. Now the new initiatives are aimed not only at self-sufficiency, but also on propelling the country's natural resource clout into international prominence. With a mineral resource base that is considered by many westerners a potential bonanza, China's new long march toward modernization will be an exciting adventure, well worth watching. Big Projects Spark Excitement China's renewed commitment to a more liberal program is as much a desire to "walk on its own two legs" as it is a backlash from the frustrating years that followed the Cultural Revolution of the 1960s and early 1970s. Much of the early excitement was initiated by China's Premier and Party Chairman Hua Guo-feng in speaking to the fifth National People's Congress (NPC) in 1978. Here, Chairman Hua presented the Communist Party's 10-year blueprint for economic development. Specifically, the Party's plans called for completion of 120 large-scale industrial projects by 1985. Mentioned were 10 new iron and steel works, 30 power plants, six new railways, 10 oil and gas fields, nine nonferrous metal

Jan 3, 1980

By J. R. Batista

Leachates from gold heap-leaching mines contain selenium concentrations as high as 2 mg/L. Previous studies report satisfactory selenium adsorption by activated alumina when using relatively "clean" drinking waters. However, the findings of these studies cannot be directly applied to the treatment of mine leachate where other ions compete for the alumina adsorption sites. This study evaluated the adsorption of selenium from a mine leachate to develop design parameters for full-scale activated alumina processes. The study revealed that 68% of the selenium in the leachate could be removed by alumina at pH > 5.0. Silica adversely affected the selenium adsorption capacity. At pH values < 4, silica was poorly adsorbed by alumina and selenium adsorption was improved.

Jan 1, 1994

By David B. Ashley

Risks in underground construction are often viewed as technical in nature; "running ground, " "squeezing ground" and "chimneys" are terms that appear in construction managers&apos; nightmares, and occasionally in their underground projects. Financial consequences of these and other project risks are reviewed. Special attention is paid to sources of cost overruns. From this study a structure evolves for setting priorities for risk management actions; these actions can also be tested for impact and potential effectiveness. Finally, case study reviews of six underground projects indicate the "state of the practice" for financial risk management.

Jan 1, 1983

By Fahimeh Dehghani, Louis Ackah, Tathagata Ghosh, Justin Godbold, Jia Liu, Meisam Peiravi, Manoj Mohanty, Azam Baharlouei

Primary economical deposits of rare-earth elements (REEs) are exhausting all over the world, and it has become necessary to find new sources and methods for their extraction. In addition, increasing the application of REEs in modern technological society has increased its demand globally. One of the important movements to compensate for the future shortages of critical metals is the recovery of REEs from recyclable materials. This paper presents a review of the classification and extraction methods, as well as general applications of REEs with emphasis on secondary sources such as coal and coal byproducts, iron ore tailings, apatite, and phosphate byproducts. An overview of the current state of knowledge on the various methods of REE beneficiation and extraction is covered. These methods include physical separation, as well as hydrometallurgical and bio-hydrometallurgical techniques. The application of these REE extraction techniques for enhanced recovery has been driven primarily by the unique industrial application of these important elements. This paper further explores the existing and potential environmental challenges associated with REE extraction. The authors have presented a wide array of literature, in-depth discussion of the subject, and a succinct summary of processes and relevant case studies.

Sep 23, 2020

By L. Cui

X. Huang (1997) recently suggested a poroelastic model for simulating the hydraulic fracturing breakdown pressure. His paper began with a discussion questioning Haimson and Fairhurst&apos;s (H&F) model. He claimed that the H&F model failed to lead to the Hubbert and Willis (H&W) model as[ a --> 0.] Huang also tried to explain why the H&F model could only work for special types of rock conditions. He pointed out that one possible reason could be that the Terzaghi&apos;s effective-stress concept had been adopted. The H&F model (Haimson and Fairhurst, 1969) was derived under the conditions that the borehole wall is fully penetrated (pp = pi) and a drained state is realized (steady pore-pressure field). Cui et al. (1997a) demonstrated that, under drained conditions, the total stresses in the penetrating poroelastic model (identical to the H&F model) degenerate into their counterparts in the elastic model (identical to the H&W model) as [a -- 0.] However, the effective-stress conditions are different for both of these models, because different pore-pressure conditions at the borehole wall were adopted. In the H&W model, p = po was assumed, i.e., the pore pressure field is not disturbed; but pp = pi was assumed in the H&F model. Assuming that Terzaghi&apos;s effective-stress controls tensile failure (that was the hypothesis adopted in both the H&F and the H&W models), only the following two special drained poroelastic cases may degenerate into the H&W model for very small a: • when the pore pressure at the borehole wall remains at the same level as the virgin pore pressure for a penetrating model and when the borehole wall is simply impermeable (i.e., the nonpenetrating model, Cui et al., 1997b). Therefore, simply setting a = 0 in the H&F model generally does not lead to the same problem described by the H&W model. On the other hand, when the porepressure boundary conditions do not correspond to the ones in the H&W model, a degeneration of the poroelastic model to the H&W model as [a – 0] should be questionable. The pore pressure at the borehole wall is generally dependent on the injection-fluid pressure and the penetrating conditions at the borehole wall, such as the existence of a filter-cake. For an impermeable wall, pp is independent of Pi, and it is basically an unknown [(how¬ever, pp -- po as t --oo).] For a fully permeable wall, pp is the same as Pi. Between these two extremes, pp should be a function of p; and the permeable condition of the borehole wall, which may be dependent of the leak-off coefficient cf. (the range of cf is from 0 to 1). Theoretically, for a rock with low permeability, a penetrating borehole wall is still possible. For saturated porous materials with very low values of a, poroelasticity shows that a pore pressure will be built up due to the stress concentration subjected to a nonhydrostatic in situ stress field (Cheng et al., 1993). This phenomenon is known as the Skempton effect. The variation of the pore pressure may be evaluated by [AP = 3 B(A rr + 06ee + A (Y,,)] (1) where B is the Skempton pore pressure coefficient. This pore pressure variation dissipates as time increases (it is totally gone as the drained state is approached). The rate of the dissipation mainly rely on the permeability of the formation. The dissipation is very slow for tight formations because their permeability is very low, and it is fast for rocks of high permeability. According to our analyses, the time period for this process could be from seconds (for sandstone&apos;s) to a couple of days (for stales). One possible reason that the H&C model did not agree well with the experimental results for rocks with low permeability might be that the time interval between the application of the loading and the fluid injection had not been long enough for the dissipation of the Skempton effect. The effective-stress law basically defines how much pore pressure contributes to the total stress. The difference between Terzaghi&apos;s effective stress and Biot&apos;s effective stress is that 100% of the pore pressure contributes to the total stress in Terzaghi&apos;s definition, while only a certain portion of the pore pressure ((ap) goes to the total stress in Biot&apos;s definition. Therefore, when the pore pressure at the boretole wall (pp) is determined according to Biot&apos;s effective-stress law, app in the total tangential stress is attributed to the pore pressure. In other words, Terzaghi&apos;s effective tangential stress is expressed

Jan 1, 1999

By Michael Chender

The rapid and continuing expansion of computer and communication capability is giving birth to profound changes in the business environment. Some commentators hold that the basis of the world economy has already shifted from industry to information. Regardless of the overall implications of these changes, it is now clear that every company potentially has both access to and a need for much more information for decision making than was the case a few years ago. The importance of information to the mining industry has been underlined by the rash of unexpected economic and political developments and by the accompanying market volatility that have marked the past decade. It should be abundantly clear to even the smallest mine operator that the price for his output can be instantly affected by unexpected developments halfway across the world. Nevertheless, many mining companies still are much less sophisticated about information than they might be. For many, the historical feeling that information is an unnecessary luxury for a production-oriented business still seems to linger. On the other hand, the overwhelming volume of source material, uncertainty as to its accuracy, and the problems of finding relevant material when needed, presents stumbling blocks to viable systems of information management. Introduction When a company needs certain information, it has two basic alternatives. It can either research and develop the information in-house or pay for someone else to do it. Few mining companies have the in-house capability to assemble information needed for careful planning. On the other hand, companies often engage consultants to find information that is in fact easily accessible. All too often companies give up on procuring needed information because of the frustration of not being able to find it, and of not wanting to pay seemingly exorbitant sums for someone else to produce it. The result is poor planning. This article addresses two aspects of the information problem-finding the right sources and then accessing the particular information desired, especially as it pertains to nonferrous metal exploration and development issues. In the first section, major English-language sources that report on exploration and development (excluding primary sources of geological information, such as technical journals) are discussed.* In the second section, some available techniques for efficiently accessing this information are presented, focusing on the new MINESEARCH database system. Part One: The Information Following the News The most obvious way to follow exploration and mining developments from a distance is through regular mining media. Many active mining districts have local newspapers, usually published in the district&apos;s major towns, that give extensive coverage to miningrelated activities. For instance, to follow activities in Idaho&apos;s Coeur d&apos;Alene silver district, one might subscribe to the Kellogg Wardner News and/or the Wallace Miner. Similarly, one might get the Sacramento Bee for news of current mining developments in north-central California. The American Metal Market, published in New York, is the daily newspaper that covers the metals industry as a whole, both in the US and abroad. Its coverage is weighted towards the refining, manufacturing, and consumption end of the business, but it frequently carries stories on mining activity, company dealings, and market outlooks. For news of major mining companies, the daily Wall Street Journal provides occasional coverage of North American companies, while the Financial Times of London serves as probably the best single source for worldwide company information. International Coverage There are three metals industry weeklies that have broad international coverage and readership. These are Metal Week, Metal Bulletin, and Mining Journal. Each has its strengths. Metals Week, a McGraw-Hill newsletter, focuses primarily on news of the metals markets, concentrating on those developments that are seen to most directly affect the price of nonferrous metals. Metals Week is strongest on North American news. Metal Bulletin, published in London, is particularly strong on

Jan 4, 1983

By Donald D. Murphy

My first contact with underground, bolt conveyors came when I was hired as a draftsman by the La-Del Conveyor & Manufacturing Company in 1935. At that tine relatively few nines were using haulage belt conveyors. Wore they were in use, they were usually loaded by chain or shaker type room conveyors which in turn were hand loaded at the working face. Duo to the low room tonnage, a gathering belt might receive who output of from six to eight rooms. For several years belts 26 and 30" in width were the favorites for coal mine use. Belt speeds very seldom exceeded 200 ft. per mm. at that time. Conveyor lengths for the majority of units lay between 1.000 and 2000 ft. For a number of years 25 H.P. drives were adequate for those conveyors. From 1940 until about 1950 loads and speeds went up slightly and 40 H.P. drives became the standard. Since the majority of mines were then using direct current power systems, we were able to use controllers with 3 or more steps of starting resistance. The slow belt speeds coupled with relatively long starting cycles kept the rate of acceleration low and gave us smooth, easy starts.

Jan 1, 1963

By Craig M. Sams

Dry grinding circuits and factors influencing the selection of the most appropriate grinding system for a given ore selection are discussed. Comparisons of the drying, grindability, installed costs and operating costs are presented for several grinding systems.

Jan 1, 1994

By M. E. Gershon

Software for coal blending has gained a lot of recent attention as micro-computer programs have come on the market. Some of this software is appropriate and some is not. This paper looks at the types of models being used and points out the strengths and weaknesses of each. Recommendations are then made concerning the level of detail required for these programs, relating this concern to the various ways in which coal companies are using these programs. A checklist of company requirements for these programs and available pro-gram-features provides an aid in matching the program to the company.

Jan 1, 1988

By Larissa Koroznikova, Steve Durkin, Patrick Bouwmeester, Michael Tuck

 This research project explored the viability of a new mining technology — thermal fragmentation — in narrow-vein mining. Thermal fragmentation technology uses a flame jet to produce extreme heat that spalls the surrounding rock to a strategically located drill hole, as an alternative to traditional blasting. This paper creates a net present value (NPV) model of a mining method using thermal fragmentation as well as one of an existing method used for narrow-vein mining. Comparisons and evaluations were made regarding the feasibility of the new technology. It was found that while overall costs for thermal fragmentation were relatively high, reductions in wages, haulage and processing costs as well as increased productivity and ore recovery meant that the new method would improve the financial performance of any operation.