Search Documents

By Paul Swatkowski

A Note About Copyrighted Material ??Permission to Use? has been granted ?Teachthe7habits ?Think win/win (4thHabit) ?Don?t stop here ?i.e., buy the book

Jan 1, 2009

Choosing the correct delay time for many blasting applications is an important and critical blast design parameter for controlling fragmentation, muckpile shape, swell, digability, throw, ground vibration and airblast. BAl and its affiliates have monitored thousands of full scale blasts in a variety of field conditions, spanning over 15 countries, with sophisticated blast monitoring instrumentation. In some blast environments, a small change in the choice of delay times used had a dramatic and pronounced effect on the overall blast results. In other blast environments, large changes in the choice of delays used had absolutely no effect on the final results in terms of specific outputs. In environments which were sensitive to the delay selection, the type of explosive, dynamic response time of the rock mass (TMIN), integrity of the material, burden and rock mass geometry, all played a very important ,role.

Jan 1, 1998

By Debasis Deb

The first version of the longwall strata control and maintenance system (LSCMS) has been successfully developed by the Strata Control Re¬search Team at the University of Alabama. The system includes a software package designed to monitor shield leg pressure, interpret the data and predict the forthcoming roof loads and the existence of geological anomalies. It can also detect maintenance problems of the face equipment. The LSCMS was installed underground and connected to the surface terminals at Drummond's Shoal Creek Mine in Alabama. The system has proven to be a useful and practical system for improving safety and efficiency in coal-mining operation. The Shoal Creek Mine is a new, large coal mine operated by Drummond with two longwall panels. The Blue Creek seam is the primary source of coal production. It is located at a depth of 275 to 440 m (900 to 1,450 ft) below the surface with an approximate 2% southwest dip. Typical strata conditions are represented by two stratigraphic columns (Figs. la and b). A fireclay/dark shale parting (called Middleman) 0.2- 0.7-m- (1- to 2.5-ft-) thick exists between the Mary Lee and Blue Creek seams. Mining conditions vary from area to area. This mainly depends on the Blue Creek seam thickness that ranges from 0.9 to 2.9 m (3 to 9.5 ft). The thickness of the Mary Lee and the parting is relatively consistent with a to¬tal of 0.9 m (3 ft). They are mined when the Blue Creek seam becomes thinner. In most of the panels, the immediate roof is composed of sandy shale 1.5-

Jan 1, 1997

Procedures employing thiocyanate and dithiol complexes of molybdenum have been developed for the determination of the metal in the presence of large quantities of ferric iron. The procedures are developed for field application and it is possible to complete 200 analyses per day with laboratory accuracy. Use is made of sulphuric acid extraction and ascorbic acid reduction in the case of the thiocyanate procedure whilst the reducing system in the dithiol procedure is potassium iodide-sodium sulphite. Using a simple photometer the range of determination possible is 0-10~g for the thiocyanate procedure and 0-5 g for dithioI.INTRODUCTIONOf the many colorimetric procedures that have been developed for the determination of molybdenum only those using the thiocyanate or toluene-3, 4-dithiol complexes of the metal are sufficiently free from interference to be of use in geochemical prospecting. Rapid methods based on both these complexes 'have been developed at the. Broken Hill Division of The University of New South Wales as part of a general programme designed to improve geochemical procedures. Whilst speed rather than high accuracy is the important factor in prospecting, the aim of the programme is to develop procedures which will allow determination of 200· samples per man-day without loss of normal laboratory accuracy for the methods concerned.In most geochemical procedures visual estimation of a coloured complex is used in the determination of the quantity of metal present. At the high rate of sample determination of the improved methods this procedure places severe strain on the eyes. For this reason all methods are designed for determination by means of a simple filter photometer...

Jan 1, 1965

By Gordon] [Reavis

Halliburton Services and Brown & Root have developed a unique foundation system that blends oilfield and construction technologies to construct deep foundations which offer significant advantages across a variety of soil profiles. This highly efficient system is being developed to meet the construction industry's needs into the 21st Century. Based on a concept initially introduced to Halliburton Services by V.L. Schellhorn in 1987, Halliburton combined their existing cement slurry mixing and pumping technology with oilfield drilling practices and a new tool design to field test the viability of the concept. Results looked encouraging, and Halliburton asked it's sister company, Brown & Root to evaluate and further develop the process. With Brown & Root's knowledge of the construction industry, the original concept has developed into a viable and efficient foundation construction system.

Jan 1, 1993

By S. S. Peng, C. T. Holland

Mountain Top Removal (MTR) mining started in West Virginia nearly thirty years ago. This surface mining method can extract multiple coal seams as thin as a few inches thick with total recovery and minimum rock dilution in very steep mountainous terrain. It is highly efficient even if coal seams are in close proximity and small in aerial extent. Consequently, MTR has been widely used in the Central Appalachian Coalfield (mainly Kentucky, Tennessee, Virginia and West Virginia) for the past thirty years with great success. In that respect, there has been no demand for research and little scientific research has been performed to investigate its impacts on the surroundings in the history of MTR mining. However, in the past two years the debate over the MTR mining has grown quickly and in times become very intensely. This paper describes chronologically the issues raised by various parties, legal actions, its impacts on mining permit application and research projects developed to address the issues.

Jan 1, 2000

By Douglas R. Cook

Exploration record In preparing this paper, a list of world class discoveries prepared in 1983 has been updated. In both surveys, the following criteria were used in the definition of world class discoveries: • deposits that are continuously operated and consistently return a profit even in periods of low metal prices; • deposits large enough to significantly affect a medium sized corporation's profits; and • these deposits should be in the lower one-third cost per unit of metal produced for all similar deposits. Only 70 discoveries in the last 40 years qualified as world class deposits using these criteria. Unfortunately, this restricted population was too low to develop meaningful trends. The numbers were therefore enlarged to include all significant discoveries. The principal feature of a significant discovery is that its size and grade would yield more than $500 million in revenue using average metal prices for the last five years. A significant deposit should also meet some of the standards for a world class deposit. A tabulation of these deposits are shown in Table 1. The number of discoveries increased to 166 from 70 using the revised classification. The relationship between the number of discoveries per year and their location by continents was prepared from these data. Figure 1 shows the number of discoveries per year for the nonCommunist world. It also shows estimated and actual nonCommunist world exploration expenditures per year and the commodity price index. These data show that modern exploration started in the late 1940s, with the tempo picking up rapidly in the 1950s. The maximum discovery rate occurred in 1962. Thereafter, the discovery rate gradually declined to the present. This occurred despite a real increase in expenditures from about $200 million/a in 1955 (1982 constant dollars) to more than $900 million/a in 1980. Thus, these data suggest a significant decrease in the exploration success ratio (total exploration expenditures a year divided by the number of significant discoveries) in the last 20 years. As an example, $70 million was spent for each significant discovery in the early 1960s as compared with $225 million in the late 1970s (expressed in 1982 constant dollars). However, with the general declining trend of discoveries, one can perceive a more pronounced drop in 1973 and then a sudden increase in 1974, 1975, and 1976. This increase is probably related to the inflation of the 1970s that in turn created an environment for the explosion of commodity prices, as shown by the commodity price index on Fig. 1. Thereafter, the decline in discoveries resumed in 1975 until the present. Exploration performance by regions North American discoveries are shown in Fig. 2. The graph shows three pronounced high discovery peaks in 1962, 1975, and 1980-81.

Jan 2, 1986

By Gabriel Gonçalves Pessoa de Castro

O trabalho teve por objetivo produzir uma liga Al AA1070 com granulometria fina a partir de um material com granulometria grosseira, por meio de deformação plástica severa (DPS) aplicada por prensagem por canais equiangulares (ECAP) via rota C, bem como esclarecer e avaliar os mecanismos responsáveis pela evolução microestrutural durante este processo de prensagem. O processo empregou a rota C com 5 passes consecutivos a frio e acumulou uma deformação ?5 = 5,95. O material de partida é proveniente de um processo de laminação a quente, com uma microestrutura de grãos grosseiros com tamanho de grão de 16 ± 18 µm. Foi realizada a caracterização microestrutural com o auxílio das técnicas de microscopia eletrônica de varredura (MEV) e de difração de elétrons retroespalhados. O refinamento microestrutural foi realizado eficientemente alcançando uma microestrutura fina, observou-se uma redução de 80% alcançando um tamanho de grão de 3,38 µm, e um aumento da fração de contornos de alto ângulo passando de 23% a 46%. A partir dos resultados obtidos nas análises conclui-se que os mecanismos responsáveis pela evolução microestrutural foram os processos de subdivisão por meio de fragmentação e rotação de grãos, recuperação e recristalização dinâmica.

Aug 16, 2017

Safety is the No. 1 concern of any drill contractor or mine operator. Everyone in the industry knows a safe site helps stabilize operational costs and enables higher productivity. When it comes to exploration drilling, research has proven a majority of injuries are caused by the mishandling of coring rods. A driller helper will typically handle up to 50 rods per shift or up to 15,000 rods per year. With an annual 340 t (750,000 lb) in rods managed by hand, the risk of serious injury is extremely high. Because of this, the top request from the exploration industry is diamond rod handling. The Boart Longyear 4200 surface exploration drill, slated for release in 2009, will give the industry a hand-free, operationally safe rig.. Developed through the collaboration of its global drilling services and products divisions and targeted at the 1,200-m (3,900-ft) NQ market, the upcoming Boart Longyear 4200 surface exploration drill features the safest and most flexible rod management sys-tem in its class. The rig includes the industry?s first, truly hands-free rod handling system. This increases operator safety on the jobsite. In addition to the rod handler, the rig also features many new innovations that boost productivity and rig efficiency while minimizing the risk of downtime due to component failure or operator error. Boart Longyear has also included an intelligent PC-based operating system designed to allow complete drilling control as well as diagnostics reporting for the rig.

Jan 1, 2009

By Paul C. Schmall, Lucian P. Spiteri, Arthur B. Corwin

Moving groundwater is generally recognized as the most adversarial condition for ground freezing. Moving groundwater can occur due to natural or man-induced groundwater flow, but either way may result in freeze formation difficulties. History has shown that if the condition goes undetected, catastrophic failure of the frozen shaft or excavation can occur. The success of ground freezing under potentially flowing groundwater conditions depends on an evaluation of the likelihood for this condition; an accurate and early diagnosis, with a careful evaluation of freeze pipe temperatures and piezometer water levels; and timely reaction to mitigate the possible delays. Successful remedial measures have included the reduction of ground permeability by modifying the soil properties between the freeze pipes with various kinds of grouting, or increasing the freezing effect by adding freeze pipes and/or the use of liquid nitrogen as the freezing agent.

Jan 1, 2007

By Choon Kooi Quan

Water availability is essential for mining and minerals processing. To provide government and industry with recent data for water use planning and management, the Bureau of Mines canvassed a number of U.S. producers of nonfuel minerals to determine their water use in 1984. Data were analyzed and compared with previously published data in order to examine historical trends in water utilization in the nonfuel minerals industry and to estimate water requirements in the year 2000. Total water use in the domestic nonfuel minerals industry during 1984 was estimated at 2,267 billion gal, of which 571 billion gal was new water and 1,696 billion gal recirculated water. The largest users of water were the phosphate rock, iron ore, copper, sand and gravel, and crushed stone industries, together accounting for almost 90% of total used. More than one-half of all water was used in Florida, Michigan, and Minnesota. In the year 2000, total water use will amount to an estimated 2,679 billion gal, of which 810 billion gal will be new water and 1,869 billion gal recirculated water. Most of this water would be used in producing the foregoing suite of minerals,

Jan 1, 1988

By William H. Lewis

Energy Research Corp., under contract to the Bureau of Mines, has developed a new miners' caplamp battery. The new battery is based on nickel-cadmium technology and offers significant improvements in performance with reduced size and weight when compared to the conventional lead-acid battery presently in use. This report describes the design and fabrication of the nickel-cadmium battery, which utilizes a roll-bonded electrode structure. The final battery design has a 15-A-h capacity in a 2-112-lb package, which is over 2 lb lighter than the present lead-acid caplamp battery.

Jan 1, 1983

By V. Brabie, S. Jansson, L. Bohlin

The rate of dissolution of solid MgO-C and doloma into liquid in CaO-Al2O3-SiO2-MgO slag at different temperatures was studied under conditions of forced convection by rotating cylindrical refractory specimens in a stationary crucible containing the molten slag. The corrosion rate was calculated from the change in diameter of the cylindrical specimens. Refractory specimens were 13 mm in diameter and 70 mm long. The specimens were rotated for15 to 120 minutes at speeds of 100 to 400 rpm in the molten slag. The rate of corrosion increased with temperature and with the rotating speed of the rod, and decreased when the slag was nearly saturated with MgO. The experimental results confirm the assumption that the diffusion of magnesium oxide through the slag phase boundary layer controls the corrosion process. The corrosion mechanism seems to be the dissolution of the refractory materials into the slag, followed by penetration of pores and grain boundaries and dispersion of the grains in the slag. Keywords: MgO-C refractory, doloma refractory, molten slag, corrosion rate, corrosion mechanism

Jan 1, 2004

With the change in legislation under the Resource Management Act 1991 (RMA), the responsibility for administering the effects of blasting on the environment, has transferred from an essentially central government system to local bodies. This naturally will allow for a variety of compliance levels and control procedures which will depend on the particular local body and rather ad hoc arrangements. It is anticipated that the existing NZ Standard on blast vibration levels will soon be replaced by the Australian Standard. These changes raise the question as to what should be used as suitable compliance levels to prevent damage to structures. The paper will address the measurement, control levels and the appropriateness of current standards in relation to the overall legal framework of the RMA.

Jan 1, 1996

By R. W. Watson

In January 1980, the Bureau of Mines initiated an experimental program to examine the fire and explosion hazards of one-hour self-contained self rescuers (SSRs). This action was prompted by a growing concern on the part of government and industrial safety officials over the potential hazards of these devices when deployed on a large scale in underground coal mines. Prior evaluation of the safety of these devices had been at best sporadic and usually limited to experimental models. The recent availability of preproduction models of a l-hour SSR fabricated by the Mine Safety Appliance Company* and a production model manufactured by Dragerwerk Ag Lubeck of the Federal Republic of Germany allowed for a more comprehensive and meaningful evaluation of their safety in underground coal mines. This report summarizes the results of a 5-month study of the potential hazards of these two items. During the course of the work, periodic progress reports were presented to officials of the Mine Safety and Health Administration and various mining organizations including the American Mining Congress, Bituminous Coal Operators of America. National Independent Coal Operators Association, and the United Mine Workers of America. The free exchange of ideas that occurred during these meetings had a significant impact on the direction of this study and a serious attempt was made to address all of the issues that were raised at these meetings. The authors are extremely grateful to the individuals that participated in defining the specific problems that could arise as a result of deploying the self-contained self rescuers in an underground coal mine environment.

Jan 1, 1980

IN this paper an attempt is made to describe the sluicing operations on the tin fields of north-eastern Tasmania. No claim is made to completeness, for much of the ground has already been covered, and nothing is to be gained by needless repetition. On this account some portions of the subject have obviously received but attention in order that others may be rather more fully dealt with; for instance, referring to the accuracy of various methods of valuing alluvial deposits, particulars of efficiencies, and water duties on both overburden and drift; also, the system of recording water distribution, &c. The plans of the tin-streaming shed, sluice and feed race, and overburden tail-race represent types of the most modern design.GEOLOGY. The principal alluvial dcposits being worked at the present time are situated either in the ancient or modern bed of the Ringarooma River or its tributaries. This river flowed in a north-easterly direction, receiving numerous tributaries on either bank...

Jan 1, 1910

The author summarizes and extends the relevant results of papers previously published by various authors and presents these results in chart form. The charts are used to demonstrate the theory on a hypothetical mine.INTRODUCTIONRecently a series of articles have dealt with leakage in a mine ventilation system and the problem of its reduction.Theories were developed by Peascod and Keane (1955) for the combined effect of flow in the airways and leakage through the porous barrier between the intake and return of an ideal mine. Later Keane and Peascoa. (1956) extended these ideas to the use of an underground booster fan in increasing the face ventilation and showed how to determine the water gauge and location of the most efficient underground fan.These articles were based on the assumption that Atkin:son's formula:P = R Q2 (1)gave the relation between the pressure drop P lb'/sq. ft., the quantity, Q kilocusecs, flowing in the mine airways and the total resistance, R Atkinsons, to air flow offered by the mine roadway. An Atkinson is defined as a resistance such that 1 kilocusec of air flows due to a pressure drop of 1Ib.jsq. ft. However for conditions prevailing in most mines a more :appropriate relation is that postulated by Reynolds and others (Lamb, 1953) :P=R Qn (2)where n has some value slightly less than 2. It should be noted that Atkinsons may not be used as units when n is not equal to 2.

Jan 1, 1958

By Steve Kral

For a state whose roots are in mining, most Colorado residents probably do not realize that the industry still contributes heavily to the state’s economy. In 2005, the industry contributed, directly and indirectly, about $8 billion to the state’s economy, according to the Colorado Mining Association (CMA). It employed nearly 10,000 people at mines and support businesses. And the mining industry in Colorado is one of the highest paying occupations in the state, averaging about $80,000 a year in wages and benefits. The state’s coal mining industry produced nearly 36 Mt (40 million st) of coal in 2005, valued at $800 million, the CMA said. That was seventh in the nation. And Colorado’s only major gold mine produced 10.2 t (329,000 oz) last year, valued at $124 million. That was third in the nation. And Phelps Dodge’s Henderson Mine produced about 12.7 kt (28 million lbs) of molybdenum, valued at $350 million. Colorado is the largest molybdenum producing state in the nation.

Jan 1, 2006

By W. W. Adams

"The fifth annual National Safety Competition conducted by the United States Bureau of Mines to determine the best safety records at mines and quarries during the calendar year 1929 has been concluded, and the general results of the contest are presented herewith. To the winner in each of the five groups into which the contestants were divided there has been awarded the bronze trophy 'Sentinels of. Safety,' donated by the Explosives Engineer magazine. The trophy for bituminous coal mines was won by a mine in Alabama; that for metal mines by an iron-ore mine in Michigan; that for nonmetallic mineral mines by a salt mine in New York; that for quarries and open-cut mines went to a limestone quarry in Michigan;. the trophy provided for anthracite mines was, of course, won by a mine in Pennsylvania, as all of the anthracite mines participating in the contest are situated in that State.Winners of the trophies were selected by a committee of sward in accordance with rules governing the contest and on the basis of accident records furnished by the various companies to the Bureau of Mines. These records were summarized by the bureau and the results submitted to the committee. Members of the committee are W. H. Cameron, managing director of the National Safety Council. William Green, president of the American Federation of Labor; James F. Callbreath, secretary of the American Mining Congress; T. T. Read, Vinton professor of mining of Columbia University and editor of 'Mining and Metallurgy'; C. B. Huntress, executive secretary of the National Coal Association; A. J., Curtis, assistant to the general manager of the Portland Cement Association; A. T. Goldbeck, director of the engineering bureau of the National Crushed Stone Association.Thirty-four States were represented in the l29 contest. Among the plants which participated were 68 bituminous coal mines, 29 anthracite mines, 54 metal mines, 19 nonmetallic mineral mines, all of the foregoing being underground mines, and 141 quarries or open-cut mines. A total of 106,533,006 man-hours of work was reported by all of the companies. Accidents during the year numbered 7,008 and represented a period of disability equal to 986,306 man-days. Hence the accident-severity rate for all plants combined represented 9.3 man-days of disability for each thousand man-hours of exposure to hazard. Similarly, the combined accident-frequency rate for all plants showed that 66.3 accidents occurred for every million man-hours of exposure to hazard. Both of these rates indicated an improvement over the combined rates for all plants in the previous year's contest. The reduction in the accident-severity rate centered chiefly in the metal mine group, though all except the quarry and open-cut mine group shared in the reduction; the improvement in the accident-frequency rate was in all croups except anthracite and metal, the rate for the former having increased while that of the latter remained unchanged."

May 1, 1930

By R. Curtis

To achieve compliance with 2015 EPA Tier 4 Final regulations, which permit only around 10% of Tier 3 particulate matter (PM) and NOx emissions, a number of technologies are being implemented. Use of a fuel borne nanoparticle combustion catalyst reduces the level of PM and unburned hydrocarbons exiting the combustion chamber, alleviating the burden on downstream exhaust after-treatment systems. The impact of an iron-ceria combustion catalyst (GO2) on carbon oxidation kinetics and on diesel engine emissions is presented. The iron-ceria nanoparticles catalyze carbon oxidation at lower temperatures and increase the oxidation rate by a factor of 18 at 400 °C. Engine tests on a generator powered by a John Deere Model engine and field tests on a Cummins ISC 330 tractor truck and CAT 3508B propulsion engines are presented. Use of GO2 resulted in a reduction in PM10 (particulate matter under 10 um) emissions of up to 26% and a hydrocarbon emission reduction of up to 41%. NOx emissions did not increase in these trials and the amount of change depended on engine type. Application of this fuel borne technology for emissions reductions in mining equipment offers significant benefits.

Feb 27, 2013