Search Documents

By Serdar Aktaş, Özgün Küçükoğlu, Burcu Nilgün Çetiner, Mehmet Hakan Morcalı

This study compares the cementation performance of metallic iron, metallic aluminum, and metallic tin in terms of the reaction conditions and parameters in synthetic antimony chloride solutions. The effects on the antimony recovery (%) caused by the cementators’ types, stirring speed, reaction time, and temperatures were explored thoroughly. The cementation kinetics of antimony were also explored for each cementator. The activation energies were determined to be 10.99, 9.09, and 13.58 kJ mol– 1 for Al, Fe, and Sn, respectively. The results reveal that the reaction is diffusion controlled, and comparable results were obtained for each cementator. At 25 °C, 40 mg of iron powder was found to reduce all antimony ions (i.e., approx. 99% recovery), but even when 100 mg of Al and Sn cementators were used, the antimony recovery did not reach 100%. This result shows that iron is the best candidate to cement antimony out of the solution.

Jan 28, 2022

By J Seccatore, F Golin, E Munaretti, M Cardu, J C. Koppe, J Bettencourt

Contour blasting is commonly performed by employing linear charges decoupled from the boreholes. This method is common in surface and underground excavations, either for civil or mining purposes. To achieve the best results in terms of rock breakage and respect of the excavation profile, blasting theory suggests that charges should be inserted coaxial to the holes to grant uniform distribution of the explosive energy, therefore obtaining a uniform radius of damage. Nonetheless, due to readiness of operations or lack of availability of specific products on the market, non-coaxial charges are often employed in blasting practice. Non-coaxial charging methods include the employ of high-power detonating cord (40 to 100 g/m), low-power detonating cord connecting small-diameter cartridges (commonly 10 g/m detonating cord priming 1” cartridges) or string loading (a thin layer of bulk emulsion pumped with controlled flow and controlled extraction of the injecting rod). This research focuses on evaluating the effects of the first two charging methods on the quality of final walls in open pit and underground operations. Different drilling geometries and charging configurations were applied to both quarrying and tunnelling blasts. The half-cast factor, the overbreak and the underbreak were evaluated as control indicators. Rock quality designation and rock mass rating were used to classify the rock mass. The research was aimed to push contour blasts to their limits, observing for which geometry and charge configuration the blast lost its design threshold with respect to the final wall for every given rock mass. Results show the operational limits of non-coaxial charges encountered in the rock masses object of this study. In good-quality rock, smooth blasting with decoupled linear charge of 40 g/m can be extended to a spacing S = 22Øf with little or no detectable drawbacks in terms of final wall quality, in contrast with theoretical formulae for the determination of the radius of damage. On the other hand, when the rock is poor, any quality of the final wall is hardly achieved at all, in spite of any care in the details of execution of smooth blasting. It is concluded that any design criterion and theoretical approach modelling the effects of contour blasting cannot ignore the features of the rock mass.CITATION:Seccatore, J, Golin, F, Cardu, M, Munaretti, E, Bettencourt, J and Koppe, J C, 2015. Evaluating the effects of non-coaxial charges for contour blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 267–278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Kenneth Maas

The Bureau of Mines devoted portions of the 1987-1988 field seasons to investigate the mineral aggregate industry in Juneau, Skagway, Haines, and Gustavus, Alaska, as part of the Juneau Mining District study. Statistics compiled for current suppliers include location, activity, reserve estimates, expected mine life, and types of commodities available. Each population center, except for Gustavus, is well endowed with suitable mineral aggregate to last at least 20 years. The Bureau of Mines quantified the mineral aggregate resource in many large potential sites within each area. Sampling, engineering and soil-index testing, site descriptions, deposit dimensions, and gold recovery information is described. Refraction seismic studies performed at three localities revealed gravel thicknesses in excess of 40 to 80 feet. In the Juneau area the Herbert/Eagle Rivers outwash area, East Fork Lace River. Antler/Gilkey Rivers, and Grizzly Bar (Taku Inlet) individually contain in excess of 60 million yd3 of excellent-quality aggregate with minor accessory gold credits. Haines is also well endowed with aggregate resources; large, quality deposits occur along and at the confluences of the Chilkat, Katzehin, Klehini, Tsirku, and Kicking Horse Rivers. Large deposits of granitic aggregate exist in the Skagway River and East Fork Skagway River.

Jan 1, 2012

By F. A. Rutledge

"The W. E. Dunkle mine, sometimes called the Costello Creek coal mine, is 8 miles N. 20° W. of Colorado Station on the Alaska Railroad. The presence of coal in this area has been known since the district was extensively pros¬pected for gold between 1911 and 1915. At that time, coal from this deposit was used by miners for blacksmithing. The increased demand for coal resulting from government defense projects in Alaska led to exploitation of this deposit in 1941.The inability of Alaska coal mines to supply the quantity of coal required by public and private consumers and by the armed forces in Alaska was responsible for establishment by the Army of the Coal Procurement Section of its Alaska Department. It proposed to investigate the deposits and to expedite production from the Alaskan coal fields. The Bureau of Mines closely cooperated in this program.The quality of the Dunkle coal and the favorable location of the deposit caused it to be one of the properties chosen for investigation under a joint Army-Bureau of Mines-Geological Survey program.During July 1943, the coal area in the immediate vicinity of Costello Creek was geologically and topographically mapped. by Clyde Wahrhaftig and Jacob Freedman, geologists, U. S. Geological Survey. F. A. Rutledge, mining engineer of the Bureau of Mines examined the property July 18 to 22, 1943, and a project of trenching, diamond drilling, and sampling was initiated on August 4, 1943. During the project Clyde Wahrhaftig remained at the Dunkle mine to interprets drill cores and assist the author in planning the explora¬tory program. The project was completed October 7, 1943.Field investigations were under the general direction of R. S. Sanford, acting chief, Alaska Branch, Mining Division. Coal analyses were made by Maurice L. Sharp, coal analyst for the Alaska Railroad.Special mention is made of the cooperation and assistance received from Clyde Wahrhaftig, geologist, U. S. Geological Survey.The many courtesies received from the owner, W. E. Dunkle, and the members of the Army Coal Procurement Section, Alaska. Department, also are acknowledged.The W. E. Dunkle coal mine is in the Broad Pass region on the south slope of the Alaska Range at an altitude of 2,800 feet (fig. 1). It is situated within the Third Judicial Division, headquarters of which is Valdez, Alaska. The area is situated approximately at latitude 63° 15' N. and longitude 149° 30' W. and is connected with the Alaska Railroad at Colorado Station by an 11-mile gravel road that is passable throughout the year. This road is maintained by the Alaska Road Commission. A private telephone line to Colorado Station connects with the telephone and telegraph service of the Alaskan Railroad.The passenger rate from Anchorage, Alaska, to Colorado station is $12.10. Freight rates are $1.60 a hundred pounds for heavy machinery and $2.66 a hundred pounds for first-class freight.The Costello Creek coal basin is in an area of low relief and has been dissected by numerous creeks flowing down the south flank of the Alaska Range. The Dunkle coal mine is on Coal Creek, a small tributary of Camp Creek, 1,000 feet from their junction. About 700 feet below this junction, Camp Creek joins Costello Creek, which in turn empties into Bull River 1/2 mile above the latter's confluence with the West Fork of the Chulitna River. The location of the mine is shown on figure 1."

Oct 1, 1948

By Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Underground mining environments bring occupational health and safety issues with some severe dangers such as mine disasters like explosions. During such events, miners might escape using main access openings, or find a safe haven like refuge alternatives (RAs) to wait and be rescued and evacuated to the surface. In this paper, RAs are explained with their early and current applications. A classification as permanent and portable is explained depending on the conditions and their abilities. This classification is followed by the utilization and survivability of RAs with the requirements and recommendations of the main mining countries. Based on the utilization and survivability constraints, basic human requirements, waiting for a rescue team, and the required physical specifications of RAs during the events are analyzed in detail for various countries with their regulations. Among these, the specification, resistance to the explosion, is discussed in particular, and the studies in the literature are examined in terms of structural deformation. The highest deformed zones, the beneficiation of reinforcing steel components such as stiffeners, and the simulation approaches are investigated through this review.

Sep 24, 2022

By Thomas M. Barczak

This U.S. Bureau of Mines report chronicles the historical development of longwall mining in the United States and speculates on future developments to the turn of the century. The involvement and contributions made by the Bureau during these developments are also discussed. Two major periods of history are analyzed: (1) from 1875 to 1950 when small advancing faces were operated manually, and (2) from 1950 to 1990 when mechanized extraction and powered roof supports provided a system to efficiently extract large coal panels. Five eras of technological development during the modern period are described and analyzed. These eras discuss the development of (1) mechanized extraction, (2) powered roof supports, (3) high-capacity roof supports, (4) shield supports, and (5) system automation. Current trends are analyzed in terms of longwall utilization, face production, support capacity, face widths, and new technological developments. From these analyses, the future of longwall mining to the year 2000 is speculated. It is concluded that longwall mining will continue to grow in importance during the next decade and that the next major technological milestone will be the realization of a fully automated longwall mining system.

Jan 1, 1992

By R. W. Stahl

Methane, a highly explosive gas evolved during the coal-formation process, is one of the hazards of mining most difficult to overcome. It is retained between particles of coal and entrapped in strata overlying and underlying the coal beds to a degree dependent upon the permeability of the enclosing strata. Considering that methane might be encountered at any time during the mining of coal, attempts have been made through the years to minimize the sources of ignition at coal-mine faces, such as the introduction of permissible electric equipment, the prohibition of smoking and open lights, and the development of safer explosives. The sparks created when mining-machine picks contact sandstone or iron pyrites2/ constitute one source of ignition, always recognized as a possibility but never greatly emphasized in the United States until recently, when ignitions began occurring with rather alarming frequency and in widely scattered coal-producing areas.

Jan 1, 1956

By O. T. Barrett, R. F. Aberethy, H. N. Cooper, Thomas Fraer, William L. Crentz

"INTRODUCTION The object of the techniques described in this report is to determine the possibilities of separating the components of a raw coal into such grades as may be necessary to recover some exceptionally clean functions for special purposes.To do this commercial gravity methods would require separation at very low specific gravities, entirely outside the range of conventional practice. Hence, a technique has been developed for breaking down cool ample, into very close fractions within the gravity range of the (-lean coal matter as well as for separating it from the refuse and particles.Such data on the fundamental specific-gravity consist of the clean-coal matter will serve to appraise the difficulty of the problem and to chow be accomplished if and when effective methods of making such separations commercially are developed."

May 1, 1945

By Joseph Hyde Pratt, Douglas B. Sterrett, CHAPEL HILL

I. DESCRIPTION. MONAZITE is one of the minerals which, for a long time, was considered rather rare in its occurrence, but, upon a commercial demand arising for it, prospectors and engineers soon located large deposits of it in the Carolinas and Brazil, and the supply has always been able to meet the demand. During 1908 further sources of supply of monazite have been discovered and developed in Idaho. North and South Carolina, however, are the only States that have thus far put any monazite on the market. Monazite is essentially an anhydrous phosphate of the rare-earth metals, cerium, lanthanum, and didymium (Ce, La, Di)PO;. There is nearly always present a varying but small percentage of thoria, ThO2, and silicic acid, SiO, which are very probably united in the form of a thorium silicate, ThSiO4 Some monazites contain but a fraction of a per cent. of thoria, while others have been recorded that showed the presence of from 18 to 32 per cent. ; but the majority contain from 3 to 9 per cent. of this oxide. It is the presence of the thorium oxide that gives the monazite its commercial value. The analysis occasionally shows also the presence of other constituents, as the yttrium and erbium oxides, zirconia, alumina, magnesia, lime, iron oxides, manganese oxide, and titanium oxide. Monazite is light-yellow, honey-yellow, reddish-, brownish-, or greenish-yellow in color, with a resinous to vitreous luster, and is translucent to subtransparent. It is brittle, with a conchoidal to uneven fracture, and is from 5 to 5.5 in hardness, and from 4.64 to 5.3 in specific gravity. It crystallizes in the monoclinic system, and some crystals have been observed that were 6 in. in length. The more perfect crystals are, however,

Jun 1, 1909

By Fred K. Stieler

The largest updraft sinter machine built has a roasting area of 132 sq.m. Sinter machines with an area of over 200 sq.m. are under consideration. These large machines require new techniques with regard to drive thrust and sealing mechanism. To optimize the results of sinter plants, the charge preparation systems and the return fines circuits were improved. Special crushers were developed for crushing return sinter of up to 800 ºC to a size of minus 6 mm. Strand cooling of Pb-sinter was investigated. Different methods for plant ventilation were compared. New processes, which might replace sintering in the future, are in the stage of large - scale testing.

Jan 1, 1977

By Herman W. Sheffer

This report describes and discusses present-day leaching technology employed to recover copper from low-grade mine and dump materials derived from the exploitation of copper ore deposits in the Western United States. Illustrations of the integral parts of the leaching, precipitation, and recovery operations at several copper-producing companies are presented. Schematic drawings are included to present typical flowsheets of leaching and precipitation operations. Operational problems common to most copper leaching and precipitation plants are discussed. Areas of present and future research to improve leaching techniques are cited.

Jan 1, 1968

By F. O. Verret

Several grindability tests were developed over the years to design grinding circuits or optimize existing operations. Each test has its own strengths and weaknesses and it is imperative to select the proper test procedure(s) to meet project deliverables and minimize the risk of a project. Pilot plant testing of large bulk samples historically constituted the traditional approach for AG or SAG design, but was gradually replaced by small-scale tests. Nowadays, conducting grindability tests requiring only a few kilos of material on several samples is a more typical approach to grinding mill design. This paper summarises the requirements and deliverables of various bench-scale test procedures, their strengths and weaknesses, and cases where AG/SAG pilot testing should still be performed.

Jan 1, 2012

By Susan M. White

Increased coal production, wider use of indiscriminate mining techniques, improved cleaning methods, and greater emphasis on clean fuels is increasing the rate at which wastes accumulate Over the next several years, Colorado Plateau underground coal production is predicted to increase. Currently, mine refuse is deposited in canyons or lowland areas near mines. This study presents information on the nature of coal refuse and disposal practices on the Colorado Plateau. Samples were collected and analyzed to provide information to help formulate alternative methods for reclaiming refuse piles. The analyses were based on determining the capability of unmodified refuse to provide a suitable medium for plant growth. Local topsoils which would be used in reclamation were used as standards. Potential environmental hazards were assessed also. A general cost analysis was done for both surface and underground disposal and the advantages and disadvantages of each were assessed. Several problems were identified which, if solved, would increase the effectiveness of state regulatory programs.

Jan 1, 1982

By Sumner M. Anderson

THE importance of the mineral industries of the Latin American area in 1964 may be evaluated in respect to a number of points of reference, a few of which are measurable and appropriate for examination. With regard to the region's contribution to total world production, it accounted for total 1964 world output of natural nitrates (from Chile), and about 97 percent of the optical and electrical grades of quartz crystal (from Brazil). The region supplied over 20 percent of world output of 7 other mineral commodities and accounted for 4 percent or more of world output of 19 other mineral products. Among major commodities, the area, occupying 15 percent of the earth's land surface, supplied within 3 percent of that proportion of the world's output of copper, lead, tin, zinc, barite, and crude petroleum. Incomplete compilation of production data, particularly that of nonmetallic minerals, precludes production estimates on some items for the area ass whole, and therefore the importance of Latin America as a world producer of some additional commodities may not be clearly assessed. For example, most of the countries of the area collect only incomplete data or no data at all on the production of clays and other ceramic materials, sand and gravel, dimension and crushed stone, lime, ornamental and precious stones, perlite, vermiculite, carbon black, coal tar products, and petrochemicals. In the case of many countries of the area, the value of production of one or more of these commodities greatly exceeded that of other mineral industry products that are carefully reported.

Jan 1, 1966

By W. W. de Graaf, M. J. Ntsekhe

Klipspruit Colliery is experiencing coal losses, which leads to a negative impact on coal production and subsequently loss in revenue. This study aimed to identify the possible causes of coal losses in the No. 4 upper and lower seams. The objectives were to identify potential sources of coal losses through a literature survey, to identify areas where the coal losses occurred, to determine factors affecting coal losses, and to identify the most cost-effective methods to reduce coal losses. Highwall losses, top-of-coal losses, and coal edge losses were identified as the major areas of coal loss at Klipspruit. These losses were mostly attributed to the drilling and blasting practises of the pre-split, interburden waste, and the coal seams. Recommendations include re-visiting the current pre-split design and the tolerances adopted for the interburden and coal seam drilling and blasting design. It is furthermore recommended that Klipspruit implement a continuous improvement plan for the drilling and blasting and refresher training for the blasting crew and operators.

Jun 10, 2024

By F. R. Jones, B. W. Taylor, A. R. MacPherson, L. J. Lamb

"The Lake St. Joseph Iron Deposit is in Northwestern Ontario. Exploration to date by Steep Rock Iron Mines Limited has indicated an ore reserve of 683 million long tons. Metallurgical investigations have proved that suitable oxide pellets and/or superconcentrates can be economically produced from this ore. Studies of the Lake St. Joseph iron ore deposits have covered the period 1956-71, and have embodied applications of the improvement in mining and processing technology over this period. Market demand in the early 1960's for high-grade oxide pellets as a replacement for natural iron ores for the blast furnace first drew attention to the potential of the Lake St. Joseph deposit. The current market trend toward utilization of sponge iron to replace steel scrap as feed to electric furnaces and cupolas now suggests that the deposit can better be exploited as a prime source of superconcentrates."

Jan 1, 1972

By J. P. Dick

THIS paper is a description of the milling practice and metallurgy at the Moneta Porcupine mine, Timmins, Ontario. The results obtained with an all-cyanide circuit and later with flotation followed by cyanidation are described. The ?investigation which prompted the various changes in milling practice have also been dealt with. Moneta ore is possibly the most refractory now being milled in the Porcupine district. This is due to the ultra fine state in which the gold occurs and to its intimate association with pyrite. No doubt there is ore of similar characteristics on the neighbouring properties but it probably forms only a small portion of the tonnage being mined, whereas at Moneta the bulk of the ore requires an extremely fine grind to liberate the gold. The fineness to which an ore can be ground economically has gone far beyond what was thought to be the limit only a few years ago. Formerly, a set of standard screens was all that was required to measure the fineness to which an ore was ground. At present, the Haultain infrasizer is practically indispensable, and the nominal micron has become a familiar unit of measurement to all those dealing with the problems of fine grinding.

Jan 1, 1941

By Thomas P. Mucho

Cable bolts are emerging as the newest ?twist? for roof support in U.S. underground coal mines. For decades cable bolts installed in underground metal mines in the United States and Canada used cement-based grouts for anchoring. The cement anchoring process, because of the time and expense for installation, made cable bolts impractical for use in coal mines. Today, the introduction of resin-anchored cable bolts provides a system more consistent with tradi­tional U.S. coal mine roof bolting practices and requirements. Expecta­tions are that the utilization of cable bolts for a number of U.S. mining applications will expand, particularly in coal mining.

Jan 1, 1998

By H. A. Schrecengost

Information presented herein was gathered by examination of 29 fluidized-bed thermal coal dryers and by conferences with manufacturers and users of such equipment to determine what safety features could b incorporated in design, installation, and op ration to minimize fire and explosion hazards. Fire and explosion hazards are inherent in certain types of coal dryers in that high temperatures are employed; the sizes and volatility of material handled are capable of propagating explosions; and drying gases are seldom, if ever, low enough in oxygen content to prevent ignitions of dust clouds, distilled gases, or their combinations. This is especially true for fluidized-bed dryers in which the coal is dried in air suspension and in which atmospheric air is constantly introduced to temper the heated furnace gases. Occurrence of fires on hated bedplates, in dust collectors, and in hot gas inlets was common in nearly all the dryers examined. Forceful explosions which produced external effects had occurred in 11 (39 percent), and internal "puffs" or ?bumps? had occurred in at least 24 (79 percent) of the plants examined in the study.

Jan 1, 1965

By J. S. Coffman

Wyoming is estimated to have more than 700 million tons and Utah more than 2.5 billion tons of +10 percent P2O6 phosphate rock considered to have some future economic potential. In Wyoming, the +24 and +18 percent P205 rock potential resources total nearly 250 and 450 million tons, respectively. In Utah, the +31, +24, and +18 percent rock total approximately 33 million, 222 million, and 2.2 billion tons, respectively. These resources are all located above the local drainage levels and do not include latent resources. All of the mining and beneficiation of phosphate rock in the two States is done by San Francisco Chemical Co. The facilities include open pit mines at Vernal, Utah, and Leefe, Wyo.; an underground mine in the Crawford Mountains, Utah, and beneficiation plants at Leefe and Vernal. One of the principal markets for the phosphate rock is Western Phosphates, Inc., fertilizer plant at Garfield, Utah. Recent exploration and development has been under-taken by different companies in the Southeastern Wind River Range, Sublette Range, and Crawford Mountains. The facilities at Leefe and Vernal are in the process of expansion. Some of the areas of western Wyoming contain vast quantities of phosphate rock in minable units, but, because of their remote location, are classed as latent areas. In these areas, there are estimated to be about 700 million, 2 billion, and 3 billion tons of phosphate rock in the +24, +18, and +10 percent P205 grade classes, respectively. The Snake River Range of Idaho and Wyoming is also estimated to contain roughly 21, 106, 177, and 214 million tons of potential resources in the +31, +24, +18, and +10 grade categories, respectively. This area also contains a large amount of latent rock in the more remote areas.

Jan 1, 1967