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Jan 1, 1928

By T. P. Kostek

"Historically, gear pumps and motors have been popular in the mining industry because of their competitive cost, simple yet rugged construction, ease of rebuild, and relative long life and insensitivity to contamination. However, with the ever increasing ""popularity"" of fire-resistant hydraulic fluids, both users and manufacturers of gear equipment must make special considerations to enable the equipment to continue giving satisfactory performance even with the water-containing fluids.The paper discusses 60-40 invert emulsions and waterglycolsIntroductionMuch information has been published on the specific characteristics of the various types of fire-resistant hydraulic fluids. Fluid manufacturers' literature and other publications have dealt with such specifics as fire resistivity, seal compatibility and wear rate characteristics. Gear pumps and motors have been, and will continue to be, applied successfully in hydraulic systems employing both the ""invert"" emulsions (60-40) and water-glycols as the hydraulic fluid.Because most external spur gear equipment has been designed to function with petroleum oil as the fluid medium, certain guidelines must be followed to ensure satisfactory service life. FluidsThere are a number of different types of fluids which fall in the category of"" fire-resistant"" , the most common'being phosphate esters, water-in-oil emulsions, oil-in-water emulsions and water-glycols. The two in most prevalent use today as hydraulic fluids are the water-in-oil emulsions and the water glycols"

Jan 1, 1980

By Postupack C

A major problem that has continued to plague the surface and underground coal industries is blast induced damage to the coal seam. Blasting Analysis International, in conjunction with a number of other organizations, has continued to address this concern through 14 years of field research in 68 full-scale production environments worldwide. Compiled results were obtained from varying field conditions. These included single and multiple seam coal mines, horizontal, rolling and steeply dipping coal seams and varied borehole diameters (ranging from 102 to 381 mm) and when using various explosive formulations. Results are discussed in detail along with the tools, test methods and analysis techniques to identify and quantify the problems. Over ten major causes of coal damage were identified. A number of practical and economic recommendations are presented that can benefit the entire coal and blasting industry especially in commercial operations whose economic growth relies heavily upon recovering an undamaged coal seam.

Jan 1, 1995

By Jerry W. Stengel

The Bureau of Mines subjected two manufacturers' chemical oxygen (K02) self-rescue breathing apparatus to a series of laboratory environmental treatments designed to simulate various conditions in underground coal mines. The environmental treatments consisted of extremes of temperature, shock, and vibration. The tests were designed to be used as predictors of the ability of the self-rescuers to survive those environmental insults with no degradation in their protection to the wearer. Based on the severity of the treatments, simulating conditions more severe than offered by the mining environment, the two apparatus tested should be able to withstand the abuse offered by the mining environment and still function as intended in an emergency. Correlation of these tests with results of long-term field evaluations is needed to provide confidence in the laboratory tests as predictors.

Jan 1, 1982

By Roy L. Wilfong

The linear expansion of high-purity oxides of yttrium, cerium, samarium, europium, and dysprosium was determined by the interferometric method for the temperature range 25° to 1,000° C. Single-crystal magnesium oxide and single-crystal aluminum oxide were used as reference materials. The bulk density and crystal form of the nonreference materials also were determined. The coefficients of linear expansion in the range 25° to 1,000° C were found to be 8.10 x 10-6 for yttria, 12.10 x 10-6 for ceria, 10.81 x 10'6 for samaria (monoclinic), 10.35 x 10-6 for europia (monoclinic), and 8.13 x 10-6 for dysprosia, each given in centimeters per centimeter per degree Centigrade. A detailed investigation of the interferometric technique for measuring thermal expansion in this temperature range was made. The interferometer was found to be a precise tool but only when adequate precautions were taken. These precautions are described.

Jan 1, 1963

By Leo J. Vogel, E. D. Hummer, David J. Akers

INTRODUCTION An efficient refuse-disposal system is a necessary part of the modem cleaning plant. The large-scale refuse system and disposal area, engineered for the lifetime of the plant, has become more important due to the greater tonnages of refuse produced from increased quantities of mechanically mined and prepared coal. Laws and increased government regulations have affected the design and operation of disposal systems. THE EFFECT OF MINE AND PLANT OPERATION Refuse disposal starts at the mining face. The mining system, the type of roof support, the machinery used, and the degree of discipline at the face contribute to the amount and type of refuse that must be removed through the disposal system. Economies gained through modification of the mining system or mining machinery may be partially offset by increased dilution of the mined coal with impurities from associated rock formations. In some cases the change in the mining system and equipment has reduced the dilution. In all cases the ratio of impurities that must be removed from the raw-coal feed to the plant not only affects the maintenance and

Jan 1, 1979

By Zhou Shu-cai

"A method has been proposed for the pre-treatment of high phosphorus iron ore by carbothermic reduction assisted with microwave irradiation and magnetic separation on a laboratory scale. Chemical analysis of the reduced ore sample, the metal sample and the slag sample were conducted. Based on the above research, the influences of carbon addition, microwave power and microwave irradiation time on the recovery of Fe and dephosphorization were discussed. It indicated that the increase of microwave irradiation time and power had substantial effect on the recovery of Fe while the influence of carbon addition was not obvious and the highest iron recovery ratio reaches some 95.5% when the dephosphorization ratio was 37.68%. A high iron recovery ratio and a reasonable dephosphorization rate were incompatible under the conditions investigated in this study due to the reduced iron and because unreduced P-contained gangues were not efficiently separated. This method may provide a reference for the future utilisation of high-phosphorus iron ore.IntroductionWith the rapid growth of crude steel production in China, the source of iron ore tends to become increasingly strained and is facing the risks of raw material shortage for the iron and steel industry. In order to decrease the production cost, China has to focus on the utilization of its domestic low grade iron ores for the iron and steel plants [1-2]. China has a large deposit of high phosphorous iron ore with a reserve of 7.45 billion tons which is unused in any large scale [3]. Therefore, the development of a successful and economically viable technology for high phosphorus iron ore is of profound importance. To remove phosphorus from the high phosphorus iron ore, several mineral and metallurgical processes have been proposed, such as bio-leaching [4], roasting reduction plus melting separation [5], pre-reduction and screening methods combined with mechanical crushing or air jet milling[6] selective agglomeration plus reverse flotation [7]. However these processes are not cost effective or are time consuming. The traditional pyrometallurgical process( BF+ BOF) refuse this kind of ore mainly because that molten iron is saturated with carbon or high carbon content and thus all phosphor us in the burden goes to the molten iron[8]. Therefore, it is important to exploit the cheap and abundant high phosphorus iron ore as a resource in ironmaking. In recent years, the microwave was widely introduced as a heat resource for extractive metallurgy of iron ore or other minerals. For example, microwave assisted ore milling, microwave assisted carbothermic reduction of metal oxides and microwave assisted mineral leaching issues[9-10]"

Jan 1, 2014

By T. Lupek, S. Plaum

"The execution of classical building services in underground mining operations is more truth than myth. From small concrete foundations for conveyor belts to the construction of huge workshops for large machinery maintenance, nearly every operation requires building services. By creating such fixed facilities, these services ensure the efficiency of the production. A distinction must be made between fixed facilities which directly enable the production and auxiliary facilities which only indirectly support the production. The construction costs of such auxiliary facilities are often roughly estimated because they do not immediately contribute to mineral extraction. The research project ‘Development of a systematic cost-calculation method for building services in underground mines’ seeks to address the question: ‘Can the construction costs concerning fixed auxiliary facilities be neglected e.g. within a prefeasibility study?’ The presentation will show the monetary relevance and significance of these auxiliary facilities and introduce a guideline for cost estimators. PROBLEM DEFINITION The overriding interest of an underground mining operator is to exploit the commodity with the maximal quality by minimum cost and time expenditure. If a new operation shall be installed, it has to promise profitability. Therefore, predictive economic feasibility studies are performed in advance of installation. Herein, all cost expenditure for installation and operation of the future underground mine is determined and compared to the expected income by selling the raw material. The described interest of the mining operator is the starting point of the research project ‘Development of a systematic cost-calculation method for building services in underground mines’. While economic feasibility studies for future operations are focused on the profitable exploitation of raw materials and the efficiency of the accompanying necessary production processes, auxiliary actions are only considered rudimentary. Necessary production processes, as well as auxiliary actions regularly require classical building services, which are normally performed in construction business on the surface in the same manner. By performing building services like masonry or concrete works in underground mines, fixed facilities shall be set up in order to enable or support the raw material production. Production enabling fixed facilities are varying from small concrete foundations for conveyor belts or other infrastructural elements to upstream processing plants situated in the mine workings. While such fixed facilities are essential parts of the production process chain, supporting facilities underground shall increase the efficiency of the mining operation. Workshops, control rooms and social installations are only a few examples for supporting facilities. Those could be situated on the surface as well, but the efficiency increases significantly by installing them underground. Especially supporting facilities are evading from the main interest of the mine operator, since they are only indirectly connected to the production process. The building costs are oftentimes only roughly assumed."

Jan 1, 2017

By Z. S. Abisheva

Results of the study targeted to development of universal acidic-extraction-precipitation technology for gallium recovery from the sublimates are presented in the paper. This will let to utilize a new non-traditional source for gallium production. Phase composition of gallium containing dust was studied. Forms of gallium in the sublimates were determined. The main form is Ga2O3, however, GaP form is also present in the cottrel dust and Na5Ga3F14 form is present in the dust of aluminum electrolysis. The possibility of gallium concentration was established via secondary pyro-selection of the dust. Kinetics of interaction of dust components with sulfuric acid was studied. The products of the interaction subsequently were leached with water. Optimum conditions for direct leaching with HCl and H2SO4 were determined providing gallium recovery from the cottrel dust and the ash carry outs up to 95 %. Gallium recovery from the primary dust and the secondary dust of aluminum electrolysis was at 52; 64 % and 63; 83 % respectively. Effect of Fe, P, K, Na and Al admixtures for gallium extraction from hydrochloric acid solutions was studied. It was shown that gallium chloride complex (GaCl4-) is extracted into the organic phase from the following acid mixtures: HCl + H2SO4, HCl + H3PO4, HCl + H2SO4 + H3PO4, HCl + HF. Kinetic regularities of gallium extraction in the system (tri butyl phosphate) TBP ? HCl - Ga were studied using diffusion cell method with agitation. Optimum conditions for gallium extraction from complex hydrochloric acid solutions with TBP were found providing 99.9 % recovery and separation coefficient for gallium and iron (III) of more than 25 in one stage. Sodium hydroxide and water were selected as reagents for re-extraction of gallium from the organic phase. Different options for disposal of by-products that are formed in the processing of cottrel dust, ash sublimates and dust of aluminum electrolysis were proposed and tested. Keywords: gallium, kinetic, sulfatization, leaching, extraction, technology

Sep 1, 2012

By Mario Carnevale, Myles Danforth, Michael Oakland

The cost and overall effectiveness of foundation design depends on a robust characterization of the subsurface geologic setting. It is common practice to formulate deep foundation design from subsurface geologic characterization based on boring programs. The confidence level of geologic characterization is directly related to that of geologic interpretations, which are based on the spatial sampling pattern of boreholes relative to the complexity of the geologic setting. This paper presents a case history illustrating issues that arise during pile construction from over-simplified geologic characterization, the challenging steps taken to improve the subsurface geologic model, and the effect of additional characterization efforts on the pile foundation program. The seismic characterization methods used include multi-channel analysis of surface waves (MASW) and seismic refraction.

By Bruce Cavender

Production managers look to innovative practices and equipment to reduce operating costs and improve efficiency. These innovations apply to both technical and social aspects of production operations and may be high-tech or low- tech in nature. They may be based on the implementation of a few large-scale "breakthrough projects or numerous small-scale activities, depending on the availability of capital funding and the company's past experience. Successful managers systematically identify innovative opportunities that capitalize on their organization's expertise. They quantify the associated benefits and risks and then manage the implementation of selected innovations to minimize cost and uncertainty. They monitor the results of the innovation after it has been implemented and adjust operating and managerial practices as necessary to maximize the innovation's benefit.

Jan 1, 1998

By Joe Harris

Large structures, such as a multistory office building or a large storage tank, are constructed the most economical way possible, which may involve a shallow foundation system placed on native soil or compacted fill material. Over the life of the structure, the foundation system may not perform as originally anticipated, leading to differential settlement. Minor differ- ential settlement is expected; however, settlement that exceeds allotted tolerance can render the structure inoperable. Compaction grouting is a well-known and accepted ground improvement technique that can be used to not only stabilize but relevel multistory buildings and large dia- meter storage tanks. Two projects, each with differing types of structures, were successfully remediated utilizing com- paction grouting as the primary method to remedy settlement.

Sep 1, 2023

By P McCarthy

Many mining operations developed in the last 15 years have not performed to expectations. Problems experienced include lower than planned development and production rates, geotechnical/stability problems, unplanned dilution, reduced metallurgical performance and unbudgeted capital/operating costs. Most of these problems can be directly attributed to decisions made on the basis of geoscience interpretations and estimates. Recent case studies continue to provide examples of unplanned events linked to the use of geoscience information. These studies illustrate the need to improve the way geological information is used in mine feasibility and operations. Comprehensive assessment of the consequences of inappropriate technical decision making is still rare; however, the information that is reported highlights the significant financial impact on a companyÆs bottom line.

Jan 1, 2006

By M. Olper, M. Maccagni, C. J. N. Buisman, C. E. Schultz

The key point of the CX-EWS process is the conversion of lead compounds, contained in the active mass of spent batteries, into lead sulphide. The obtained lead sulphide is leached with ferric fluoborate electrolyte to dissolve lead and oxidize the sulphur from sulphide to the elemental form. The lead-rich solution is fed into a diaphragm electrolytic cell depositing lead and regenerating ferric fluoborate. The introduction of sulphate reducing bacteria technology in the sulphidization step of the battery paste improves dramatically the economics of the CXEWS process, reducing the costs of chemicals, avoiding gypsum disposal and minimising the unit operations of the process. This paper describes in detail this technology change with reference to the economics of the process.

Jan 1, 2000

By Rainer M. Lotzien, Michael J. G. Battersby, Jan Kleefeld, Julian V. Brown, Rainer M. Imhof

A new flotation system has been developed to improve the generally slow separating differentials of fine bubbles and fine particle suspensions. The new technology is based on established pneumatic flotation designs called Imhoflot which use intensive in-line pre-aeration to aerate the flotation pulp prior to its introduction to the separating cell. In the new system (see figure 1) this separation is speeded up dramatically by the introduction of centrifugal motivation in the separating vessel, without the use of internal moving parts. The design focuses on providing increased differential forces on buoyant mineralised bubbles and hydrophilic fines. The commercial benefit to industry is much reduced residence time, less than 30 seconds, which offers considerable cost savings in equipment and infrastructure.

Jan 1, 2003

As the gold price, and consequently ore reserves, improved in the late 1970's, a programme of upgrading the gold recovery circuit at the Phoenix treatment plant at Central Norseman was initiated. The introduction of oxidised ore with a high clay content from the North Royal open cut caused a reduction in thickening and filtering capacities, which in turn restricted plant throughput and increased gold losses in the residue solutions. Test work into alternative washing facilities showed that the installation of a five stage counter current decantation system would restore throughput and reduce soluble gold losses. Installation of the system achieved the objectives of increased plant tonnage, increased proportions of the high grade oxidised ore in the mill feed and decreased gold losses in the residue waters.

Jan 1, 1978

By Hélio Blak

The Paranapanema Group was created in February 1996 when a group formed by the Brazilian pension funds acquired four companies dealing with nonferrous metals. The new Paranapanema Group, basically related to the tin and construction business, became the sole Brazilian primary copper producer, the second zinc producer and one of the most important producers of copper products, mainly tubes and fittings. To put together such different companies, managed before by family groups and with different cultures and principles, was and still is a big challenge. The strategy of developing and consolidating it as an homogeneous group is based in three pillars: an increase in production, quality and technological improvements on products and market mix and a permanent cost reduction program, using all the potential synergies founded.

Jan 1, 1998

By A. Pradakar, J. G. Groppo, J. W. Leonard

All coal transportation systems from the coal face to the final point of use would become more productive if additional tonnages, obtained through improvements to bulk density, could be placed in fixed volume containers such as scoops, shuttle cards, trucks, barges and ships, as well as conveyors. This paper reviews previously reported work where the treatment of coals with small amounts of mining chemicals (0.12 to 0.28 kg/t or 0.25 to 0.56 lbs/st) during lavoratory testing was show to increase loaded coal bulk density by about 15%. The latest bulk density enhancement findings to develop from ongoing research involving underlying chemical and physical theory together with the added use of simple mechanical excitation are discussed.

Jan 1, 1995

This paper discusses the type of scaling operations presently in use in underground mines. It defines a scaling factor that is expressed as the area necessary to scale to extract 1 t (1.1 st) of ore. The problems associated with conventional scaling methods are discussed as well as recent developments in mechanized hand-held scaling de- vices and methods of loose detection. The elements of the scaling process are further analyzed. The conception and design of a mechanized scaling device, developed at Universite' Laval is also described. The results of field tests conducted in Quebec hard rock mines are presented. The experimental findings show that the mechanized hand-held scaling device shows potential in improving the productivity and safety of underground mining operations.

Jan 1, 1996

By John F. Barkley, J. W. Woomer, H. F. Yancey, H. B. Charmbury

The coal picture in 1955 was much brighter than in 1954, when the tonnage produced dropped to the 1939 level. Bituminous coal and lignite production are expected to approach 465 million tons, against 392 million tons in 1954, an increase of about 19 pct. On the other hand, the production of anthracite declined about 7 pct to some 25 million tons. There was marked improvement in coal consumption in all industrial lines except railroads. At the end of November 1955 the largest consumer, electric power utilities, had used about 126 million tons, an increase of some 22 million tons over the previous year. Coke-oven consumption increased about 19 million tons and coal coked in beehive ovens increased about 1.5 million tons, due to heavy coke

Feb 1, 1956