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By John H. Perry

Strata III is a full-spectrum roof control system which provides the mine operator the ability to upgrade his roof control in place. The procedure is easily adaptable with current roof bolting techniques. To use the system, the operator starts by installing a special hollow core mechanically anchored roof belt during the roof bolting cycle. This bolt can be upgraded to a fully grouted tensioned rebar bolt by injecting StrataGee G-300, a special polyurethane grout, around the bolt through an injection port in the roof plate. This same bolt can then be used to inject RokLok binders for roof consolidation by pumping the binders through the core of the bolt. This concept in roof control was developed to provide the mine operator a flexible way to maintain roof control in areas which deteriorate over time, or must be kept open for long periods of time. Possible locations of use would be: longwall set-up rooms, recovery rooms, headgates, intersections, and belt entries.

Jan 1, 1987

By Coida D. S. Renata, Gerald Okwuchi Onyedika, Moura E. B. Esperidiana, Graca Valenzuela-Diaz, Martin Chidozie Ogwuegbu, Francisco R. Valenzuela-Diaz, Amauche Cyprian Achusim-Udenko

This work aims to incorporate Mgbee clay, vegetal fibre (Costus afer) in recycled low density polyethylene (rLDPE). The incorporation of clay and vegetal fibre in rLDPE was carried out using a twin screw extruder machine and the nanocomposites were obtained. The nano composites were characterized by the Young’s modules test, tensile tests, bending test, XRD, SEM, DSC, and TG and other properties evaluated. The results of morphological and thermal properties showed a good interaction between the clay, and rLDPE as compared to neat rLDPE.

Mar 1, 2017

By K. K. Landes

The north central and northeastern states supply over 50 pct of the chemical and metallurgical limestone produced annually in the United States, and Ontario is the leading source of this material in Canada. About three fourths of the chemical and metallurgical stone produced in this area comes from Michigan, Pennsylvania, Ohio, and Ontario. The specifications, physical and especially chemical, for chemical and metallurgical stone depend upon the end use, but in general the tolerance for impurities is so low as to rule out most limestones and dolomites. Both high calcium limestone and dolomite are used in the metallurgical and chemical industries. The principal metallurgical use is as a flux in iron ore blast furnaces and open hearth steel furnaces. The major chemical uses are in lime burning and soda-ash manufacture. Other important uses include glass manufacture, in making calcium carbide, and in sugar factories. All deposits of high quality carbonate rock are definitely finite. Invariably and inevitably they diminish in either thickness or quality laterally so as to become unworkable as chemical and metallurgical stone. The size of these high quality lenses ranges from a few thousands of tons to hundreds of millions of tons. The best hunting for new supplies is in the geologic formations known to contain premium quality deposits. However, because of high transportation costs, carbonate rocks, to be workable, must be close to market, dollarwise. Definitions: Chemical stone is limestone or dolomite used as a raw material by the chemical industry. The major chemical uses are in lime burning and soda-ash manufacture. Other important uses include glass manufacture, making calcium carbide, and in sugar factories. The specifications for chemical stone depend entirely upon the end product. Some uses require dolomite, some require high calcium limestone; in a few instances, notably in lime burning, either type of carbonate rock can be used as raw material. As a general rule, a fairly pure stone is necessary and for certain particular uses the tolerance for some elements such as sulfur, iron, and phosphorus may be extremely small. Metallurgical stone is used as a flux in furnace operations, especially in the blast furnace where iron ore is converted into pig iron and in the open hearth furnace where pig iron is made into steel. Either limestone or dolomite can be used in the blast furnace, but only high calcium stone is charged in the open hearth (except for rice-size dolomite used as a refractory). There are no rigid chemical specifications for blast furnace stone, but low silica, alumina, sulfur, and phosphorus are desirable. For open hearth use, in addition to low magnesia, a very low sulfur content is also specified by many furnace operators. For furnace use, fluxstone also must be sufficiently shatter resistant that it will remain in lump form during transport and charging into the furnace. Commercial stone is the term applied in the trade for crushed stone used for roadstone and in concrete aggregate. Many of our best chemical and metallurgical limestones are too soft to qualify in the Los Angeles abrasion test for use as commercial stone. However, some limestones, and a higher proportion of dolomites, do qualify for commercial stone and so can be sold to either market. Place Value: Even the highest grade limestone is still a bulk commodity with a relatively low value per ton. As a matter of fact there is very little difference in the average price per ton between high grade chemical and metallurgical stone and crushed limestone used commercially. Most high quality stone is produced in large operations with consequent low cost per ton whereas most commercial stone is produced in relatively small local quarries. As in the case of other bulk commodities most limestone buyers pay more for transporting the raw material than the cost of the stone at its source. For this reason steel furnaces and chemical plants

Jan 1, 1961

By F. S. Kendorski

This report presents the results of a program to improve, using existing and proven technology, unstable highwall conditions through better blasting practices in Appalachian strip coal mines. Better borehole blasting agent distribution and optimization of burden, spacing, and delay periods allowing satisfactory breakage with minimal backbreak were the objectives. At a selected field site, geologic conditions were closely examined with regard to joint orientation and spacing, and resulting slope stability considerations. A test series of eight blasts was completed and the resultant highwall monitored by repetitive photography. The study of drilling and blasting economics along with equipment performance led to an economic model of blast parameters and the identification of blast design cost benefits. The work demonstrated that small strip mining companies' are able to achieve a more stable highwall excavation utilizing presently available technology, equipment, and explosive products at improved operational cost and safety.

Jan 1, 1981

By M. Goto, T., Matsutani, T. Igarashi

"PT. Smelting was established in February 1996 as a company to· construct the first copper Smelter and Refinery in Indonesia with US$500 million direct construction cost and operate it. The plant is located in Gresik, East Java, Indonesia and 20km northwest from Surabaya, 2nd largest city in Indonesia. The site was selected due to following .advantages.1. Adjacent PT: Petrokimia Gresik, - a fertilizer company, purchases all sulfuric acid produced through pipeline.2. Facing on the seashore of the Madura Strait, it is possible to unload copper concentrate from West Papua (3,000km from Gresik) and load granulated slag to the market.3. Close to the good harbor facilities at Surabaya for export the products.4. Gresik Industrial Area has adequate infrastructure.5. Surabaya is a quite nice city to live for people from abroad.The shareholder of PT. Smelting are Mitsubishi Materials Corporation (60.5%), PT. Freeport Indonesia (25:0%), Mitsubishi Corporation (9.5%) and Nippon Mining and Metals Co. Ltd. (4.5%).The Gresik Copper Smelter and Refinery is designed to produce 200,000 tpy of copper cathode from 660,000 tpy of copper concentrates supplied 100% by 'Grasberg Mine of PT. Freeport, Indonesia in West Papua (former Irian Jaya). Other by products are 600,000 tpy of sulfuric acid, 30,000 tpy of gypsum, 509 tpy of precious metal slime and 400,000 tpy of granulated slag. These are sold to domestic and international markets.This project adopted the Mitsubishi Continuous Copper Smelting and Converting Process in the Smelter for anode casting, Contilanod process comprising Hazelett twin belt caster and a Mannesmann's travelling shear were selected. ISA stainless steel cathode process is applied in refinery. The combination of contilanod anode and stainless steel cathode ensured good cathode quality from the very beginning of start-up SO2 gas generated from Smelter is treated by Lurgi-Mitsubishi double contact/absorption acid plant. All contact. wastewater from the plant is treated in multistage wastewater treatment plant.Electricity and oxygen are ·supplied ""over the fence"" by a company which is located in the site of the Gresik Smelter and Refinery."

Jan 1, 2000

By H. L. Riley

Cleaning and handling of fine coal are generally conceded to be more difficult problems than preparation of the coarser sizes. Increased mechanization in the coal-mining industry has, in general, resulted in an increased percentage of the fine sizes in the total coal mined. If the coal fines are cleaned by wet methods, the minus-1/16-inch square-mesh particles cause most of the sludge and slurry problems encountered in preparing wet coal. Equipment that separates coal from refuse on the basis of specific gravity is not efficient on sizes that, because of their fineness, do not follow the same laws of hindered settling as the larger particles. Probably the best solution of fine-coal cleaning problems is to use other methods, such as flotation, that utilize other physical characteristics than those determining hindered-settling ratios. Regarding the type of flotation known as the Elmore vacuum-flotation process there has been a scarcity of data and information available in this country. An investigation has therefore been made to obtain additional date and information on this process under laboratory conditions. During this investigation an effort has been made to evaluate the relative efficiencies of vacuum and mechanical laboratory froth flotation cells. The investigation included float-and-sink, screen-sizing, and flotation tests on 2 different samples of 14-mesh to 0 raw coal and an a sample of slurry from the settling-tank overflow of a typical washer. One raw-coal sample was obtained from the American bed and represented a type of coal that is relatively easy to clean. The other raw-coal sample was from the Mary lee bed and represented a type considered difficult to clean.

Jan 1, 1954

By Charles A. Ashburner

The manufacturing and domestic consumers of anthracite are beginning to realize the fact more fully, that the coal purchased for any one year does not seem to burn so freely, does not fire with so little trouble, and does not last so long as that purchased during other years, or vice versa. Where coals of different sizes, or from different districts, are offered to the trade by the same or competing salesmen, the question suggests itself, which shall we buy ? Among housekeepers, who are the most numerous class of consumers, though on the smallest scale, distinction is seldom recognized among these anthracites. By other consumers the coals are grouped into those which, when burned, will produce either a white or a red ash, special qualities being arbitrarily attached to each. Others, again, know only of three varieties : (1) Those from the WYoming and LacKawanna fields, or the coals shipped from the northernmost basins over the railroads running through northeastern Pennsylvania direct to New York—notably, the Delaware. Lackawanna and Western, Delaware and Hudson, and Erie railways; (2) those shipped by the Lehigh Valley Railroad and the Lehigh and Susqaehanna division of the Philadelphia and Reading Railroad down the Lehigh Valley ; and (3) those shipped over the main line of the Philadelphia and Reading Railroad down the Schuylkill Valley. In special localities, where a favorite coal is largely used, the consumer will speak of one class, composed of his favorite coal, which possibly comes from two or three collieries, with a total aggregate annual production of less than a million tons; and of a second class, composed of the coals from all the other collieries in the anthracite

Jan 1, 1886

By Joe Zhou

"Mineralogical characterization and metallurgical extraction of silver is challenging due to its complex mineralogy and chemistry. Over 200 Ag-bearing minerals have been identified and a silver-rich ore body would typically contain 5 to 10 different silver minerals. Silver can occur not only as discrete microscopic (visible) silver minerals but also as submicroscopic (invisible) silver in other minerals. During processing, silver may form passivation compounds such as silver hydroxide, silver sulphide, jarosite-like silver sulphate, silver halide or silver cyanide precipitate, all of which may negatively impact on silver extraction. Knowing the deportment of silver in the ore and its metallurgical products is important in flowsheet design and plant optimization. This paper begins with the classification of silver ores and minerals and a review of processing techniques, and focuses on the major mineralogical factors to explain why and how these factors affect silver extraction. Case studies are provided to demonstrate the application of silver process mineralogy in flowsheet design and plant optimization.INTRODUCTIONSilver was known to and utilized by mankind since ancient time. Actually, it was one of the earliest metals discovered and utilized by mankind after gold and copper.Silver is the whitest metallic element. It is rare, strong, corrosion resistant, and unaffected by moisture, vegetable acids, or alkalis. Silver is also resonant, moldable, malleable, and possesses the highest thermal and electric conductivity of any substance. The chemical symbol for silver is Ag, from the Latin argentum, which means white and shining. Although silver does not react with many chemicals, it does react with sulfur, which is always present in air at trace amounts. The reaction causes silver to tarnish, and consequently it must be polished periodically to retain its luster.Silver possesses many special physical characteristics and qualities that make it useful to a variety of industries. The photography industry is the biggest user of silver compounds. Silver forms the most light-sensitive halide salts, which are essential to developing highquality photographic prints. Silver also has the highest electrical conductivity per unit volume of any metal, including copper, so it is used extensively in electronics."

Jan 1, 2010

By Michael M. Hamilton

U.S. Bureau of Mines personnel examined mines, prospects, and mineralized areas to determine mineral resources and resource potential in and adjacent to the North fork Smith RARE II study area. Most mineral resources identified in this area are in laterites, highly-weathered residual soil zones. In the RARE II area, resources of nickel, cobalt, chromium, and magnesium were identified at 15 laterite properties and chromium resources at one chromite mine. Other commodities include copper, gold, silver, and mercury (fig. 1). Approximately 1,100 lode and 1,200 placer claims have been located in or adjacent to the area. Most placer claims are for literites. There are no patented claims or mineral leases. Forty laterite deposits on 15 ,properties within the RARE II area (fig. 2) contain about 16 million tons of identified marginal reserves and subeconomic resources containing nickel, cobalt, chromium, an magnesium (table 1). Most deposits have keen explored and are currently claimed. California Nickel Corporation is developing laterites on Gasguet Mountain, within and adjacent to the southeastern and western parts of the study area. If this project proceeds to production, a laterite processing plant on Gasquet Mountain would enhance the minability of other deposits in the study area. The Climax, PFM, DF, and Stone Corral properties (fig. 1, nos. 1, 6, 9, and 23) have deposits of sufficient tonnage and grade to attract mining interest; resources at these properties are in and adjacent to the RARE II area.

Jan 1, 1983

By P. B. Grote

The report is concerned with the issue of the possible transfer of U.S. and other developed country deep ocean mining (DOM) technologies to developing countries. This subject is one of several major issues in current UN Law of the Seas negotiations. As background to the subject, the report provides a detailed critique of the various terms and conditions pertaining to technology transfer in recent negotiating texts. It also provides a description of the relevant DOM technology, sources of innovation, and methods of proprietary protection. Functional requirements for viable technology transfer are developed and used as a basis for the definition of alternative levels of programs and implementation approaches, including required changes in the negotiating text. The consequences of these technology transfer options on the various parties are investigated.

Jan 1, 1978

By Francis J. Arland

The installation of augered cast-in-place (ACIP) piles requires careful quality control to assure a successful pile installation. Unlike steel, pre-stressed concrete or other types of driven piles, which are shop fabricated, delivered to the site and typically driven to a minimum tip resistance, augered cast-in-place piles are installed to a pre-determined tip elevation or to a refusal criteria. The structural section of the ACIP pile is constructed during pile installation and cannot be inspected prior to installation. Therefore, a carefully administered quality control program is essential to a pile foundation that will meet or exceed design requirements. This requires an experienced team consisting of the Geotechnical Engineer, Contractor and Inspector. The focus of this paper is to discuss the responsibilities and duties of the ACIP piling Inspector. Qualifications of the Inspector The qualifications of the inspector are related to the complexity and difficulty of the proposed project. Ideally, the Inspector should be an individual with a degree in civil engineering with special emphasis in geotechnical engineering. A properly trained technician with geotechnical engineering experience working under the direct supervision of a geotechnical engineer may be able to provide competent inspection on some projects. It is important that the Inspector have a good understanding of subsurface and ground water conditions and how they will affect pile installation. The Inspector must understand ACIP pile installation procedures and be able to communicate with the Contractor, Structural and Geotechnical Engineers; and maintain a detailed pile record for each installed pile.

Jan 1, 1997

By J. S. Megahan

This report covers the design, fabrication and testing of the first and second generation mechanical scaling bars for more safely removing loose rack from mine roofs and walls. Included are discussions covering a survey of mine conditions and presently used hand scaling bar types as well as the design, fabrication and testing of the first and second prototype.

Jan 1, 1982

By Mark A. Willian

The purpose of this short paper is to present soil profiles and basic soils information for the portion of the I-880 Replacement Project alignment where highway structures are to be built. The information presented here is derived primarily from foundation investigations conducted by the Caltrans Foundation Unit (currently the Structures Foundation Branch, Office of Structural Foundations) and by others under Caltrans direction. The foundation investigation for the I-880 Replacement Project began in May of 1991. The field work was completed in May of 1992 and consisted of 93 rotary sample borings, 11 consolidation sample borings, 6 TEXAM® pressure meter borings, six in-place vane shear borings and 57 electronic cone penetrometer soundings.

Jan 1, 1996

By Gregory J. Canivan

Three test pile programs were conducted in Charleston, South Carolina to evaluate differences in bearing resistance due to installation methods. The tested piles were installed with impact hammers and vibratory drivers through soft clays and/or loose sands into the Cooper Marl, a stiff calcareous marine clay or silt. Piles driven into the Cooper Marl experience significant capacity gain with time following initial installation due largely to pore pressure dissipation. Pile size and pile type were both known to affect pore pressure generation during installation and subsequently the capacity gain with time. The test programs were primarily conducted to optimize pile design values and construction methods with regard to trestle construction but the results also contribute to the understanding of driven pile behavior. High strain dynamic testing was performed on several open-end pipe and H-piles. The measured difference in long-term bearing capacity of the H-piles as a result of the two installation methods was negligible, while the short-term bearing capacity of the pipe pile was larger when the piles were installed using impact hammers. The lower short-term resistance in the vibratory driven piles is attributed to larger excess pore pressures generated during installation compared to those generated during impact driving.

Jan 1, 2002

By Raja V. Ramani

Discussion in this section of the Handbook is limited to the working environment of miners, the mine workers themselves, and the machines used in mining (Fig. 11.0.1). The contents emphasize personnel health and safety aspects and engineering design and control practices to ensure a productive health and safety environment. Reference is to the health and safety of the individual miners as well as to the safety of the working environment. This Handbook also contains references to health and safety regulations in Chapter 3.2 and environmental protection in Chapters 3.4 and 7.3.

Jan 1, 2008

By S. K. V. Avasarala

This paper presents a case history of design, prediction, probe and production pile driving monitoring, loading tests and installation of over 3,300 prestressed concrete piles for a building complex consisting of 12, 5- and 6-story over parking buildings. The project was recently completed in three-phases over a span of 4 years. The subsoil conditions were explored by performing 25, Standard Penetration Test (SPT) borings throughout the site. Various types of driven pile foundations were considered and following an evaluation of high structural loads and site-specific constraints such as variable depth of bearing layer of Florida limestone and quality of clay and limestone layers, a prestressed concrete pile support system was selected as the most economical and effective foundation approach. The building foundations were designed for a pile capacity of 353 kN (40 tons) in compression, 45 kN (5 tons) in lateral capacity for a deflection of 0.64 cm (0.25 in.), and 133 kN (15 tons) in uplift capacity. The axial and lateral allowable pile capacity and lengths were predicted using SPT91 and LPILE computer programs, which are generally used in Florida. The validation of these capacities was derived from 144 probe piles and performance of 12 pile loading tests on selected probe piles. Prior to installation of probe or production piles, a termination criterion was established using 1-dimensional wave equation analyses in addition to the design pile embedment requirement. The predicted pile capacities compared very well with the capacities from the loading tests on probe piles. This information was effectively utilized as part of the overall quality control program to install a total of 4,186 prestressed concrete piles (including 144 probe piles) in different building areas across the project site to depths ranging from 8 to 21 m (25 to 90 ft) below existing ground elevation as part of foundation support system. This engineered, monitored, and tested foundation solution provided an effective and satisfactory basis for completion and approval of the foundation work for this 12, 5- and 6-story over parking building complex. A recent reconnaissance has indicated that all the building foundations are performing satisfactorily.

Jan 1, 1995

By B. A. Eaton

The subject of many discussions and technical papers in the last 20 years has been the prediction of the well-bore pressure gradients that are required to induce or extend fractures in subsurface formations. The subject merits this attention because of the frequently recurring problems that arise from an inability to predict fracture pressure gradients. Encountered in several common types of operations in the oil industry are problems associated with the prediction of formation fracture pressure gradients. When wells are being drilled in both new and old fields, lost circulation is often a very troublesome and expensive problem. Complete loss of circulation has been disastrous in some cases. Many times, such disasters could have been avoided if techniques for calculating fracture pressure gradient had been employed in the well plans, and if casing strings had been set, and mud weight plans had been followed accordingly. In areas of abnormally pressured formations, the prediction of fracture gradients during the well-planning stage is extremely important. In fact, it is as important as the prediction of formation pressure gradients, which has received a great deal of attention in recent years. There are several published methods used to determine fracture pressure gradients. However, none of these methods appears to be general enough to be used with much reliability in all areas. In 1957, Hub-bert and Willis published a classical paper that included the development of an equation used to predict the fracture extension pressure gradient in areas of incipient normal fau1ting.l Overburden stress gradient, formation pore pressure gradient and Poisson's ratio of rocks were the independent variables that were shown to control fracture pressure gradient, the dependent variable. In 1967, Matthews and Kelly published another fracture pressure gradient equation that is different from that of Hubbert and Willis in that a variable "matrix stress coefficient" concept was utilized.3 Later the same year, Costley wrote about a similar idea.5 Goldsmith and Wilson used a least-squares curve-fitting technique and field data from the Gulf Coast area to correlate fracture pressure gradient with formation pore pressure gradient and formation depth.' They noted that the fracture pressure gradient increased with increasing depth while the pore pressure gradient remained constant. In each of these cases, the problem for which a solution was sought was to determine the bottom-hole pressure gradient required to initiate or extend a fracture. Results of the previous work show that fracture pressure gradient is a function primarily of overburden stress gradient, pore pressure gradient, and the ratio of horizontal to vertical stress. There is argument for a fourth variable in that in many cases breakdown fracture pressure gradient is greater than the fracture extension pressure gradient. However, if the fracturing fluid is able to penetrate the formation through the pores or existing cracks, there is very little

Jan 1, 1970

By McHenry Mosier

The object of this investigation is to determine the field for the use of detachable bits in metal mines of the United States by correlating the data developed through the experience of mines using these bits. Most of the metal-mining districts in the Middle Western and Eastern States already have been visited. The purpose of the present circular is to define the problem and to discuss the factors that must be considered in order to determine, under different operating conditions, the advantages and disadvantages of this type of bit. Some of the data obtained to date are presented to emphasize points made in the discussion. It is hoped that, as the study progresses, a great many data on drilling will become available. It is evident that since in some cases these data will be confidential they cannot, therefore, be published except as they may be included in average figures covering several different mines. Some data already secured are of this nature, Although considerable information on drilling operations has been gathered at different mines, there were only a few instances in which there were available complete data on all the factors entering into the total cost of drilling with detachable bits and with conventional bits on regular drill steel.

Jan 1, 1936

The last one decade in India had witnessed phenomenal growth in the coal, lignite, iron ore, limestone and many other minerals. To meet the production of minerals, the energy requirement is also very high both in terms of petroleum products and electrical energy. Because of spiralling prices of crude oil and also of the electrical energy, attempts have been made by various mining companies to select energy efficient mining machineries (in underground and surface) mines, together with energy efficient mining and mineral processing operations. Mineral sector of India is working seriously in tune with the Planning Commission stipulations to conserve energy.Apart from energy use (both electrical and fossil fuels) in mining, it is also significantly contributing to the cost of mineral processing depending on the quality of ore/rock being processed. Over the years a number of studies have been initiated and implemented to reduce cost of energy bill. An attempt has been made to present the various aspects of energy conservation, Impact of Energy Conservation Act 2001, Relevance of energy audit, areas of energy consumption and conservation efforts, etc in this paper. The paper also deals with some of the case studies to show how energy conservation programs has been implemented in the Indian mineral sector.

Dec 6, 2010

Surface subsidence that results from longwall mining can be large magnitude and can affect significant areas. Conventional methods for subsidence monitoring include leveling, global positioning system (GPS), and photogrammetric surveys. Remote sensing techniques, including aerial LiDAR, terrestrial laser scanning, and satellite-based differential interferometric synthetic aperture radar (DInSAR), are also used to measure deformation associated with subsidence. DInSAR data are different than data from conventional subsidence surveys. Images capture data over large areas (hundreds of kilometers), and each pixel (data point) in an image quantifies the average displacement over an area of square meters. DInSAR data can have fairly high time resolution; imaging periods typically range from weeks to months.

Jan 7, 2020