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By James Y. Oldshue

"Very seldom is it possible when contacting a gas with a slurry to measure the dissolved gas concentration in the slurry, and even were it possible, seldom are equilibrium data available with a suitable Henry’s law constant.In general, by assuming a reasonable value for the dissolved gas concentration in the slurry and a corresponding equilibrium gas partial pressure P*, Kga values can be calculated for the pilot plant and scaled up. Then, with the same P* value at various reaction conditions, a mixer can be designed which is quite satisfactory, having a reasonable design factor for full-scale performance.We will take as an example a slurry of a known solids composition and use a continuous 4 tank system. By assuming a percentage saturation of the dissolved gas in the first tank, the dissolved gas concentration can be obtained in the other three tanks. It usually is possible to measure the off-gas composition in each of the 4 tanks. If the top of the tanks is connected in the form of a multi-compartmented horizontal autoclave, then a modified top off-gas composition in each compartment must be used."

Jan 1, 2003

Study on Oil Agglomeration Flotation for Deinking

Sep 13, 2010

In practice, frothers are selected following general guidenlies and verification by laboratory and/or plant flotation tests. The terms “powerful” or “selective,” which are commonly used to characetrize frothers, have intuitive rather than scientific meaning. A research program has been set out to study fundamental properties of the flotation frothers and to identify the tests which can provide information needed to characterize and classify such flotation agents.

Jan 1, 2004

By K B. Quast

Changes in feed size distribution can have significant effects in rod mill grinding. The product sizing resulting from wet batch milling of a tin ore showed little influence on fines production after truncating the feed at either the coarse or fine end. The addition of fine material caused a less amount of fines to be produced and a possible increase in grinding at coarse sizes, although this is complicated by the changing feed size distribution. The changes in feed size distribution caused no tendency for preferential grinding of the cassiterite.

Jan 1, 1998

By Jean-Michel Rendu

Computer systems are an integral part of the mining industry. Before a new operation is started, software requirements, and the need for hardware and communications must be determined. The personnel required to use the software, and to support the necessary infrastructure, must be hired and trained. In this sense, this paper emphasized the needs that geologists and mining engineers have for technical software. Similar requirements apply to all other aspects of a mining operation. These requirements will become even more critical in the years to come, and must be fully assessed before construction of a new mine begins. Dependency of a mine operation on its computer systems must never be underestimated.

Jul 17, 2000

By Danny W. Hagood

High methane liberation and mining depth were two major factors which prompted the development of a high- capacity face ventilation system at Jim Walter Re- sources, Inc., No. 4 Mine. No. 4 Mine, one of four deep shaft mines presently under development, is located approximately 50 miles southwest of Birmingham, near Brookwood, Alabama (Figure 1). The coal seams under development are located in the Warrior Coal Field and include both the Blue Creek and Mary Lee Seams, Depth of cover averages 2000 ft. (610 m) with an average total mining height of 8 ft. C2.4 m). [ ] It is generally accepted that the methane content of a particular coal increases as the overburden depth is increased [l] ; experience to date has shown that the gas condition of the No. 4 Mine is no exception to the rule. To further compound the problem, the over- burden depth, coupled with the relatively soft nature of the Blue Creek coal, has resulted in an initial layout based upon 150 x 150 ft (45.7 x 45.7 m) centers. Considering the above-mentioned mining conditions, the means and the effectiveness of the face ventilation system becomes paramount where productivity is concerned.

Jan 1, 1980

By John Frostiak, Lloyd Buckingham, Kenneth G. Thomas, Luis Wilson

"The El Indio roasting facility associated with El Indio Mine in Central Chile has operated since 1981. It is a facility developed to remove arsenic and antimony from gold bearing enargite/pyrite flotation concentrates.The three installed roasters are Nichols Herreschoff units each with 14 hearths and measuring 4.85 metres diameter. Hearths are rabbled by central shaft driven rabble arms. Product is progressively heated to 750°C under neutral to reducing atmospheric conditions to drive off labile sulphur, arsenic and antimony.Ancillary equipment includes skip hoist feed arrangements, water cooled screw conveyors for transporting and cooling calcine, gas cyclones, post combustion chambers, heat exchangers, electrostatic precipitators, bag houses, gas scrubbers and packaging facilities .Operating practices, history, mineralogy and results are reviewed. The improvements to arsenic and antimony extraction, ambiental conditions and environmental achievements are discussed.INTRODUCTIONHistoryThe El Indio property lies in the El Indio belt, a copper, gold and silver area approximately 175 km long by 10 km wide. The property is located in the Andes Mountains of the central part of Chile at latitude 30"" South and 160 km from the sea-side city of La Serena. Plant location is at 3850 meters above sea level.The property currently consists of two underground mines feeding the El Indio plant and an open pit feeding the newer Tambo leach plant. The property has been controlled by a succession of owners (St. Joe Minerals, Fluor, Bond Gold International and Lac Minerals Ltd.) before acquisition by Barrick Gold Corporation in 1994."

Jan 1, 1999

By Esher Hsu

In Taiwan, around 8,000 tons of batteries are consumed per year but only 17% of which were collected and transported to oversea for recovery. The dumping used batteries have become a potential environment problem. How to increase the collection efficiency of used batteries is an important issue for EPA in Taiwan. Besides, some treatment plants are on process to get permission for recovering used batteries. The objective of this study is to estimate the recycling cost of spent consumer battery and explore the feasibility of recovering used consumer batteries in Taiwan based upon the principle of cost-efficiency. The recycling cost including collection cost and recovery is estimated based on a survey. Results would provide some suggestions to Taiwan EPA regarding feasibility of recovering used batteries in Taiwan.

Jan 1, 2006

Agnico-Eagle Mines Ltd. comprises a Gold Division at Joutel, Quebec, and a Silver Division at Cobalt, Ontario. In 1979 the Silver Division milled 41,700 mt (46,000 st) of ore at a recovered grade of 139 g per mt (4.06 oz per st) for a production of 5,816 kg (187,000 oz) of silver. The 100 -year -old mining, camp of Cobalt has long been noted for its high-grade silver ores, and now seems to be on the threshold of being revived with several companies operating in the area. In 1979, the Gold Division milled at the rate of 27,200 mt per month (30,000 st) and processed 333,000 mt (367,000 st) at a grade of 6.58 g per mt (0.192 oz per st) with a mill recovery of 91.670 to produce 2,013 kg (64,700 oz) of gold. The average total cost per ton milled was $22.10 per mt ($20.05 per st) which was $3.66 per g ($1 13.90 per 0s). These figures make Agnico-Eagle one of the lowest cost producers in North America. Gold occurrence in the Joutel ore is fine-grained and contained within sulfide facies composed mainly of pyrite with minor pyrrhotite. Two underground mining methods are employed with long hole stoping accounting for about 75% of the ore mined and shrinkage stoping the remainder. Ore from underground is hoisted into a 545 mt (600 st) coarse ore bin from where it is conveyed to a 45 mt (50 st) surge bin ahead of the 10-51 Hydrocone crusher. Crushed ore is then screened to make a 13 mm (112 in.) product with the oversize being recrushed in a 7-60 Hydrocone. Mill feed is conveyed to two 900 mt (1,000 st) fine ore bins. The Hydrocones were installed as part of a new crushing plant in March of 1980 and have contributed substantially to an increase in mill capacity. Space has been left to install a third crusher in the future. The fine ore bins discharge to a 2.75 m by 3.66 m (9 ft by 12 ft) rod mill, followed by a 3. 7 m by 5.5 m (12 ft by 18 ft) ball mill in closed circuit with a Krebs 380 mm (15 in.) cyclone to produce a 7070 minus 37 micron (400 mesh) .flotation feed. This pulp is first treated in a 34 cu m (1, 200 cu ft) Maxwell flotation cell and then in an additional twelve 2.8 cu m (100 cu ft) cells. Combined flotation concentrates are reground to 9070 minus 37 microns (400 mesh) in a 1.8 m by 4.9 m (6 ft by 16 ft) ball mill in closed circuit with a single Krebs 254 mrn (10 in.) cyclone. Flotation tailings are sent to the tailings dam. Reground concentrates are then aerated with lime to a single Pachuca and thickened in a 16.75 m (55 ft) diameter thickener with the addition of diesel fuel to render any activated graphite inert to adsorption of

Jan 1, 1981

In this work, the crystallization of Carnallite from waste brine of Qaidam Basin in Qinghai province was studied based on NaCl-KCl-MgCl2-H2O phase diagram. According to this study, a new crystallization pathway to recycling waste brine was developed. The carnallite salt was formed by using this technology during the waste brine evaporation. The experiment data shows that 5 tons of waste brine was required to form one ton of the carnallite. The average grade of carnallite prepared by using this procedure was about 19.40% of KCl, 16.92% of NaCl, 28.80% of MgCl2, and 0.82% of CaSO4. This study provides an opportunity to utilization of the waste brine.

Jan 1, 2012

By H. C. Wade

"Description and UseDischarge liners or pulp lifters as they are sometimes called are a trough type liner used at the discharge end of the mill where ground ore passes to the trunnion.There are basically two methods of discharging pulp. The First and most common is the overflow method. Here ground ore travels from the feed to the discharge end where it exits through the discharge trunnion in an overflowing manner, hence the name ""overflow"". (See Figure I) The second method of discharging pulp is the grate method. With this method you block-off the trunnion and hold the ore inside the mill for a longer period of time. This allows only the desired size of ore out of the mill. Ore passes through the grate liners, into the Vibrathane Discharge liner, and finally down to the trunnion. Greater control of the ore size results wit1 this method as compared to the overflow method and it also eliminates reclassifying and regrinding. (See Figure 2)Types in UsePresently the majority of discharge liners in use today are rubber. (Metal insert and rubber covered) In some extremely course applications steel and nihard are used."

Jan 1, 1980

By A. K. Mishra

The mineral industry is leading towards a technology driven optimization process. Drilling and blasting are such unit operations in a mine, which can alter the balance sheet of the mine if not planned properly. The development, improvement and utilisation of innovative technologies in terms of blast monitoring instruments and explosives technology are important for cost effectiveness and safety of mineral industries. The ever-growing demand of mineral has compelled the industry to adopt mega opencast projects with big equipments. This has necessitated use of few hundred tonnes of explosives in each blast. The bulk delivered fourth generation explosives has solved the problem of explosive loading to a large extent. The priming of bulk delivered explosives in Indian mines uses the conventional PETN/TNT based cast boosters. As the conventional cast booster possess safety problems in terms of handling and use, so Indian Explosives Ltd., has developed an emulsion based cast booster (Powergel Boost).

Jan 1, 2005

By H. R. Peiffer

The increase in electrical resistivity, ?pT,at 78°K was measured as a function of elongation, E, at 78°K for a 2 pct (approximately) by weight finely divided alumina in silver material. The amount of increase in electrical resistivity (?pT) is a function of the amount of alumina present and can be represented by: ?pT = cen where c and n are constants. The constant c increases and the exponent n decreases with increasing alumina content. Approximately 33 pct of the resistivity increase is recovered upon annealing at room temperature. RECENTLY, dispersed phase alloys' have shown promise for use at elevated temperatures. These materials have a high creep resistance, a high-temperature strength considerably above that of the pure matrix, and a high electrical conductivity. These materials also show other properties such as retardation of re crystallization and resistance to flow even above the melting point of the matrix.' It is believed that high-temperature creep is retarded in these materials because the dispersed phase blocks the motion of dislocations. According to schoeck3 and also Weertman,4 the rate controlling process is the climb of dislocations around the dispersed phase particles. Any mechanical property of these materials, or any other material for that matter, can be explained on the basis of defect structures and their interrelations. It would certainly be interesting to learn something about the effect of a dispersed phase on dislocation densities and also their effect on point defect concentrations following cold work. This is the purpose of the research discussed herein. The method used was the measurement of the electrical resistivity as a function of elongation at low temperatures. This scheme has already been applied to the studies of pure metals.5 Electrical resistivity measurements conducted on pure metals such as copper, silver, gold, and so forth, have indicated that defects such as vacancies and dislocations are formed during deformation.5 It has been shown by van Bueren6 that the resistivity change, ?p, should increase with elongation, E, according to the following relation: Ap=Al/2 + B£3/2 where A and B are constants of the system; ?p is in µ? cm. The first term refers to the amount of resistivity change associated with line defects and the second term with the change associated with point defects. A later calculation yielded exponents of 3/4 and 5/4, respectively.6 Manintveld7 has shown that the resistivity of copper increases with strain according to a 3/2 power law, whereas van Bueren has shown that the resistivity of silver increases according to a 5/4 power law. Assuming then that van Bueren's calculations are correct, it appears that line defects contribute very little to the electrical resistivity. There is some doubt, however, as to the validity of van Bueren's expressions for all cubic metals.' In fact, the data on copper and silver are not conclusive. In this in-

Jan 1, 1962

By Susana Bolhão Muiños, José Hipólito Monteiro, Martin Frank, James R. Hein, Henrique Garcia Pereira, Fátima Abrantes, Tracey Conrad, Luís Gaspar

In spite of all the work that has already been done on ferromanganese deposits, studies on the Atlantic Ocean occurrences are still in their infancy and there is a clear need for investigations concerning the origin, distribution, and resource potential assessment of these deposits. Nevertheless, studies already carried out on northeast Atlantic seamounts indicate the general presence of ferromanganese deposits of hydrogenetic origin, i.e. deposits formed by direct precipitation of colloidal, hydrated metal oxides that are scavenged from the water column on hard-rock substrates. The hydrogenetic precipitation promotes the enrichment of ferromanganese crusts in many trace metals, most of which are of economic interest, such as Co, Ni, Te, rare earth elements, and platinum-group elements and thus ferromanganese crusts are considered an important metal resource.

Sep 1, 2014

By V. D. Jalevsky

A new methodology of an experimental-analytical approach has been developed. It is used in building an information geomechanic monitoring system for the modeling of geomechanic processes during coal seam working. The approach synthesizes experimental (in-situ) measurements of rock pressure manifestation in separate points, methods of numerical modeling of processes on rock boundaries with coal, and a seam analytical calculation of rock mass in a spatial strained state. One of the realizations of this approach is the developed theory and calculation method of adjoining rock surface shift (overhang) formation during underground working of sheet deposits and of rock mass geomechanic state determination. There are description algorithms of cavity configurations with broken lengths of faces during underground working of useful mineral sheet deposits. These algorithms have been used in computer modeling of formations of adjoining rock surface overhangs and abutment pressure upon rock mass in the area of coal faces with irrectilinear longwalls. Peculiarities of surfaces shifts and stress allocation are established for different face schemes. The use of theory and methods alloww working out techniques of automatic control to receive processing algorithms of RPM measurement results and calculate geomechanic situations within panels in the process of planning and development as well as during mining, i.e., to carry out long-term prediction, in-line control, and short-term prediction of rock pressure manifestations.

Jan 1, 1996

A technical exhibition was held in conjunction with the 4th DFI International Conference on Piling and Deep Foundations, Stresa. The exhibition was located in the ground floor of the Conference Hall. It was open from 15.30 on Monday April 8 till 16.30 Thursday April 11, 1991. The following is an alphabetical list of firms who took part. 1) A.P. VAN DEN BERG MACHINENFABRIEK B.V. P.O. BOX 68 8440 AB HEERENVEEN The Netherlands Tel: +31 5130 31355 Fax: +31 5130 31212 Stand Executive: A. Duyfjies

Jan 1, 1994

Jan 1, 1967

By J Lea, P Hatherly, J L. Edwards

Coal exploration has traditionally involved the acquisition of data to enable a resource to be quantified and qualified to the extent that its economic potential can be determined. This process commonly relied on: drilling to determine the depth and thickness of coal seams, broad characterisation of the overburden and interburden, and to provide cores for coal quality analyses; basic wireline logging to cross-check the depth and thickness of coal seams and provide some indication of rock mass strength; and basic surface geophysics and remote sensing to identify major geological structures. In recent years, the adoption of the JORC Code as a basis for the reporting of resources and reserves has placed a greater emphasis on the need for detailed, reproducible data sets that not only satisfy the traditional requirements of mine planners, but also satisfy the governance requirements of corporate and financial institutions. Similarly, the development of sophisticated numerical modelling techniques for use in both open cut and underground mine design, has seen a greater demand for precise geotechnical data, in situ stress characterisation and hydrological information as routine input to the design process. These requirements, coupled with the prevailing trend toward high capital, relatively inflexible mining techniques less tolerant of geological surprises, and the need for consideration of environmental issues such as groundwater impacts and surface subsidence, requires that modern exploration programs be multifaceted, and designed to commence capturing data relevant to ædownstream issuesÆ even during the initial phases of exploration planning.

Jan 1, 2009

By N. Kumar Kittusamy

ALTHOUGH MANYSTUDIES HAVE SHOWN an association between operating heavy construction equipment and symptoms of musculoskeletal disorders (MSDs), little research has been performed that systematically characterizes the exposure of operating engineers to ergonomic hazards. This study evaluated: 1) vibration at the seat/operator interface;2) transmissibility of vibration in the Z-axis; 3) psychophysical ratings of vibration level and vibration discomfort; and 4) postural requirements of the job. Results indicate that the digging operation had higher levels of total weighted acceleration than high- or low-idling conditions. Transmissibility data showed that the seat amplified vibration, particularly in the lower frequencies. Seats demonstrated that they may not be sufficient in protecting operators from long-term effects of vibration exposure. High positive correlation was found among subjective ratings (vibration discomfort and vibration level), but moderate positive correlation was found between subjective ratings and quantitative vibration levels. Postural evaluations revealed that the operators were required to assume awkward postures of the neck, shoulder and trunk while performing their jobs. Work-related injuries and illnesses pose a continuing threat to the health and well-being of American workers. The construction industry has been historically recognized as having higher rates of fatality, injury and illness than other industries (McVittie285+; BLS). In 1994, an estimated 218,800 lost-work-day injuries were reported in the construction industry (BLS). Construction also had the second-highest incidence rate for sprains and strains. Although the industry has made progress since then, injuries and illnesses, including MSDs, continue to because for concern.

By Yuanbo Zhang

Zinc leach residues produced by hydrometallurgical zinc plants contain many valuable elements (zinc, iron, lead, gallium, indium silver, etc), while they have not been utilized effectively hitherto. In this paper, a new process of flotation-reduction roasting-magnetic separation to recover these valuable elements from zinc leach residues is developed on a basis of mineralogy investigations of them. The results show that silver concentrate with grade of 4321.6 g/t and recovery of 80.69% have been obtained, using 1750 g/t Na2S as conditioner, 750 g/t ammonium dibutyl dithiophosphate and SN-9 (assistant collector) as combined collector and 100 g/t terpenic oil as frother, if zinc leach residues with 523 g/t silver are floated at pH = 5.0. When the flotation tailings are subjected to reduction roasting at 1100? for 2 h, the volatilizations of zinc, lead and indium are over 96%. After roasted products are treated by wet-grinding and magnetic separation, the grade of gallium and gallium in the concentrates achieved respectively reaches 1805 g/t and 1536g/t, and the recovery of them is high to 94.67% and 93.20%, respectively.

Jan 1, 2006