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By R. W. Smith, M. C. Fuerstenau, G. X. Xang

Nonliving dried water hyacinth (Eichhornia crassipes (Mart.) Solms) roots were investigated for the biosorption of cadmium, lead and other heavy metal ions from aqueous solutions. Dried water hyacinth roots, when suspended in solution, strongly and rapidly sorb several different metal ions. Factorssuch as reaction time, pH, the initial concentration of metal ions, the presence of other metal ions and biomass concentration were investigated. The adsorption was shown to follow the generalized Langmuir adsorption equation. The relative affinity of the roots for lead is greater than that for cadmium. The batch sorption kinetics of the uptake of cadmium and lead can be described by an apparent first-order reversible reaction model. The roots could be regenerated after the metal ions were stripped. Successful desorption of Cd and Pb from the biomass by acidic CaCl2 solutions revealed that the metal uptake phenomenon is reversible, implying physical sorption of Cd and Pb.

Jan 1, 2000

By H. E. McCoy, C. J. McHargue

Single crystals of columbium containing various levels of oxygen, nitrogen, carbon, or hydrogen were deformed by slaw compression and impact loading at -196°C. For the slow deformation rates. 1500 to 1900ppm oxygen, 500 pprn nitrogen, or 150 to 200 ppm carbon completely suppressed mechanical twinning. Hydrogen in concentrations to 1000 ppm had no apparent effect on ease of twinning. Impact loading caused twins to form at all levels of contamination studied, and cleavage mucking on (100) planes occurred in specimens having higher interstitial contents. It is well established that, under some conditions, the bcc metals vanadium, columbium, tantalum, chromium, molybdenum, tungsten, and iron deform by formation of mechanical twins. In general it has been accepted that high strain rates, low temperatures, and large grain sizes are conducive to this kind of deformation.' Since interstitial impurity atoms have a relatively large effect on slip in bcc metals, one might sus- pect a similar effect on twinning. This could occur directly by the interstitials affecting the nucleation or growth of the twins or indirectly from their effect on slip. It has often been argued that the large increase in yield stress caused by interstitial elements enables the effective stress to exceed that necessary to cause twinning. The twinning stress has always been thought to be higher than the stress necessary to cause slip in pure metals.2 simonsens and Tipper and Hall4 found profuse twinning in very pure a iron even at room temperature, whereas Low and Fueste15 and Churchman and tottrell' observed twins in a iron containing carbon but none in highly decarburized specimens. McHargue7 reported mechanical twins to form readily in vanadium which contained 390 ppm interstitigs, while Clough and Pavlovic8 found twins only in the one or two grains adjacent to the fracture surface in vanadium which contained 1500 to 1700 ppm interstitials. In columbium, McHargue9 found high-purity single crystals to twin easily whereas Churchman,10 Adams, Roberts, and mallman,11 and Johnson12 studied less pure material and found far fewer twins. Although the results of Leadbetter and Argent13 showed oxygen to inhibit twinning, a study by sheely14 indicated the opposite to be true. Chromium exhibits this mode of deformation15,16 but there are no data regarding impurity effects. Lawley, Van den Sype, and Maddin17 observed twins in very pure molybdenum single crystals deformed at 77°K but none in less pure crystals. The work by Cahn18 and

Jan 1, 1963

By Rashchenko AF, Voiloshnikov GI, Elshin VV, Khomutov VV

The sorption method for the precious metals recovery fromsolutions and pulps are a perspective trend of modernhydrometallurgy. Russian gold mining industry uses thesemethods, anion-exchange resins being applied as sorbents. Theanion exchange resins allow effective recovery of preciousmetals, however, they have several drawbacks as compared withactivated carbons: high cost of sorbents; difficulties arisingduring treatment of pulps with complex ion composition;necessity of using titanic equipment and thiourea for gold elutionfrom loaded anion-exchange resin and its regeneration.

Jan 1, 1993

By Seshadri Seetharuman

The present paper summarises a series of measurements of the interaction parameter of oxygen in liquid copper with respect to a third element, e(M)o, where M is Mn, Zn, As, Se or Te which are common impurities in the liquid metal. The technique employed was the solid electrolyte galvanic cell method. The cell used may be represented as Pt, W or cermet / Cu-O-M // ZrO2 - CaO // AO, A /PT where AO/A represents a suitable oxide/metal reference. The measurements indicate that Mn and Zn interact very strongly with oxygen in liquid copper while, in the case of arsenic the interaction parameter is nearly zero. The behaviour of the elements Se and Te is unique with respect to oxygen interactions in copper bath. At oxygen levels, xo= 10-4 ? 10-5, the apparent interaction parameters are negative, comparable to that for sulphur. On the other hand, at lower oxygen levels, the results indicate that the interaction parameter values are positive. The results are discussed in the light of some of the theoretical models for solute interactions in liquid metals.

Jan 1, 1993

By Kugan Kuganathan

Pastefill is being increasingly considered as a viable fill by underground mine operators. Mount Isa Mines (MIM) chose pastefill to fill their deep copper mine (>1200m deep) after considering various other types of fill in the feasibility studies. During the development of pastefill at Mount Isa (1996 - to date) the Mining research of MIM developed two cost effective, reliable and simple testing methods and used. With the help of these tests the behaviour of MIM pastefill was studied thoroughly and the most optimum mix design for pastefill was achieved. The MIM's pastefill plant, the largest in the world with a capacity of 450rph continuous pastefill production and unique in the process used, has been built (1998-1999) to produce pastefill to the specification developed through extensive testing program using the Flow Cone and Mini Slump cone Tests. As a consequence, it is now possible to select the optimum pastefill mix designs and predict their flow behaviour in bore holes or pipe lines using only these tests. MIM Blended Tailings Pastefill (BTPF) uses 3-3.55 Portland cement and the cost of pastefill is much lower than the total tailings pastefill, that could be produced from the same tailings.

Jan 1, 2001

By Eugene S. Perry

The only outstanding development in Montana oil or gas fields during 1935 was the extension of the Cut Bank oil and gas field 7 miles southward. This field is now about 20 miles long and 3 to 8 miles wide, with 218 producing oil wells and 39 producing gas wells. Average daily production of the oil field during December, 1935, was about 6700 bbl.; total production for the year 1935 was approximately 2,020,770 barrels. The Cut Bank field in northern Montana is in a flat to rolling glaciated area used mainly for grazing purposes. Oil and gas occurs in sandstones and shaly sandstones in the Kootenai (Dakota) formation of Lower Cretaceous age at depths ranging from 2700 to 3000 ft. Prominent anticlinal or domal structure is not present, but small plunging anticlines occur locally. Strata dip westward from 75 to 200 ft. per mile. The field lies on the western flank of the Sweetgrass arch, a broad gentle upwarp over 150 miles long. Localization of oil and gas appears to be due either to pinching or lensing out of the sandstone beds, or else silting of the sandstones with clay minerals so that porosity becomes low. Within the field offset wells show marked variation in initial production, which suggests that differences in porosity of sandstone is the controlling factor. The gas-producing portion of the field is entirely updip (east) from the oil-producing portion, and the producing horizons are the same. Initial production of oil wells ranged from about 50 to about 200 bbl. per day, and initial open flow of gas wells ranged from about one million to about 37 million cubic feet per day, with an average of 11 million cubic feet. Initial gas pressures were slightly greater than 700 lb. per sq. in. Oil is brought to the surface by pumping. Both rotary and standard churn-drilling equipment are used. In the remaining 14 oil and gas fields but little new activity took place other than the drilling of offset wells and wells in proven territory. Continuation of "acid treatment" of wells in the Kevin and Pondera oil fields led to reconditioning of many old wells and the drilling of a number of new wells within these fields. Acid treatment of the oil-bearing horizon, which is the dolomitized and silicified Madison limestone of Mississippian age, has proved quite satisfactory, and some "bone dry"

Jan 1, 1936

By Eugene S. Perry

The only outstanding development in Montana oil or gas fields during 1935 was the extension of the Cut Bank oil and gas field 7 miles southward. This field is now about 20 miles long and 3 to 8 miles wide, with 218 producing oil wells and 39 producing gas wells. Average daily production of the oil field during December, 1935, was about 6700 bbl.; total production for the year 1935 was approximately 2,020,770 barrels. The Cut Bank field in northern Montana is in a flat to rolling glaciated area used mainly for grazing purposes. Oil and gas occurs in sandstones and shaly sandstones in the Kootenai (Dakota) formation of Lower Cretaceous age at depths ranging from 2700 to 3000 ft. Prominent anticlinal or domal structure is not present, but small plunging anticlines occur locally. Strata dip westward from 75 to 200 ft. per mile. The field lies on the western flank of the Sweetgrass arch, a broad gentle upwarp over 150 miles long. Localization of oil and gas appears to be due either to pinching or lensing out of the sandstone beds, or else silting of the sandstones with clay minerals so that porosity becomes low. Within the field offset wells show marked variation in initial production, which suggests that differences in porosity of sandstone is the controlling factor. The gas-producing portion of the field is entirely updip (east) from the oil-producing portion, and the producing horizons are the same. Initial production of oil wells ranged from about 50 to about 200 bbl. per day, and initial open flow of gas wells ranged from about one million to about 37 million cubic feet per day, with an average of 11 million cubic feet. Initial gas pressures were slightly greater than 700 lb. per sq. in. Oil is brought to the surface by pumping. Both rotary and standard churn-drilling equipment are used. In the remaining 14 oil and gas fields but little new activity took place other than the drilling of offset wells and wells in proven territory. Continuation of "acid treatment" of wells in the Kevin and Pondera oil fields led to reconditioning of many old wells and the drilling of a number of new wells within these fields. Acid treatment of the oil-bearing horizon, which is the dolomitized and silicified Madison limestone of Mississippian age, has proved quite satisfactory, and some "bone dry"

Jan 1, 1936

By Sunil S. Gandhi

Magmatic-hydrothermal deposits rich in magnetite and/or hematite form a broad group that includes monometallic Fe deposits and polymetallic (mainly Cu and Au) deposits. They show a considerable variation in deposit characteristics, but share the genetic processes of magmatic differentiation and related hydrothermal activity in intermediate to felsic melts, and in some cases involve brines and/or meteoric waters during mineralization. They include several world-class deposits. They range in age from Proterozoic to Recent, and form important metallogenic districts in Scandinavian, Canadian, Brazilian and Australian Shields, Circum-Pacific regions, and in China, Iran and Turkey. Monometallic deposits have been important sources of iron in the past and still contain significant resources of the metal, e.g., the Kiirunavaara deposit in Sweden. The giant Olympic Dam Cu-Au-Ag-U-REE deposit was discovered in 1975, and since then explorationists have focussed on search for analogues worldwide. This has brought to light a number of economically important new deposits and prospects, including examples in Canada. The discoveries have in turn prompted considerable research on individual deposits and the group as a whole. This short paper is an attempt to summarize the main aspects of the group from the literature cited in Gandhi and Bell (1996), and from the papers published recently in two milestone volumes on these deposits, edited by Porter (2000 and 2002).

May 1, 2003

By J. M. Font, R. G. Reddy

Jan 1, 2004

By ROBERT B. COONS

SELECTIVE SERVICE must meet three important demands for man power: (1) Activities concerned with production of war goods. (2) The armed forces. (3) Civilian activities and institutions the continuance of which are essential to maintaining the structure of our American democracy. In the above enumeration of demands I have placed everything, including most of our most prized possessions and activities, after the demand for men for war production and the armed forces. To establish an order between the latter two is difficult. For the time being, at least, the Selective Service policy is to make sure that we avoid the risk of "too little and too late." No soldier, sailor, or marine should be sent from these shores to risk his life without the assurance of having a gun, clothes, food, and medical supplies. Therefore, the premium is now being placed on man power for war production and in our process of selection no stone is left unturned to see that our agencies are fully informed of the needs of war production. Our procedures set up recourses for employers of war-production man power so that their activities need not be disrupted, at least not until they have had time to train replacements.

Jan 1, 1942

By William A. Faust

At Gold Fields' Chimney Creek Mine, major reviews of the reclamation and closure plans are done concurrently with the annual mine planning required for budget preparation. This review includes identifying and scheduling reclamation work that can be done within the next few years and development of associated costs. Longer term mine, leach pad and waste dump development are examined to take advantage of any design changes that can reduce ongoing reclamation or closure requirements and reduce costs. The success and cost effectiveness of past efforts are continually evaluated to determine the best methods for reclamation.

Jan 1, 1992

By Peter Edmunds

Durante mucho tiempo, la perforación subterránea se adaptaba a la energía eléctrica. Actualmente, la transición se sufre en la perforación de la superficie. En este sentido, el presente texto describe algunos aspectos de la perforadora hidraúlica de percusión -en tanto posible perforadora del futuro. Las aplicaciones posibles de las perforadoras hidráulicas de percusión en la perforación de superficie son: la perforación de banqueo de alta producción en canteras, perforación secundaria en minas metálicas a cielo abierto, explotación de minas de carbón a cielo abierto, construcciones importantes y otras obras de ingeniería civil. Asimismo, este tipo de perforación tiene futuro donde la productividad es alta y los costos de rendimiento bajos. De otro lado, al comparar las ventajas de la energía hidráulica y la neumática en la perforación de superficie, se considera como productiva la primera -en tanto existe una mayor capacidad, un mejor ambiente laboral y unos costos de operación más bajos.

Jan 1, 1980

By M. Scobie, T. Atkinson

"This paper reviews the development of new designs in extensible and high angle conveyor systems. These aim to overcome the limitations of prior alternative concepts in design. The application of such systems in strip, terrace, open pit and mountain mining is reviewed. IntroductionTruck haulage costs have tended to escalate in recent years. This has been primarily due to operations generally moving to greater depths with associated increases in haul distances . Periods of high inflation rates have also been experienced for diesel fuel oil, tires and other petroleum based products. Recent international political events have tended to regenerate concerns over future oil supply and price stability. For such reasons, conveyor based transport is becoming increasingly attractive. Truck haulage maintains an inherent flexibility and improvements continue to be made in performance and capacity. Doubts must exist, however, over the extent to which further economies of scale may be made. Conversely, belt conveyor systems do not suffer this constraint and have the following advantages:• Electrical power is used and the specific energy consumption is at least half that required for truck haulage.• Operating costs and skilled labour requirements are lower.• Equipment has superior longevity and is ""inflation proof"" .• Access roads can be steeper and narrower in most mine environments, reducing construction and maintenance costs.• They are less prone to breakdown and bad weather delays .• In long haul, high capacity operations conveyors can save substantially on capital cost.• Environmental impact is improved with reduced noise level, dust and atmospheric pollution. Although conveyor systems are less flexible in operation than truck haulage and although a breakdown in any part of the system can immobilize the total system, mechanical availabilities of + 80% are constantly reported by large operators. There would appear in the past to have been some prejudice against conveyor systems in hard rock mines due to lack of experience. Apparent reservations would apply equally 10 underground coal mines, yet practically all of these mines (and some underground hard rock mines) find conveyor systems more economical than other transport systems."

Jan 1, 1991

By George S. Koch

We have devised a multivariate statistical model useful to interpret data from exploration geochemistry and also pertinent for the analysis of data from petrology, paleontology, and other geological fields. The model is applied to several simulated cases in order to compare anomaly recognition by inspection and by quadratic regression.

Jan 1, 1977

By H. R. G. Steeghs

Recently developed organic binder systems have the advantage of eliminating bentonite contamination. This results in better chemically reactive taconite pellets. Both acid and fluxed pellets show increased R40 reducibilities, whereas mechanical and physical properties of the taconite pellets are not adversely affected. Blast furnace performance of these pellets is excellent, and substantial economic benefits are achieved.

Jan 1, 1989

By R. J. McGregor

The Internet has revolutionized worldwide communications. Any real or perceived mining incident or environmental spill, no matter how small or remote, can become a disaster of "biblical proportions" through the judicious use of the Internet by environmental and anti-mining groups. In addition, mining companies' own Web sites and unofficial message boards can provide plenty of additional ammunition to the anti-mining forces. This paper explores how the Internet and readily available information are used by anti-mining groups active on the Web.

Jan 1, 2001

By P. J. Ryan

Phelps Dodge’s Candelaria copper-gold mine is located 20 km (12miles) south of Copiapó in northern Chile’s Atacama province (Region III) (Fig. 1). The Candelaria Mine is about 800 km (500miles) north of Santiago and 75 km (47 miles) east of the Pacific Ocean. Its elevation is 600 m (1,970 ft) above sea level. The Copiapó River Valley is 6 km (4 miles) northeast of the mine site. It is the only major source of water in this arid region. The average rainfall is 14mm/a (0.5 in./year). During 1995, the mine produced 521.4 kt (574,800 st) of copper concentrate containing 150 kt (165,000 st) of salable copper and 3 t (98,800 oz) of gold. The 1995 unit cash cost was less than 50 cents/lb of copper. This makes Candelaria one the world’s lowest cost copper producers.

Jan 1, 1996

By E. T. Wessel

UNEXPECTED brittle failures of metals in practical applications are a serious problem to many industries and to the nation as a whole. Considerable effort has been devoted to studies of the brittle behavior in metals. However, the major portion of this effort has been directed at developing techniques and apparatus for the purposes of determining the susceptibility of metals to brittle failure and of making various types of observations of the phenomena. Relatively minor effort has been made to understand the basic mechanisms involved in initiating brittle failures. A more complete understanding of the nature and mechanism of the brittle failure problem would be very helpful in efforts directed toward predicting and avoiding brittle failure and toward the development of suitable materials and designs that are not susceptible to a brittle behavior. The intent of the present investigation is to acquire this basic understanding. The pronounced transition from a ductile-to-brittle behavior is most prevalent in metals having the body-centered-cubic lattice structure, primarily be- cause metals of this structure exhibit a strong dependence of yield strength upon temperature and the rate of straining. The generally recognized qualitative concept of the ductile-to-brittle transition is that brittle (cleavage) failure occurs when the yield strength exceeds the cleavage fracture strength. This condition can apparently be achieved by decreasing temperature or increasing strain rate. Likewise, a normally ductile metal can be made to fracture in an apparently brittle manner by the introduction of triaxial stresses (notches) where the ratio of normal to shear stresses can be increased to such an extent that the normal stress exceeds the fracture strength before the critical shear stress for plastic flow is achieved. Neither of these concepts require any prior plastic deformation or explain why the observed fracture strengths are so much less than the theoretical cohesive strength. The results of several investigations of the ductile-to-brittle transition in body-centered-cubic metals illustrate rather conclusively that measurable amounts of nonelastic deformation do precede cleavage fracture, even at extremely low temperatures. These studies suggested that the early stages of plastic flow, particularly abrupt yielding, and their relationship to brittle fracture should be examined

Jan 1, 1958

By F. L. Wideman

Materials handled at metal and non-metal mines in the United States increased 10 percent compared with those of 1965 as a result of expansions in output at existing mines and development of others to meet increasing demands for mineral products. The tonnage of commercial materials mined or quarried increased as did the quantity of waste handled. Crude material from which metal or nonmetal products were derived comprised 71 percent (75 percent in 1964) of the total materials handled. Great strides were made in mining technology and there were indications that, in the future, earth moving by the mining industry will involve materials-handling systems of increasing size and complexity. Materials Handled.-Output of ore and waste at metal and nonmetal mines and quarries in the United States in 1966 totaled 3,518 million tons (3.213 million tons in 1965). The quantity of materials handled has increased at an average annual rate of 5 percent since 1962. Ore production increased 4 percent over that of 1965, also comparable to the average annual rate of increase in the last 5 years. Waste removal in 1966 increased 25 percent over that of the previous year.

Jan 1, 1967