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By Philip C. Tully

These modifications to the Redlich-Kwong equations for pure hydrogen and neon were developed after an unsuccessful attempt to generalize a modification technique previously developed for helium. New coefficients of the B terms were developed by minimizing the residuals. No changes were made in the coefficients of the A terms. For normal hydrogen, B was changed to [0.08063Tc PcT] for temperatures from 980 to 423° K and pressures up to 1,050 atm. The average deviation in Z was 0.36 percent with maximum deviations less than 1 percent for all but a few low-temperature points. For neon, B was changed to [PCT 0.1025T], for temperatures from 120° to 973° K and pressures up to 1,500 atm. The average deviation in Z was 0.34 percent with maximum deviations less than 1 percent for all but a few high-pressure and low-temperature points. Efforts to attain a lower temperature range to comparable accuracy with this type of modification were unsuccessful. In the range of applicability, these equations should be used with caution when calculating derived thermodynamic functions, such as the isobaric specific heat.

Jan 1, 1968

By K Williams, A Lavrinec, V Gurung, D Ilic

The moisture content of iron ore during handling can range from the dust extinction moisture at the point of arrival at the port to the transportable moisture limit at the point of loading ships for maritime transport. Moisture content and ore composition, specifically fines content, have a large influence on ore flowability. Typically, elevated moisture can result in bottlenecks, downtime and lost productivity due to build-up, conveyor carry-back and blockages, increasing maintenance costs. On the other hand, low moisture can result in increased dust emissions influencing the environmental footprint and product losses. Managing the use of water across the supply chain is therefore critical for service life of equipment, productivity, but also has environmental and social impacts, affecting the social license to operate. Previously, experiments have shown that oscillations induced in iron ore during handling and transport can result in movement of moisture through the ore. This kind of moisture migration depends on the nature of these oscillations, such as the undulation of idlers during conveying, the inherent ore properties and the initial moisture content. Moisture has been observed to move either upwards and/or towards the bottom of the burden. These effects can be exploited to remove excess water from the ore influencing handleability and operation, however, the actual mechanisms of moisture migration are currently poorly understood. The study presented herein involves the use of simulation to examine moisture and ore interactions. Simulations using discrete element method (DEM) and coupled with smoothed particle hydrodynamics (SPH) are implemented to investigate the behaviour of moisture in wet ore in the presence of oscillation. This is conducted at a fundamental level first using glass beads and water which is then compared to iron ore at high moisture content. The results of the modelling are discussed in view of experiments conducted.

Sep 18, 2023

By F. Boudreault, M. J. Scobie, J. Szymanski, C. Hendricks

The development of new stoping methods and more effective control over dilution, recovery and fragmentation depends on improved accuracy in blasthole drilling. The mechanisms and factors which control accuracy are poorly understood. Canadian blasthole stoping and the practices adopted for monitoring and controlling drilling accuracy are reviewed. The techniques and problems associated with blashole set-up and trajectory surveying are discussed. Four new blasthole trajectory survey systems are evaluated on the basis of their performance in recent underground trials. Conclusions are drawn as to the technological developments required so that more precise control over drilling accuracy can be achieved.

Jan 12, 1992

By John T. Bartlett

During the last decade, the increasing price of gold has renewed interest in the various metallurgical techniques for recovering precious metals. Much of the recent technology advance has been aimed at low grade deposits resulting in more complex processes and the necessity of tighter economic control. These factors along with more stringent environmental constraints have made it necessary to optimize each process to minimize energy and raw material consumption and reduce waste discharge. In most cases, detailed process analysis is required to detect inefficiencies and provide alternative solutions for process improvement. Also during this same period, the computer has become widely accepted and computerized mathematical modeling has been applied to an increasingly broader range of problems. Microcomputer based process modeling and simulation systems are routinely used to analyze and improve communition, hydrometallurgical, and pyrometallurgical processes for the recovery of precious metals.

Jan 1, 1987

By Ludwig Schmidt

This report, the second of a series, presents the results of laboratory corrosion studies which were made in connection with a one-year test on aluminum lease tanks conducted by the United States Bureau of Mines. Part 1 of the report contains the results of the field tests. The studies were made on an oil lease in a so-called "sour district," near Borger, Tex., where free hydrogen sulphide accompanied the production of oil, gas, and salt water. Steel tanks previously used on the lease had suffered severe corrosion, because steel is inherently susceptible to attack by hydrogen sulphide. Because of the high resistivity of aluminum to the action of hydrogen sulphide, it was believed that this metal had promising possibilities as a material for the construction of lease tanks in "sour districts." The results of the one-year field test proved that aluminum lease tanks will withstand corrosion by hydrosulphide, but it as found that aluminum was susceptible to attack by salt water, which was invariably present in certain portions of the tanks, and that hydrogen sulphide accelerated this salt-water corrosion in an indirect manner, as will be explained hereinafter. In order to study corrosion conditions encountered in the tanks during the test period, a laboratory was maintained at the site of the aluminum lease tanks.

Jan 1, 1931

By Wilbert J. Huff

For the past 9 years , the technical studies conducted by the Explosives Division of this Bureau have been summarized in a series of reports issued annually . The following account presents investigations undertaken from July 1 , 1943 , to June 30 , 1944. The work is detailed under a number of main headings corresponding to the organizational structure of the Division , the various activities being under the immediate direction of unit chiefs , who report directly to the author . Specific credit , however , is due to the individual unit leader and his assistants .

Jan 1, 1945

Process variables in flotation circuits are outlined with a view to producing mathematical models of circuits. The nature of the kinetics of flotation are discussed and the effect of process variables on the kinetics considered. An approach for a possible model is briefly outlined.

Jan 1, 1971

By Deborah A. Peacock

"Outer space technology and exploration have reached a tipping point, so that mining and mineral processing in outer space is now a certainty and not a dream. Several competing companies worldwide are on the way to building spaceships to land on the Moon and eventually mine the Moon and asteroids for volatiles, rare earth metals and Helium-3.The Google Lunar XPrize offers a $30 million prize1. China has recently landed a spacecraft on the Moon. The European Space Agency, with cooperation from the United States, has landed a spacecraft, Philae, on a comet. And, Mars One is planning a one-way trip to establish a settlement of humans on Mars.How and why are the Moon and asteroids and their resources of interest to private space industry companies? Why are the Moon and asteroids viewed as a potential business venue?Geology of the Moon and asteroids — Why do we want to mine there?Space enterprises are actively working toward establishing and operating lunar and asteroid mining locations for resource extraction, resource processing, conversion to salable products and distribution of the products and services in space and to Earth and beyond2.Forty-five years ago, the Apollo manned missions to the Moon returned rocks and regolith to Earth, which were studied and analyzed. What they found was that the Moon contains valuable minerals and resources. These minerals are largely due to meteor and asteroid impacts, which have, over eons, created this mineral-rich regolith. These impacts have occurred on Earth as well, for billions of years, particularly early on in the history of the solar system. However, on Earth, wind, water and vegetation have erased most of these impacts. On the Moon, in contrast, the only weathering is caused by subsequent impacts and the solar wind."

Jan 1, 2017

By P. L. Richard

An open pit a mine can be thought of as a business unit, with capital, operating and maintenance costs that exceed those of many large business enterprises. Truck-and-shovel operations have an inherent ?looseness? to them, unlike manufacturing or processing operations where production components are tightly coupled (through conveyors, material flow in pipes, assembly lines, and so on). Effective monitoring and control of truck-and-shovel operations requires a combination of both information systems and performance management. Production monitoring systems can impact operations at three levels: minute-by-minute decisions during the shift, procedures, and policies. The technology of production monitoring ranges from real-time data collection to manual entry of time card data into a computer. Time card information is too coarse to effectively manage a multi-million dollar fleet of mobile equipment, so a higher level of production monitoring is required. People issues affect whether the implementation will be a success or a disappointment. Considerations that affect the people issues are discussed, including common obstacles, and key success factors. A balanced scorecard approach must be used, since uni-dimensional measures of performance like tons produced give no indication of whether the production was achieved at the expense of another factor.

May 1, 2004

By P. L. Richard

An open pit a mine can be thought of as a business unit, with capital, operating and maintenance costs that exceed those of many large business enterprises. Truck-and-shovel operations have an inherent “looseness” to them, unlike manufacturing or processing operations where production components are tightly coupled (through conveyors, material flow in pipes, assembly lines, and so on). Effective monitoring and control of truck-and-shovel operations requires a combination of both information systems and performance management. Production monitoring systems can impact operations at three levels: minute-byminute decisions during the shift, procedures, and policies. The technology of production monitoring ranges from real-time data collection to manual entry of time card data into a computer. Time card information is too coarse to effectively manage a multi-million dollar fleet of mobile equipment, so a higher level of production monitoring is required. People issues affect whether the implementation will be a success or a disappointment. Considerations that affect the people issues are discussed, including common obstacles, and key success factors. A balanced scorecard approach must be used, since uni-dimensional measures of performance like tons produced give no indication of whether the production was achieved at the expense of another factor.

Jan 1, 2004

"The present and possible futures commercial production of potash from various sources in the United States is discussed below under the following heads:1. Potash from the saline lakes.(a),Nebraska lakes.(b),California lakes.(c),Other lakes.2. Potash as by-product from the cement kilns.3. Potash as by-product from the iron blast furnace.4. Potash from silicate rocks.(a),Feldspathic material.(b),Leucite rocks of Wyoming.(c),Sericite slates of Georgia.(d),Glauconite (greensand) of New Jersey.5. Potash from Alunite.6. Potash from organic sources other than kelp.7. Potash from kelp.In this discussion very little more than passing reference, if any, will be given to those projects which up to date have been de¬veloped only slightly, if at all, beyond the small scale laboratory stage, or for the development of which there appears to be very little financial and technical backing at the present time. Nether or not many of these proposed projects have merit can be determined only by an actual operating demonstration.Generally speaking, the potash industry of the United States has been hardly more than marking time since the armistice. This is, largely due to the fact that the consumers of potash have been expecting that heavy shipments of foreign potash to the United States would be resumed soon at somewhere near the pre-war prices, and they have not been buying domestic potash at present prices for many months. The result has been that domestic producers have been unable to sell their product at even cost and many producers of potash have been obliged to close down. Thu Nebraska lake plants were closed down in February. The California saline plants were operating at below capacity, and the only large alunite plant is closed down. Even the cement plants have little or no inducements to recover the potash being lost in their waste gases, and the production is very small at present."

Jan 1, 1919

By HOWARND N. EAVENSON

THE year 1930 resembled the preceding one in the coal industry in continuing the era of falling prices and 'of the abandonment of unprofitable mines. Practically all coal prices fell, and in the steam sizes during the last half of the year this was particularly true, due to the small industrial demand. No new mines of any size were opened in the bituminous coal industry, but there was a steady increase in the number of cleaning plants of all kinds built in all fields. It is estimated that at least nine million tons per year were added to the previous total of washed coal. The largest washing plant started during the year was that of the Buckeye Coal Co., at Nemacolin, Pa., with a capacity of 650 tons per hour. Fig. 1 shows - the mixing-bin, conveyor galleries, washing-plant and skip hoist, and Fig. 2 the 120-ft. Dorr thickener for collecting the 48-mesh material from the wash water. Dryers are used for drying the steam coal product. The following statement by J. R. Campbell shows the effect of cleaning on Pittsburgh coal in Greene County: "With the advent of the 650-t.p.h. efficient washing plant in Greene County at the Nemacolin mine of the Buckeye Coal Co., it has undoubtedly been demonstrated that the potential coking-metallurgical coals of the county can be brought within the pale of the highest grade high-volatile coals for steel manufacture. A few months' operation indicates that 9% per cent ash in the raw coal can be easily reduced to under 7 per cent ash in the washed coal and the sulfur from 1.60 per cent in the run of mine to 1.20 per cent sulfur in the washed coal.

Jan 1, 1931

Nineteen eighty-seven was a year of significant change in the Bureau of Mines-change to help it better adapt and respond to the wide range of new challenges facing the U.S. mineral industry. The Bureau has been regarded as the world's premier mineral information and research agency. Its authoritative, comprehensive data and its pioneering research have contributed significantly to the minerals position of the United States. Yet no organization in today's complex, dynamic world, with its rapidly advancing technologies, can afford to rest on its laurels. Mission and program must be constantly fresh and relevant to the day's issues and problems. Moreover, rather than reacting to events, the organization must strive to anticipate and prepare for them. It must have a sense-a vision, if you will-for the future.

Jan 1, 1987

By F. J. Tozer

Canal communication between Lake Erie and Lake Ontario has been one of almost constant enlargement and reconstruction to meet the rapid growth of trade and commerce, and the consequent steady increase in the size of vessels plying the Great Lakes. The original canal was built by the Welland Canal Company. The first sod was turned in 1824 and the first vessel passed through in. 1829. There were 36 lift-locks, built of oak timber, 110 feet long and 22 feet wide, with a depth of water over the sills of 8 feet. The second canal, now known as the 'Old Welland Canal' was built by the Dominion of Canada (1842 to 1850). There were 26 masonry locks, 150 feet long, 26.5 feet wide and with a depth of water over the sills of 9 feet. The walls and banks were raised in 1853 to give a 10-foot draught. The third canal, known as the 'New Welland Canal, built by the Dominion of Canada, was started in June 1874 and the first boat passed through in the spring of 1882. There are 25 masonry lift-locks, 270 feet long, 45 feet wide and with a depth of water over the sills of 12 feet. The walls and banks were raised in 1891 to give a 14-foot draught. This is the canal in use at present.

Jan 1, 1926

By Jack Eloranta

Optimization of blasting requires the comprehension of processes including drilling through milling. The author has previously considered the role of powder factor in relationship to downstream processing costs. Recent modeling done by Lownds provides improved prediction of fragmentation based on the distribution and level of blast energy. Many recent studies have indicated improved downstream costs due to higher powder factor. However, changes in powder factor are accompanied by changes in pattern. The purpose is to segregate the effects of higher powder factor from powder distribution. This paper will attempt to use typical Mesabi Range iron ore parameters and costs to illuminate the subject of total process optimization.

Jan 1, 2001

By K. Huttu, A. van Wageningen

"The Kittilä underground mine in northern Finland is extracting one of the largest known gold deposits in Europe. Kittilä achieved commercial production on May 1, 2009, becoming Agnico Eagle’s first mine to open outside of Canada. The Kittilä orebodies were initially mined from two openpits – Suuri and Roura – and underground operations were added in October 2010. The pits were mined out in November 2012, so mining is now entirely underground in the Suuri and Roura deposits. Additional, small openpits will mine any remaining near-surface reserves in the future.The Kittilä Mine is located in the Lapland region of northern Finland, approximately 900 km (560 miles) north of Helsinki and 150 km (93 miles) north of the Arctic Circle. With a mine life estimated through 2034, Kittilä is Agnico’s longest-life mine.The mine’s proven and probable reserves contain 32 Mt (4.7 million oz) at 4.6 g/t (0.13 oz/ st) gold. Ore has been mined from underground since 2010. The original 3 kt/d (3,300 stpd) operation underwent an expansion project to increase the throughput capacity of the mill by 1 kt/d (1,100 stpd), starting by the end of 2014.The region around the Kittilä Mine is underlain by mafic volcanic and sedimentary rocks of the Kittilä Greenstone Belt oriented nearly vertical. This greenstone belt is similar to those hosting Agnico Eagle’s Canadian deposits in Quebec’s Abitibi region and Nunavut. At the contact point between ironrich and magnesium-rich rocks lies a 100- to 200- m (330- to 660-ft) thick structural zone known as the Suurikuusikko Trend. This trend hosts the Kittilä deposit, where multiple mineralized zones have been traced over a strike length of more than 25 km (15 miles).Most of Agnico Eagle’s work has focused on a 4.5-km (2-mile) segment of the Suurikuusikko Trend that hosts the five main zones of the known gold reserves and resources. From south to north they are: Ketola, Etela, Suuri, Roura and Rimpi.The ore at the Kittilä Mine is refractory, making gold extraction relatively difficult because the gold is generally locked inside the two main sulfide minerals – arsenopyrite and arsenic-rich pyrite. Only about 4 percent is very fine-grained “free gold” (not locked in sulfide grains) and easier to extract. Most of this free gold is found in the outer, oxidized or eroded sections of the ore."

Jan 1, 2015

By Larry M. Southwick

Extraction of gold and other metals from ores suspended in liquid slurries often involves gases (such as oxygen) as a participant in the reaction. An important factor then in setting the rate of extraction can be mass transfer of the gas into the liquid and/or solids. A number of recent studies have indicated that as solids loadings increase, mass transfer rates of gas into solid-liquid mixtures decreases. This would seem to imply that lower solids loadings would be beneficial to increased reaction rates. However, since it is the solids which are being reacted, a most intriguing paradox is created. More solids should lead to more surface area to react, but it seemingly also provides less gas to react. So is the reaction faster or slower as solids loadings increases? The creation of this paradox is imbedded in how mass transfer and reaction data is collected and measured, how it is analyzed and correlated, and finally on the rate controlling steps in the reaction. An alternative analysis of these studies is presented which clarifies and eliminates the paradox. The analysis applies to water slurries as used in gold or other metal leaching processes or in bio-hydrometallurgy, as well as to molten metal/solid/gas mixtures such as might be encountered in submerged gas injection.

Jan 1, 1999

By Harry R. Nicholls

Six different chemical explosives were detonated in a test series to com-pare their relative performance in granite. From 5 to 255 feet from the detonation point, strain, acceleration, and particle velocity were recorded and analyzed for amplitude and pulse shape. Strain energy was calculated from strain data, and displacement data were obtained from particle velocity data by integration. The results show that explosives which have a characteristic impedance more closely matching that of the rock generate larger peak amplitudes than explosives with a lower characteristic impedance. The results also show that as the ratio of characteristic impedance of exp1osive-to-rock approaches unity, more rock is crushed and a larger percentage of the avail-able explosive energy is transferred to the rock as seismic energy. The effect of characteristic impedance is shown to be greater than the effect predicted from acoustic theory and is believed to be indicative of shock wave effects at the explosive-rock boundary.

Jan 1, 1965

By Ludwig Schmidt

This report, the second of a series, presents the results of laboratory corrosion studies which were made in connection with a one-year test on aluminum lease tanks conducted by the United States Bureau of Mines. Part I of the report contains the results of the field teats.5 The studies were made on an oil lease in a so-called "sour district," near Borger, Tag., where free hydrogen sulphide accompanied the production of oil, gas, and salt water. Steel tanks previously used on the lease had suffered severe corrosion, because steel is inherently susceptible to attack by hydrogen sulphide. Because of the high resistivity of aluminum to the action of hydrogen sulphide, it Was believed that this metal had promising possibilities as a material for the construction of lease tanks in "sour districts." The results of the one-year field teat proved that aluminum lease tanks will withstand corrosion by hydrogen sulphide, but it was found that aluminum was susceptible to attack by salt water, which was invariably present in certain portions of the tanks, and that hydrogen sulphide accelerated this salt-water corrosion in an indirect manner, as will be explained hereinafter. In order to study corrosion conditions encountered in the tanks during the test period, a laboratory was maintained at the site of the aluminum lease tanks.

Jan 1, 1931

By D. A. Rhys

"The Red Bluff porphyry is a tabular 2 km long north-west trending Early Jurassic quartz diorite to monzodiorite body that intrudes a folded Triassic greywacke sequence in the lskut River area, northwestern British Columbia. The porphyry is 500 m to 800 m northeast of the Snip orebody, which is a southwest-dipping shear-vein, termed the Twin zone that contains approximately 35 tonnes of gold.The intrusion associated with the mineralization is characterized by 0.3 cm to 4 cm phenocrysts of K-feldspar in a mediumgrained plagioclase porphyritic matrix. It is overprinted by pervasive sericite + quartz ± K-feldspar ± biotite (potassic) alteration characterized by intense stockworking of quartz veins containing magnetite--hematite bands. This assemblage is cut successively by quartz veins with minor iron-oxides and pyrite, and by younger pyrite veins with phyllic envelopes. The system is gold-rich but copper-poor, with typical grades between 0.25 g/t and 0.6 g/t Au, and 0.1% and 0.2% Cu. All styles of alteration and veining have similar abundances of these metals. Where southwest- and north-east dipping shear zones are developed in the porphyry, veins of all types are sheeted and foliation parallel. These sheeted zones are interpreted to be syntectonic. Asymmetric phenocrysts, folded veins and oblique foliations developed in the 130 haulageway of the Snip mine imply oblique normally-directed shear on the southwest-dipping foliation.The adjacent Twin zone is a high-grade auriferous shear-vein system that is internally banded with: (1) carbonate-chlorite-biotite veins, with textures indicating formation at least partially by wallrock replacement, and (2) dilatant quartz-sulphide veins. Veins commonly have potassic alteration envelopes that contain biotite ± calcite ± K-feldspar. The zone is highly deformed and schistose, with numerous kinematic indicators including shear bands, asymmetric folds, rotated porphyroclasts and oblique foliations that indicate a normally-directed shear sense which is parallel to that indicated by fabrics within the porphyry.Precious and base metal veins within 2 km or 3 km of the Red Bluff porphyry are zoned. Veins and shear-veins proximal to the intrusion, such as the Twin zone, are typically enriched in gold, copper and molybdenum, and have potassic alteration envelopes dominated by biotite. Distal veins usually contain relatively abundant zinc and lead and have sericitic alteration envelopes. Structures of both types have an Early Jurassic galena Pb-Pb isotope signature.The similarities in structural fabrics and alteration histories in both the Twin zone and the porphyry, the zoning of the vein systems in the area, and the apparently concordant Early Jurassic zircon U-Pb age from the porphyry and galena Pb-Pb dates from the Twin zone and surrounding vein systems suggest that intrusion, semi-brittle deformation and a large mineralizing hydrothermal system were closely related temporally and genetically."

Jan 1, 1995