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By C. Kloppers

The aim of this investigation was to reduce the cost of primary steel de-oxidation by substitution of aluminium primary de-oxidation with a practice that uses carbon. The cost of carbon is four times lower than that of aluminium. The application of carbon would directly result in raw material cost savings. Investigations were conducted at Iscor?s Newcastle steel plant on various steel grades. Specific production aspects were emphasized to ensure that the cost savings accrued would not create secondary expenses. These production aspects entailed: ?Yields on de-oxidation elements ?De-oxidation capabilities ?Alloying yields (Mn and Si) ?Carbon-pickup ?Nitrogen-pickup ?Temperature loss during tap ?Steel cleanliness ?Slag morphology. This project proved that carbon de-oxidation, apart from reducing de-oxidation raw material cost due to cheaper raw materials being used and lower consumption rates, resulted in steel that is cleaner and has lower nitrogen concentrations. Carbon primary de-oxidation has been implemented at Iscor?s Newcastle plant on a large range of steel grades, ranging from ultra-high carbon (> 0.60% C) to ultra-low carbon (< 0.03% C) grades. A net saving of between R100 000 and R200 000 per month was achieved.

Jan 1, 2001

"1.0 DESCRIPTIONThis work consists of furnishing all necessary labor, equipment, and materials to install prefabricated vertical (wick) drains in the ground in accordance with the Plans and as specified herein.2.0 REFERENCED CODES AND STANDARDSASTM D4716-08 Standard Test Method for Determining the (In-plane) Flow Rate per Unit Width and Hydraulic Transmissivity of a Geosynthetic Using a Constant HeadASTM D4632-08 Standard Test Method for Grab Breaking Load and Elongation of GeotextilesASTM D4533-11 Standard Test Method for Trapezoid Tearing Strength of GeotextilesASTM D4491-99a Standard Test Methods for Water Permeability of Geotextiles by Permittivity (2009)ASTM D4751-04 Standard Test Method for Determining Apparent Opening Size (A.O.S.) of a GeotextileASTM 6918-09 Standard Test Method for Testing Vertical Strip Drains in the Crimped Condition3.0 QUALIFICATIONSThe Contractor shall have successfully completed a minimum of five wick drain installation projects in similar ground conditions, and installed not less than 5,000,000 linear feet (1,525,000 linear m) of wick drain in the past five years. The Contractor shall have a minimum of five continuous years of wick drain installation experience."

Jan 1, 2014

By R. E. Cole, A. M. Gaudin

OLEIC acid, a standard flotation reagent, has generally been preferred to other fatty acids. Because oleic acid differs from saturated fatty acids by the presence of one carbon-to-carbon double bond and because the flotation operation is one in which extremely intimate exposure of the reagent to oxygen is obtained, it appeared possible that the value of oleic acid as a flotation collector was related to the oxidizability of its double bond. To test this hypothesis, the floated mineral, fluor-ite, was leached with a solvent capable of extracting the adsorbed reagent and the extract was analyzed.&apos; Results show that oleic acid is not oxidized during flotation, although some oxidation can be obtained if the flotation operation is repeated many times and if oxygen in place of air is employed as the gas during flotation. Incidentally, it was found that lino-leic acid which has two nonconjugated double bonds is not affected appreciably more than oleic acid. Linolenic acid which has three nonconjugated double bonds is measurably altered even during one flotation step, using air. The fatty acids used, from the Hormel Foundation, were of the highest purity. The quantity of fatty acids employed in each test was sufficient to float the mineral, but less than the theoretical amount required to form a monolayer at the mineral surface. The purpose of this limitation was to eliminate droplets of oil smeared on the adsorbate-covered mineral surface. The mineral was dried in vacuum at about 60 °C. Effective leaching was obtained by use of a solution of 1 pct hydrochloric acid in absolute alcohol. The extract was separated from the solvent by distillation, with final recovery of the extract in carbon tetrachloride. The identity of the extract was tested by a combination of analytical procedures including infrared spectroscopy, saponification number, iodine number, and index of refraction. At the outset, great hopes for accurate quantification of oleic acid oxidation had been entertained in regard to the method of infra-red spectroscopy. Unfortunately, because the double bond in the oleic acid is so sym- metrically located at the center of the molecule that it provides very weak absorption bands, accurate quantitative analyses were not obtained. Nevertheless, infra-red spectrograms suggested the absence of double-bond oxidation during flotation. Iodine number, semi-micro method, provided a critical test of the extent to which fatty acids oxidized during flotation, see Table I. The index of refraction was used in a qualitative rather than quantitative fashion, and its findings corroborated those obtained by the iodine-number method. It is concluded, in the case of fluorite and C-18 fatty acids having one or two nonconjugated double bonds, that there is practically no change of the fatty acid molecule or ion during the flotation operation. It would appear, therefore, that the extraordinary utility of these reagents is related to some property of the compounds other than the oxidizability of their double bonds. Acknowledgment The research reported herewith was sponsored by the Research Division, U. S. Atomic Energy Commission, and for this help the authors express their appreciation. Reference &apos;R. E. Cole: "Double-Bond Reactivity of Oleic Acid During Flotation." Thesis submitted in partial fulfillment of the requirements for the degree of M.S. at the Massachusetts Institute of Technology.

Jan 1, 1954

By K. Viking

The vibratory characteristics of full-scale sheet piles, vibratory driven into the ground, have so far not been described systematically in detail. This paper concerns the preliminary results of a series of full-scale field tests where both the driveability and induced ground vibrations have been continuously monitored. Furthermore, the results of measured ground vibration levels have been measured at two different sites characterised as having hard and easy driving conditions. In the light of the presented results, the paper briefly discusses how the complexity of a driveability and vibration prediction can be subdivided into three parts, namely, vibrator-, sheet pile-, and soil-related parameters, all of which significantly affect both the driveability and induced ground vibrations.

Jan 1, 2000

By F F. Pitard

Observation from attending many conferences around the world reveals that many people are constantly shifting from the word ‘error’ to the word ‘uncertainty’ without a clear vision of what the subtle difference is. The same applies to a large swath of the scientific literature, in which these two concepts are unfortunately often used synonymously, which is a scientific flaw of the first order. In practice, as demonstrated in the Theory of Sampling (TOS), there are both sampling errors and sampling uncertainties. Sampling errors can easily be preventively minimised, while sampling uncertainty for a preselected sampling protocol is inevitable. P M Gy’s work, supported by G Matheron’s critical reviews, demonstrates beyond any possible doubt that sampling uncertainty cannot be achieved if sampling errors are not preventively minimised by applying very stringent rules that are too often ignored by sampling practitioners. A clarification, in line with the TOS, is presented to mitigate the confusion created by circles favouring the use of uncertainty versus the use of the word error. Both words are very different in nature and scope and they are both necessary in their due place and time.CITATION:Pitard, F F, 2017. From errors to uncertainty – a clarification for proper use by the Theory of Sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 355–358 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Gary W. LaChapelle

Cyprus Miami Mining Corp. has a history of overcoming adversity through innovation and adaptation to changing conditions. Requirements to remain profitable in the 1990s include a combination of advanced technology, employee involvement and training, attention to customer satisfaction, environmental awareness and quality management. The Miami property is located in the Globe-Miami area of Arizona, 130 km (80 miles) east of Phoenix and 160 km (100 miles) north of Tucson. The complex is located in a high desert environ¬ment at an elevation of 1065 m (3500 ft). The region receives about 480 mm (19 in.) of precipitation annually. History Mineralization at the Miami property was first discovered in the 1880s, which led to underground mining of copper by the 1890s. In 1911, the Inspiration Consolidated Copper Co. was formed by combining the Inspiration and Live Oak Mines. Full-scale production began in 1915. Block caving methods were used at both mines. Open-pit mining commenced in 1948. Underground mining had ceased by 1954, and all production was obtained from surface operations. Innovation has been the key to Miami&apos;s success. Development of sulfide flotation and the ferric cure process for vat leaching were advanced at Miami. In situ leaching of oxide material, remaining after block caving had removed the sulfide ore, was also used.

Jan 1, 1993

By M. W. Hildyard

A blast was engineered close to a tunnel in a deep-level mine with the purpose of studying the wave interaction with the tunnel. Numerical modelling of seismic wave propagation was used in both the forward planning and the back-analysis of this experiment. This paper presents the forward analysis. A likely model for a propagating blast was investigated and developed. This model predicts the influence of the velocity of detonation of the blast and the rise-time of the blast on the radiation pattern, and hence on the expected positions of maximum velocity at the tunnel surface. An attempt was made to quantify the parameters of the blast model, using waveform data from two other blast experiments. The blast model caused particle velocities which were an order of magnitude lower than these measured velocities. Large values for blast pressure were required to match the amplitudes of the recorded velocities. An alternative ?effective? source with a similar mechanism but increased diameter was proposed to account for the higher velocities. It was established that distant velocities scale with the square of the borehole diameter. A calibration blast at the experimental site was also modelled. Agreement in the waveforms was not sufficient for conclusive statements to be made about the validity of the source model. However, the modelled waveforms show an encouraging correspondence with some measured waveforms. This gave confidence that the model could be used to examine wave propagation around the tunnel, and allowed a scaled source to be developed for forward analysis of the main experiment.

Jan 1, 2001

By Zhao Guangwen, Wu Tan, Qiuzhan Tian, Duan Shuzhen

"A thorough study of lost currents in bipolar cells has been made for the development of the great potential of bipolar cells in energy saving. A proper equivalent circuit for bipolar cells has been found, and mathematic methods for computing lost currents at all kinds of polarization have been developed.At linear polarization, the lost currents can be computed by solving either a tridiagonal matrix or an ordinary differential equation of second order. This kind of values can be used to evaluate the minimal lost currents at given conditions. At other kinds of polarization, the lost currents can be computed by the same methods as above if the necessary experiments of measuring the cell voltages of every electrolytic compartment have been made. This kind of values can be used to design bipolar cells at practical conditions.Extensive experiments have been made to evaluate the effects of electrode polarization, emf of galvanic cell for the formation of electrolyzed substance, gaseous products, geometric dimensions of electrolytic cells, special resistance of electrolyte used, and the total and ordinal number of electrolytic compartments on lost currents. It is the first time to make such a systematic research by experiments in the world. Experiments showed that theoretic models were in good agreement with measured data. Experiments also showed that D.C. energy consumption of 0.45 kwh/kg of Pb for lead electrolysis from molten chlorides could be achieved in a cell with 7 bipolar electrodes.IntroductionIt is very promising to apply bipolar electrolytic cells to electrolysis of aluminum, magnesium, lead, zinc and perchlorinates for their great potential of energy saving for example, bipolar cells had been used in the production of magnesium and saved more than 30% of energy, being one of the three main techniques of energy saving in the production of titanium sponge (1)."

Jan 1, 1988

By Robert J. Hundhausen

This report describes Bureau of Mines investigations of a low-grade scheelite-bearing granodiorite intrusive situated on Henderson Creek, Granite County, Mont. The intrusive is in a narrow, V-shaped valley at the head of extensive placer workings. Since May 1943 the H. & R. Mines Co. of Portland, Oreg., has recovered scheelite sand and gold from the placer workings. A modified Yuba, 4?cubic foot bucket dredge was used in the operation. By February 1947 this operation had recovered and marketed over 215,000 pounds of scheelite concentrates containing 63 percent WO3. The scheelite in the placer was found to be derived principally from erosion of the granodiorite intrusive. The intrusive is one of a series of four similar, dikelike masses of granodiorite whose outcrops are aligned along a 10-mile zone of weakness trending N. 60° E. The intrusive has a triangular outcrop exposed over an area of 57 acres. Trenching and sampling by the Bureau of Mines demonstrated that scheelite is sparsely distributed throughout the granodiorite. This work delimited the outcrop of the intrusive and indicated a large submarginal reserve of low-grade tungsten mineralization. The deposit is ideally suited for exploitation by large-scale, open-pit mining operations; it would be easily available in a national emergency. Additional exploration would be necessary, however, before large-scale production plans could be made efficiently or accurately.

Jan 1, 1949

By Steve Wilson, Bern Klein, Jeff Drozdiak, Stefan Nadolski, Andrew Bamber

"In the adaptation of high pressure grinding rolls (HPGRs) to hard-rock mining applications, circuit development has mainly focused on placing HPGRs in the role of tertiary crusher in the preparation of ball mill feed. In order to take advantage of the potential energy benefits associated with HPGR and stirred mill grinding technologies, work was done to investigate the potential of and resultant energy benefits of placing the HPGR in series with a high speed stirred mill in replacement of the conventional cone crusher / ball mill arrangement. The proposed circuit was designed to operate with two stages of HPGR grinding followed by high speed stirred milling.Using a pilot-scale HPGR unit inline with a 20 liter stirred mill, the design criteria, circuit arrangement and consequent comminution energy requirements for a circuit processing copper sulphide ore from Teck Resources’s Mesaba Copper project were determined. These results were then compared to two other circuits, an HPGR / ball mill circuit and a conventional crusher / ball mill circuit processing the same ore.The testwork indicated at a proof-of-concept level that the HPGR / stirred mill circuit could potentially be appropriate for this duty and further work on the concept is merited. While the results indicate that the HPGR component of the circuit was more energy efficient than conventional cone crushing, the energy efficiency of the stirred mill was found to be lower than that of a comparable ball mill undertaking the same duty. However, increased energy efficiency of the stirred mill portion of the circuit is possible with further optimization and further work on the concept is indicated."

Jan 1, 2010

By K. R. Becker

The addition of a force gage and a reaction detector to the Bureau of Mines drop-weight impact apparatus made it possible to examine the details of the force exerted on the specimen and make estimates of the time to reaction. With the current setup the force was found to be oscillatory and not reproducble. However, single well-defined pressure pulses can be delivered to the explosive sample by modifying the drop-weight tools. With a modified test arrangement, the time to reaction and the peak force and energy at the time of reaction were determined as a function of drop-weight height for several different explosives. All these parameters were found to decrease as the rate of force application was increased. The same parameters were also found to vary with the thickness of the test sample. The implications of these results are discussed in terms of practical drop-weight testing.

Jan 1, 1972

By B P. Banerjee, D Patra, S Raval

Roof bolts are an essential component of roof support systems in underground mines. They are used to provide structural support to the roof of the mine and prevent it from collapsing. Therefore, it is imperative to perform regular assessments of these roof bolts to avert any hazards. Manual investigations of roof bolts are done by surveyors in underground mines, which is extremely timeconsuming and challenging due to the low-light conditions in underground mines accompanied by stringent mine access rules. To this end, automated recognition of roof bolts in 3D point cloud data obtained through laser scanning in underground mines serves as a potential solution to aid roof bolt monitoring. With the continuous advancements in laser scanning-based 3D data acquisition systems, the feasibility of making such surface estimations from 3D point cloud data has increased severalfold.

Sep 1, 2024

By T. P. Weldum, W. Conger

"The objective of the study conducted by the authors is to determine what media size(s) addition will maximize any given plant ball mill’s grinding efficiency (Fig. 1). The functional performance parameters “mill grinding rate through the size of interest,” and “cumulative mill grinding rates” from both plant and smallscale tests are applied to this task. A plant media sizing methodology, and industrial case studies, are provided.BackgroundA previous article (“Ball mill classification system optimization through functional performance modeling,” Nov. 17, McIvor et al., 2017, Mining Engineering) described circuit classification system efficiency (CSE), equal to the percentage of coarse (plus circuit P80 target size) material in the ball mill. It can be measured and then increased through pump and cyclone adjustments. By so transferring the application of ball mill power from fine (minus P80 product size) to coarse material, circuit efficiency is increased and overgrinding is decreased.The other factor that determines overall circuit efficiency is how well the power that is applied to the coarse material grinds it. This is affected by design and operating variables like the media sizing and mill percent solids. From circuit functional performance (McIvor et al., 1990):Circuit production rate of new fine material (t/h) = Power applied to coarse material (kW) x Mill grinding rate of coarse material (t/kWh) (1)The power applied to coarse material is the total mill power multiplied by the CSE. Therefore:Circuit production rate of new fine material (t/h) = Total mill power (kW) x CSE (%) x Mill grinding rate of coarse material (t/kWh) (2) Production rate, mill power and CSE can be measured during a plant circuit survey. The mill grinding rate of coarse material is then calculated. At the circuit target P80 size, this is the mill grinding rate (of coarse material) through the size of interest. The objective is to maximize this rate. The mill grinding efficiency can also be calculated by taking the ratio of the mill grinding rate over the material’s grindability as measured in the lab. Mill percent solids optimization has thusly been achieved (McIvor et al., 2000). For media sizing, maximizing the mill grinding rate on a given ore is equivalent to maximizing the mill grinding efficiency. Ores of different grindability will be part of the discussion."

Jan 11, 2018

By N. M. Can

The effects of microwave treatment on the floatabilities and magnetic susceptibilities of some sulfide minerals, namely, pyrite, chalcopyrite, galena and sphalerite, were studied. Pure mineral samples were prepared in -425+212-µm, -212+106-µm and -106+38-µm size fractions. Microflotation and magnetic separation tests were carried out on the samples after microwave treatment at 600, 950 and 1,300 Watts for 5, 20, 60, 90, 120 and 240 seconds. The maximum temperature values of the samples were measured during the microwave treatment, and possible altera-tions on the mineral surfaces were determined by X-ray diffraction (XRD) analysis. The effects of microwave treatment are discussed based on the result of microflotation and magnetic separation tests. The results revealed that pyrite, chalcopyrite and galena were heated very quickly and that their surface temperatures reached ~700° to 900°C, while the temperature of sphalerite reached only ~130°C. The floatability of pyrite, chalcopyrite and galena were decreased when microwave energy and the duration of treatment were increased, owing to oxidation of the mineral surfaces caused by relatively high temperature. As expected, there was no change in the floatability of sphalerite. The magnetic properties of pyrite and chalcopyrite were improved by the increase in microwave energy and the duration of treatment to such an extent that 90% of the feed separated as magnetic product. But no change was observed in the magnetic properties of galena and sphalerite.

Jan 1, 2007

By J. B. Austin, R. H. H. Pierce

IN developing a consistent picture of the thermal expansion of the commercial chromium steels, which cover a range of, carbon contents, it is desirable to know the expansion in the limiting case of the binary, carbon-free, iron-chromium alloys. We have, therefore, determined the thermal expansion of a series of five special alloys, ranging in chromium content from 3 to 10.5 per cent, with not more than 0.03 per cent carbon, over a temperature range extending beyond the transformation region; this low carbon content enables us to draw reasonably reliable conclusions as to the behavior of the carbon-free system. Moreover, the measurements serve to determine the beginning and the end of the alpha-gamma transformation; and they emphasize once more the fact that a transformation temperature determined by any method in which the specimen is .cooled at an appreciable rate is apt to be seriously in error, particularly if the metal contains a transformation-retarding element such as chromium or managanese. The lag, or undercooling, observed at the ?-a transformation is explained in terms of the influence of temperature on transformation velocity; the rather unusual shape of the ? loop is attributed to a change with temperature and with composition of the distribution of chromium between the alpha-iron and gamma-iron solid solutions. The exact composition of the alloys which were obtained through the courtesy of Dr. W. Rohn, of the Heraeus Vakuumschmelze A-G., is given in Table 1. Determinations of the linear thermal expansion and of transformation temperature were carried out in the vacuum dilatometer previously described,1 using a rate of heating and of cooling of 3.0° to 3.5° per minute unless otherwise stated. Magnetic susceptibility, which was measured in studying the rate of transformation, was determined with a magnetic balance, which also has. been described.2

Jan 1, 1935

Federal lands often contain extensive mineral resources and decisions affecting access to those lands are made with knowledge of the possible minerals-related consequences. Information is provided to the Bureau of Land Management (BLM) in this report for use in preparing environmental impact statements on the Western Mojave Management Area (WMMA) and the Desert Tortoise Priority Habitat (DTPH). To augment U.S. Bureau of Mines (USBM) efforts such as the Mineral Assessment of the Planned Foil Irwin Expansion, Modified Silurian Valley Alternative, San Bernardino County, California which is in progress, and the Economic Analysis of the Minerals Potential of the East Mojave National Scenic Area; California, the USBM studied mineral deposits and estimated the potential impacts of mining in a segment of the California desert; the 8.7-million-acre WMMA, an area which includes the 1.2-million-acre Desert Tortoise Priority Habitat (DTPH). In addition, this information is intended to assist administrators, legislators, and the concerned public in understanding the economic importance of mineral resources in the California desert, especially that portion designated as the WMMA. See figure 1.

Jan 1, 1993

The war story of the engineer corps at home and in France is told officially for the first time in the advance sheets of the War Department&apos;s brief history of American war efforts. Many of these accomplishments have been published before as isolated incidents, but they gave no idea of the extraordinary duties modern warfare has laid upon engineering troops. In the engineering units that reached the other side, there were seven regiments and two battalions of railway construction engineers; five battalions for maintenance of way; two battalions for maintenance of railway equipment; four regiments and one battalion to operate the main American railways in France; three regiments to operate light railways and their repair shops; two regiments to operate the regular railway repair shops; two regiments and six separate battalions on general construction work; two regiments for storing and transporting engineer supplies; a forestry regiment; a light-railway construction regiment; a roadbuilding regiment; a water-supply regiment; a mining regiment; a quarrying regiment; a technical regiment for surveying and sound ranging; three survey and printing battalions; two railway transportation battalions; an electrical and mechanical regiment; several separate companies to operate cranes; a camouflage service; five inland waterway companies, to operate canal boats and the like; five pontoon trains and a pontoon

Jan 6, 1919

By Christopher J. Bambridge, Lee Seng Hoor

The Stormwater Management and Road Tunnel (SMART) Tunnel is a world first in the use of tunnel space transmitting both road and water through the same spatial envelope. The unique aspect of the SMART project is that the highway decks are used periodically for the conveyance of water. This aspect of the project has posed its own technical challenges that have been overcome in the design stage of the work allowing the project to be taken forward to construction with confidence in the systems to be Installed in the tunnel.

Jan 1, 2005

By R. J. Johnston

"INTRODUCTIONPoint Mines is located about 65 miles east of Hay River on the South Shore of the Great Slave Lake. It is connected to the Northern Alberta Railway System by the Great Slave Lake Division of CN Railways at Roma Junction, Alberta.The operation started in the fall of 1965 with a capacity of 5000 t.p.d. An addition was put into operation late in 1968 to bring the capacity up to 8000 t.p.d. The present milling rate is 11,000 t.p.d.The location of Pine Point Mines is such that long end cold winters are to be expected end temperatures of lower than -200F are encountered from late October to late March, with extended periods of -300F being common in January and February.It was recognized by Cominco engineers during the initial design period that since freezing would be encountered with open pit ore somewhere in the crushing circuit, the problem was to reduce it as much as possible. Other mines, working under similar conditions, found that the fine ore bins feeding the grinding circuit were the main problem area. The decision was reached, therefore, to have heated fine ore bins and to make sure thst the ore was sufficiently warm to prevent freezing.CRUSHING PLANT FLOWSHEETThe crushing plant has a standard open flow circuit (flowsheet). Ore from the stockpile is loaded into R-50 Euclid trucks by Caterpillar 992 Front End Loader with 11 cu. yd. bucket and dumped into a 42 x 65 C.A.C. Superior Crusher driven by a 300 HP motor. The crusher is set at a nominal 5 inches. The ore falls through into a 100-ton surge bin. There are high level and low level nuclear gauges to allow the primary operator to optimize for optimum orientation."

Jan 1, 1972

By Litvinenko V. I

Being a source of structural materials for many centuries, the modern image of the ferrous metallurgy is burdened with obsolete technologies with disregard towards new environmental protection requirements. The production cycle of metallurgical products have two clear-cut stages: I . production of liquid metal and casting into steel billets; and 2. processing of steel billets in solid state under high temperature to produce various shapes and profiles of metal products. Plastic deformation of metal at the second stage is least associated with environmental pollution and is presently being provided with more and more advanced equipment.

Jan 1, 1999