Search Documents

This paper describes results of an investigation of fracture during tube expansion of 5052 and 5754 aluminum seam-welded tubes to optimize the forming of aluminum tubes during hydroforming. The tubes were produced in laboratory by press forming of tubular blanks and pilot-scale high frequency induction welding. The effect of property mismatch between the weld and base metal has been investigated. The material work-hardening was obtained by roll forming of sheet blanks in the 0-temper and H32 temper condition. The results showed that a significant work-hardening can be present in aluminum tube without causing weld fracture during tube expansion. The work-hardening increases the yield-strength mismatch between base metal and weld. Annealing reduces the hardness of base metal leading to more uniform deformation during tube expansion. As a result the occurrence of weld fracture is reduced. The study showed significant deformation of the welds during tube expansion. Weld thinning can be as large as parent-material thinning before fracture. To avoid fracture at the weld joint, good formability and high yield strength of the weld is needed. FEM simulation showed that minimizing the width of the weld joint can reduce thinning of the weld.

Jan 1, 2004

By F. W. Liang

The geology of pearl River estuary belongs in strong weathered rock quaternary geological systen, so the conditions are complication. Since 80's we built the first deepwater wharf of Shenzhen chiwan port which has 3 berths of 10000 dwt, We have built 3 berths for vessels of 40000 dwt both in Shekou Port and Chiwan port. The berths for carriers of 10000 dwt in Yantian Port of Dapeng Bay are constructing now. In the five years, We built more than 20 deepwater berths of 5000 dwt to 40000 dwt. This paper will introduce how to solve the difficulties of the complex geological conditions and how to use the new fashion construction. We will reduce the period of engineering construction and get good quality and make a good beginning of rapid development of port construction in ShenZhen Special Economic Zone.

Jan 1, 1991

By C. Guria

A modeling, simulation and optimization study of a complex industrial fluorspar beneficiation plant (Kadipani, Gujarat, India) with fourteen/ten flotation banks is carried out to find an optimum/near-optimum circuit for the given quality of feed ore. The phenomenological flotation model developed by Mehrotra and Kapur (1974) is used for circuit optimization. Two different optimization problems are formulated and solved. The first optimization problem involves a single objective function, which uses available plant data to estimate the feed-characterizing parameters, i.e., the flotation rate constants, by minimizing the weighted sum-of-square errors between the computed and plant values. The second optimization problem involves two objective functions to obtain several simplified circuits. The number of non-linking streams and the overall recovery of the concentrate, i.e., the acid-grade product, are maximized simultaneously in this problem. The single-objective variant (SGA-II-mJG) of the binary-coded elitist non-dominated sorting genetic algorithm with the jumping gene adaptation, NSGA-II-mJG, is used for the first problem, while NAGA-II-mJG (Guria et al., 2005 a) is used for the second problem. Simplified circuits with a few split streams are proposed on the basis of the present optimization study, which enhance the recovery of the acid-grade product without affecting its quality, for a given total volume of the flotation cell-bank. Even though the optimal solutions have certain drawbacks, they suggest a meaningful direction in using an iterative fitting of parameters to such optimal circuits, followed by re-optimization. Key words: Froth flotation, Mineral processing, Industrial fluorspar beneficiation, Feed identification, Circuit/network optimization, Global optimal, Jumping gene, Genetic algorithm, Multi-objective optimization

Jan 1, 2009

By N. J. Keys

This paper concerns the development and application of a high throughput multi-stream photometric sorting machine developed for the South African gold mines. It is now believed that this sorter and its progeny may be found suitable for a large proportion of all possible sorting applications. A laser light source and sensitive photomultiplier are employed in a scanning system to detect light reflected from the surfaces of rocks passing through the sorting zone. Electronic circuitry then analyzes the photomultiplier signal, which represents the varying intensity of the reflected light, and produces control signals to actuate the appropriate valves of an array of air blast rejection devices to remove from the feed certain particles selected by the analyzing process. Typical throughput per machine ranges from 50 tons/hour for a-2 ½? + 1 ¼? feed to 200 tons/hour for -6" +2 ¾ " material.

Jan 1, 1974

By John J. Henn

An evaluation is presented of the Bureau of Mines process for the recovery of metal and mineral values from municipal incinerator residues. This process employs standard mineral beneficiation techniques and is operating on a pilot-plant scale of 1,000 pounds of incinerator residue feed per hour. Products from this separation process include ferrous, aluminum, and copper-zinc scrap, and colorless and colored glass. Cost estimates were prepared for four plant sizes. The estimated capital and operating costs For the four plants follow: [ ] It is assumed that the separation plant is located adjacent to a municipal incinerator. Provision is made, however, for part of the residue feed to be delivered by truck so that one large separation plant can be used for residue from more than one incinerator.

Jan 1, 1971

By G. M. Kintz

It is estimated that 10,000 lives were lost and $285,000,000 worth of property was destroyed by fire in 1937. Of the 103 fatalities in tie petroleum industry in 1938, 36 resulted from fires and explosions.3/ Everyone can help to prevent the tremendous losses, both in life and property, caused annually by fires and explosions, Forest fires occur every year, in which the tremendously intense heat wave ahead of the flame turns beautiful green trees into blazing torches like so much gasoline, vapor, and jumps over the tops of trees to start fires behind the firs fighters; prairie-grass fires occur, and a farmer in the path of the fire must plow a furrow around his home and outbuildings before the flame reaches them; and frequently automobiles are burned up in filling stations. Persons who have witnessed such sights know better than to throw a lighted match, cigarette, cigar, or hot coal from a pipe out of an automobile or to discard a fire or flame of any type in the forest, in the country, or in the city.

Jan 1, 1941

By Yuzhe Zhang, Xiaodi Huang, Xinli Wang, Bowen Li, Matthew Andriese, Jiann-Yang Hwang, Zhiwei Peng

The recycling of waste tires has been a big environmental problem. About 280 million waste tires are produced annually in the United States and more than 2 billion tires are stockpiled, which cause fire hazards and health issues. Tire rubbers are insoluble elastic high polymer materials. They are not biodegradable and may take hundreds of years to decompose in the natural environment. Microwave irradiation can be a thermal processing method for the decomposition of tire rubbers. In this study, the microwave absorption properties of waste tire at various temperatures are characterized to determine the conditions favorable for the microwave heating of waste tires.

Jan 1, 2015

By K. C. Hendrick

The paper will review the significant developments in world copper over the past ten years and their impact on the Canadian industry. It will also examine the outlook for the future.

Jan 1, 1971

By D Tucker, K Harney

Hatch forecasts that an increasing share of seaborne traded iron ore will be ultrafine, being either concentrate or pellet feed. This provides several challenges for the iron and steel industries, but the principal concern is: how much ultrafine iron ore can be consumed on sinter strands and with a minimal effect on productivity?This paper will identify new supply by project through 2020. Demand will be estimated for sinter production and practical steps will be identified to increase ultrafine consumption in sinter strands. The long-term iron ore price will be forecast to balance supply and demand. The paper will conclude by assessing how the pricing of ultrafine ore will develop relative to the Chinese iron ore indices.CITATION:Tucker, D and Harney, K, 2015. Iron ore ultrafines challenges and opportunities, in Proceedings Iron Ore 2015, pp 501–504 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By H. Sevim

Three transportation and handling alternatives for delivering dry coal combustion residues from power plants to underground coal mines were evaluated technically and economically. The objective was to transport, handle, and inject the residues into the old workings of the mine at a minimum cost. This objective was accomplished in two steps: I) Simulation models were developed and utilized in identifying technically feasible designs in each alternative, 2) Technically feasible designs were economically evaluated to obtain the cost-per-ton of material transported. The designs that provided the minimum cost-per-ton were declared optimal An analysis was conducted for varying distances and tonnages to reveal favorable operating ranges of each alternative.

Jan 1, 1996

By W. Z. Yin

It is investigated systemically in this paper that the granularity of the precursor, ZnC2O4?2H2O, is influenced by synthetic conditions. Instantaneously adding of precipitation agent is able to control the mean size of precursor ZnC2O4?2H2O under 300nm, which has great function to obtain well-dispersed ZnO nanoparticles in the next step, pyrolysis. The pyrolysis kinetics model of ZnC2O4?2H2O powder is obtained. Two steps take place during the pyrolysis. The first is dehydration, which the pyrolysis kinetic model is 2(1-a)2/3(chemical reaction), A=8.3×108s-1, E=(75.82±3.00) KJ/mol. The second is formation of ZnO, which the pyrolysis kinetic model is (1-a) (random nucleation and latter growth), A=8.45×1028s-1, E=(360.54±12.00)KJ/mol. ZnO nanoparticles obtained by pyrolysis take on self-growth behavior. It is resulted that for precursor ZnC2O4?2H2O pyrolysis time takes obvious influence on the partilces size under 420?, 500? and 600?. Finally, a new flow sheet for synthesis of ZnO nanoparticles is investigated, in which blendes is used as raw material and hydrometallurgy is introduced into it. The whole flow sheet has no industrial wastes, that is all byproducts can be used in the flow sheet recycled, resulted in the de-crease of productive cost and industrial wastes.

Jan 1, 2014

By J. W. Thompson

MINERALS OWNERSHIP AND POSSESSION. The owner of minerals under a conveyance from the surface owner does not lose his right or his possession by mere nonusage of the minerals. McBeth v. Wetnight (Indiana), 106 Northeastern, 407, p. 410, October, 1914. QUIETING TITLE TO MINERALS-PLEADING. A complaint in an action to quiet title to minerals and to the min- eral rights in certain land is insufficient in the absence of a direct allegation of possession, although it avers that the plaintiff from the time of receiving the conveyance assessed the mineral interest for taxes each year and paid the taxes thereon and exercised various acts of ownership of such mineral interests, in that he caused test pits to be dug on the land for the purpose of exploring the minerals and ascertaining their quality and extent, in going upon the land and looking after them from time to time, and that he accompanied or caused his agents to accompany prospective purchasers of such mineral interests and exhibited the same to such prospective pur- chasers in efforts to sell them. Fowler r. Alabama Iron & Steel Co. (Alabama), 66 Southern, 672, p. 673, Novem- ber, 1914. SALE BY MARRIED WOMAN-VALIDITY. A conveyance by a married woman of the mineral rights in certain described land is void where she had previously conveyed the land to another grantee who had acquired title by adverse possession under the deed.

Jan 1, 1915

By Ross Glanville

The Optimum Production Rate (OPR) is one of the most important parameters in the evaluation of a mineral deposit. The OPR cam also be expressed as the Optimum Mime Life (OML) in years since the expected mime life is determined by dividing the OPR per year into the estimated ore reserves. Unfortunately, very little time and effort has been directed towards the determination of the OPR. Instead, "rules of thumb" are often applied to select a mime life without due consideration of the economic implications of such a selection. A "justification" for a particular production rate is often based on a pre-conceived arbitrary requirement for a mime life of 5, 10, or 15 years, for example. In this paper it is demonstrated that such arbitrary selections for high-grade/low¬-tonnage mines (such as many underground gold/silver deposits) often lead to sub¬optimal results. In fact, am apparently uneconomic deposit at am arbitrary production rate may be economic at the OPR. Consequently, investment opportunities may be overlooked if one analyzes mime' properties based on arbitrary production rates.

Jan 1, 1984

By S Chatterjee

The production scheduling of an open pit mine determines the optimal extraction sequencing that significantly impacts a mine’s life as well as net present value. The optimisation of production scheduling of large open pit mines with geological uncertainty is a computationally very intensive process. In this paper, an approximation algorithm is proposed to schedule an open pit mine, where instead of solving the whole problem at once, the production schedule is generated by sequentially solving subproblems. The subgradient method is used to generate the upper bound solution of the Lagrangian relaxed subproblem. If the upper bound relaxed algorithm is not a feasible solution, a mixed integer programming is solved on the generated upper-bound solution. An application at a copper mine with an orebody represented by 16 532 mining blocks is presented using the proposed algorithm. Results show that all constraints are satisfied. The net present values are also calculated and results reveal an 11 per cent higher net present value (NPV) is generated when compared to the NPV generated when the same approach is applied to the deterministic model of the deposit where uncertainty is not accounted for.CITATION:Chatterjee, S, 2014. Stochastic production scheduling – solution through Langrangian relaxation with the branch-and-cut algorithm, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 323–328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By M L. Muller, A R. O’Donnell

The Mount Isa Mines (MIM) Copper Concentrator has an extensive history of reagent trials, with different reagents coming in and out of favour over the years. The research and use of carbon depressants is particularly prevalent, as carbonaceous pyrite is a major source of concentrate dilution. Years of research led to the use of naphthalene sulphonate due to its excellent carbon depression properties. However, due to rising reagent costs carbon depression ceased in the late 1990s. This led to the loss of knowledge about the use and value of naphthalene sulphonate. Cyanide is used at the Copper Concentrator for the sole purpose of pyrite depression and over the years multiple projects have been devoted to finding alternatives to it. In 2012 the neighbouring MIM Lead-Zinc Concentrator replaced cyanide with naphthalene sulphonate which resulted in cost savings and the elimination of a hazardous reagent. In 2013, plant trials were conducted at the Copper Concentrator in hopes to replicate the outcomes obtained at the Lead-Zinc Concentrator. The results of the trials conducted at the Copper Concentrator showed that naphthalene sulphonate could not replace cyanide and this work was set aside to pursue more promising projects. Further research conducted in 2014 found that mineralogy and a better understanding of the depressing mechanism of naphthalene sulphonate held the key to improved pyrite depression at the Copper Concentrator. The findings showed that Mount Isa copper ore contains two forms of pyrite; euhedral pyrite (cubic pyrite) and framboidal pyrite (carbon rimmed spheres of pyrite), both of which require different reagents to sufficiently depress them. Naphthalene sulphonate was found to be an excellent carbon depressant, suitable for depressing graphite and framboidal pyrite, whilst cyanide specifically targets euhedral pyrite.In 2015 laboratory test work was conducted to examine the use of naphthalene sulphonate in conjunction with cyanide to selectively target both forms of pyrite. This work led to a full plant trial, the results of which showed a significant increase in plant performance, with higher copper concentrate grades and recoveries being achieved. This paper aims to focus on the benefits and importance of understanding past work and linking a detailed knowledge of feed mineralogy to reagent selection for improved plant outcomes.CITATION:O’Donnell, A R and Muller, M L, 2018. Selectively targeting hydrophobic gangue minerals at the Mount Isa Mines Copper Concentrator, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 413–421 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By James P. Bennett

To identify construction materials for emerging technology in chemical and metallurgical processes, the Bureau of Mines investigated the acid resistance of ceramic materials. Eight commercial ceramic materials comprising two red shale, two fire clay, a silica, a five-claybonded silicon carbide, a carbon, and a high-alumina brick were evaluated. Samples were exposed for 110 days to 20 wt pct HCl at 50°, 70°, and 90° C and to 30 wt pct HCl at 70° C. Statistically significant changes in cold crushing strength, volume, and weight were generally small or not detected. The leach rates of Al, Ca, Fe, K, Mg, Na, Si, and Ti ions were monitored. The carbon brick sample had the best acid resistant properties with a maximum total leached ion weight loss of 0.004 wt pct. The silicon carbide, the silica, and one of the fire clay bricks also had excellent acid-resistant properties.

Jan 1, 1983

By D. A. Paice

Direct current electrical systems are used in most coal mines primarily to power the main haulage trains and secondarily to feed other equipment and passageway lighting. Electrical power is supplied from rotary machines or static rectifier equipment and is distributed through the mine by open trolley wires and feeder cables. The rails of the haulageway are used as a current return path. This exposed power distribution system is very vulnerable to conditions which lead to undesired leakage currents and short circuits and, consequently, the possibility of fires or other hazards to personnel. Present techniques and equipment have been utilized in so far as practical to improve the safety of the dc electrical system; however, there still appears a need for further improvement. Because of this need, this program was sponsored by the Bureau of Mines to investigate two specific technical areas related to improvement of dc electrical system safety. One area included the determination of the characteristics of mine electrical systems and their protection requirements and the verification of the adequacy of available protective devices for mine service. Despite the widespread application of industrial protective equipment in mines, there was little detailed technical information available related specifically to the performance of this equipment in service. Our task was not only to develop useful information regarding mine system protection, but also to define and verify the adequacy of the protective devices available. The second area of investigation called for development of a practical technique for detecting low level electrical fault or leakage currents. Conventional protective devices

Jan 1, 2012

By Valeh Aghazadeh, Shima Barakan, Mina Soleymani, Ehsan Bidari, Morovvat Faridazad

Molybdenite is the most important molybdenum concentrate, which is mainly recovered as a by-product from porphyry copper deposits. Due to the low efficiency of purification processes such as flotation in the reduction of copper content of molybdenum concentrate to a standard level (i.e., less than 0.5 wt.%), further purification by a hydrometallurgical method is required. Although different types of chemical reagents were found to be effective in the leaching of copper minerals from molybdenum concentrate, the mechanisms of these processes remain largely unexplored. In this study, optimal conditions for maximum copper leaching (> 99%) were obtained at the concentration of HCl = 1 M, FeCl3 = 0.5 M, CuCl2 = 0.05 M, CaCl2 = 0.5 M at 75 °C, 500 rpm, and S:L = 1:10 during 60 min. CuCl2 was identified as the most effective leaching reagent for copper dissolution in agreement with Visual MINTEQ model results due to the formation of various types of copper chloride complexes. Furthermore, the electrochemical behaviors of FeCl3, CuCl2, and CaCl2 reagents before and after the leaching process were investigated by the cyclic voltammetry technique. The results of cyclic voltammograms at different scan rates verified the presence of copper chloride complexes, and ferric ions as the oxidizing reagents for better dissolution of copper sulfides. Based on kinetic study results of shrinking core models, both chemical and diffusion reactions controlled the copper leaching process with an obtained activation energy of 33.56 kJ/mol. For recovery of the leached copper, the precipitation process was done by the addition of Na2S at 45 °C, S/Cu = 1, and pH = 9.

Dec 26, 2022

By G. L. Anderson

The critical importance of wire rope integrity to the mining industry has led to the creation of standards for the retirement of wire rope as well as to the development of electromagnetic devices and procedures that would allow wire ropes to be tested against these standards without destroying them, The U.S. Bureau of Mines (USBM) conducted research to evaluate these devices by measuring loss of metallic cross-sectional area and the number of wire breaks, or local faults. The intent was to define the extent to which the technique can identify degradation within the rope, e.g., broken wires, corrosion, and wear. Experimental results showed that instrument sensitivity depended on a number of factors, including rope diameter, placement of sensors, location and characteristics of flaws, rope speed, and tension on the rope. The experiments also demonstrated the importance of having an elongated recorder trace and a properly trained and experienced operator to interpret overall results. A design of a rope and test procedures for use in laboratory evaluation of instruments have been recommended by the American Society for Testing and Materials Committee E07.07.10, Wire Rope Applications. The USBM is working through this committee to develop standards for an electro-magnetic method of wire rope inspection.

Jan 1, 2010

By E. L. Rawlins

The Bureau of Mines, with the cooperation of the Natural Gas Association of America, has conducted a study of leakage losses from natural-gas transmission lines. This study has shorn that surveys to determine the leakage from transmission lines lead to line repair work that not only aids in the conservation of gas, but can be made to show financial returns of large magnitude.2 In order to conduct the study, it was necessary to develop accurate and reliable methods of determining the actual leakage from pipe lines. METHODS OF TESTING Three methods that were developed and used to determine the leakage losses from high-pressure natural-gas transmission lines are: (1) The "pressure-drop" method, (2) The "metering-in and metering-out" method. (3) The "metering-in" method.

Jan 1, 1926