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By Darryl Amick, Keith A. Prisbrey, Lee E. Plansky

The problem addressed was to develop automated image analysis of metal welds to replace unreliable and costly 100% visual inspection. The objective was to evaluate neural networks combined with features from gray level surfaces. Photomicrographs of the welded seam in Zircaloy-4 channels used in nuclear fuel rod assemblies were examined. The methodology used was to select a set of morphological feature coefficients from Bessel Fourier morphological feature coefficients extracted from digitized photomicrographs. The selected morphological feature coefficients were then used to train a neural network. The approach was verified initially by successfully training a neural network using the known, secondary chemistry of the alloy welds. The results were good. The Bessel Fourier coefficients captured sufficient information from the metallographic images to distinguish weld quality. This approach has the combined advantages of compressing the images through Bessel Fourier coefficients and give the ability to rapidly process large amounts of data using neural networks.

Jan 1, 1993

By Kal V. S. Sastry

Mineral processing simulation has come a long way since its beginning about thirty years ago. With our increased understanding of mineral process systems and the advent of new software and hardware technologies, we can visualize an ideal mineral processing simulator. This paper attempts to identify a number of desirable features of an ideal mineral process simulator and to describe the exciting trends in making such an ideal simulator a reality.

Jan 1, 1992

By B. Govindarajan, T. C. Rao, J. P. Barnwal

A simple modelling methodology has been proposed to predict the performance of industrial coal flotation circuit based on the observations made on the actual performance. The solid content in the tailings of the coal flotation circuit has been identified as a lode-star to predict the performance in terms of yield and ash content of the concentrate. The modelling parameters are directly measurable.

Jan 1, 1995

By S. D. Thompson, G. T. Lineberry, A. J. Basu

Conveyor belt haulage has become the preferred mainline transport method in underground coal mining, especially for multi-unit mines. Proper designs for belts (width and speed) and surge bins (placement, capacity, and discharge rate) are necessary to achieve efficient mine haul- age. Two computer simulation models, CMBCS and BELTSIM, available for designing these parameters were compared. These comparisons included modeling, input data requirements, statistical flexibility, accuracy of simulated loading, and execution time.

Jan 1, 1991

In 1990, US mine production of barite increased 54.1 %. Barite consumption, sold or used by grinding plants, increased by 27.6%. Imports were about the same as 1989. World mine production in¬creased 12.3%, according to the US Bureau of Mines. The value of domestically produced barite, fob mine, decreased 12.7%, according to the Bureau. The declared value, cif US port, of all imported crude barite during the year 1990 increased from $40.27/t ($36.54 per st) in 1989 to $40.61/t ($36.84 per st). Nevada continued to be the leading producer of barite with 82% of the total, followed by Georgia and Missouri. It is estimated that 750/c, of the domestically mined barite was used as a weighting agent in drilling fluids. The remaining 25% was used in barium chemicals, glass or as a filler. Most of the production from Missouri, Georgia and Tennessee was used in the non-oilfield sector. Of the total barite used by grinding plants and chemical manufacturers, it is estimated that 90% was used in drilling fluids and 10% in the non-oilfield sector. This includes barium chemicals and fillers in paper, plastics, and glass. Tonnage consumed in the drilling fluids market increased due to the higher average rig count during 1990. The average number of rotary rigs operating, (1010), was 16.2% more than the 1989 average of 869 in the US.

Jan 1, 1991

By Richard B. Muter

In determining the layout or combination of unit operations to be utilized in a modem preparation plant, several factors must be taken into account. Among these are the washability data, size consist data, the particular market or markets for the coal, the mining method used, the degree to which the coal must be prepared, expected fluctuations in raw coal and markets, and the overall economics of the process. In addition, there are the health and safety aspects of coal utilization and preparation. Chapter 1 of this book discusses the characteristics of coal and coal markets, while Chapter 2 deals with the design of preparation plants. Once the unit operations for a particular plant have been decided upon, these arrangement may be depicted by using a flowsheet. A coal preparation plant flowsheet is a two-dimensional graphical representation of the sequence of operations, the arrangement of machinery, and the flow of materials for a particular coal cleaning operation. The flowsheet is usually qualitative in nature, becoming more quantitative as material balances, water balances, numbers and sizes of various pieces of equipment, etc. are added. The usual convention in preparing a flowsheet is to show the feed flowing from left to right, starting at the top left and working down as in an all-gravity process. Various symbols are used for each unit operation as depicted on a flowsheet, and Fig. 14-37 is a compilation of the commonly accepted international standard symbols for each unit operation. Fig. 14-38 through Fig. 14-40 are flowsheets of various coal cleaning processes as published in the January 1976 issue of Coal Age. Each process has its own unique features which, among others, depend upon the coal being cleaned, the coal market, and the mining operation. Fig. 14-38, for example, is a flow diagram for a jig plant preparing steam coal from two strip mines located a few miles apart. In addition to the jig washer, cyclones are used to treat the finer size coal. Fig. 14-39 is a flowsheet of a heavy media plant using a heavy media washer for + %-in. (+6.3-mm) coal, froth flotation for -28 Tyler mesh (-0.6 mm) material, and dewatering phase units (dwp) for Y, in. x 28 Tyler mesh (6.3 x 0.6-mm) cleaning of steam coal. In addition, thermal drying, centrifuge drying, and the use of vacuum disk filters and thickeners for dewatering are depicted. Fig. 14-40 is a flowsheet of a plant producing metallurgical coal. In addition to the heavy media and froth flotation circuits, a tabling circuit is also employed. These flowsheets are intended to give the reader an example of how the various unit operations for coal cleaning may be linked together. Figs. 14-41 and 14-42 illustrate the conversion of block diagrams into an IS0 prescribed set of symbols.

Jan 1, 1991

By D. Forbes

The results of a fundamental study involving zeta-potential and turbidity determinations of solid suspensions are discussed. Illustrations of how these results are utilized to design field applications of solid-grade polymers to clarify mine-drainage water are presented. Operational and economical advantages are examined.

Jan 1, 1997

By M. Georgescu

In the framework of the rapid development of contemporary society, the use of underground space represents an emerging opportunity because it can contribute to decreasing pressure of occupation of ground space while in the same time it can increase the economic value of the useful mineral substances, also through underground establishment of dangerous surface activities, contributing thus in environmental protection. This paper underlines the most important benefits of underground space utilization with the objective the exploit the potential of this real resource.

Jan 1, 2006

By Gary L. Simmons

Over the past several years, Newmont Gold Company (previously Santa Fe Pacific Gold Corporation) developed a new technology for the flotation of refractory auriferous sulfide minerals which is referred to as the N2TEC flotation process. Starting in April 1997, the first commercial flotation plant utilizing N2TEC technology was successfully commissioned at the Lone Tree Mine near Valmy, Nevada. The Lone Tree flotation plant was designed to process 4,085 mt/d of ore producing 494 mt/d of sulfide concentrate. A flotation tails leach CIP circuit was added to recover cyanide-soluble gold from the flotation tails. A portion of the flotation concentrate is blended with whole ore feed to the Lone Tree autoclave, up to the limit imposed by the current oxygen plant capacity. The remainder of the concentrate is shipped to either the Twin Creeks autoclaves or the Carlin roaster for subsequent oxidation and gold extraction. This paper discusses the results achieved in the commercial flotation plant compared to pilot plant testing and engineering design flotation modeling. Capital and operating cost information are also presented.

Jan 1, 1999

By G. Bhaskar Raju, S. Prabhakar

The amenability of column flotation for the beneficiation of fluorspar was investigated, and the overall performance of the column, flotation was compared to the performance of the existing conventional flotation cells at the plant. It was estab¬lished that improved grades and recoveries could be obtained by adopting column technology. Acidspar concentrates as¬saying 97% CaF2, suitable for HF manufacturing, can be produced by adopting two-stage column cleaning in place of multistage cleaning by conventional cells. Similarly, metspar concentrates assaying 90% CaF2, suitable for metallurgical applications, can be achieved in a single-stage cleaning by column flotation. This is an improvement over what is now being achieved using the existing conventional rougher and three-stage cleaning cells in the plant. The number of stages, i.e.,four in the acidspar circuit and four in the metspar circuit, including rougher stages, can be eliminated by adopting a three-column configuration. Thus, the cost of production, the complexity of the circuit and the power consumption can be effectively reduced with other attendant benefits.

Jan 1, 2000

By Steven A. Moreno

Geochemical returns from commercial analytical laboratories are often delayed because of postal and other bulk distribution inefficiencies. Consequently, minerals exploration programs are handicapped due to insufficient time for treatment, analysis, and diagnosis of the data. The minerals industry lacks a system for rapid transmission of geochemical data which allows immediate entry into statistical and plotting routines. Over the past three years, Houston International Minerals Corporation (HIMCO) has developed a computer-based system to receive, treat, and distribute geochemical data. In the past two years, Bondar-Clegg (Denver) and Chemex (Vancouver) have developed systems to transmit' data directly to HIMCO via the world-wide Boeing Computer Services (BCS) network. The main benefits to HIMCO have been ten less days for reporting turnaround, ten less days for keypunching, less data handling, accuracy. The benefits to the laboratories have been improved in-house data management, reporting, and HIMCO's increased geochemical activity.

Jan 1, 1982

By Dan Slyter

This paper prov ides comparisons be­tween Merrill-Crowe and Carbon Adsorption pl Rnts 11sed for Pree ious Metal Heap Leach Operations. During the first stage of mine devel­opement, the question arises as to type of gold recovery circuit to be employed, Car­bon or Zinc. Several important factors to consider in answering this question are: Au/Ag ratio Solution grades Daily plant production Plant throughput required Plant gold inventories

Jan 1, 1992

By M. R. Wormald

A real time data acquisition system has been developed for implementing standard radiometric analytical techniques, applied to the monitoring and control of mineral processing plants. The system uses standard ECB-bus microprocessors and peripherals, in conjunction with a specially designed nucleonic pulse ADC. It is being applied to the accurate on-line analysis of naturally-,occurring radioelements in processing plants, for example by simultaneously measuring the intensity of 1.46 MeV gamma-rays from the naturally-occurring radioisotope K-40, and the stream density by gamma-ray transmission of 662 keV gamma-rays. Gain stabilisation of the NaI(T1) scintillation detectors is maintained by the microprocessor in slave units, each of which may control up to four sample presentation systems. Data analysis - including corrections for bulk density, radioactive decay of the Cs-137 gamma-ray source, pulse pile-up, dead time and external background - is carried out in a master computer which is connected to the slave unit, and can be interfaced to the plant control computer via data links.

Jan 1, 1986

By Son Hoang Nguyen, Thanh‑Hai Pham, Duoc Van Tran, Dung Thi Kim Nhu

Apatite ore plays a critical and irreplaceable role in fertilizer production and is being upgraded in quality in northern Vietnam. The old tailing of the Bac Nhac Son beneficiation plant (Vietnam) has a significant apatite amount in the form of coarse unliberated particles. These millions of tons of tailing ore have 6–8% of P2O5 content, which can be retreated to provide fertilizer factories. This work presents the results obtained in recovering apatite from this tailing in the laboratory. By the combination of the processes of classification, preliminary flotation, re-grinding and cleaning in the flotation column, an apatite concentrate of 30.68% P2O5 can be obtained with the total recovery of 37.76% from the initial tailing of 7.56% P2O5. The study results not only provide an appropriate technical solution for recovering the apatite ore from tailing ore but also have outstanding meaningness in the recovery of mineral resources under the context of a circular economy.

May 24, 2023

By Ivan Caetano Machado

Good morning ladies and gentleman. During 1995 Prof. R. P. King (University of Utah Comminution Center) presented 2 papers on new horizons in comminution: "Comminution Research in the United States " was presented at the 1995 Meeting of the National Mining Association, while "Comminution: Meeting the Needs of Fundamental Research in the Mineral Industry" was presented at the 2nd SME Research Forum - 1995. In both papers a very interesting graph named "Energy usage for various comminution schemes" illustrated some poignant issues proposed by Prof. King. We do think that some of Prof. King's ideas might very well serve as "warm-ups" for this Comminution Panel Discussion, which are ultimately the goals to be reached by the 3-minute presentations. Thus, we shall be addressing in the sequence Prof. King's most relevant ideas (as well as introducing his graph), intending therefore show how important creative and state-of-the-art Mill Modeling is, if it is to become a Tool to Effective Cost-Saving Optimization Strategies.

Jan 1, 1996

By Lawrence A. Taylor

The rocks and minerals of the moon will be included among the raw materials used to construct a lunar base. The lunar regolith, the fragmental material present on the surface of the Moon, is composed mostly of disaggregated rocks and minerals, but also includes glassy fragments fused together by meteorite impacts. The finer fraction (i.e., < lcm) of the regolith, the soil, is probably the most important portion of the regolith for use at a lunar base. For example, soil can be used in bulk as insulation against cosmic rays, for lunar ceramic and abodes, or for growing plants. However, beneficiation of the soil can provide other feedstocks. For example, the soil contains abundant solar-wind implanted elements, as we1 1 as various minerals, particularly oxide phases, which are of potential economic importance. These components of the soil are sources of oxygen and hydrogen for water and rocket fuel, helium for nuclear energy, and metals such as Fe, Ni, Al, Si, and Ti. The uses of the lunar materials only await a fertile imagination.

Jan 1, 1990

By Peter Joralemon

Introduction The Sierra Nevada Foothill Gold Belt in California extends from Mariposa north for more than 420 km (200 miles). It includes the Grass Valley and Alleghany districts in the zone of Northern Mines and the famous Mother Lode to the south. The gold belt has produced more than 3.1 kt (100 million oz) of gold since its discovery in 1848. This remarkable production, at the present gold price, would be valued at more than $40 billion. The Law of Gambler&apos;s Ruin supposes that averages are based on systematic rather than random variations. It emphasizes the vast differences between finite and infinite probability. By applying this Law to this figure, it can be seen that the belt has produced an average of 15.5 t (500,000 oz) of gold per running mile. Many geologists believe, with some justification, that less than half the gold in this belt has been mined. Sixty per cent of the past production has come from lode deposits, the balance from Tertiary and Recent placer gravels. This paper will concern itself with the developing lode mines along the Sierra Nevada Foothill Gold Belt. As a further and final note regarding placer mining along this belt, Mark Twain suggested that placer miners, having lost their senses, had contributed liberally to the population of California&apos;s insane asylums. After a 40-year lull with little or no gold production, the lode mines of this famous belt are showing signs of renewed activity. Two open pit mines, the Sonora (Jamestown) and Carson Hill, are now in operation at substantial scales. Two others, the Goldenbell (Pine Tree-Josephine) and the Royal-Mountain King, are being readied for production on equally impressive scales. All are in the southern part of the Mother Lode. Exploration farther north, at Sutter Creek, Drytown, and Georgetown, is showing encouraging results in developing deeper lode deposits. This new activity has been sponsored to a large extent by junior Canadian mining and exploration companies. Most of the established American mining companies have looked the other way, not participating in this important development. One major reason for domestic disinterest in this opportunity is there is little chance for heap leachable open pit ore in this belt, excluding Carson Hill. And heap leaching has become fashionable with American mining companies today. Also, this great old gold belt must have been worked out, for why else is there so little activity here - Catch 22 logic. Another reason is that if a new deposit of size and grade similar to the mines in the past was found, high costs would preclude a profitable operation. And, finally, California environmentalists would not permit mining, even if a rich deposit were found. These may all be pefectly valid reasons not to explore for gold along this belt. But a look at the history of gold mining in California may suggest that the future for exploration and development of the gold resources in the Sierra Nevada Foothills can be greater than the past. It was during the Depression of the 1930s that this gold belt saw its maximum activity, with more than 3000 mines in operation. Some were father and son operations producing only a few tons of ore a day. Other mines employed hundreds of miners to hoist more than 900 t/d (1000 stpd). Some ores were of marginal grade. Others, like the Sixteen to

Jan 7, 1987

By C. J. Ferron

Gold occurrence in operating plant tailings ranges from gold in solution, fine free gold, gold associated with sulphides/arsenides/tellurides and gold occluded within iron oxides or arsenates and silica gangue. This paper briefly presents various alternatives to reprocess gold tailings, with examples. These include the use of centrifugal gravity separators, CIL, magnetic separation, flotation and pressure oxidation.

Jan 1, 1993

By Stanley A. Bunk, Desmond J. Bruyns

The purpose of roasting gold ores is to release for extraction, typically by cyanidation, the small particles of gold which are surrounded by refractory stone. The roasting simply opens up passages for the penetration of solution into the interior of the ore particles. This is accomplished by the removal by volatilization or formation of volatile oxides of certain constituents such as sulfur, arsenic or antimony. Temperature is an important parameter. High temperatures tend to form a dense iron particle rather than a "spongy" calcine. The dense iron particles result in lower gold recoveries. High temperature can cause melting of some components which also results in gold encapsulation. Roasting of refractory gold ore concentrates has been practiced for decades. Multiple hearth, rotary kiln and muffle reactors were first used for roasting. Fluid bed roasting provided a low capital cost, low maintenance technology with better process control and soon became the favored technology. The first fluid bed concentrate roasters were commissioned in the late 1940's. Early fluid beds were "bubbling" type. Environmental considerations did not significantly impact on the design. Feedstocks were highly exothermic and reaction rates were relatively rapid. Roasting today must compete with other technologies for treatment of refractory ores. Ore bodies which are not

Jan 1, 1993

By Joaquin Ruiz

Although Mexico is known for its important base-and precious-metal deposits, and lately oil, some industrial minerals play an important role in the Mexican economy. Sulfur, the most important industrial mineral produced, accounts for approximately 7.5 percent of the total value of mineral production. This commodity is followed by fluorspar, which accounts for 6.4 percent. Predominantly, the fluorspar deposits are very high grade (75 percent CaF) and are contained in lower Cretaceous limestone in the states of Coahuila and San Luis Potosi. Base-metal deposits in the area of Parral (notably San Francisco del Oro), however, have become important fluorite producers in their own right. (San Francisco del Oro has 12 percent fluorite gangue.) Salt from the Guerrero Negro solar-evaporation ponds in Baja California account for 6 percent of the total shares; phosphate from Baja California also accounts for 6 percent. Barite from man to deposits in Lower Cretaceous limestone in Coahuila and exhalative deposits in the Paleozoic section of Sonora account for 1.0 percent. In addition, Mexico is an important producer of gypsum, graphite, and celestite. Although graphite and celestite are not large-scale operations and thus do not contribute much to the Mexican economy, the Mexican graphite and celestite deposits are among the most important in the world; Mexico is one of the world&apos;s few sources of celestite. The celestite is in the form of large, high-grade mantos in Cretaceous limestones in northern Mexico.

Jan 1, 1987