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By P. Myllykoski, J. Nylander, A. S. Korhonen, J. Larkiola

The coefficient of friction and the deformation resistance have been determined from the measured rolling parameters by applying the Bland-Ford-Ellis rolling force model and the artificial neural network model (ANN). The dependence of friction on the parameters such as reduction, rolling speed, front and back tensions, contact pressure and deformation resistance have been studied by the ANN model. Measured data of over 10 000 coils have been used in the training stage. Various dependencies have been examined and the results show that the friction coefficient does not depend much on the rolling speed. The reduction and deformation resistance seem to have the strongest effect on the friction coefficient. A friction model based on neural computing has been included into the existing rolling force model.

Jan 1, 1994

By Norman L. Kotraba

Zia Metallurgical Processes, Inc. has developed and patented a steelmaking process capable of converting iron bearing metallurgical wastes into high quality steel products. The process utilizes a proprietary design rotary hearth furnace to convert iron bearing wastes, pelletized with coal, or other forms of carbon, into direct reduced iron (DRI). This DRI is fed, hot, from the rotary hearth furnace into a Zia All Purpose Vessel (ZAV) where it is smelted and refined into high quality steel. A specially designed turret with three independent arms, each supporting a separate ZAV, comprises the heart of the meltshop. No overhead cranes are required to transport molten metal from the smelting/refining operation to the ladle metallurgy station to the caster to an inspection station and back to the smelting/refining point. The molten steel is contained in the ZAV throughout the operations eliminating the possibility of steel con¬tamination by non-metallic inclusions occasioned by the exposure to ambient air during metal transfer into ladles. The result is the creation of very clean steel that can be alloyed to produce virtually any desired grade from stainless steel to common structural steel.

Jan 1, 1994

By R. G. Hilton

This paper deals with application of Super Detox? stabilization technology to the treatment of electric arc furnace dust (US-EPA listed hazardous waste KO61 ). The process has been used on approximately 170,000 tons of electric arc furnace dust. In addition to the nearly four years of commercial experience at Sterling, Illinois, the process is now being permitted for application at two other locations. The process was originally developed by the Bethlehem Steel Corporation and then further improved by Conversion Systems, Inc. (Bethlehem Steel's Licensee). The treatment process offers many unique bases for its selection, including: A) Low cost compared to the treatment alternatives; B) Lowest available TCLP leachate levels for any process treating K061. Many other processes leave some residue that represents a disposal requirement, although often not addressed; C) Produces minimized final waste disposed, including the fact that the total volume of dust generated and less than the volume occupied by the residue slag from HTMR; and, D) Opportunities for the beneficial utilization of part or all of the waste stream through the development of chemical and physical characteristics. Each of these aspects will be specifically discussed in the paper, including that status of the operations now under permit.

Jan 1, 1994

The offshore Maui gas/condensate field was discovered by Shell BP and Todd on Services Limited in 1969. Subsequent appraisal drilling and negotiations with the Government led to a development agreement, æThe Maui White Paper' being concluded in 1973. Part of this agreement provided for the Government to take a 50 per cent shareholding in the field. The field is comprised of a double domed anticlinal structure containing two gas reservoirs at depths ranging from 2700 - 3000 m. Water depth is 110 m. The development plan called for two standalone steel platforms to be installed sequentially over a period of some years depending on gas demand. The first platform (MPA) was put in place in 1976 but difficulties were experienced with piling and drilling of the 12 (later increased to 14) wells did not start until 1978. First gas was piped ashore late in 1979.

Jan 1, 1994

By Benoit DeBecker

Laboratory-scale experiments have shown that chromium metal could be recovered from chromate wastes by modifying slightly the chromium electrowinning flow-sheet. After reduction by sulhr dioxide and precipitation of chromic hydroxide, the solid residue is dissolved in the chrome alum solution and the metallic impurities are removed by cementation on manganese. The presence of dissolved manganese in the electrolyte does not affect the cathodic deposition of chromium and it eliminates the anodic production of Cr(V1).

Jan 1, 1994

By J .. R. Dalton

"Blasting in high sulphide content ores presents at least two major safety considerations: (1) compatibility of the explosives with the ore while resident in the borehole; and (2) introduction of a flame and shock producing explosive into this environment, while minimizing the risk of reactive ignition in the chemical reaction products/sulphide dust cloud resulting from the detonation. This paper will discuss only the second consideration, i.e. post detonation reactivity.The ETI (Explosives Technologies International) Technical organization, in consultation with the U.S. Bureau of Mines, reasoned that the most relevant considerations in the development of an explosive for this application are:• minimization of reactive gaseous detonation reaction products;• flame duration reduction;• flame temperature reduction;• increased explosive sensitivity;• reduced probability of ""low order"" detonation; and• maintenance of energy level as high as possible.Obviously, not all of these are totally independent properties, i.e. increased sensitivity will reduce the probability oj low order detonation as will higher energy levels. However, these considerations were examined separately as if they were independent."

Jan 1, 1994

By Arturo Carranza Edwards

One hundred ninety nine beach face sand samples from an equal number of beaches from the Mexican Pacific were studied. Based on petrological and chemical analysis some locations have been studied in more detail. Black sands from the following areas are discussed: (1) west Baja California Peninsula, where black sands rich in magnetite and ilmenite have maximum values of 50% iron and 14% titanium in the very fine sand fraction; (2) east Gulf of California, in its northern portion, the black sands show maximum values of 43% iron and 5% titanium in the fraction 2 to 4 0;-(3) the south Mexican Pacific, characterized mainly by medium sands, moderately well sorted, show that the fine sand fractions reach values of 35% iron and 41% titanium. X-ray fluorescence applied on selected samples constituted by feldsarenites and lithic feldsarenties, showed the presence of rare elements in some of the studied samples.

Jan 1, 1994

By T. H. Eyde

Natural Zeolites are a less expensive and in certain applications a superior alternative to organic ion exchange resins. Mining and metallurgical waste streams are difficult to treat because the effluents which contain potentially valuable heavy metals such as copper, lead, and silver are often highly acidic and contain significant quantities of suspended solids. Under rigorous operational conditions, certain natural zeolites can remove the metals, which if desired can be recovered by either elution or conventional smelting techniques. There are significant differences in cation exchange rate, selectivity and capacity as well as resistance to either high or low pH, blocking cations and tolerance to elevated or depressed temperature and pressure not only between different zeolite minerals but between the same mineral from different deposits. Applying natural zeolites to the treatment of mining and metallurgical waste streams depends on matching the specific zeolite to the effluent by characterization of the zeolite minerals.

Jan 1, 1994

By John C. Adams, Robin Irwin

In early 1993 a test program was designed to determine if mining costs could be reduced by using a high density ammonium nitrate mini-prill blasting agent. The goal was to reduce mining costs by expanding blast hole patterns while maintaining or improving dig-ability of the shot material. The program was conducted at Santa Fe Pacific Gold's Lone Tree gold mine near Valmy, Nevada.

Jan 1, 1994

By G. L. Palmer

"Abstract- ln 1986, anomalous sampling results for heavy minerals were obtained at various sites in Namaqualand on the west coast of the Cape Province. Drilling in 1987 at Graauwduinen penetrated up to 35 meters of heavy mineral-bearing Tertiary sands which extend several kilometers inland from the coast. The heavy mineral suite includes ilmenite, rutile, leucoxene, zircon and monazite, along with garnet, pyroxene and amphibole. Three deposits are recognized, two of which comprise the resource to be mined by Namakwa Sands Limited, a recently formed Anglo American Corporation subsidiary company.Mineable reserves in excess of 500 million tonnes have been delineated, sufficient to sustain mining for over 35 years at projected production rates. During the feasibility study, on-site investigations included test mining at various sites to assess mineability and to provide material for metallurgical testing in a pilot plant located at the site. Ilmenite produced at the mine will be smelted at a new facility to be built at Saldanha Bay . Saleable products comprise titania-rich slag, pig iron, zircon and rutile.During the exploration phase, company environmental guidelines were established and monitored. The feasibility study incorporated a Class 1 Environmental Impact Report, the contents of which were made public following the principles of the Integrated Environmental Management legislation."

Jan 1, 1994

By August V. Castelli

Drilling fluids have changed over the years from water and/or water frequently mixed with local clays to scientifically com- pounded materials (mud). This change has occurred due to changes in drilling methods from percussion to rotary: depth maximum from 21 m in the first oil well to more than 9 000 m; and variety in types of well or hole to gas, oil, water, and mineral exploration. Environmental concerns about the composition of the fluid as to heavy metals and oil on the cuttings has recently caused changes in the materials used in the mud. The drilling fluid should perform the following functions (Darley et al., 1980): 1) Carry cuttings from beneath the bit, transport them up the annulus, and permit their separation at the surface. 2) Cool and clean the bit. 3) Reduce friction between the drilling string and the sides of the hole. 4) Maintain the stability of uncased sections of the borehole. 5) Prevent the inflow of fluids-oil, gas, or water-from permeable rocks penetrated. 6) Form a thin, low-permeability filter cake which seals pores and other openings in formations penetrated by the bit. In addition to these, the fluid should: 1) Not injure drilling personnel nor be damaging or offensive to the environment. 2) Not require unusual or expensive methods of completion of the drilled hole. 3) Not interfere with the normal productivity of the fluid- bearing formation. 4) Not corrode or cause excessive wear of drilling equipment. A number of industrial minerals, chemicals, and other materials are used as additives in the drilling fluid to accomplish these functions. Industrial minerals make up the highest percentage of the additives in a drilling fluid. Drilling fluids are classified according to their principal components: water, oil, and gas. If the major component is either water or oil, the component along with the suspension of solids, cuttings and additives is referred to in the trade as a mud. The largest use of some industrial minerals, such as barite and bentonite, is in drilling muds. For other materials, such as gypsum and limestone, drilling usage is only a small percentage of total demand. RAW MATERIALS [Table 1] lists the industrial minerals used in drilling fluids, their form, specifications, and uses. Each raw material will be discussed as to its mineralogy, physical and chemical properties, and the location of major deposits with respect to drilling fluids. Attapulgite Attapulgite is a crystalline hydrated magnesium silicate clay mineral, prized for its viscosity in saline waters. The particles are needle-like rather than the platelets common to most clay minerals. The specific gravity is 2.5 and the Mohs hardness is 1 to 1.5. Attapulgite is one of the materials sometimes referred to as fuller's earth. The major producing areas in the United States are southern Georgia and northwestern Florida. It also is mined in Spain, Senegal, the Republic of South Africa, Turkey, India, and Australia. Barite Barite is crystalline barium sulfate. It has a high specific gravity for a non-metallic mineral, 4.5 when pure, and is used as a weighting agent. Generally, the specific gravity ranges from 4.20 to 4.35. It is relatively soft with a Mohs hardness of 3 to 3.5 and is not very abrasive. Barite is inert, non-toxic, and clean to handle. Common contaminants are quartz, iron minerals, gypsum, and calcium carbonate. If there is considerable gypsum in the barite, it will thicken the mud. The major deposits in the United States are in north central Nevada, near Battle Mountain. The major producing countries, other than the United States, are China, India, Mexico, the former USSR, Turkey, and Morocco. The major deposits in India and Nevada, and some in China, are stratiform, commonly quite pure bodies in bedded sedimentary rocks.

Jan 1, 1994

By Jack Eloranta

Proper selection of stemming has a profound effect on blast performance. This paper describes several methods of evaluating stemming performance in 16-inch blastholes. Tests are done on stemming ranging in size from nominal 1/4" crushed rock up to railroad ballast size rock (2 1/2" > diameter < 3/4"). Concrete plugs (both pre-cast and poured) are evaluated as well as air decking.

Jan 1, 1994

By T. A. Gray

The environmental liabilities of coal waste disposal sites can have a major impact on a mining project&apos;s economic viability. Developing a waste disposal site is no longer simply an exercise in completing paperwork to obtain a permit, with the proliferation of environmental regulations in recent years, managing disposal sites now requires design creativity, short term and long term planning and detailed monitoring to maximize the benefits to the mining company. Operating costs and future capital costs for expansion of existing sites, new site development and regulatory compliance should be reviewed periodically and considered in the overall management plan. This paper discusses various management methods that are being employed in the industry to improve waste disposal operations both environmentally and profitably.

Jan 1, 1994

By J. B. Cocanour

Pioneering work at the U.S. Bureau of Mines (USBM) has produced a personal computer (PC)-based, software-driven video photometric color sensor for real time process control of metallurgical streams. The video photometer is an inexpensive optical sensor which operates in the visual area of the electromagnetic spectrum and collects color information through plastic optical fiber. The red, green, and blue (R/G/B) voltage components of the color video signal are digitized and characterized through software and then presented as the control variable for software-based proportional-integral-differential (PID) control. This sensor has been successfully employed in the control of a laboratory copper electrolytic circuit. With this sensor, copper solutions were analyzed on-line without the need for sample removal, dilution, mixing or reagent addition, thereby allowing for the real time control of the circuit.

Jan 1, 1994

By T. P. Meloy

Oily and particulate befouled waste water discharges are a common industrial problem. Removing these water bourn emulsions from process discharges become increasingly important for both recycled and discharge water streams. Low cost, efficient and easily maintained systems are important. This paper evaluates design factor of such a water cleaning system -a trough filter. This is a continually operating filter that removes oil droplets by wires that wet the oil droplets.

Jan 1, 1994

By F. Wendling, J. A. M. Cano

To increase its product competitiveness in the foreign market, Samarco Mineracão S/A has developed, at its pilot plant, high-MgO pellets for performing direct reduction simulation tests. Additives, such as dolomitic lime and magnesite, were used for increasing the pellet MgO content. Comparative direct-reduction simulation tests were conducted in Samarco and foreign laboratories. The results show that direct-reduction pellets with satisfactory metallurgical properties can be produced and successfully processed at increased temperatures in direct reduction furnaces.

Jan 1, 1994

By Jennifer Riefenberg

A family of personal computer programs that calculate the Coal Mine Roof Rating (CMRR) has been developed by the U.S. Bureau of Mines. The CMRR rock mass classification system provides a link between the qualitative geologists&apos; description of coal mine roof and the quantitive mine engineers&apos; needs for mine design roof support selection, and hazard detection. The program CMRR is a user-friendly, interactive program into which raw field data are input. A CMRR is calculated and output along with two graphic displays. The first graphic display is a plan view trap with the CMRR&apos;s displayed on a color-coded scale. The second display shows a stratigraphic section of the bolted roof interval and its resultant CMRR. In addition, a Lotus 1-2-3 worksheet, computer file BOM-CMRR.WK3, has been developed for easy storage of field data. The worksheet includes four macros that automatically calculate CMRR&apos;s, store field test data in a database format, and print a two-page report of the field data and CMRR parameters. Production of summary port; for analysis of site-specific information are readily generated using Lotus 1-2-3 software. These programs help to facilitate the engineer in utilizing the CMRR in ground control studies.

Jan 1, 1994

By Len Blackman

The Absaroka-Beartooth Study Area is a tract of approximately 1.4 million acres of National forest land in southern Montana, part of the Greater Yellowstone Area. This study evaluated the mineral potential of four mineral terranes containing undiscovered resources in the area. The geological data is probabilistic, with estimates of the possible number: of deposits and their grades and tonnages. Possible future development scenarios range from no development to many mines, including some very large. As two thirds of the study area is within the Absaroka-Beartooth Wilderness, the future development scenarios reflect the area&apos;s mineral potential, not what we expect to see in the foreseeable future. Based on the analysis performed on these four terranes, the most likely future scenario for the study area would include the potential for two medium sized, (predominately) gold, mines, each employing a few hundred workers. There is a small chance, less than 5%, that a large Porphyry Copper or Superior Iron deposit would be discovered and be economically feasible to develop.

Jan 1, 1994

The Ok Tedi open pit mine will have final wall heights in excess of 750m. The behaviour of these excavated slopes will be influenced by the presence of numerous defects. This paper discusses the identification of possible failure mechanisms within the pit walls based on mapped fault and joint data. Results from analyses using these data have formed the basis for the ultimate pit design.

Jan 1, 1994

By Carl C. Nesbitt

A study was conducted to examine the treatment of metal-bearing effluents by precipitating the metals as sulfides and simultaneously collecting the particles by flotation. The precipitant was hydrogen sulfide gas which was introduced into a bench-scale column cell with air. The study included experiments of various flotation reagents and column configurations in treating solutions containing dissolved copper, lead, mercury, iron, zinc and cadmium. An acidic laboratory waste from a local copper operation was used to test the column with a solution containing several metals and arsenic. Precipitates were observed to form at the gas/liquid interface when the gas mixtures were rich in H2S. Copper, mercury, lead, and cadmium were precipitated from solution as sulfides to concentrations near detection limits. The flotation of these precipitates was enhanced with small amounts of S-7151 promoter from American Cyanamide Company and Dowfroth 1263 mixed with the feed. The recovery of the precipitates in this manner produced a smaller volume slurry which was easier to dewatering than a slurry produced by conventional precipitation techniques. The low pH and high oxidation-reduction potential in the cell from H2S addition was not conducive to form precipitates of iron, zinc or arsenic. However, these ions were precipitated as sulfides by raising the pH of the column discharge.

Jan 1, 1994