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By Matias Pentinnen, Wayne Dickinson

Electrowinning is a key process for copper production contributing roughly twenty percent globally and thirty to forty percent of production in the Americas1. Copper grade is assessed largely on deposit smoothness and on level of impurities in the metal. Smoothing aids are essential to create dense, low porosity deposits and guar has long been the material of choice for this purpose. Guar is, however, poorly stable under the strongly acidic electrowinning conditions, underlying ongoing research to identify an effective, acid-tolerant replacement. Current efficiency is also a critical factor in controlling copper production costs and chemical additives should ideally improve current efficiency as well as improving deposit smoothness.

Feb 1, 2025

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

1.1 GENERALIZED METHODS OF SUPPRESSING THE INFLOW OF GROUND WATER DURING THE CONSTRUCTION OF SHAFTS, DRIFTS AND TUNNELS Various methods are used to prevent or minimize the inflow of ground water into underground workings during their excavation. The two most common methods include freezing the saturated rock and grouting using cement, sodium silicate, polyurethane and/or other chemicals. Each of these technologies for combatting the inflow of ground water is effective only under specific hydrogeological conditions. For example, although the freezing of saturated ground is among the more universally adopted methods, it is designed to provide only temporary protection during construction. Before the saturated rock thaws it is necessary to emplace a waterproof liner which is labor intensive, time consuming, and expensive. Consequently, freezing is used only in exceptionally complex hydrogeological conditions, namely in those cases where the water-bearing strata consist of unstable rock or the ground water has an anomalous hydrochemistry. The classical grouting of saturated rock, carried out from the surface or from the face of the underground workings for the purpose of limiting the inflow of ground water during excavation, utilizes both cement and a variety of chemical grouts. Cement grouting has been regarded as the main method of combatting the inflow of ground water in fractured rock throughout the world. In such countries as the Federal Republic of Germany (FRG), Canada, the Republic of South Africa and Great Britain, cement grouting is the main method of reducing the inflow of ground water during the excavation of mine openings. In Great Britain and the FRG, cement grouting has been used in 80% of all shaft excavations. In the Republic of South Africa cement grouting has been used in almost 100% of all the shafts that have been constructed. The installation of grout curtains into permeable water- bearing strata significantly reduces their permeability and increases the rock strength. Grouting has the greatest effect in fractured sandstones, certain well indurated shales, fractured granites, fractured quartzites, and karstic limestones or dolomites. The following principal factors must be considered when assessing the expediency of grouting rock with cement: the geometry of the network of fracture openings, the saturated hydraulic conductivity of the fractured rock, the hydraulic head acting on the water in the rock, and the chemical composition of the ground water. On the basis of the geometry of the fractures and the thickness of each hydrostratigraphic unit, the characteristics of the cement grout are selected. As a rule, the cementing of large fractured zones with high ground water velocities is carried out using inert fillers (sand, mill slag, loam, loess, crushed limestone), special types of cement, setting accelerators, and high cement concentrations in water. Calcium chloride, soda ash, sodium silicate, sodium nitrate, amino alcohols, tin bichloride, trisulphate nitrate, and lumnite are used extensively as the setting accelerators for cement grouts. In the FRG and Poland, special cement injection compounds that embody a mixture of cement and active cement metal salts, water additives and binding substances are being used for the cementing of saturated zones with rapid ground water velocities. These reagents accelerate the rate of structure-forming reactions. In spite of the wide variety of additives used for cement grouts, the effectiveness of the method in large fractures below the water table is either poor or it leads to a very large consumption of cement due to the erosion of the grout through the cracks before it hardens. At the present time, a large number of cement types and brands are being produced by various countries. These variations permit cementing to be employed in a variety of geological conditions. However, both pure cement grout and grouts with fillers constitute unstable systems with a high water loss rate. Therefore during the grouting of finely fractured rock the cement grout's premature loss of a large amount of free water causes its consistency to increase, whereupon the grout solidifies. Consequently, it inadequately penetrates into the fine fractures of the stratum. In addition the high water loss rate in the cement grout causes unreacted cement particles to remain, which greatly reduces the grout hardness and the resulting rock strength characteristics are weakened. As a result, the binding properties of the cement are utilized perhaps up to 60%. The remaining portion is left in the grout as a filler. All these conditions significantly decrease the efficiency of the isolation effort both with respect to strength and cost. In order to expand the cement grouting method, re- search is being conducted to improve the quality of cement grout, to increase its range of application with respect to permeability control, to reduce its water loss rate and to increase its capacity to withstand the erosive and corrosive effects of poor quality ground water. For example, mixtures of bentonitic clay, carboxymethyl cellulose, aerated sodium sulfide, sulphated alcohol distillery waste, nitrolignin, gip-

Jan 1, 1993

By Kang-Hyun Kim, Ho-Jong Kim, Jong-Ho Shin, Hoon-Ki Moon

"In urban areas, it is often required to construct additional railway tunnels beneath existing railway tunnels. In this case, dynamic interaction between tunnels at the intersection becomes an important issue, as it amplifies structural behavior causing damage to structures and inconvenience to passengers. In this study, vibration superposition effect at the intersection between existing and newly constructed tunnels is investigated by the numerical method. Dynamic interaction mechanism is firstly examined using simple sine wave load, and then a typical analysis for actual multi-leveled tunnel intersection is performed. The results show that the dynamic amplification due to dynamic interaction of tunnels is 149% at the crown of lower tunnel. This indicates that the vibration superposition effect must be considered when the planning and design of a new tunnel beneath the existing tunnel. 1. INTRODUCTION In these days, there are increasing cases that trains cross without transfer stations in metropolitan areas. Consequently, either tunnel is necessarily to be neighboring or crossing, thus tunnel sections closely located are created as shown in Figure 1. If a new tunnel is constructed beneath the existing tunnel, the vibration due to trains passing through each tunnel can mutually affect. The behavior of coupled vibrations may occur and exceed the allowable structural limit, and cause inconvenience to passengers. Theoretically, when vibration waves are propagated from a source to different locations, amplification or decrease of the vibrations can occur by the principle of wave superposition and interference. Multi-leveled tunnel intersection is one of the cases mentioned above. In the actual tunnel, it is difficult to investigate the vibration superposition effect due to a complex ground conditions and structural geometries. In addition, train vibration itself is multi-source vibration, which cannot be theatrically analyzed. Thus, at the tunnel intersection, train vibration from two tunnels make the problem more complicated."

Jan 1, 2016

By Clement K. Chase

Although flotation is the generally accepted process employed to recover gold and silver as well as copper, lead, and zinc from primary sulfide ores, the metallurgical requirements for the treatment of massive sulfide ore deposits differ markedly in many respects from those employed for the more common disseminated porphyry deposits. In Arizona, some properties classified as other then massive sulfide deposits because of mining and geological characteristics have produced mill-feeds similar to those from massive deposits. Several such occurrences are noted. The process requirements for massive sulfide deposits and unique mill-design implications are discussed in the perspective of world-wide economic considerations and the individual regional metallurgical and economic constraints in the United States.

Jan 1, 1986

By Y. F. Vasyuchkov

In general a term "unconventional mining or "non-traditional mining technology" getting more and more familiar to the mining engineering media. There are several alternating terminological combinations such as "in situ mining", "borehole mining", "shaftless mining", "mineless mining", "geotechnology" etc.; specific terms denote particular method of unconventional mining technology: "underground coal gasification in situ", "underground coal combustion in situ", "borehole hydraulic coal mining" and others. Principal scheme of unconventional coal mining technology is shown in Figure I:

Jan 1, 1997

By Nelson R. Shaffer

Glamorous, burgeoning biotechnology and mundane industrial minerals would at first glance seem to share little in common, but in truth, modern biotechnology depends on many minerals. Biotechnical processes also can be used in industrial mineral extraction and processing. Biotechnology is broadly defined as the application of biological organisms, systems, or processes to manufacturing and service industries. Genetic engineering has reinvigorated one of mankind's oldest sciences, biotechnology, into a booming business. Many modern processes depend on microorganisms cultivated under very stringent conditions in bioreactors. Minerals from carbonate, sulfate, chloride, nitrate, phosphate, and silicate families are used to provide essential nutrients and to regulate growth conditions (such as pH) in order to assure optimal growth of organisms. Certain cells or enzymes perform better when immobilized upon or within solids, and minerals are often used to immobilize cells, especially in continuous process. Minerals are also used extensively in separating and purifying products of biotechnology. Diatomite, zeolites, and silica are especially useful in purification processes. Industrial minerals also are commonly used to clean up large volumes of process water that must be treated. Biotechnology can be employed in exploration, extraction, and processing of geologic materials and in reducing mining or other environmental problems through bioremediation. Microbes have been shown to solubilize certain elements and so promote extraction of heavy metals, phosphate, aluminum, potassium, and even rare earth elements. In a related technique, unwanted materials such as pyrite impurities can be leached microbially to produce cleaner products in sand and clay industries. Microbial actions can modify surface characteristics and so enhance certain ceramic properties. Certain organisms can accumulate useful elements from dilute sources; others can transform unusable chemical species to more useful forms. Deterioration of stone, concrete, and even glass or brick, can be accelerated by microorganisms. Control of such biodeterioration could improve long-term performance of industrial mineral products. Microbial processes have shown promise in improving several mine-related problems. Certain bacteria help remove clays from phosphate slimes and other suspensions. Others are used to degrade cyanide or other organic chemicals such as floatation aids. Cells immobilized on clays have been especially efficacious in bioremediation. Biotechnology industries, like the industrial minerals industries, encompass huge ranges of materials and processes. Costs of products from these industries range from pennies to thousands of dollars per unit, and their products are vital for maintaining modern life styles. Many biotechnical processes depend upon industrial minerals and certain biological processes can be harnessed to do useful tasks in the minerals field. The interplay of industrial minerals and biotechnology is important today, and as biotechnology advances, its interaction with the industrial minerals industry can only increase.

Jan 1, 1995

By Scott D. Thayer, George H. Milly

INTRODUCTION Ambient concentrations of radon and its daughter products have been measured and analyzed by a number of investigators for a variety of purposes. Principal among these purposes have been: (1) descriptive, to characterize the distribution and changes in concentrations under various conditions; (2) research in the use of radon as a tracer gas in the study of atmospheric characteristics and motions, such as eddy mass transfer, diffusivity profiles, large scale circulations, and the like; and (3) the use of radon as an atmospheric tracer in exploration for uranium deposits.* This information forms the basic data for this paper and for its placing the ambient natural, or non-anthropogenic, radon concentrations into the perspective of ambient radon health standards and lung cancer risk calculations. To enable better understanding of some aspects of the ambient radon data, review and analysis is also performed on selected measurements of radon emanation or flux from the surface of the earth into the atmosphere. These measurements have generally been made for purposes similar to those for ambient radon, i.e., (1) description of radon emanation characteristics; or (2) to support and justify the use of ambient concentration measurements in atmospheric research; or (3) in exploration for uranium. Interest is also developing in the use of such measurements for earthquake prediction. In addition, to complete the perspective, brief examination is given to anthropogenic ambient and flux radon measurements related to the mining and milling of uranium, so that comparison can he made with the values from natural sources. As a frame of reference we cite here previous summaries of studies which have presented representative values and ranges of ambient concentrations and emanation rates. H. Israel, in the Compendium of Meterorology (1951), cites eight studies of ambient radon concentrations which we have selected as representative of non-anomalous continental values. Their means generally range from [0.06 to 0.15 pCi lit-1 with the smallest reported minimum of zero and the largest maximum 0.53 pCi lit-1. The overall mean is 0.10 with a standard deviation of 0.03 pCi lit-1. Means over oceans are much smaller, and the data scarcer, with only three values ranging from 0.0004 to 0.003 pCi lit-1 and a mean of 0.0016 pCi lit-1.] Thirteen studies from Israel's list were selected as representative of mountainous terrain. These data, except for the cases of higher elevations, frequently show significantly higher values than the average cases in non-mountainous terrain described-above. The averages range from 0.10 to 0.59 pCi lit-l; the smallest minimum is zero and the largest maximum is 9.2 pCi lit-1. The overall mean is 0.30 with a standard deviation of 0.17 pCi lit-1. Israel also cites five studies of radon emanation (flux) from the earth's surface. These show a mean of 0.40 pCi-2m-2 sec-1 and a range of from 0.21 to 0.74 pCi m-2 sec-1. Data on flux are naturally scarcer in the literature than data on ambient concentrations, because of the greater interest in and utility of the ambient information. In this paper we also give special consideration to observations of the variability in time and space of radon flux rates, and to the impact of these phenomena on the use of such data for a variety of purposes. NATURAL(NON-ANTHROPOGENIC)AMBIENT RADON CONCENTRATIONS We have examined the following reports for the data selected for this category; these studies were generally intended to describe radon characteristics in the atmosphere. Jonassen and Wilkening (1970); Bradley and Pearson (1970); Wilkening (1970); Lambert, et al (1970); Pearson and Moses (1966); and DickPeddie, et al (1974). Another set of studies which was reviewed was selected because the investigators made ambient radon measurements in the course of examining the use of radon as a tracer in atmospheric research. This set consists of: Israel and Horbert (1970); Carlson and Prospero (1972); Subramanian, et al (1977); Larson (1978); Cohen, et al (1972); Hosler (1966); and Shaffer and Cohen (1972). Finally, unpublished data from uranium exploration activities (Milly and Thayer, 1976) was analyzed. [Treating the ocean cases first, the mean values are generally consistent with those quoted earlier from Israel (0.0004 to 0.003 pCi lit-1); they range from 0.001 to 0.011 pCi lit-1, with 0.003 the most frequently reported value. Continental values, from eight studies, range in means from 0.07 to 0.41 pCi lit-1 (not including mineralized areas, or "uranium country", discussed later), with maxima as high as 2.4 pCi lit -l. For comparison, the means from Israel are 0.06 to 0.15 pCi lit-1, with a maximum of 0.53 pCi lit-1. Some of these studies also present the typical decrease of-1 concentration with height to 0.01 to 0.04 pCi lit at 5 to 7 km. The vast numbers of uranium prospecting radon data of]

Jan 1, 1981

By Patricio Zarate

Due to the intrinsic variability in orebodies, similar metallurgical behaviour of all material sent to the concentrator is expected to have some variability. Still some specific ores have anomalous performance which can severely impact on the concentrator’s production of metal, in this case copper. The study first will show the mineralogical characteristics of “usual ore” and of this specific “abnormal ore” which will have to be processed by the concentrator in the future. After that base conditions on both ores and flotation test procedure will be explained. Later the different alternatives tested regarding collectors and modifiers results will be compared. Finally, after discussing the different results with different reagents and considering operational variables of the concentrator, Floticor PD 702 is recommended to obtain the best copper recovery without increase in excess mass recovery.

Feb 1, 2025

By William A. Prosser, Kyle R. Ott, Philip Rice

"INTRODUCTION The existing Baltimore and Potomac (B&P) Tunnel accommodates Amtrak (National Railroad Passenger Corporation) and MARC (Maryland Rail Corporation) service between Baltimore, MD and Washington, DC and occasional local freight service. The Baltimore and Potomac Tunnel Replacement Project proposes new tunnel construction through Baltimore, Maryland along the Northeast Corridor (NEC) that maintains connections to Baltimore Pennsylvania Station. After the Replacement Project is constructed and operational, the disposition of the existing tunnel must be determined. The tunnel could be abandoned; however, considering its location in a congested downtown, alternative uses have been considered to take advantage of this unique piece of infrastructure by repurposing it. Alternative uses for the existing 140-year-old B&P Tunnel may end up being cost effective and should be considered, as the tunnel can be made accessible to construction crews for extended periods of time that will allow for efficient work activities unlike when it is fully operational. Possible alternatives include conversion for non-rail use, rehabilitation, or complete modernization for continued rail traffic. The following paper describes the four potential fates of the conceptual designs for the existing B&P Tunnel. The four concepts include: • No Build – rehabilitate to keep the tunnel operational. • Abandonment – complete or partial sealing of the tunnel. • Adaptive Re-Use –repurpose the tunnel with sustainable building practice. • Full Rehabilitation and Modernization – bring to current fire-life safety aspects. Of the four concepts, only the no build addresses maintaining the tunnel while it is under traffic. The remaining fates address the existing tunnel after the new tunnel is operational and railroad traffic has been diverted to it. Development of these conceptual designs were provided in a concept design study (Parsons Brinckerhoff/Parsons, 2015) that supports the National Environmental Policy Act (NEPA) review process for the Project, which includes evaluation of possible alternative uses of the existing B&P Tunnel."

Jan 1, 2016

By M. J. Garcia, Howard Hallman, G. M. T. Marshall, Ken Higby, Louis Cope, Robert S. Hess, John Peters, A. G. Law, William C. Larson

After a good year in 1979-strong mineral demand, adequate prices for most metals, minimal labor problems-1980 was not so good. The US produced $24.8 billion worth of nonfuel minerals last year, up 3.5% from 1979, according to preliminary US Bureau of Mines figures. But the $800 million increase was the smallest annual gain since 1977 and reflected reduced auto and construction industry demand, strikes, and energy shortages. Preliminary figures for 68 minerals show that production of 42 decreased, 25 increased, and one was unchanged. Production of 11 of 21 US-produced minerals was up. Noteworthy mineral events in 1980 included a copper industry strike, increased gold and silver prices, troubles in the iron ore and uranium industries, discussion about a US nonfuels mineral policy, and corporate interest in mining companies as merger targets. Recessionary conditions experienced by the Western world in 1980 resulted in a slowdown in new mine development, evident in the relative scarcity of major new base metal projects. This could lead to short term supply/demand anomalies within the next few years which, in turn, could have a significant effect on metal prices, according to Mining Magazine (Jan. 1981). World Mining (Sept. 1980) noted that US mining strength is in open pit operations. A much lower tonnage is mined underground and is centralized in trona, uranium, lead, zinc, molybdenum, potash and, to a lesser extent, copper. The most notable increase in new underground mines has been in Wyoming's trona district where new mines are being developed and production will increase, the magazine said.

Jan 5, 1981

By Agne Rustan

INTRODUCTION This work is a continuation of the preparatory study by Rustan and Stöckel 1979 (3) and (4) of the possibilities to introduce automatic mine ventilation in Swedish mines and construction works. The preparatory study has been financed by the Swedish Board of Technical Development. In the study it was recommended that an automatic step by step control of the fans near the working place due to diesel exhaust emission would be the best solution. A more advanced alternative would be to regulate the fresh air continuously in proportion to the contamination. The latter alternative has been studied by Boliden Mineral Co in the Udden mine. In this study it was found that the air supply could be regulated continuously but it was very important where the sensors feeling the contamination were placed. An intense study of the environment underground is now being planned by our division together with specialists from the National Board of Health and Safety, The Swedish Work Environment Fund, LKAB and the local Governmental Inspection of the Workers Safety. Different gases, radon, dust, airspeed, moisture temperature and pressure is planned to be measured continuously and correlation between the parameters is going to be established to decide the best measurement parameters for regulating the system. The best situation of sensors is also going to be studied. Despite this work hasn't been done yet this paper covers some of the problems which could be encounted with continuous regulation. In this report the environment has been studied during the test with step by step regulation of fans by radio. Diesel vehicles are the largest polluters under ground in Swedish mines and we have therefore suggested that the large diesel vehicles should regulate the fans. The goal of this study has therefore been to find how active diesel vehicles should be able to start and stop gallery fans at both intake and return air. In this paper different methods for activating fans are discussed. Then the best methods are chosen and tested in the mine. In this study we have found that changes of temperature is a cheap and effective method to start and stop cross cut fans in sublevel caving and radio signals seem to be an attractive system for start and stop of gallery fans. This work has been done in close collaboration between LKAB in Kiruna and the University of Luleå - Division of Electronics and Division of Mining and Rock Excavation. A reference group for the project has been established with ventilation experts from the mines, representatives for the local mine worker's unions and authorities from the local Governmental Inspection of the Workers Safety. VENTILATION SYSTEM STUDIED In the project the ventilation system at LKAB in Kiruna has been studied. The mining method used is sublevel caving with 9-13 m slice height. The air is heated winter time over ground by hot water heat exchanger. The main fans are pushing air down to a main distribution level along the 4000 m long and about 100 m wide orebody. From the distribution level, air is taken through shafts down to the sublevels, where it is pushed through the levels by local gallery fans on both intake and return side, see fig 1. The air ( ~ 8 m3/s) is moving freely through the gallery head. The cross cuts are ventilated with smaller fans, diameter 500 mm, and flexible duct, see fig 2. The aim of this study has been to study how to start and stop gallery- and cross fans and examine the environment when the fans are stopped . In Sweden there are no regulations telling that a minimum of air amount must be supplied. Instead the hygienic limits must be fullfilled.

Jan 1, 1981

By Terry Ramsey, N. Finkelstein

INTRODUCTION The Cyprus Pima Mine is located 20 miles southwest of Tucson, Arizona and about fifty miles north of the Mexican border. The Cyprus Pima orebody was discovered in 1950. Feasibility studies were begun in 1952 employing underground development. Economic studies showed open pit operations to be feasible and stripping of overburden was begun in late 1955. The first ore was reached in October of 1956. A 3,000 tpd (tons per day) concentrator was completed and began operation January 1, 1957. From these beginnings, Cyprus Pima Mining Company has expanded into a plant processing approximately 54,000 to 56,000 tpd. Four expansions were required to bring the plant up to its present capacity. Each expansion incorporated what had been learned in previous operation of the plant. The first expansion was completed in August of 1963 doubling design capacity to 6,000 tpd. In reality, because of softer than average ore, capacity was closer to 8,000 tpd. Expansion I1 was completed in July 1966 bringing design capacity to 18,000 tpd. Expansion I11 followed immediately. Completed in the summer of 1967, this expansion increased the design capacity to 30,000 tpd. The actual dry tonnage of this portion of the operation in 1974 averaged 38,400 tpd, again, primarily as the result of treating softer than average ore. The latest expansion (Expansion IV), completed in December 1971 and utilizing a semi-autogenous grinding circuit, is located in a separate building (Mill 11) approximately 200 yards southeast of the original mill (Mill I). Expansion IV was designed for 14,000 tpd, but after circuit modifications, averaged 16,500 tpd in 1974.

Jan 1, 1976

By D. K. Grubbs

Anorthosite is an abundant, domestic source of alumina with reserves in individual deposits ranging from a few billion to hundreds of billions of tons. While anorthosite contains less alumina than does kaolinite, its CaO and Na20 contents are significantly higher (Figure 1). Alumina can be produced from anorthosite by alkaline, soda-lime sinter or acid processes. CaO and Na20 are advantageous because they are reactants consumed in alkaline processes. Acid processes require high calcium plagioclase feldspars (bytownite-anorthite) to obtain high alumina extraction because the lower calcium plagioclase feldspars (andesine-labradorite) are not as readily dissolved during digestion. The layered Raggedy Mountain Gabbro group in the Wichita complex in southwest Oklahoma is a high calcium anorthosite that could be processed by acid, sinter, or alkaline methods. Chemical grade limestone in the Arbuckle Group is located within 45 km of the anorthosite (Figure 2).

Jan 1, 1980

By D. W. Jahn

Road construction in the near future will require contractors to guarantee that a project will remain trouble free for years after the project has been completed. These guarantees will challenge aggregate producers to become technically proficient in judging performance of their products. Testing procedures are described that may be used to predict performance of concrete and asphalt pavements before being committed into a construction project, and may also be used as quality assurance tools during construction to monitor performance as construction proceeds.

Jan 1, 1995

By Edie Trimmer

Utah statute defines sovereign lands as "those lands lying below the ordinary high water mark of navigable bodies of water at the date of statehood, and owned by the state by virtue of its sovereignty." The lands within the bed of Great Salt Lake (GSL) are, by this definition, sovereign lands, acquired at statehood in 1896 in accordance with the "equal footing" doctrine, granting each state control and ownership of navigable waters and the lands underneath those waters within its borders. Under public trust doctrine, the state, as trustee for the people, bears responsibility for preserving and protecting the right of the public to use of the waters for navigation, commerce, fishing, recreation, and wildlife habitat. Also by statute, sovereign lands are defined as "state lands," to be managed by "multiple use sustained-yield principles." The Division of Forestry, Fire and State Lands is given management authority for sovereign lands and, as manager, has responsibility to prepare comprehensive plans, initiate studies of the lake and its resources, implement comprehensive plans through state and local entities, and coordinate the activities of various divisions within the Department of Natural Resources (DNR). The Division of Forestry, Fire and State Lands also has responsibility for management of mineral leasing on sovereign lands. The many resources on the lake--water, minerals, wildlife, recreation, archeological and historical values--are managed by as many state agencies which occasionally creates conflicts. The brines of GSL contain several ions that crystalize into valuable minerals during evaporation. The major ions in the lake are, in order of relative abundance, chloride, sodium, sulfate, magnesium, and potassium. Mineral products which are currently extracted from lake brines are sodium chloride, magnesium chloride brine which can be sold as flake magnesium chloride or further processed into magnesium and chlorine gas, and potassium sulfate. Mineral products which have potential for extraction include gypsum, sodium sulfate, and trace amounts of lithium, boron, and bromine. The GSL contained an estimated 4.3 billion short tons (st) (3.9 billion metric tons [mt]) of dissolved salts in 1998. Utah Geological Survey (UGS) estimates of the dissolved salt content in GSL have fluctuated from 4.0 to 5.5 billion st (3.6 to 5.0 billion mt) due to the dynamic conditions in the lake as salts are precipitated and redissolved, and due to the diversion of brines from GSL, such as the West Desert Pumping Project. The lake has four areas of varying salinity, separated by dikes or other man-made structures: north arm and Stansbury Bay brines at near saturation (25 to 27 percent total dissolved solids [TDS]); the main body of the south arm with concentrations ranging from 7 to 15 percent TDS as lake elevations fluctuate; the waters in Farmington Bay at approximately 3 to 5 percent TDS; and Bear River Bay at <1 to 7 percent TDS. The percent TDS in Bear River Bay fluctuates with lake level, and changes in Bear River inflow. The transfer of salts from the south arm to the north arm has raised questions about the viability of the mineral and brine shrimp industries. The UGS and the U.S. Geological Survey (USGS) continue to monitor salinities at designated sites on the lake to document changing lake salinity. A recurrent theme is that placement of dikes and diversions can have significant and rapid impacts on various conditions in the lake. Hydrocarbon resources on the lake are significant, but presently undeveloped. The hydrocarbons are low gravity (4 to 9 degree API) and tar-like, contain high nitrogen concentrations, and up to 12 percent sulfur. The unusual characteristics of the oil have been the subject of studies by chemists at Weber State University and University Louis Pasteur de Strasbourg. However, these resources are difficult, and at present, uneconomic to extract using current technology because of the nature of the hydrocarbons, and production in "an offshore, highly saline environment." Oolitic sand deposits make up many of the beaches and shorelines around the lake. Because of their high calcium carbonate content, oolites have been used by Magnesium Corporation of America (MagCorp) and its predecessors for acid neutralization and dike construction. Oolites are also used in very minor amounts in flower drying. The Utah Division of Oil, Gas and Mining reports up to 130,000 st (118,000 mt) mined annually by MagCorp from U.S. Bureau of Land Management (BLM) lands adjacent to GSL. Currently, there are twelve producing mineral leases which generated slightly more than $1,000,000 in royalties during calendar year 1998. IMC Kalium Ogden Corp. (IMC Kalium) produces potassium sulfate and magnesium chloride from brines concentrated through solar evaporation in Bear River Bay and Clyman Bay. By-product sodium chloride is transferred to IMC Salt, which packages and sells the salt. MagCorp produces magnesium metal from brines concentrated in Stansbury Bay. Cargill Salt produces sodium chloride from brines provided by MagCorp under a lease agreement. Morton Salt produces salt at the southeast end of Stansbury Island. Lastly, North Shore Limited produces cocentrated brines for use in dietary and mineral/vitamin supplements near Spring Bay in the north arm of the lake. Producers of magnesium, potash, and salt from GSL contribute significantly to the value of metals and industrial minerals in Utah. Together these companies contribute approximately $240 million in gross value, or 18 percent of the value of the state&apos;s nonfuel mineral production. Most of this production is exported.

Jan 1, 2001

By I. Jashnani, J. R. Lawter, D. B. Lindsay

INTRODUCTION It is a generally recognized obligation of owners and operators of underground mines in the United States to protect the health of miners against the potential carcinogenic effect of airborne alphaemitting radionuclides, in particular the shortlived radioactive daughter-products of 222Rn. In meeting this obligation, a number of strategies are available, and it is largely up to the operator to decide what combination of methods he will use. Because the officially accepted theory of the mechanism by which radon and its short-lived progeny cause cancer of the respiratory system, the objective in controlling this health hazard is to limit as far as possible the inhalation of the three daughter products, 218Po, 214Pb, and 214Bi. (214Po, the fourth nuclide in the chain, is so short-lived that its alpha-decay occurs almost instantaneously after the beta-decay of its parent, 214Bi.) The reasoning in this theory leads to the conclusion that the alphadecay of radon itself causes essentially negligible physiological damage, and that the amount of daughter product activity attributable to decay of radon within the respiratory system is also very small. As every ventilation engineer in this business knows, however, focusing remedial actions exclusively on the daughter products themselves is choosing the hard way, and will probably never lead to effective control of this health hazard in underground mining activities. The reason for this troublesome fact can be seen in Figure 1. Let us say that we have air containing 222Rn and its short-lived daughters in near-equilibrium, a not-uncommon condition in the air of a poorly ventilated underground mine, and that we wish to purify it by removing only the toxic daughter products. If we have been very thorough in our purification efforts, we might expect to achieve a 99% reduction of the Working Level (WL) measurement. Figure 2 allows us to examine closely the early regrowth of WL&apos;s in this freshly cleaned air. Within the first five minutes, for instance, the WL&apos;s are back to 10% of their full equilibrium value, and ten minutes later the level has more than doubled and is on its way to an almost complete defeat of the clean-up effort by the end of the next hour. It is quite clear from this simple illustration that no matter how effective an air-cleaning system may be if it is directed only at the selective removal of the toxic trio, 218Po, 214Pb and 214Bi, its beneficial effect will be quite temporary. A truly effective attack on the problem must always include methods aimed at the control of the unruly parent, radon. Then, even if its progeny have an inalienable "right to life", their brief lives will not be spent in the miners&apos; lungs. The object of the present paper is to show how state-of-the-art environmental air

Jan 1, 1981

By J. C. Agarwal

Major scientific discoveries cannot be programmed. New or frontier technology, however, can and should be planned. It is the vital force underlying the business strategy of a vigorous and profitable mining and metals company. Generally, a radical departure from existing technology is required to 1) Enhance the competitive value of ore reserves, i.e., to turn low grade or marginal reserves into competitive reserves. 2) To increase yield and decrease costs. 3) To decrease investment. 4) To increase mine life. 5) To improve product quality to meet market demands. The very definition of frontier technology implies that it is so different that the old plant, if already in use, will not be directly suitable to use the new technology. Therefore, a priori, we know that the commercialization of frontier technology would very likely involve new investment. The recommended technique of economic and technical analyses, I propose to call "Success Analysis.&apos;&apos; Simply stated, it forces us, by step- by-step procedure, to ask "what is needed to succeed in this particular project." Therefore, the first step is to identify what is meant by "success." The definition of "success" requires an agreement with top management or sponsors of the project as to what constitutes "success" in their minds as contrast to the technical people perception of "success." In general, top management would define success as meeting: 1) The technical objectives, i.e., technology being developed would produce the desired product at the acceptable quality. 2) Financial objectives, i.e., when commercialized, the project&apos;s capital cost, operating costs and return on investment are better than the projects they would normally fund. The return has to be better because new technology is inherently riskier. 3) Marketing objectives in that the project will produce product of acceptable quality in timely manner, i.e., scale-up to commercial plant would not cause undue delays in start-up and that large fix-up expenditure would not be required to protect the projected return on the investment. Many projects are started in the laboratory to develop "Frontier Technology" in mineral processing. Most of these efforts are never commercialized. There are many causes of these failures. The major causes are listed below: 1) Inadequate communication with the sponsors of the project so that project objectives are defined and agreed to by all. 2) Ill-defined technical problems. 3) Incomplete development of technology. This has two major components: a. Incorrect scale-up and engineering. b. Inadequate start-up and maintenance planning. 4) Incomplete and over-optimistic process economics. 5) Lack of understanding of the future behavior of the marketplace. 6) Failure to complete R&D effort by the time it is needed. 7) Incorrect projections of human resources required; that is, technical, managerial and operating. 8) Lack of realistic forecast of the expenditures required for commercialization of the R&D effort. These pitfalls can be avoided by comprehensive planning and the use of success analysis technique. The major elements in "Success Analysis" are: 1) Identification of the "need" for new technology. 2) Unbiased and complete scale-up engineering. 3) Acceptable economic feasibility with enough margin of error in the sale prices and operating costs to justify the inherent risks in frontier technology. 4) Timing for availability of investment capital and markets. Many failures in the development of frontier technology are preordained because the initial selection of the research project has been without adequate attention to the needs of the industry. Many very innovative hydrometallurgical processes for recovery of copper from concentrates were developed in the past twenty years. They have not adapted except to a very minor extent because they did not satisfy the success analysis criteria. The copper industry in North America needed a process to compete against high grade ores and to avoid

Jan 1, 1985

Although there was a significant improvement in the world economy, recovery in the iron and steel industry followed its traditional pattern and lagged the general economic recovery in 1983. World crude steel production increased from 645 Mt (711 million st) in 1982 to 664 Mt (732 million st) in 1983, an increase of less than 3%. Domestic iron and steel production showed a modest increase over 1982. Weekly raw steel pro¬duction levels ranged between 1.5 and 1.75 Mt (1.6 and 1.9 million st) for the last 10 months of 1983, compared with less than 1.25 Mt (1.4 million st) for the last half of 1982. The peak was 2.5 Mt (2.7 million per st) per week in 1978-79. This how level of steel operations kept most pelletizing and sintering operations at curtailed production levels. Extended shut-downs of pellet plants were also common. Pressure by management to reduce operating costs has continued with an increasing emphasis on maintaining quality and efficient unit productivity. With the extended decline, there have been significant personnel reductions in both operating and headquarters staffs. Many companies are anticipating a long-term how growth period in the iron and steel sector. Pelletizing Domestic pellet production showed a slight increase last year to about 34 Mt (38 million st), less than 50% of total capacity. What is indicative of the inevitable is the announced intention to chose down facilities, such as US Steel Corp.&apos;s Atlantic City ore operations pellet plant at Lander, WY, and the recent aborted move by US Steel to purchase National Steel with the apparent intent to chose the National pellet plant in Keewatin, MN. There is excess domestic pellet capacity that will not be needed. The question is what form attrition will take. South American pellets can be brought into the Chicago area at a cost competitive with Great Lakes plants. This raises the possibility that imported pellets can, in fact, displace domestic pellets at almost any US steel plant. The need to re duce total production costs at domestic pelletizing plants is crucial. Efforts to reduce fuel costs for pelletizing have focused on re placing natural gas or fuel oil with coal. More recently, petroleum coke has become available at an attractive cost, but systems must cope with its higher sulfur con tent, which limits its potential The direct firing of grate-kiln systems with pulverized coal hay been fully proven. The use of solic fuel in the straight-grate process however, is still being developer and no straight-grate system i running on solid fuel alone. The further development o coal-water slurry systems may provide a suitable fuel for both systems. It would appear, how ever, that the same ash quality restriction would hold for coal water systems as for direct-firin systems. So, the choice is based of the relative cost and convenience of a wet-grinding system with additives, compared with a dry-grind direct-fired unit. The high-temperature (two stage) heat recuperation system installed at US Steel&apos;s Minnta plant (Step III) has provided the fuel savings anticipated, any modification of additional in durating lines is planned. Other operators are hooking at similar heat recuperation improvement. Another area of potential cost savings has been in the reduction of bentonite requirements. A CCI&apos;s Tihden plant, major improvements have been made in this area. Progressive bentonit reductions were achieved over several years from the 8- to 9-kg (16- to 18-lb per st) range to the 5-k (12-1b) level by progressive moisture reductions and chose attention to operating practice. Further reductions were achieve by raising bentonite specifictions. In this instance, the wate plate absorption test specifia

Jan 5, 1984

By S. W. Swerson

25.1-THE PURCHASING FUNCTION The word "purchase" means "to obtain by paying money or its equivalent; to buy for a price." This definition is all too simple to properly describe the word "purchase." One should consider the basic objectives of purchasing-to procure the right material, of the right quality, in the right quantity, at the right time, from the right source at the right price. Here it should be noted that in purchasing it is recognized that the best quality or grade of materials may be the only grade to purchase for a specific job. However. there are other jobs where the medium, standard or poor grade of materials is the right quality, as the lesser grade will perform adequately. In some companies the purchasing department makes the decision as to the right quality, while in others this function is shared with other departments. Years ago in business the owners controlled the purchase of required materials and services by performing the task themselves. The owners obtained the type materials and services they needed and paid the price demanded. This function was performed along with all the other duties requisite to the owner of a business, namely, clerical, hiring and firing of personnel, financial management, etc. As companies grew in size, clerical duties were assigned to other personnel and the owner usually retained the purchasing authority. This same division exists today in many small companies. However, in the larger companies, the purchasing function has been assigned to a separate department. Importance of the Purchasing Function-The larger the company the greater the need for a separate department to perform the purchasing function. Today the purchasing agent for most larger progressive companies has policy-making authority. Therefore, it is reasonable for him to report to the president or vice president of his company. Studies of several hundred companies show the purchasing department head reporting to top management 87.5% of the time. This fact in itself is indicative of the importance of recognizing that effective purchasing requires a department staffed with specialists in the field of procurement with knowledge and experience sufficient to perform in today&apos;s complicated business atmosphere. In the manufacturing field it is a common axiom that usually half of the company&apos;s dollar expenditures are for materials. If a purchasing department functions properly and the right product or service is purchased and a savings accomplished, the contribution to the net profit of the company is much greater, as opposed to sale dollars, where only a small portion is carried forward to net profit. Thus, the importance of the purchasing department and the contribution it can make to the success of the company are obvious. 25.1.1-THE PURCHASING FUNCTION 1. Responsibilities of the Purchasing Function-The purchasing agent in performing his function is acting as an agent for the company and others in the company requiring materials and services. Accordingly, he is committing the company for materials and services subject to certain limitations which the board of directors may stipulate. In view of this, the purchasing agent,&apos;^ position must of necessity he

Jan 1, 1973

By Virgil R. Huff, Ihor Havryluk

P. T. Pacific Nikkel Indonesia (PTPNI) was incorporated in Jakarta, Indonesia in February, 1969 by a group of Dutch and North American companies. At the same time, a Contract of Work with the Government of the Republic of Indonesia was signed, granting Pacific Nikkel all the necessary licenses and permits to explore and develop all nonradioactive minerals in two separate areas in Irian Jaya, eastern Indonesia. Nickel mineralization occurrences were confirmed by Dutch geologists in the two areas in 1952 and 1955, however, detailed exploration began in June 1969 after the Contract of Work was signed. Since that time, numerous studies and investigations have been conducted to determine the feasibility of producing metallic nickel in Irian Jaya. Four engineering studies, two bulk sample tests, an oceanographic survey, and a preliminary site investigation indicated that construction and operation of a nominal 100 million pounds per year metallic nickel plant on Gag Island were technically feasible. The fourfold increase in the price of oil in late 1973 without a corresponding adjustment in the price of nickel necessitated a reevaluation of the project, the results of which showed that the project required other conditions to be viable. Subsequently, analysis of: the future projected nickel supply-demand and cost-price relationships, the economics of treating a higher grade feed, and participation by the Government of Indonesia, indicate that the project will be viable. Therefore, planning of the Gag Island Nickel Laterite Project is continuing with the objective of commencing production to supply the market in the 1983-1984 time period.

Jan 1, 1979