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By R. L. Miller

The potential for recovery of enriched uranium from spent nuclear fuel which has been consolidated into a nuclear waste form was explored in the studies reported here. The waste form of interest is iron-enriched basalt (IEB)--a silicate-based, fused-cast ceramic. IEB samples were prepared containing fuel assembly materials that simulate the core debris of Three Mile Island Unit II;1,2 the nominal composition of the consolidated waste form is given in Table 1. Ore Types The IEB samples, or man-made uranium ores (MMUO), are in two different mineralogical forms. Each MU0 was made by melting the constituent materials and holding at about 1500°C for 1 h. The MMUOs were then heat treated to control crystallization and crystal growth and then cooled to room temperature.

Jan 1, 1983

By W. Miles

Introduction From a historical perspective, bentonite is the common rock term for various uses and applications. Its name originates from water-based muds near Fort Benton used for lubrication of wagon wheels during the 19th century migration to western territories (which are presently part of the United States) when the pioneers ran out of axle grease. From a clay mineralogy perspective, bentonite is composed primarily of montmorillonite, an expandable magnesium aluminum silicate clay mineral. When magnesium occupies an octahedral structural site that usually contains an aluminum atom, a negative charge is created. In order to neutralize negative charges, cations are drawn to the interlayer surfaces between clay mineral sheet structures. Modern applications for bentonite depend on the sodium or calcium cation populations and other characteristics of the clay mineral. When sodium is the dominant cation, the material is also called sodium bentonite, also known as swelling bentonite, western bentonite or Wyoming bentonite. When calcium or magnesium is the dominant cation, the material is called calcium bentonite, also known as nonswelling bentonite or southern bentonite. Swelling bentonite is recognized for its rapid hydration of interlayer sodium and subsequent dramatic expansion up to more than 20 times its original volume. Low shear can then disperse the hydrated sodium bentonite to form suspensions that increase viscosity and suspend solids. However, when shear is subsequently eliminated a sodium bentonite slurry gels. Characteristically, nonswelling calcium bentonite has relatively poor hydration properties and thus low expansion of the clay mineral. When subjected to low shear, calcium bentonite exhibits very little viscosity and poor suspension. Additionally, when shear is subsequently eliminated no more than minimal gelling takes place. The domestic and export markets related to both swelling and nonswelling bentonite are discussed below.

Jan 1, 2007

By Mike O'Drisooll

There is no doubt, if any existed, that the commercial minerals world has now moved into a new era of unprecedented challenges in the sourcing, mining, processing, trade and use of industrial minerals. Industrial (nonmetallic) minerals remain the often unsung workhorse of mineral commodities and specialist raw materials that frankly keep the world’s manufacturing industries ticking over, and everyday products we use in sound availability. They are also very much present among the so-called “critical minerals” necessary to advance cutting-edge developments in growing high-tech markets such as in energy transition: for example, lithium, rare earths, graphite and fluorspar. Indeed, in the United States during 2024, industrial minerals again accounted for the majority share of total sourcing, and, yes, geopolitics. The last few years have witnessed a series of geopolitical issues that have impacted and continue to impact international trade in industrial minerals. Above all, it has been the threat and implementation of recent trade tariffs between countries that have been most damaging in creating a potential trade war. mine production by value at $72.1 billion, or 54 percent, followed by metals, 25 percent, and coal, 21 percent, according to the latest data from the U.S. Geological Survey (USGS). But right now, “industry resilience” seems to be the rallying call, with industrial mineral producers and traders facing straitened times from market slowdowns; environmental regulations; decarbonization and other sustainability issues; pressure to diversify; and near-shore mineral sourcing, and, yes, geopolitics. The last few years have witnessed a series of geopolitical issues that have impacted and continue to impact international trade in industrial minerals. Above all, it has been the threat and implementation of recent trade tariffs between countries that have been most damaging in creating a potential trade war.

Jul 1, 2025

By P. Amelunxen

Over the past several years, the combination of higher energy and steel costs and the recent commercial deployment of high-pressure grinding rolls (HPGR) technology in hard rock mining have led many multinational mining companies to evaluate the suitability of HPGR technology for their particular comminution circuits. HPGR technology is perceived to require a higher capital investment while delivering lower long-term operating costs. This paper undertakes a critical evaluation of this perception. By evaluating the capital and life-of-mine operating costs of competing circuit designs for soft, medium and hard ores, the HPGR break-even point can be identified, at which the incremental capital cost of an HPGR circuit is equivalent to the net present value of the projected operating cost reductions. For ores with hardness parameters above the break-even point, HPGR circuits could offer economic benefits, while for softer ores, SAG mill/ball mill/pebble crushing (SABC) circuits are likely to be more economical and energy efficient. This evaluation considers both an SABC reference circuit and a traditional stage crushing configuration. Other influential factors are also discussed.

Jan 1, 2011

By Badiozamani Khosrow

Introduction The mining industry has been using computers since the late 1950s. Despite this early start, the use of mine planning software is not a common practice in many operations. But the trend might be changing because of the availability of relatively inexpensive personal computers (PC). The introduction of these machines has generated unprecedented interest by mine managers to computerize their planning operations. However, some managers have become disappointed with the PC's lack of adequate software and the inability to handle the massive amounts of information required for modeling. This paper is an attempt to shed some light on the future of computers in the mining industry. It will examine: • historical progress in the computer industry, • future advances in the computer industry, • historical usage of computers in mining, and • future alternatives available to mining. Historical Progress The computer industry has come a long way since the first full-fledged electronic digital computer Electronic Numerical Integrator And Calculator (ENIAC) was built in 1946. This machine weighed more than 27 t (30 st). It contained 19,000 vacuum tubes, occupied 139 m2 (1500 sq ft), and could perform 5000 additions per second. By contrast, today's fastest, commercially available computer is the CRAY-X. It weighs less than 5 t (6 st), has no vacuum tubes, occupies less than 9 m2 (100 sq ft), and performs over 100 million operations per second. This is an incredible advancement in less than 40 years. One person commented on the rate of advancement in the computer industry. He suggested that if the auto industry had advanced at the same rate as the electronics industry, we could buy a Rolls Royce for $2.75 and it would run

Jan 9, 1984

By John Reilly

"INTRODUCTION Successful management of megaprojects, meaning delivery within budget, on time and according to expectations, is a fundamental requirement. Many projects have been successful, some have not. This paper reviews megaprojects1, drawn from the author’s projects over the last 50 years, with “lessons-learned” and a summary of recommendations that, if implemented, would improve megaproject management and delivery. Characteristics of these projects are summarized – including outcomes related to key factors such as politics, management, organizational structure, contracting methods, cost estimates, risk and other elements. The projects include the Washington D.C. Metro, Boston Southwest Corridor, LA Metro, Toronto Rapid Transit Expansion Program, BART San Francisco, MARTA Atlanta, London Underground and the Washington State Highway megaprojects – including the SR520 Floating Bridge and the Alaskan Way tunnel. Other projects that illustrate successful, innovative management and contracting methods include the Madrid Metro (low-cost delivery), the Sydney Northside Storage tunnel (outturn cost, alliancing) and the Lake Mead tunnel (working in partnership, risk management). KEY ISSUES A characteristic of megaprojects is that their complexity increases exponentially with size (Reilly 2010, Galloway et al. 2012). These projects are very visible politically, have many stakeholders who must be satisfied and generally span many years and political election cycles. To be successful they must meet expectations, function efficiently, and be delivered under, at or close to budget and schedule. There is a widely-based perception that large, complex projects are always delivered late, over budget and with problems. Specific examples include projects such as Tren Urbano in Puerto Rico – $1.28 billion over initial budget (+133%), the Silver Line Transitway Project in Boston – $286 million over budget (+90%), the London Jubilee Line Transit Project – 2 years late and £1.4 billion (+67%) over budget, the Channel Tunnel Rail Project – £3.7 billion (+80%) over budget, Denmark’s Great Belt Link rail and road link (54% over budget), the 2003 Woodrow Wilson bridge tender in Virginia (72% over estimate) and Boston’s Central Artery Project – several billion (perhaps 100%) over what would have been a realistic initial budget and years late (Reilly 2001c, 2004a; Salvucci 2003)."

Jan 1, 2016

By Peter Kolitsch, Galyn Rippentrop

INTRODUCTION On April 14, 1994, the joint venture of Kiewit Construction Company and Kenny Construction Company was awarded a 76 million dollar contract for the construction of the New Hampshire Avenue Tunnels in Washington D.C. The Notice to Proceed was given on May16, 1994 and scheduled completion is September 1997. This project is one of five contracts for the Mid-City E Line as part of the Washington Metropolitan Area Transit Authority (WMATA)Greenbelt Route. Once completed, the Mid-City E Line subway tunnels will connect service between the U Street-Cardozo and Fort Totten stations (See Figure 1). The New Hampshire Avenue Tunnels project consists of approximately 6800 feet of twin single track subway tunnels, three vertical shafts, associated utility work and comprehensive restoration work. Section E4b involved two methods of tunneling along the project alignment. The first method consisted of the well known soft ground open face shield driven tunnel and the second method consisted of tunnels driven using the New Austrian Tunneling Method (NATM) . The NATM section of twin tunnels begins at the Buchanan Vent Shaft and proceeds approximately 2630 feet under Rock Creek Cemetery, including the Farragut Emergency Access Shaft and connects approximately 390 feet beyond to the existing Fort Totten running tunnels (See Figure 2). Special considerations had to be given to the portion of the tunnel alignment which passed beneath Rock Creek Cemetery. The analyses and subsequent selection of the tunnel support system were based on anticipated geological conditions and the sensitive tunnel alignment. The New Hampshire Avenue Tunnels project was the second soft ground NATM project in Washington D.C. The first, by no coincidence, was completed at the adjacent Fort Totten Station and Running Tunnels Project by Mergentime/Hochtief, AJV. Currently, on a nearby WMATA jobsite, the J.F. Shea Construction Company has started a third NATM soft ground tunnel. Tunnel support systems were studied with respect to three tunneling methods: •A one-pass system consisting of a bolted precast concrete segmental lining •A two-pass system consisting of an unbolted precast concrete segmen

Jan 1, 1997

By M. A. Trevits

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

Jan 1, 2009

By Warfield Garson

Few, if any, of the non-ionizing radiation health hazards to be found in either surface or underground coal mining are uniquely different because of their being found in the work environment. Hence, they can be considered generally for their bio-effects on the worker when found in the mining work environment. The same may not be said, however, for the lack of non-ionizing radiation and its bio-effects, particularly as it relates to underground coal mining. The term "non-ionizing radiation" refers to various forms of electromagnetic radiation of wavelengths longer than those of ionizing radiation. As the wavelength gets longer the energy of electromagnetic radiation decreases. Therefore, all non-ionizing forms of radiation have less energy than cosmic, gamma, and X-radiation. In order of increasing wavelength, non-ionizing radiation includes ultraviolet, visible light, infrared, microwave, and radiofrequency radiations. The energy frequency and wavelength range of both the ionizing and non-ionizing electromagnetic forces are shown in Table I. To convert the wavelengths of various radiations to Ångström units, one multiplies millimicrons by ten. In a vacuum, all electromagnetic radiation has the same velocity, namely 3 x 1010 centimeters per second. The natural source of radiant energy here on earth is our sun which emits radiation continuously over a wide spectrum. This radiation on average reaching earth ranges from 290 nm in the ultraviolet range to over 2,000 nm in the infrared range with a maximum intensity of about 480 nm in the visual range. You will note this falls into the visible blue wavelength and accounts for our blue sky and blue ocean and deep water effects. We are all familiar with the fact that the passage of solar radiation through the atmosphere to the earth changes the spectrum considerably because the atmosphere absorbs and scatters many of the sun's rays. The ozone in the upper atmosphere absorbs the shorter ultraviolet wavelengths and water vapor absorbs some of the infrared wavelengths. Smoke, dust particles, gas molecules and water droplets scatter the rays, especially those of shorter wavelengths. In addition to the sun, every gas, liquid or solid object at a temperature above absolute 0° radiates energy. Solid objects emit almost continuous spectra. At low temperatures only radiation of the longer wavelengths in the infrared range is emitted, but as the temperature of the object is increased, more and more of the shorter wavelengths are added. This fact is most readily demonstrated by heating a piece of steel. When a piece of steel reaches a temperature of about 1,700° Fahrenheit, it gives off radiation at the red end of the visible spectrum and appears dull red. As the temperature is further increased, the shorter rays are also emitted, until at about 2,100°F, the metal appears white, due to the emission of wavelengths throughout the entire visible range. Gasses, on the other hand, when heated emit radiant energy only at certain wavelengths, which are characteristic of their chemical structure. This latter fact is of importance in underground coal mining as high intensity gas and vapor lamps are becoming more and more utilized for illumination in underground coal mining. The biologic effect of non-ionizing radiation exposure depends upon the type and duration of exposure and on the amount of absorption by the miner. The effects of this radiant energy on the miner fall into four distinct types: (1) the heating effect of infrared radiation, (2) the effect on the eye of visible radiation, (3) the effects of ultraviolet radiation, and (4) the growing potential effects of the misuse of microwave radiation. Each non-ionizing type of radiation will be considered individually. ULTRAVIOLET RADIATION The sun is the major source of ultraviolet radiation, which is of concern in open pit and surface mining at certain seasons and in certain climes necessitating protection for the surface miners under those conditions; nonetheless, there are some man-made sources such as electric arc lights, welding arcs, plasma jets, and special ultraviolet bulbs for illumination underground that demand surveillance in the underground environment to be aware of whether the miners are at risk above the threshold limit values allowable. Since ultraviolet radiation has little penetrating power, the organs that are affected are the skin and the eyes. Ultraviolet radiation is strongly absorbed by nucleic acids and proteins, and the effects in man are largely chemical rather than thermal. Short-term effects on miners include acute changes in the skin. These are of four types: (a) darkening of pigment, (b) erythema (sunburn), (c) increase in pigmentation (tanning) and (d) changes in cell growth. Ultraviolet radiation also causes acute effects on the tissues of the eye. Overexposure can lead to keratitis, inflammation of the cornea, and conjunctivitis. Long-term effects of ultraviolet exposure include an increase in the rate of ageing of the skin with degeneration of skin tissue and a decrease in elasticity. Late effects of ultraviolet on the eye include the development of cataracts. The most serious chronic effect of ultraviolet exposure is skin cancer. Ultraviolet radiation effects are increased by some industrial materials and drugs. After exposure to such compounds as cresols, the skin is exceptionally sensitive to ultraviolet radiation. Photosensitivity reactions occur after exposure to a variety of other chemicals and drugs including dyes, phenothiazines, sulfonamides, and sulfanylureas. On the other hand, we must remember that ultraviolet radiation has an important role in the prevention of rickets. Vitamin D is produced by the action of

Jan 1, 1981

By John Durkin, Steven Wirch, Fred N. Kissell, Steven Ruggieri

The Bureau of Mines has developed two expert systems to give advice on coal mine dust control, one for continuous miner sections, and another for longwalls. Prototype versions have been evaluated by coal operators and MSHA. Both systems query the user as to the nature and extent of the dust control problem. Typical questions asked deal with matters such as cutting sequence, current dust standards and characteristics of current dust control techniques. Advice given by the system generally does not focus on a single issue, but may suggest a variety of approaches consistent with the ability of the operator to practically implement what is suggested. Both were written using expert system development software called Insight 2+. The advantages of Insight 2+ for the user are: low cost, IBM-PC compatibility, and the fact that little prior experience with computers is required. For the developer, Insight offers an easy to use production rule language and goal driven structure as well as a wide variety of capabilities.

Jan 1, 1987

By E. A. Adey, C. Baciu, P. Whitbread-Abrutat, M. Varul, T. Ejdemo, R. K. Shail, F. Wall

Responsible mining requires stakeholder engagement throughout all operational stages and after mine closure. By assessing the current and anticipated future socio-economic and environmental impacts, a company can maximise the positive impacts they can have on a community, whilst minimising any negative impacts. Despite the current emphasis on companies maintaining effective stakeholder relations to gain their ‘social license’ to operate, findings of the present study reveal a wide variation in community expectations, with different degrees of ‘acceptability’ evident across seven sites in Romania (Rosia Montana), Sweden (Kristineberg), the United Kingdom (Cornwall), Bosnia Herzegovina (Vihovici) and Russia (Karabash, Gay and Mednogorsk). These variations reflect the current status of mining within a community, as well as its socio-economic background and the nature of existing engagement with mining companies already operating in the region.

Jan 1, 2011

By R. W. Smith, Z. Sadowski

INTRODUCTION Problems encountered in barite flotation from various waste materials such as spent drilling muds are likely to be closely connected with the effect of contaminant metal ions and other chemicals on the flotation. Investigations on the recovery of barite from tailings ponds and mining wastes (Sullivan and Lamot, 1981) have shown that such barite materials can contain large quantities of carbonate and silicate minerals (including clay minerals). Also iron oxide slimes can be present. From these substances, cations such as Ca2+, Mg2+, Fe2+, and A13+ can potentially dissolve and be present in the aqueous phase accompanying the various minerals. These ions and their hydrolysis products can have a substantial effect on any subsequent flotation scheme. The present study investigates the effect of the noted ions on both the stability and electrokinetic behavior of barite suspensions. Some adsorption (abstraction) experiments were also performed. Experimental materials and methods The barite used was a high-purity, naturally occur¬ring mineral sample (Kings Creek, SC). The material was ground in a porcelain mill and a fine fraction (mean particle size 11.49 µm) separated out by air elutriation. The mean size was determined by an aqueous sedimentation method using a CAHN electro-balance. In the method, an 0.6-g sample of the barite was dispersed in 450 cm3 of pH 7 water containing 0.01 g of sodium tripolyphosphate. The mean particle size was denoted X0. The stability of the barite suspensions was determined by a comparison of the mean size of the investigated barite suspension aggregations with the mean size of barite powder determined in the presence of sodium tripolyphosphate. The mean sizes (X) of the barite aggregations were determined using the same amount of water and barite sample as in the measurements of dispersed barite particle size but without the presence of polyphosphate. The ratio X/Xo is thus a measure of the stability of a suspension (the greater the ratio, the less stable the suspension). The adsorption (abstraction) experiments were carried out in polyethylene bottles containing 1 g of barite powder in 200 mL of solution. The solids were added to a solution containing a known concentration of metal chloride salts (AlCl3, FeCl2, MgCl2, and CaCl2) . The pH was controlled by both HCl and NaOH addition. The suspensions were agitated in a shaker for three hours. The final ion concentrations in solution were determined by atomic absorption analysis. The electrokinetic measurements were made using a Komline-Sanderson Zeta Reader in a conventional manner. All experiments were carried out in the presence of 1.0x10-3 k.mol/m3 NaClO4. Experimental results Figure 1 shows the zeta potential of barite particles as a function of pH in the presence of iron(II). The

Jan 1, 1988

By B. Huang, H. Sevim, R. Honaker

The use of medium-to-high sulfur coals has been negatively impacted by the 1990 Clean Air Act Amendment (CAAA). In this article, a method is demonstrated that can render these coals competitive and yet compliant with Phase II of CAAA. The method uses strategic mining and optimized preparation plant operation to minimize production costs, and it utilizes advanced coal-cleaning technology and an SO2 allowance to produce a compliant coal. The method is illustrated through an example from southern Illinois. For an annual production of 3.2 Mt (3.5 million st) and with a $150/st SO2 allowance cost, it was possible to produce a competitive coal for $0.84/million Btu. The production and allowance costs were $0.608/million Btu and $0.232/million Btu, respectively.

Jan 1, 2002

By Waclaw Trutwin, Stanislaw Wasilewski

Application of computer-based systems for ventilation process monitoring makes it possible to widen the system functions with those connected with long-term data analysis. It allows the mine ventilation engineer to carry out necessary preventive actions. In future the wide application of computers and sophisticated expert systems together with automation equipment (like remotely controlled regulators and fans) will allow to gradually introduce minewide systems for air flow control. To achieve this goal research work is carried out using data from a mine ventilation monitoring system and methods of computer analysis of time series. With the use of digital filtering the measuring signal spectrum has been divided into three subranges components of which are important with regard to various needs of mine ventilation staff as well as to monitoring and control system functions.

Jan 1, 1991

By A. E. Prokop, J. P. Rider

Previous research on continuous mining operations has shown that significant interactions exist between dust-control parameter application and the resulting respirable dust levels. However, simply increasing the level of the controls does not guarantee a reduction in respirable dust levels. Full-scale laboratory tests are being conducted to provide information to longwall operators that would assist them in selecting control parameters to reduce dust levels for mine-specific conditions. The interactions between face air velocity, shearer water quantity, drum water spray pressure, external water spray pressure and spray system design were evaluated in a simulated 2.13-m (7 ft) coal seam for two cutting directions. Locations around and downwind of the shearer were monitored to evaluate relative changes in respirable dust levels as a function of each control parameter.

Jan 1, 2003

By John P. Hunt

Early disseminated copper mineralization at Quebrada Blanca, Chile, accompanied 38 million year old quartz monzonite stocks and dikes. Early mineralization was followed by hydrothermal mineralization, mineralized breccias, and post-mineral faulting. After supergene leaching and enrichment, Quebrada Blanca was buried under late Tertiary gravels, and then partially re- exposed in Quaternary time. Based on work to date the orebody appears to contain more than one hundred million tons of plus one percent secondarily enriched copper ore, overlying several hundred million tons of protore averaging more than 0.5% copper. A source of industrial water appears to have been located. Pilot scale metallurgical tests, mine planning, and feasibility studies are in progress.

Jan 1, 1981

By Luzheng Chen

Pulsating high-gradient magnetic separation (PHGMS) of fine hematite from tailings was studied using a pilot PHGMS separator to investigate the possibility of its application in industry. The results of this investigation indicate that PHGMS is effective for recovering fine hematite from the tailings and greatly improved the separation performance compared with the conventional high-gradient magnetic separation at the same conditions. By applying the pilot separator with a 1-mm rod matrix to a tailings containing 28.76% Fe, a concentrate assaying 54.35% Fe with 35.89% recovery was achieved. It was found that the separation performance of the pilot separator closely correlates with the main pulsating parameters, i.e., pulsating stroke and frequency. It was also found that a change in the wire diameter of the rod matrix from 2 to 1 mm causes a weak drop in concentrate grade but results in a considerable rise in recovery. This finding proves that the improved performance achieved by the pilot separator is attributed to the pulsating of slurry and to the use of a 1-mm rod matrix. When the first commercial SLon-2500 PHGMS separator with a 1-mm rod matrix was applied to recover fine hematite from the tailings, the results duplicated those achieved with the pilot PHGMS separator.

Jan 1, 2009

By J. Gonzales

For this paper, blending is conceived as a linear process that takes a proportion from one stockpile or location and mixes it with another proportion from another stockpile or location, with the aim of obtaining a set of attributes in the final combination that satisfies a given quality standard. A blending class is the combination of ore attributes and grade limits that should be stockpiled in order to achieve the target quality for the process Plant. Current literature considers the number of blending classes in the Open Pit Scheduling Problem as fixed; however, this paper shows how to define specific blending classes for a given deposit so that the schedule can be solved with Sequential Linear Programming. Finally, a practical application in a Peruvian copper mine is shown, involving four ore attributes: alteration code, arsenic, oxide content and copper grade. INTRODUCTION In copper ore deposits, blending for quality has not been a typical issue as it was for coal and iron ore; however, current copper deposits in the world are becoming geologically and chemically more complex than in the past and is not uncommon to have quality standards involving up to four attributes, introducing an additional complexity to the mine scheduling process [1]. In order to solve the Open Pit Scheduling Problem with multiple ore quality constraints, two assumptions are necessary [2]: - Grade constraints are defined only by specifying an upper and lower limit; - Ore attributes in stockpiles are pre-determined, i.e., the upper and/or lower grade limits defining each stockpile are already known at the time of setting the schedule. Assuming each ore attribute is classified as high, medium or low, and there are four attributes to be controlled in the target ore quality, the number of possible blending classes would be 3^4 = 81. This number is impractical to manage in Operations, and increases the complexity at the time of running the schedule; therefore, a more efficient way of classifying ore is required. Note that in practice, one blending class can be split into more than one stockpile location due to physical capacity constraints. Therefore, the number of stockpiles could even be more than 81. BLENDING CLASSES DETERMINATION For a given set of ore grades with lower and upper limits to be achieved, one has to find all feasible ore classes such that when blended, their grades will lie within those limits.

Jan 1, 2019

By M. J. Shulman

An algorithm used by the US Coast Guard to find lost objects is utilized to optimally allocate exploration efforts during initial stages of an exploration program. Based on classical search theory, the algorithm assumes a target probability distribution function, a detection func¬tion, and a cost function. The three Junctions are analogous to delineating areas of possible mineralization, choice of exploration methods, and exploration budget. Application of the algorithm is shown for a hypothetical target distribution. Using the maximum number of field days available as the cost function, the optimal allocation of effort is shown for different exploration methods, e.g. electromagnetic survey and induced polarization. The adaption of the algorithm for the exploration process is discussed.

Jan 3, 1984

By Robert H. Carpenter

Abstract, Syngenetic uranium in pre metamorphic Idaho Springs volcanics and sediments probably, was mobilized during metamorphism (1.7 b.y.) and partly retained along unconformities. Precambrian Silver Plume intrusives (1.4 b.y.) and Pikes Peak granite (1.0 b.y.) may have mobilized uranium from the craton and. Idaho Springs metamorphics to concentrate it in cauldron sites in migmatites, pegmatites, alaskite, disseminations and greissen. Tertiary intrusives also may have upgraded uranium by anatexis, leaching and differentiation. Tertiary vein and shear zone uranium mineralization may have-been-derived from underlying magma sources, leached from Idaho Springs metamorphics and from syngenetic leaching of overlying sediments and introduced by deep hydrothermal convection systems.

Jan 1, 1979