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By O&apos, M. W. Neill

Mini-piles have been found to be a practical, technically correct remedial underpinning method. They can be constructed in limited access areas with very little disruption. Experience indicated that mini-piles installed using a down-the-hole soil displacement hammer would be particularly effective in the "bottomless" Beaumont Clay formations in the Houston, Texas, U.S.A. area. The University of Houston Foundation Testing Facility was ideally suited to perform tests on mini-piles. The availability of extensive geotechnical data and previous pile test results was invaluable in evaluating the mini-pile test data. As expected, the mini-pile test results were consistant with test results from large sized driven piles in the same soil formation.

Jan 1, 1989

By David Cole

AT the time flotation appeared upon the metallurgical horizon in Arizona, the writer, under the direction of Dr. Ricketts, was engaged in remodeling and enlarging the No. 6 Concentration Plant of the Arizona Copper Co. at Morenci, and the work had been in progress nearly a year before the Inspiration experiments with flotation had disclosed the revolution in concentration that was at that timè impending. The simplified flowsheet worked out for the remodeling of the Morenci plant had been based upon the removal of the freed metal in a minimum number of stages by treatment upon tables equipped with Butchart riffles, the latter being adapted to accomplish both classification of feed and removal of the metal at one operation, substantially as described in my previous paper.1 The scheme of treatment for the slime was based upon the well-known fact that after copper sulphides, such as chalcocite and chalcopyrite, etc., are reduced to a certain extremely fine state of comminution they are definitely beyond the reach of separation upon any of the concentrating devices then known. By using drag-belt classifiers (which served as conveyors as well as separators), the overflow would be of the usual "slimes" class. Experiment had shown that when these drag-belt overflows were, properly diluted (that is, to about 5 to 7 per cent. solids in the feed under treatment) . the very fine sand, and especially the very fine but still granular sulphide particle's, would, if given a short distance to fall, quickly settle out in prime condition to yield an excellent recovery on vanners; a further valuable feature would be that the very fine non-separable final overflow tonnage might be discharged direct to tailing, thus conserving space requirements so as to permit within the old building, without embarrass-ment, the increase of capacity required.

Jan 9, 1916

By M. Bustin, A. Hosseinian, G. Preisig

Hydraulic fracturing and hydraulic shearing techniques are essential for the development of unconventional oil & gas and geothermal resources. Such techniques will also play a key role in the development of CO2 sequestration, and management of high stresses encountered with deep mining. However, the optimal design of hydraulic injections is often limited by continuum treatments of the rock mass without consideration of the influence of the natural fractures present. These may interact with the hydraulic fracture to promote offsets or arrest, or may cause the natural fractures to undergo shear and dilation. Given the limited access to the rock afforded by deep boreholes common to oil & gas and geothermal projects, advanced numerical modeling is critical for understanding key mechanisms and interactions. In this work, we first present a coupled hydromechanical distinct-element model focusing on the propagation of a hydraulic fracture. Normal and shear displacements arising from the generated hydraulic fractures are subsequently integrated into a fracture flow model for detailed analysis of specific flow behaviour and fracture permeability. For this, a scanned 3-D profile of a natural fracture is used to correlate surface roughness to dilation as a function of shearing. Fracture flow is computed at different time steps corresponding to different fracture propagation states and geometries. Modeling results indicate that the opening of a tensile hydraulic fracture is accompanied by millimetre-scale shear displacements associated with slip and wedging between adjacent blocks. This may leads to a mismatch between the upper and lower walls of the fracture if asperities are irregular and strong enough. However, fluid-induced tensile fractures have low Joint Roughness Coefficients (JRC), and associated millimetre-scale shear displacements are too small to ensure a significant offset of asperities that prevent a fully-elastic closure when the hydraulic fracture is depressurized. Injection of proppant is thus critical to keeping hydraulic fracture apertures open. Future work is planned that will see the models calibrated against field data including microseismic event locations, magnitudes and source mechanisms, tiltmeter deformations, stress change, and pore pressures.

Jan 1, 2015

By Richard L. Fowler

[Study and development of sensing techniques and sensors were performed to aid shuttle car drivers in detecting, obstacles and in guiding the car along the face haulage route. Microwave, acoustic, and optical sensing techniques were considered as part of the feasibility study for obstacle detection. Various guidance techniques, including wire-following and rib-ranging were investigated. Active optical sensing was selected for obstacle detection to obtain the bear overage and sharp angular cutoff characteristics required within the packaging limitations defined by the shuttle car configuration. Rib-ranging guidance was selected to achieve completely self-contained shuttle car system which responds to the mine geometry without need for wires, stripes, or other path defining devices. Extensive hybrid computer simulation runs were performed to valuate various guidance techniques during the feasibility study. Subsequent simulation rues were performed to establish parameter values for the rib-ranging guidance system. The obstacle detection and guidance system was designed, fabricated and installed on a standard shuttle car. The system satisfied all applicable permissibility requirements of Schedule 2G. An experimental permit was issued to Bendix for operation in an underground coal mine. System evaluation tests were performed first above ground at the Bendix Research Laboratories. The simulation model was validated by these runs. Final testing wan performed underground in an operating mine with an experienced shuttle car driver. All sensors successfully demonstrated Chi predicted performance capability during underground face haulage tests. Dust did not Impair system performance and lens cleaning was not required during working shifts. Further development is required to achieve the desired obstacle detection performance Closed loop steering control with manual override is recommended o: mended for the lateral guidance e system. The guidance system should be an invaluable aid to low-coal shuttle car drivers where continuous mining machines are utilized.]

Jan 1, 1973

By D. Gagnon, B. Dubreuil, J. -M. Lalancette, D. Lemieux

"The pilot scale extraction of gold with a brine of sodium chloride and bromide at 30 ºC, in an atmosphere of halogens at atmospheric pressure, leads to gold chloride with 95% gold recovery. The use of dilute hypohalites (1 – 3%) instead of free halogens, which is strong enough to oxidize hypobromite into bromine, simplifies the recycling of halogens by electrolysis. With the recycling of water and brine, the regeneration of hypohalites and with a barren solid that is inert and stable. The Nichromet Extraction technology is a green process where the protection of the environment does not preclude profitability.INTRODUCTIONThe use of chlorides for the extraction of gold predates the discovery of chlorine by Scheele in 1774. In the Plattner chlorination process (Christy, 1888) sodium chloride and copper salt were used to promote gold recovery by amalgamation with variable results. The introduction of the cyanide technology in 1889 has led to a general use of this method for gold recovery. In the last decades, a return to chlorine in extractive processes has been noted (Ferron, Fleming, O’Kane and Dreisinger, 2002), mostly because of environmental pressure for non-cyanide technologies.This paper describes a closed circuit proprietary approach (Lalancette, 2009) developed and piloted by Nichromet Extraction Inc. for the extraction of precious metals with recycled mixed halogens; chlorine and bromine from hypohalites. DESCRIPTION OF THE PROCESSThe attack of gold by halogens can vary significantly. The rate of reaction is substantially higher with bromine (Br2) than with chlorine (Cl2), by a factor of more than five, although the oxidation potential of Cl2 is higher than Br2, as shown in Equation 1a and Equation 1b (Latimer, 1952)."

Jan 1, 2012

By Haipeng Li, Jacob Masliyah, Barun Gorain, Jian Huang, Qingxia Liu, Zhenghe Xu, AuTec Innovative Extractive Solutions Ltd.

"Froth flotation is widely used to selectively separate one or more minerals from an ore over a wide range of particle sizes with high efficiency. Bubble–particle attachment is one of the most critical steps in flotation. The objective of this project is to demonstrate the need for an innovative dual bubble generator to improve flotation efficiency. This dual bubble generator was designed to generate two different sizes (micron size and typical flotation size) bubbles. The micron size bubbles generated on the crevices of particle surfaces in venturi type of cavitation tubes enhanced the attachment of fine particles to the bubbles in conventional flotation systems. They also acted as a secondary collector, which has the potential to reduce operation cost and improve flotation recovery. The dual bubble generator was evaluated for a double refractory gold ore with 3g/t Au, 1.5 wt% TCM (total carbonaceous matter) and 0.7 wt% sulfides. The results were compared with those obtained using a commercial bubble generator. Compared with the commercial bubble generator, the dual bubble generator showed not only a higher gold recovery, but also an improved separation efficiency, demonstrating the potential of dual bubble generator in fine particle flotation.INTRODUCTIONFroth flotation has been widely used in mineral processing and waste water treatment. However, flotation has been proven inefficient for fine particle recovery although it becomes increasingly inevitable to process fine particles with the depletion of easy processing ores. The critical problem of fine particle flotation is the low attachment of fine particles to flotation size bubbles due to their low collision rate. Based on a commonly acceptable flotation model given by R =F*[Pc*Pa*(1-Pd)], the probability of bubble–particle collision (Pc), attachment (Pa) and particles detachment from air bubbles (Pd) collectively determines fine particle recovery (R) (Yoon and Luttrell, 1986). Since Pc = (3Dp/Db) where Dp and Db are diameters of particles and bubbles, respectively, bubble size and particle size impact the bubble-particle collision in opposite directions. It is evident that the probability of bubble–particle collision decreases with decreasing the size of particles, leading to a low recovery of fine particles. In this case, reducing the bubble size and/or increasing the apparent size of particles by fine particle aggregation are clear means to improve fine particle recovery."

Jan 1, 2016

By J. B. Scott

"A computerized cost estimating program developed with the use of the Lotus 1-2-3 spreadsheet program has produced dramatic savings in preparing estimates for operating costs, equipment fleet size and manpower requirements for underground mines.The program is used by Dynatec to support its consulting engineering projects, particularly feasibility studies. The 'first principles' approach is used to prepare detailed estimates under direct labour and supplies categories and maintenance costs for each mining operation . User notes have been developed to guide the estimator and ensure appropriate consideration is given to the specifics of the particular mine.A typical case history is illustrated and the ease by which alternatives and sensitivity analyses can be prepared is demonstrated. IntroductionHistorical MethodsMining engineers have used one or a combination of methods to prepare operating cost estimates for new or existing mine s. Operating companies have access to historical cost data and generally use this for preparing estimates. Consulting engineers do not usually have direct access to such information and must rely on mining companies (the present or previous clients); publications (text books, equipment manufacturers manuals, CMJ reference manual, etc.); annual reports (applicable to public companies); previous studies (to be used with caution as conditions change from mine to mine); and first principles (the subject of this paper), for cost information:Definition of First PrinciplesA first principles approach to cost estimating considers individual primary work elements of an operation. Quantities of work items are developed from the mine plans, production rates, geographic and physical layouts etc. The knowledgeable estimator, assisted by experienced operations personnel, can assign appropriate resources (equipment, labour, supplies and services) to each work element and establish productivities. Completion of the cost estimate is then largely arithmetic."

Jan 1, 1988

By Andrzej Warczok

Intensive smelting of copper concentrate in Teniente Converter (CT) leads to the production of high grade matte and highly oxidized slag. Smelting slag is processed in Teniente vascular slag cleaning furnace. The slag composition and forms of copper affect the slag cleaning process and final copper content. Converting of high grade matte in Pierce-Smith converter faces some difficulties in proper slagging of iron oxides. Overblowing in copper making stage allows for slag liquidation but leads to high content of copper oxide in converter slag. Converter slag recycling into CT results in the increase of the participation of oxidic copper. Separate treatment of converter slag and its impact on the forms of copper in CT slag has been analyzed. Thermodynamic properties of a system and kinetic limitations pointed out the negative effect of converter slag recycling on the forms of copper and copper recovery in slag cleaning stage. Experimental results of slag cleaning tests in a crucible scale as well as microscopic examination of laboratory and industrial slag samples supported the above analysis and permitted to formulate recommendations of separate processing of converter slag. Keywords: copper, losses, slag, recycling

Jan 1, 2001

By Jintao Gao, Zhancheng Guo, Chong Li

A new approach to enrich MFe and RO phase from the converter slag by super gravity was investigated. The samples obtained by the gravity coefficient G=600 and cooling rate V=5K/min from 1623K to 1373K appeared significant stratification and the MFe gathered at the bottom of sample. With the help of metallographic microscopy and X-ray diffraction, it is found that large quantity of white RO phase gathered at the lower part of the sample as the concentrate, with volume fraction appearing gradient distribution along the direction of super gravity, while the upper part was mainly composed of dicalcium silicate as the tailing. The mass fractions of the FeO, MgO and MnO in the concentrate are up to 40.46%, 6.9% and 3.91%, while that in the tailing are just 11.65%, 2.15% and 1.55%. The recovery ratios of FeO, MgO and MnO in the concentrate are 60.35%, 58.45% and 72.24%, respectively.

Jan 1, 2016

By R. W. Raymond

(Pittsburg Meeting, March,1910.) THE Giroux Consolidated Mines Co. is equipping a five-compartment shaft at Kimberly, Nev., which will serve the Alpha mice. The depth of this shaft, January, 1910, is 963 ft., and of this depth 948 ft. was opened by raising, 15 ft. of sinking was done so that the bearers, collar-set, and three shaft-sets might be installed and concreted, and with this done it was possible to erect the necessary surface-equipment for resuming shaft-timbering on the completion of the raise. The arrangement of the shaft-timbering is shown in Fig. 1. At the 1,000-ft. level of the Alpha, and 750 ft. SW. from the Alpha shaft, a 14- by 18-ft. station was cut, and a 25-h-p. air-hoist *as installed. From here the raising commenced on July 5, 1909. The raise was cut approximately 13 by 21. ft. in area, and supported by timbering with square sets, illustrated in Fig. 2, which shows the division into four compartments. The end compartments, which were used as chutes, had the center girts heavier than in the others on account of the wear from falling rock. The chute-lining was braced by inserting 8- by 8-in. stiffeners parallel to and half way between successive caps. Similarly, the lagging on the wall sides of the cage-way and the compartment for pipes and ladder was stiffened with 4- by 6-in. timbers. In the pipe-and-ladder compartment the chute-stiffeners were reinforced with 8- by 8-in, struts, and as the cage-way was partitioned off by braced lining, there was practically no chance of rock entering the ladder-way in case a chute burst into the cage-way. Over the two center compartments the last two, sets were always bulkheaded with 8- by 12-in. timbers, shown in Fig. 3, and from the lower bulkhead the cage sheave-wheel was suspended. After a round of holes had been blasted and the loose

Jun 1, 1910

By Ross Cutts

As a public servant geotechnical engineer, I observed how costly and valuable geotechnical field explorations are to the success of every project. Often however, the field exploration is a long and complex process that is made less efficient by the difficulty of retrieving and utilizing nearby internal or external historic geotechnical datasets. As an employee of a public agency, we would often start our investigations for every project from scratch, given the difficulty of locating and utilizing historic geotechnical data. This is an ethical and technical failing of our profession. When we start subsurface explorations from scratch, not only do we often duplicate investigations, we are also likely defaulting to reapplying tradi- tional test methods that yield con- servative geotechnical parameters, resulting in overly conservative and potentially costly construction. To address this issue while working as a public servant, I started a research program with Yunfeng Zhang, Ph.D., of the University of Maryland, to build a tool that could compile internal historic geotechnical data and extract additional value from it, using machine learning. This tool was able to provide, upon request, nearby historic geotechnical data, estimated soil parameters and recommendations for geotechnical test methods best suited for a given project site. This prevented common field ex- ploration problems such as, requesting duplicate data, requesting test methods that were not applicable for the project geology, not realizing presence of karsts, missing permits for wetlands, private property and others. This tool allowed for more efficient field investigations with regards to time and money saved. There was one problem with this tool: it could only be used by internal employees of a single state's depart- ment of transportation (DOT) for which this data was compiled. I realized at that point that it would be of tremendous value to make this concept universally accessible to the geotechnical engi- neering profession. I left public service to devote time to building a platform that would host historic geotechnical data from publicly funded sources throughout the country. The tool I helped build as a public servant was the foundation of Geosetta, a nonprofit company dedicated to serving the geotechnical profession. The nonprofit structure was adopted to prevent acquisition by a for-profit company and to ensure that Geosetta remains an independent steward of our profession's valuable data. Geosetta provides a GIS (geographic information system) platform that enables users to view historic geo- technical data and extract value from it with machine learning-based predictions and visualization tools. This data is provided in an open and interchangeable format called DIGGS, which stands for Data Interchange for Geotechnical and Geoenvironmental Specialists, making it easy for users to integrate it into their workflows. Geosetta is collaborating with the American Society of Civil Engineers' Geo-Institute and other sponsors to extract public data at no cost to the agency and provide the profession with free access to the existing data and access to advanced tools through a subscription to support the nonprofit mission.

Nov 1, 2023

By Robert Bittner

The following is a report on the development of two unique and separate cofferdam systems used in the construction of the marine foundations for the I-205 Columbia River Bridge at Portland, Oregon for the Oregon Department of Transportation. The first of these two systems utilized interlocking H-pile 100 ft long to form a cofferdam 145 ft by 58 ft in plan and 100 ft deep. The second system consisted of two immense bell shaped steel forms. The larger of the two forms was 83 ft by 66 ft in plan, 62 ft high and weighed 450 tons. This form was externally stiffened for a designed hydrostatic head of 54 ft. Both forms were designed, except for the top 14 ft, to be set and stripped in one solidly welded unit. The supporting geological formation for the bridge foundations is the Troutdale, a cemented sand and gravel. This formation is at the ground surface on the Washington Shore and slopes downward to a depth of 115 ft below normal high water at about mid-channel. In this area the Troutdale formation is covered with a layer of fine to medium sand 90 to 100 ft thick. It was the variable depth of the Troutdale which determined the two types of foundations and the corresponding to the two cofferdam systems.

Jan 1, 2013

By Jack L. Henry, Davis E. Traut, L. R. Penner

The Bureau of Mines conducted solvent extraction batch tests to evaluate the usefulness of neodecanoic acid ( NDA) for extracting Co 3+ from ammoniacal leach liquors high in ammonium sulfate . This work is an outgrowth of previous Bureau research in which technology was devised for the recovery of cobalt , nickel , and byproduct copper from domestic laterites . The previously devised technology uses an oxidative ammoniacal sulfate leach to treat the laterite , and nickel and copper are then recovered from the leach solution by solvent extraction and electrowinning . This report deals with the subsequent solvent extraction of cobalt from the nickel - copper raffinate solution . The results showed that about 70 pct of the contained Co 3+ can be extracted batchwise at pH 8 using NDA ( a 10 - carbon - chain highly branched carboxylic acid ) . However , NDA had a solubility of approximately 0.6 to 0.8 g / L in aqueous raffinate following extraction , and this high solubility makes it impractical for use with alkaline solutions that are low in cobalt . In addition , the extracted cobalt species ( predominately cobaltic hexammine ) is not amenable to the electrolytic recovery of cobalt metal because of its extreme stability . This fundamental prob-

Jan 1, 1965

By J. F. Breedis

The stabilization of austenite in Fe-Ni alloys against martensitic transformation after reversion has been attributed' to the lattice imperfections remaining from previous transformation. More recently, however, such stabilization has been associatedzy3 with compositional changes which occur in martensite during slow heating. Dislocation arrangements in deformed austenitic stainless steels strongly influence transformation to martensite on quenching.4 Therefore, it is of interest to observe the transformation behavior of stainless steel after reversion, especially since previous studies have been confined to Fe-Ni alloys. The transformation-product morphology also differs in the two iron-alloy systems;6 plate martensite forms in the latter while stainless steel transforms to lath-type martensite. Samples of Fe-16 wt pct Cr-12 wt pct Ni (maximum C + N = 0.005 wt pct, 0 = 0.02 wt pct), prepared by vacuum melting and casting from high-purity components, were annealed at 900°C for 24 hr, after cold rolling to produce a 40-p grain diameter. The M, temperature of this alloy is -80°C and samples are fully austenitic after annealing. The amount of martensite present after quenching, annealing, and requenching was determined magnetically, to within 0.01 wt pct, using a vibrating specimen magnetometer. Nearly 14 pct of martensite forms during the initial quench in 1 min at -196°C. Two-min and 2-hr anneals were done in air and in evacuated quartz capsules, respectively. All specimens were electro-polished before making the magnetic measurements.

Jan 1, 1967

By Z. Yang, R. W. Smith, Jr. Wharton

"Microorganisms have the ability to remarkably adsorb and/or absorb heavy metal ions. Hence they are being studied widely as a means of removing metal ions from aqueous solutions both in order to clean up toxic streams and to recover valuable metals from these and other streams. It is often difficult to harvest organisms such as bacteria and unicellular algae since they are usually too small to be readily screened out. Froth flotation may prove to be a feasible method to harvest such organisms subsequent to the ad/absortion of the metal Ions. The present paper discusses the surface/electrokinetic properties of microorganisms and the modifier-collect conditions under which they should float. The zeta potential of the green alga Chlorella vulgaris was measured in the presence of AI(III) and Pb(II) ions and in the presence of dodecylammonium chloride and sodium dodecylsulfate. Present and past data suggest that the organisms should behave similarly to other finely divided, charged (polar) solids with their behavior sometimes modified by the non-polar surface regions present.IntroductionThe overall field of bioengineering is growing at a remarkably accelerating rate. Hydrometallurgy and mineral processing are included among those disciplines where there has been actual or proposed commercial use of bioorganisms. Further, the actual or proposed use includes bacterial enhancement of leaching of a number of different types of ores (1-5), modification of the flotation or oil agglomeration separation of minerals by bacteria (6,7) and microorganism (algae, bacteria or fungi) concentration of metal ions present in effluent or other mineral processing or hydrometallurgy aqueous streams (8-23)."

Jan 1, 1988

By G. E. Johnson

LEAD SMELTERS AND REFINERS in 1932 were confronted with the problem of adjusting operations and costs to curtailed production and consumption at reduced prices, a problem which has been partially solved at least by improvements in operating technique and increased efficiency. At the Mount Isa properties in Australia, a third blast furnace and additional Dwight-Lloyd sintering machines were installed during the year, designed to increase the production to 6,000 tons of bullion per month. The large proportion of lead carbonate in the ores to be treated has presented metallurgical problems. Of the total lead contained in the concentrates to be smelted, two-thirds is Dresent as carbonates and one-third as sulfides. In the iiitial operations, the resulting Dwight-Lloyd sinter was soft, contained an excessive amount of fines, and was easily fusible. When charged to the blast furnaces it developed accretions in the upper part of the furnace owing to the easily fusible lead carbonates softening and fusing at the top of the charge column. This was remedied by the addition to the sinter feed of diluents of higher melting point, granulated slag and crushed limestone. The sinter feed consists of concentrates, Cottrell dust and wind-box cleanings, totalling 57 per cent of the charge; return sinter fines 15 per cent; granulated slag 23 per cent; and crushed limestone 5 per cent. The sinter produced contains 34 per cent lead and 0.5 per cent sulfur. Experiments indicated that double sintering under these conditions was of no advantage, so the original plan of single sinter treatment was retained.

Jan 1, 1933

By Charles B. Forgan

THE Stan Trg ore body now being exploited by Trepca Mines, Ltd., originated by the metasomatic replacement of limestone and consists mainly of an intimate mixture of sulfides associated with little admixed gangue. The chief sulfides are galena, marmatite, pyrite, and pyrrhotite. Geological structure, embracing both igneous and sedimentary agencies, exerts important control on ore deposition and presents many features of great interest. Geological Formations and Intrusives Stag Trg Series-The dominant formation is the Stan Trg series, which

Jan 1, 1936

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. DPM exposure is therefore regulated by the U.S. Mine Safety and Health Administration (MSHA). The current monitoring process takes days or weeks for exposure levels to be known, and a real-time monitoring device is needed. It is believed that infrared spectroscopy has potential for use in a real-time, field-portable device. This paper presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. 

By M. Bennett, L. Twidwell

Montana Tech has embarked on a coordinated series of studies to delineate the characteristics of the Berkeley Pitlake containing over 36 billion gallons of acidic, metal-contaminated water formed after the cessation of open-pit copper mining in Butte, Montana, USA. The objectives of the overall series of studies are to summarize presently available information and to generate new and needed information to formulate a conceptual environmental model for the pitlake and to provide characterization data for the development of advanced treatment technologies. In this presentation, the chemistry of the Berkeley Pitlake water is partially reviewed. It is known that the pitlake consists of two distinct layers of water referred to as surface and deep water. Samples of deep water were collected and placed in a 12-ft high and 6-inch diameter column and exposed to different wavelengths of UV radiation as well as atmospheric conditions. Measurements of pH, redox potential (EH), dissolved O2, turbidity, conductivity, temperature, and elemental composition show that the water reacts differently and indicates that the diurnal effects of sunlight likely play a major non-biological role in its chemistry. Resulting technology could be useful for developing an alternative to treating acid-rock drainage.

Jan 1, 2007

Forecasting, particularly when applied to meaningful issues, is known irreverently as 'futurology'. There is quite a range of opinion ext.ant in the world when mineral resources are looked at. The opinions range from the doomsday view that there will be acute shortages of all essential commodities, to the optimistic outlook that new 'discoveries will prevent any possibility of shortages. The environment is, as yet, only studied locally and quite parochially; surprisingly there is little integration when considering the spatial atmosphere, the seas in depth and the earth's crust.

Jan 1, 1981