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By Q. Liu, P. Katsabanis, J. A. Meech

A thermohydrodynamic computer code has been used to simulate dust explosions. For sulphide dusts, the thermodynamic predictions are used to investigate the effect of dust concentration, mineral content and inert materials as well as the quantity of sulphur dioxide produced. It was found that the amount of oxygen available for the explosion is very important and that the dust concentration which gives maximum explosion pressures is obtained at zero or slightly negative oxygen balance values. The sulphide minerals were found to have the following explosibility sequence: pyrrhotite, pyrite, chalcopyrite, sphalerite, covellite, chalcocite and galena, which is in agreement with mine experience. The results show that theoretical calculations can be used to predict explosion pressures and toxic gases produced by a dust explosion and therefore they can assist in the design of protective measures .

May 11, 1988

By Aidan Giblett, Michael McGlynn, Peter Radziszewski

"On the basis that 99% of the energy input into a mill is converted into heat, it is possible to estimate the amount of energy captured in the slurry, the amount that is lost to the environment as well as the possible means to reduce such losses. As a result it becomes possible to estimate the potential amount of energy that can be captured by technologies such as thermoelectric generators or even Sterling engines. Furthermore, it has been suggested that the energy recovery potential dry grinding circuit could be as high as twice that of wet grinding circuits.In this paper, the energy recovery potential of dry grinding will be explored by examining the case of the Newmont Carlin mine dry grinding circuit. The paper will open with a review of the energy recovery potential of a few wet grinding applications followed by a description of the dry grinding circuit and a definition of the control volume around that circuit. A thermodynamic model will be used to estimate the circuit discharge temperature and an estimate of any losses as well as provide an estimate of the potential impact of different means to reduce energy losses. The paper will close with a discussion of the assumptions used in model development."

Jan 1, 2016

By Oleg G. Tovmachenko

We have studied optical properties of fluorescent nanoparticles. These particles consist of a metal (gold/silver) core, an empty and a dye labelled silica shells. The different dye molecules with moderate quantum yields (about 0.3) has been used. Almost all of types of nanoparticles show fluorescence enhancement. This enhancement is strongly dependent on the degree of the overlap between the surface plasmon band of the metal and the absorption/emission band of the dye molecules. The results are interpreted in terms of competition between local field enhancement and quenching of fluorescence by the metal surface.

Oct 1, 2003

By Y. Wang, S. Liu, K. Jiang

China is the world’s largest producer and consumer of non-ferrous metals. In recent years, significant progress has been made in research and commercial application of pressure leaching technology to produce some nonferrous metals. Research and development activities include a low-pressure, low-temperature leaching technology for complex copper concentrates, a hematite process to treat pressure leach solutions from zinc concentrates, and a pressure leaching - solvent extraction process for molybdenum and rhenium. Examples of commercial practices include a two-stage pressure leach technology in a zinc plant in Danxia, a direct leaching technology in a zinc plant in Zhuzhou, a high pressure acid leaching process for a nickel laterite project in RAMU, and a pressure leaching technology to treat arsenic sulfides in a plant in Guixi. The development of pressure leaching technology for the recovery of lead, vanadium, gallium, germanium, and precious metals in China will also be described in this paper.

Jan 1, 2015

By Alan A. Barton

Introduction The Little Long Lac mine is situated in the Thunder Bay mining district, township of Errington, Ontario. The mine is located on the south side of the most westerly bay of Little Long Lac. The property consists of 36 claims, which comprise some 1,400 acres. This group of claims was staked in August, 1932, by Tony Oklend and Tom Johnson, and, after surface sampling, was optioned by the present controlling interests, who diamond-drilled it during the winter of 1932-33. In early spring, a small steam-driven plant was installed, and shaft sinking commenced on June 1st, 1933. During the summer, all supplies are transported to the mine from Hardrock station, at mileage 18 on the Canadian National Railway line from Longlac to Port Arthur. At Hardrock, which is seven miles from the mine, the railway skirts a bay of Little Long Lac, and supplies are loaded directly from railway cars to scows. Two scows are used, of 30-and 45-ton capacity, respectively. A 36-ft. pointer, powered by a 35 h.p. engine, is used as a tug. A good winter-road has been cut out from Geraldton to the mine, for winter transportation. Geraldton is about two miles north of the mine, and is also located on the Canadian National railway. A hard-surface road is now being constructed for summer as well as winter use. Geology The Little Long Lac gold area covers the northern limits of a large synclinal structure, the contact of the Keewatin flows and sediments, striking about twenty degrees north of west, with the dip of the sediments varying from eighty degrees north to seventy degrees south, the average being around eighty degrees south. The vein worked by Little Long Lac Gold Mines occurs in massive sedimentary rock of about the composition of arkosic or quartzitic greywacke, and consists of a shear-zone up to fifteen feet in width, striking N.75°E. and dipping steeply to the south, which has been filled by numerous narrow, parallel quartz veins and. veinlets. These are well mineralized. with arsenopyrite, pyrite, and some chalcopyrite and stibnite, and carry considerable quantities of visible gold. They show more than one age of quartz deposition, the quartz being fractured and re-cemented. The arkosic rocks separating the veins and veinlets are also slightly mineralized with pyrite. Work to date has indicated the probability that the vein-shear is controlled by local drag-folding.

Jan 1, 1935

By S. k. Kim, H. B. Trinh, R. R. Srivastava

"Spent auto-catalyst is a promising secondary resource of platinum group metals (PGMs), which are being extensively used in automobiles catalytic converters to control the hazardous gaseous emissions (CO, NOx and hydrocarbons). Several pyro or hydrometallurgical routes has been employed to recover PGMs from such spent materials but there is no proper process for recovering the other constituents metals. Therefore, it causes the loss of other major constituents like, Al and Mg along with rare earth metal Ce. In the present study, we investigate the dissolution of Al and Mg using sodium hydroxide (NaOH) roasting followed by a sulfuric acid (H2SO4) leaching; thereby concentrating the PGMs and Ce in leached residues. The effect of roasting temperature, time and amount of NaOH were varied. Subsequently, the dissolution behavior of metals in H2SO4 as a function of acid concentration was investigated from the roasted samples. At an optimal condition for roasting at 600°C with 1:1 NaOH-to-catalyst ratio and 60 min duration, the maximum of Al and Mg were dissolved in 1 M H2SO4 solution at ambient temperature (~25°C). Thus obtained leached residues containing enriched PGMs and Ce content can be treated separately for the recovery of these high-value metals.INTRODUCTION Spent auto-catalyst has been considered as a potential resource for recovering the platinum group metals (PGMs) (Jha et al., 2013). The commonly used auto-catalyst is made of cordierite (2MgO.2Al2O3.5SiO2) in which the chloro complexes of PGMs are impregnated onto the surfaces of porous washcoat of alumina substrate (Aberasturi et al., 2011). The average concentration of PGMs in ore are 2-4 g/ton for Pt, 7-2 g/ton for Pd and 0.2-0.5 g/ton for Rh, whereas, an individual catalytic converter weighing about 1 - 2 kg contains on average 1.56 g Pt, 0.62 g Pd and 0.156 g Rh (Upadhyay et al., 2013). Moreover, recovery of PGMs from spent auto-catalyst offers other advantages like, simple process, low cost and less pollution, as compared to recovery from primary resources (Dong et al., 2015).Therefore, technologies to recover PGMs from spent auto-catalyst has become attractive in the recent past and their recycling contribution has been accounted for 35% Pt, 26% Pd and 36% Rh of the quantity consumed in the production of auto-catalysts (Johnson Matthey, 2016)."

Jan 1, 2017

By Robb. V. M., F. Walraven, L. J. Robb

"Abstract -The old Albert Silver Mine is a polymetallic deposit comprising concentrations of Cu­ Pb-Zn-Ag-U-F within a set of sub-parallel quartz-hematite veins which occur within the fine-grained apical phase of the 2050 Ma old A-type Bushveld granites. Mineralization occurs as an early pyrite­ chalcopyrite-arsenopyrite-galena-sphalerite-(argentiferous) tetrahedrite paragenesis followed by a later, more oxidized assemblage comprising chlorite-hematite-fluorite-pitchblende. Accumulation of metals appears to have taken place at the interface between a coarse-grained porphyritic granite and an overlying fine-grained phase: veins occur in the latter and represent leakage of magmatic fluids from the differentiated, water-saturated, subjacent granite.Mineralization processes in the Bushveld granites are believed to be related to long-lived circulation of dominantly magmatic fluids stimulated by the high heat productive capacity of the host rocks. Endo- and exogranitic tin-tungsten and base metal mineralization formed during an evolving hydrothermal system that lasted for several hundred million years, forming innumerable small- to medium­ scale polymetallic deposits. At the Albert Silver Mine, unroofing of the cover sequences at circa 1600 Mato 1700 Ma resulted in the incursion of lower-temperature, high-f02 meteoric fluids which remobilized the earlier sulfides and introduced the paragenetically late U-F mineralization ."

Jan 1, 1994

By Stefan Boshkov

THE ADVENT of mining at great depth has brought to the fore the question of stresses around mine openings. The many-pronged attack on this problem is certified by the accelerated appearance, in the mining literature, of articles on various topics related to this subject (1). Whereas it may be agreed that we, of the mining profession, have fallen woefully behind in research and the development of an understanding of this important facet of the general problem of mining, it must also be accepted that the analysis of the stresses in a mine structure is usually more complex than is the case in the majority of structures encountered and dealt with in civil engineering. Whereas homogeneity and isotropy are readily acceptable for most metals, such properties are but crudely approximated in rocks. Whereas the external loads on a structure in civil engineering may be readily determined, those on a mining structure are subject to ?conjecture. Whereas the limits of the structure may readily be defined in civil engineering, the boundaries of the mining structure are, in most cases, indeterminate, and subject to intelligent guesswork, at best.

Jan 1, 1956

By Long Han, Beijing General Research Institute of Mining and Metallurgy, Yu Xie, Yunhai Zhang, Yangge Zhu, University of Science and Technology Beijing, Yanbo Shang, Xingrong Zhang

"The first-principles method was employed to study the adsorption of hydroxyl calcium (CaOH+) and hydroxyl (OH-) on hematite and quartz surfaces. The calculation results suggested that OH- preferred to interact with the active Fe sites on the hematite surface, whereas OH- adsorbed on the quartz surface by weak hydrogen bond. Though CaOH+ could easily adsorb on the hematite and quartz surfaces by the formation of Ca-O bond, the covalence formed on the quartz surface was apparently stronger than that on the hematite surface, meaning a stronger and more stable adsorption. CaOH+ adsorbed on quartz surface was mainly through the interaction of O-2p and Ca-3d states, and this interaction on hematite surface was weaker.INTRODUCTIONIron Increase and Silicon Reduction Technology (Yu & Duan, 2002) of hematite is mainly through the reverse flotation (silica is floated away from the iron concentrate). There are two ways to achieve this (Houot, 1983). One is to collect quartz by cationic collector directly; the other is to activate quartz by lime and then collect it by anionic collector. There are two main different views with respect to the mechanism of quartz activation: mono-hydroxyl compound theory (Fuerstenau, Rice & Somasundaran, 1965; Fuerstenau & Palmer, 1976) and surface hydroxyl precipitation theory (Hu & Wang, 1988; Wang & Hu, 1990). The former indicated the formation of the mono-hydroxyl complex is one of the two criteria of quartz flotation. The later theory, on the other hand, suggested that surface precipitation is the adsorption of active species of metallic ion on quartz surface. However, most of those researches are based on the solution chemistry of flotation and little is done at the microscopic level.In this paper, by the help of first-principles calculations, the adsorption models, bonding conditions, Mulliken charge populations and adsorption energies of hydroxyl and calcium hydroxyl ions (OH- and CaOH+) on hematite (001) and quartz (100) surfaces were investigated to find out the lime activation of quartz at atomic level, which is significant for the researches of quartz activation theoretically and practically."

Jan 1, 2016

By C. F. Chung, F. P. Agterberg

"Prediction of a variable sulphur content in Cape Breton seams is important for planning the production of a highgrade metallurgical coal. Two extrapolation methods (Kriging and a version of Universal Kriging) to predict sulphur content in blocks of coal before mining are presented and applied to the New Lingan Mine reserves in the Harbour seam. The uncertainty of the predicted values is expressed by using standard deviations. Some statistical results for the Phalen seam, which occurs about 400 ft below the Harbour seam, are presented for comparison. The two mathematical models consist of two sets of equations which have been used in computer algorithms. Some limitations of the present approach and possibilities for further statistical work are indicated."

Jan 1, 1973

By P. C. Parsons, G. C. Milligan

"IN FIELD WORK in the Cape Breton Highlands, which are heavily covered with vegetation, it is necessary to run traverses along the valleys of small brooks. We encountered difficulty in closing such traverses, and the following technique was developed to solve this problem. It has been tested in the field for four seasons by several people, and found to be simple, efficient and more accurate than any other compass-and-pace system of which we are aware. So far as we can find, the technique has not been described previously. It may be of use to others.The Cape Breton Highlands of Nova Scotia consist of hills of old intrusive and metamorphosed sedimentary rocks protruding up to 1,000 feet above the general level of the younger sediments which underlie the valleys. The flat hill-tops are the remnants of a plateau; drainage off the edge of this plateau has produced many small steep brooks. They occupy valleys which are up to 800 feet deep, and V-shaped in cross section, with steep sides covered by mixed conifers and hardwoods. The stream at the bottom is rarely more than a few feet wide, with a negligible meander belt, but with many bends, rapids and falls. Visibility along the stream, in consequence, is rarely more than a few hundred feet, and in many places much less.It was found impractical to map the streams by the method of meander lines, as described in many standard surveying texts and hand-books. The limited visibility, and the numerous bends of the brooks, necessitated many corners. Every corner introduces errors. To 'close' a survey with 40 or 50 such corners proved either very time-consuming or impossible. In most cases, however, the general direction of a valley may be obtained from an aerial photograph, or by direct observation, and this became the basis of the method adopted."

Jan 1, 1971

By Daniel J. Schulze

Abstract-Eclogite is an important source of diamond in the upper mantle, but is more localized than peridotite. Using eclogitic minerals in kimberlite and diamond exploration is also more problematic than using the well-known peridotite-derived indicator minerals Cr-pyrope and magnesiochromite. The problems include color similarities between orange garnets from eclogites, Cr-poor megacrysts, and crustal garnets, chemical similarities with Cr-poor megacryst suite garnets (specifically elevated Na2O contents), and low abundance of eclogite garnet xenocrysts in most known kimberlites. Chemical screens must be used carefully to distinguish between varieties of orange garnets in exploration samples. For example, most orange garnets of crustal origin have >22 wt% FeO, with mantle eclogite garnets having lower values. Na2O-bearing garnets from the Cr-poor megacryst suite can be distinguished from Na2O-bearing garnets from diamondiferous eclogites by the elevated TiO2 contents of the former. The low abundance of eclogite garnet xenocrysts in kimberlites worldwide, however, may dictate that use of eclogite garnets in diamond exploration in most cases be restricted to advanced stages of kimberlite exploration and evaluation of kimberlite diamond potential. Crpyropes, Mg-ilmenites and Cr-rich chromites are more useful than eclogitic garnets in most stages of diamond exploration. If orange garnet xenocrysts are sought in a kimberlite exploration program, those from the Cr-poor megacryst suite will be more useful than eclogite derived garnets, due to the typical great abundance of the former, although they carry no information of the diamond potential of the host kimberlite.

Jan 1, 1997

By Daniel J. Schulze

Eclogite is an important source of diamond in the upper mantle, but is more localized than peridotite. Using eclogitic minerals in kimberlite and diamond exploration is also more problematic than using the well-known peridotite-derived indicator minerals Cr-pyrope and magnesio-chromite. The problems include color similarities between orange garnets from eclogites, Cr-poor megacrysts, and crustal garnets, chemical similarities with Cr-poor megacryst suite garnets (speci?cally elevated Na2O contents), and low abundance of eclogite garnet xenocrysts in most known kimberlites. Chemical screens must be used carefully to distinguish between varieties of orange garnetsin exploration samples. For example, most orange garnets of crustal origin have >22 wt% FeO, with mantle eclogite garnets having lower values. Na2O-bearing garnets from the Cr-poor megacryst suite can be distinguished from Na2O-bearing garnets from diamondiferous eclogites by the elevated TiO2contents of the former. The low abundance of eclogite garnet xenocrysts in kimberlites worldwide, however, may dictate that use of eclogite garnets in diamond exploration in most cases be restricted to advanced stages of kimberlite exploration and evaluation of kimberlite diamond potential. Cr-pyropes, Mg-ilmenites and Cr-rich chromites are more useful than eclogitic garnets in most stages of diamond exploration. If orange garnet xenocrysts are sought in a kimberlite exploration program, those from the Cr-poor megacryst suite will be more useful than eclogite derived garnets, due to the typical great abundance of the former, although they carry no information of the diamond potential of the host kimberlite.

Jan 1, 1997

By B. A. Strathdee

An arsenical ore containing both pyrite and arsenopyrite was heated to a temperature at which decomposition and distillation took place. The condensate consisted of metallic arsenic and arsenic disulphide, although the analysis of the ore showed that volatile arsenic and sulphur were present in proportion to produce a condensate of arsenic trisulphide and sulphur. Distillation tests on the mineral arsenopyrite also produced a condensate of metallic arsenic and arsenic disulphide. This arsenic sulphide gave a distinct x-ray diffraction pattern which was not listed in the A.S.T.M. data file. This same sulphide can be produced by heating a mixture of arsenic and sulphur in vacuo. Its chemical analysis corresponds to As2S2. The dissociation pressures of arsenopyrite and the vapour pressures of arsenic disulphide and arsenic metal were measured, using a quartz "spoon" gauge. The dissociation pressures of arsenopyrite were compared with the published data for the dissociation pressures of pyrite to account

Jan 1, 1961

By E. Uzun

"In this study, H2SO4 and HCl leaching behaviour of an ore sample containing 1.87% of Ni, obtained from the Karaçam (Eskisehir-Turkey) lateritic deposit that started operation recently was investigated. Acid concentration, temperature and reaction time were investigated as variables by comparative leaching tests and the optimum leaching conditions were selected on teh basis of Ni, Fe, Co and Mg behaviour. For H2SO4 leaching, optimum leach parameters were 95°C, a 12 normal H2SO4 concentration and 90 minutes of reaction time, and under these conditions Ni and Fe dissolutions were 97.6% and 95.4% respectively. On the other hand, 70°C, an 8 normal HCl concentration and a reaction time of 90 minutes were found to be the optimum parameters for HCl leaching, and Ni and Fe dissolutions found were 97.1% and 97.8%, respectively.INTRODUCTION Today, nickel and various nickel compounds are obtained from sulphide and lateritic nickel ores (Moskalyk & Alfantazi, 2002). Even though about 72% of the world's nickel reserves constitute lateritic ores, only about 42% of nickel is produced from these ores. The decrease in production from sulphide deposits, on the other hand, and increases in the use of nickel in the iron and steel, and battery production sectors, and especially the production of nickel cast irons in recent years, have accelerated the importance of making use of lateritic deposits (Luo et. al., 2010; Chang et. al., 2010). In the beneficiation of sulphide nickel ores, mostly pyrometallurgical methods are used. On the other hand, about 39% of lateritic ores are beneficiated by pyrometallurgical, and 61% are beneficiated by hydrometallurgical methods (USGS, 2009). In laterite beneficiation, the ore properties are of significance; that is to say, limonitic ores are eneficiated by high pressure acid leaching or via the Caron process, nontronitic ores are beneficiated by high pressure acid leaching or heat treatment (smelting), and ores containing serpentine by pyrometallurgical methods (Berezowsky, 2004; McDonald & Whittington, 2008a; Dreisinger et. al., 2015)."

Jan 1, 2017

By A. R. Sorta, D. C. Sego

ABSTRACT The settling, shear strength, and index properties of oil sands fines-sand mixture tailings (FSMT) for a wide range of solids and fines content are investigated. Results indicate that the liquid limit of FSMT obeys a linear mixture law. The fines-water ratio (FWR) governs the permeability of composite tailings (CT) and CT with comparable geotechnical behaviour can be produced from the same initial FWR mixtures. A phosphogypsum (PG) dosage > 900 mg/kg does not improve the dewatering behaviour of CT. The undrained shear strength of FSMT at the liquid limit is approximately 2.4 kPa, but is dependent on fines content at the plastic limit.

Jan 1, 2013

The original JKMRC AG/SAG mill model was developed over 30 years ago and has been upgraded a number of times since then, with the current published version being the Variable Rates model that is now over 15 years old. Since this model was developed further enhancements have been derived, some of which are applied in-house and some which have yet to be incorporated. The published and the commercially available model in JKSimMet is currently undergoing a comprehensive overhaul with a vastly extended data base for model evolution and validation. Improvements developed within the AMIRA P9 project, in-house development and a number of collaborative projects, are being incorporated into the upgraded model structure. Enhanced capabilities will include: power-based breakage rates scaling; a far wider mill filling range (from 10% to 40%) that exhibits peak in throughput as mill filling increases; higher ball loads; improved pebble discharge function; improved slurry discharge function incorporating important mill design and operational influences; and the new size dependent breakage function. The model will also be able to accommodate some influence of liner design and multi-component ores (blends of hard and soft components). This upgrade is still a work in progress but substantial changes have been made to date. This paper presents some of the new improvements and their influence on the predictive capability of the model.

Jan 1, 2012

By W J. Riva

This paper reviews the coal mining operations of The Canmore Mines, Limited, at Canmore, Alberta, paying particular attention to the use of this coal by the metallurgical and chemical industries. The characteristics of the deposits are outlined, and the mining and processing methods used are discussed. Introduction M INING in the Cascade coal area of Alberta began form-ally in 1886 when the Canadian Anthracite Coal Company was granted its charter. Earlier operations had been confined to prospecting and family-type enterprises serving the market area within barging distance on the Bow river. From 1886 to 1964, seven mines were opened between Banff and Ribbon Creek; six of these have since been abandoned, leaving the B c 0 L. original tenant, under the name of The Canmore Mines, Limited, as the sole survivor. The town of Canmore, hub of the mining ventures, is located on the main line of the C.P.R. and on the Trans-Canada Highway, 67 rail miles west of Calgary and 57 4 miles east of Vancouver, as shown in Figure 1.

Jan 1, 1965

By I. Le May

"The assessment of integrity in plants is discussed, together with the codes that are being developed for in service evaluation of engineering fitness for service. The use of Risk Based Inspection is described and some examples are provided of the evaluation of in service components in which flaws have been detected. An example of the assessment of the structure of a mine processing facility is described, and application of Risk Based Inspection and plant assessment procedures to mines is discussed. Periodic assessment of large plants and components to determine their integrity for continued safe operation is becoming a more accepted approach than formerly when regular shutdowns were the normal practice. This is on the way to becoming the preferred procedure for petrochemical plants and power generating plants, and the same philosophy is appropriate for many mining operations. Both the American Petroleum Institute (API) and the American Society of Mechanical Engineers (ASME) have committees developing codes for the continued operation of equipment as distinct from the existing design codes. The philosophy is one of risk-based inspection, which can be on a purely qualitative basis or more quantitatively based.The purpose is to reduce the inspection of unnecessary and non-critical items and to concentrate on the most critical components, reducing costs and downtime and increasing safety. The approach differs from that considered by many maintenance engineers, in that defects that are identified during an integrity evaluation do not automatically cause a component or structure to be condemned or require that repairs are made right away. The seriousness of the defect must be considered and the safe operating life can be estimated before it becomes necessary to replace or repair the unit or component. This is no different from what is done today with passenger aircraft and, to an increasing extent, with pressure vessels, reactor vessels and similar components in the petrochemical and power generating industries."

Jan 1, 1998

By John E. Udd

"For decades, writers have expressed concern about impending shortages of professionals for Canada's minerals industry. Even under the present difficult economic circumstances, it is anticipated that the supply which will be available will not be adequate to meet the requirements in certain key areas including mining and petroleum engineering. It is evident that, unless further initiatives are taken, shortages will exist for some time.In this paper, the writer reviews information which relates to both the demand for, and the supply of, persons with advanced-level education in minerals-related disciplines. In particular, a summary is made of the information regarding supply which has been collected by the CIM General Committee on Education for many years.In concluding, the writer expresses some personal opinions regarding imbalances between demand and supply and offers some recommendations for future actions.IntroductionLast year, in a paper which was presented at the Annual General Meeting of the CIM in Calgary, the writer presented a review of the situation regarding professionally educated manpower for the minerals industry, and concluded that indications were that the gap between demand and supply was widening and that the situation could be expected to continue. Since that time, the deterioration of the nation's economy has caused an appreciable reduction in demand. Simultaneously, a further annual survey by the CIM has shown that the numbers graduating in certain specializations, notably geology and some of the technologies, are rising very rapidly. One of the great concerns of educators at present is that adequate opportunities may not exist for all of those who are now graduating.The danger of the present situation, then, is that a momentary lack of opportunities may cause potential students to choose alternative careers . Because of the lead-time which is involved, it is very possible that this could result in greater shortages during a period of economic recovery or expansion. Action must be taken to ensure that adequate numbers will be attracted to the industry, and this applies particularly to those who have already made the career decision and who are enrolled in minerals-related programs."

Jan 1, 1982