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The mineral composition and microtextures of a cubanite-rich sulphide ore are described and cubanite breakdown textures are illustrated. The occurrence of cubanite in macroscopic dimensions is featured.The origin of the ore is tentatively related to a composite ore fluid arising initially from an ultramalic source and extracting some metal components from an older granite mass along the margin of which the serpentine was emplaced. Some alternative possibilities as to origin are also mentioned.

Jan 1, 1969

By Robert Drummond

Away back in the eighties of the last century, when Sir Charles, then Doctor, Tupper, was not only a prominent but a dominant figure in the political life of Nova Scotia, his opponents brought the railing accusation against him that he was the foremost of egotists because of his frequent use of the personal pronoun. I heard Tupper speak and had no sympathy with the railers, because I could not well see how the pronoun could be dispensed with without laying himself open to a charge of affectation. I shall make reference in what follows to incidents in which I have taken part, and shall be at no pains to dispense with the pronoun, even though thereby I lay my-self open to the charge of being a pupil of the deceased states-man. EVENTS LEADING UP TO THE ORGANIZATION OF THE PROVINCIAL WORKMEN'S ASSOCIATION The Springhill Mining Company began development work at Springhill in the early seventies of last century. So vigorously was the work prosecuted that in 18 7 4 two slopes, the east and the west, were in active operation, with a considerable. output, the east slope on occasional days producing 800 tons. The President of the Company, the late Senator McFarlane, was a Nova Scotian, the other directors were mainly merchants from St. John, N.B. From the first the enterprise was an .astonishing success, due in the greatest part to its geographical position, and in large part to the untiring vigilance of the directors, a majority of whom visited the collieries at short intervals, thereby keeping the manager, much of the time, on tenter hooks.

Jan 1, 1924

By Howard P. Hamlin

This Bureau of Mines report is concerned with the testing procedures for evaluating clays, shales, and slates for lightweight aggregates using the rotary-kiln method of production. To meet the increasing demand for light-weight concrete, rapid, accurate methods for appraising raw materials for light-weight aggregate are needed. Preliminary tests were made on samples of clay, shale, and slate, using laboratory equipment, and the data were used to establish operating conditions for pilot-plant-size rotary-kiln tests. Lightweight concrete was made from the processed aggregates and the properties determined. The results show that the laboratory data can be used to guide rotary-kiln testing, and, with the exception of sampling, a complete appraisal of a raw material for lightweight aggregate concrete can be made in 3 days by the methods described in this report.

Jan 1, 1962

By J. E. Harris

By elimination of other possible nucleation processes, it has been demonstrated, for commercially pure magnesium and a Mg-Al alloy, that at stresses less than that necessary for triple-point cracking creep cavities are most probably nucleated heterogeneously at second-phase particles. Evidence for the existence of such particles is presented and the role of grain boundary sliding in the nucleation process is examined quantitatively. DURING creep deformation of polycrystalline magnesium and its dilute alloys in the temperature range 0.45 to 0.7 Tm (Tm = absolute melting temperature) cavities form mainly along grain boundaries oriented normal to the stress axis and failure eventually occurs by their growth and impingement.' The possibility of low-ductility creep failure of magnesium-alloy reactor cans during service has prompted a number of studies of cavity formation in these materials.2-5 In this paper divergent theories of cavity nucleation6-10 are examined critically and conclusions drawn regarding the most probable mechanism of formation of cavities in magnesium. The paper is divided into two parts. The first section consists of the review and quantitative assessment of the possible role of grain boundary sliding in the nucleation process. In the second part an experimental program is described where an electron-microscope technique has been used to determine if second-phase particles exist in as-received commercially pure magnesium and in a magnesium alloy 1) THEORETICAL REVIEW Possible nucleation sites for creep cavities are: a) high-angle grain boundary triple points,11-14 b) subboundary/grain boundary intersections,15-18 c) ledges in the grain boundary, 19-25 d) second-phase particles. 9,26-30 Each of these possibilities is now considered with special reference to deformation of magnesium. 1.1) Triple-Point Cracking. The stroh31 condition to nucleate fracture is: " > vr [1] where ss = applied shear stress, ? = surface energy, C = shear modulus, L = length of sliding interface. This relationship is independent of the nature of the interface and it is possible to calculate the stress concentration at the end of a sliding high-angle grain boundary and thus deduce, approximately,* the minimum applied stress necessary to nucleate triple-point cracking. Such theoretical predictions for Nimonic alloys have been made by McLean13 and found to agree quite closely with the minimum stress determined by experiment. Stresses capable of nucleating triple-point cracking should also be sufficient to nucleate fracture at a grain boundary due to intragranular slip, for the lengths of sliding interface in the two cases are approximately equal. Thus the minimum stress for triple-point cracking should represent a demarcation between failure due to general "cracking" and that due to cavitation. Hauser, Landon, and Dorn32 have demonstrated that for polycrystalline magnesium in the temperature range 78° to 298°K the fracture stress is inversely proportional to the square root of the mean grain diameter. As pointed out by stroh31 this result indicates that Eq. [I] describes the fracture characteristics of magnesium at low temperatures. Heal3 has reported that for rapid deformation (112 pct hr-1) of polycrystalline magnesium the transition from cracking to cavitation occurs in the temperature range 175" to 275°C. He also presented the fracture-stress values for the same material tested under similar conditions. From Eq. [I] taking G = 1.3 x 10" dynes , ? = 600 ergs . cm-2,33 and L = 0.017 cm, a Stroh-McLean13,31 tensile stress of -266 kg. cm-2 is calculated, corresponding to a transition temperature of -190°C; this is in

Jan 1, 1965

By Mariella Cortez Caillahua

No presente estudo o gesso FGD (flue gas desulfurization) foi avaliado como aditivo retardador do tempo de pega, substituindo o gesso natural na fabricação do cimento Portland (CP II E-32). Os resultados da caracterização físico-química e morfológica do gesso natural e do gesso FGD identificaram um material de alta pureza, sulfato de cálcio di-hidratado para o gesso natural e a presença, principalmente, de bassanita (CaSO4.0,6H2O) e hannebachite (CaSO3.0,5H2O) com baixas concentrações de impurezas no gesso FGD. Baseado nos resultados, o gesso FGD é uma alternativa adequada para substituir o gesso natural. O tempo de pega mostrou cerca de uma hora de retardo em comparação com gesso natural e seu efeito sobre a resistência à compressão para as amostras de 3, 7 e 28 dias dependem da composição das misturas, atingindo um valor máximo para a argamassa com 2,1% de gesso FGD e 1,4% de gesso natural. Seguindo a norma ABNT NBR 10004:2004 o resíduo é classificado como não perigoso e não inerte.

Aug 8, 2018

By Thomas Barkley

Mining tradition holds that a parallel round underground can not be any deeper than it’s smallest face dimension. ln other words, a mine using a 12’ (3.7 m) high by 24’ (7.3 m) wide room and pillar mine, the deepest pull that can be achieved is plus or minus 12’ (3.7 m). After experience with decking of rounds in a 12’ (3.7 m) diameter shaft to achieve more than 12’ (3.7 m) advance per round, the concept of deepening the pull on horizontal parallel rounds seemed to be a feasible concept. Tests were conducted in a conventional room and pillar metal mine with a round size of 12’ (3.7 m) high by 24’(7.3 m) wide. Standard rounds were drilled with a 16’ (4.9 m) steel as parallel rounds to an average depth of 14.5’ (4.4 m). The average depth of pull on these rounds was about 13’ (4.0 m). Using the available drilling equipment, 20’ (6.1 m) drill steel was used to drill holes to an average depth of 18’ (5.5 m). Five rounds were drilled and shot with a resulting aven$e pull of 16.2’ (4.9 m) or 90 % of drilled depth. Rounds were designed with decked bum cuts to maximize depth of pull in the cut area An innovative method of de&mining drilling accuraq was used to estimate it’s effect on depth of pull in the rounds. This method used a standard automatic 35-mm camera and scaling to determine the average drill deviation for many of the holes in the rounds.

Jan 1, 2000

By H. N. Treaftis, J. W. Cahn

THE previous determinations of the solvus of tin in solid lead disagree with one another by as much as 40°C or almost 10 at. pct. Even determinations that appear to be careful differ considerably in both the solubility and its temperature coefficient. Recent kinetic workl -3 on the rate of precipitation of tin from lead-tin alloys and thermodynamic work4 on the heat of solution of tin in lead have given some insight into the time necessary to reach equilibrium in this system. As this time is longer than that used in almost all previous determinations of the solvus, these determinations are questionable. Since the interpretation of recent kinetic results requires accurate values of the equilibrium solubility the present work was undertaken. DISCUSSION OF PREVIOUS RESULTS The methods used in previous studies may be placed into three classes: 1) Several alloys covering a range of compositions are allowed to reach "equilibrium" at a certain temperature.5-7 Some property, such as the X-ray lattice parameter of the lead-rich phase or the re- sistivity of the alloy, is then measured as a function of composition. The solubility limit for that temperature is taken to be that composition at which a discontinuity in the property occurs. However, the recent kinetic work has shown that tin precipitates in two stages. The first stage is rapid but leaves the lead still supersaturated. The second stage is very slow, and it seems from the equilibration times quoted by the investigators of the solvus that the end of the first stage of precipitation was usually mistaken for equilibrium. This is especially true at temperatures below 100°C where the first reaction is still quite rapid (from minutes to months), but where the second stage is so slow that very long holding times are required to reach equilibrium. Alternatively micrographic work8 on several alloys of different compositions seems to have given good results if done carefully. 2) The beginning of precipitation in a homogenized alloy is measured as it cools slowly8-10. Since reactions in solids undercool easily, such determinations will always give too low a temperature for the solvus. 3) Some property of an alloy is measured as a function of temperature while the alloy is above the solvus.5,9,11 The range of temperature can usually be extended slightly into the two phase region. Then the alloy is precipitated at a much lower temperature and slowly reheated. The solvus is taken to be the lowest temperature where the property of the reheated alloy is equal to that previously determined for the homogeneous alloy. Usually one also expects a discontinuity at the solvus in the temperature variation of the property for the reheated alloy. The difficulty in this method is the sluggishness of the dissolution process, and this method may give too high a solvus temperature. EXPERIMENTAL The phase boundary or solvus temperature was determined by a modification of method 3 for a series of chemically analyzed high-purity alloys, ranging from 5.1 to 26.4 at. pct Sn. The resistance, as a function of temperature, of a sample of homogenized alloy (which could easily be undercooled) was compared with the equilibrium resistance which that alloy sample attained after precipitation at room temperature followed by long isothermal anneals at various temperatures. Before each anneal the sample was rehomogenized and reprecipitated. The solvus temperature could be located to within 1°C as the intersection of the resistance vs temperature curves for the homogenized and equilibrium alloys. No attempt was made to locate the phase boundary more accurately since the limiting factor was the precision with which the alloys could be analyzed. This precision was ±0.1 wt pct Sn and corresponds to an error of 1 deg in temperature. This use of isothermal anneals differs from some of the previous investigations in which method 3 was used with baths of slowly rising temperatures. It was found early in the investigation that solvus temperatures tended to be high if the latter method was used even at extremely slow heating rates. For example a

Jan 1, 1961

By Bobby J. Timmons

Luck; blind, beginner's, fisherman's, or whatever type, plays an important role in romance, racing, football, gambling, and mineral exploration. However, for each of these; education, training, technique, and experience are necessary for a long, continuous, successful relationship. Success, no matter how obtained, is easier to defend than almost success, regardless of the education or the degree of refinement of the seeker. Similarly, investment dollars are more readily available to a successful, uneducated and unscientific practitioner than to his beginning or unlucky professional counterpart.

Jan 1, 1983

By A. J. Barry

This report presents observations made by Bureau engineers regarding hydraulic-powered roof supports that are currently being used or have been used on nearly all operating longwalls in the United States, A comparative summary of specifications for various types of powered supports with a brief description of the mine conditions has been compiled to enable mining engineers and mine operators to readily evaluate the differences in design data. Some of the support data furnished in the field may vary from those listed in manufacturers' brochures because of the trend to customize various support components to meet specific mine conditions. A method of estimating support requirements for different assumed operating conditions is presented. Similar computations for specific mine conditions may be used to make preliminary estimates of support requirements.

Jan 1, 1969

By Francis J. Kelly

This Bureau of Mines study was made to obtain and present facts concerning the production and marketing of rare-earth metals and thorium in the Central and Southern Rocky Mountains (Arizona, Colorado, New Mexico, Utah, and Wyoming, referred to in this report as the region) and to review the current demand for these elements in the United States. Little or no published information was available on the marketing practices for these commodities. As a result of many inquiries from industry, potential prospectors, and the general public, the various factors of resources, production (present and potential), marketing, and consumption have been investigated, and the results are set forth in this report. Material concerning occurrences and deposits is from published references detailed in the bibliography.

Jan 1, 1962

By N. Kyriazi

The U.S. Bureau of Mines subjected the CSE SR-lOO self-contained self-rescuer (SCSR) approved by the National Institute for Occupational Safety and Health (NIOSH) and the Mine Safety and Health Administration (MSHA) to a series of laboratory treatments designed to simulate various environmental conditions in underground coal mines. The tests were designed to predict the ability of the self-rescuers to withstand those environmental stresses without causing a decrease in wearer protection. The apparatus were heated to 710 C for 48 h, cooled to -450 C for 16 h, vibrated for 9 h, and dropped 1 m on each axis. A critical concern was internal damage to an apparatus, without any obvious external signs, that would cause it to malfunction or seriously degrade its performance. Carbon dioxide (C02) levels in apparatus with combined treatments were higher than in apparatus with individual treatments and untreated apparatus. The higher levels remained within safe limits, however. None of the treatments caused venting of the small oxygen cylinder that provides starter oxygen. Some bottles were found to be empty because of manufacturing defects in the burst disks. This problem was corrected in later models. The heat treatments did make the case ends more difficult to remove and the breathing bag sticky and subsequently more difficult to unfold. An apparatus that was dropped and vibrated had a broken desiccant bag that released some of its contents which compromised the seal of the relief valve. The case was dented from the drops. As with the first-generation self-rescuers, if there is visible damage to the case of the apparatus, the apparatus should be considered to be internally damaged and must be removed from service.

Jan 1, 1990

By E. D. Gordner

Irrespira ble gutses issuing from the rock fofflb tions ere tJ source of expense ond danger in some metGLl mines. There is a great Variation in the compos i-· tion of such gdses and, os shown 'by recent sampling by the Bureau of ines, the gas rr;;,.y consi$t mostly ct carbon dioxide, (Rocle Strata Gtsses in the Mines of the East Tintic Mining District, by G. E. McElroy, Bu.retau of Mines Serial 2Z75) or f methone (Metruine in Ccalifornia C.old Mines, by B. 0. Picl-Q:lrd i:lnd !.. D. ("iordner, Bure, cf Mines Serial 2303), or nitrogen, sin the present instonce. A nl.liilber of unventilated rt:t.ises in some of the mine of l:l Neva&. district conuin «i'ccumulCltions of l;i hih-nitrogen gas the1t will not supi:ort life or combus­tion. The rdises ore in different geologiecil formations and in widely sep1:1rated. loecslities in the mining district. One ot" two ri::lises in the sme fc.rtr.ation may be full of the gos cand einother nec-r'by be t'ree ot· it. Lives have been lost t:lnd a number of men heave been overcome on enteing unvetilated rtsises in which their­respircable tss hcsd c1ccuni..1.l1::1ted between sldfts. Gener1:1lly, however, the gas see:ns to noozett from the .t'onrbtio:1 ond to ecc1: .. ,i.-1,;.1:.1te so slowly tMt its presence is not suspected t the tfr.1e, bu.t discovered. ed:'t&.c' the raise is t)band.oned. OcCE.isionelly 1 t issues from a ne•.,ly cut cre·tice or fissure under considerca ble pressure and in lar!?e enough '3.'16ntities to overcome or drive 011t men working in unventilated places.

Dec 1, 1922

By Robert J. Tuchman

This report presents the origins of the Bureau of Mines and the evolution of the Pittsburgh Research Center from its inception to its present form. Areas of major research emphasis over the years, as well as administrative reorganizations, are discussed.

Jan 1, 1998

By William H. Grady

FactoRs entering into the market value of coal are its grade, and the cost of labor, material, and capital. Reduction in these costs cannot be expected in the future, and it therefore follows that greater economy in their use must be accomplished if it is desired to hold the present markets; more tons of product per unit must be obtained in a given time from both men and material, and means devised for increasing the percentage of lump and domestic sizes. This paper is presented for the purpose of inviting discussion and stimulating thought in regard to the influence of methods of procedure and plans of mining, upon the quality of coal, the economical use of labor, material, and capital, and the cost of production. Even the better methods of the present day leave much to be desired, and a review of the reasons and necessities for their use may be of value in pointing the way to more economical mining. The writer does not attempt to discuss untried methods of mining, but rather to state clearly and concisely a summary of the results obtained under the several methods of procedure that have been adopted. In some instances a high degree of concentration has been effected, and comparisons of the results obtained with the results of lesser degrees of concentration form an interesting study. It is believed that much may be accomplished in improving the quality, and in the more economical use of labor, material, and capital, by concentration, and it is to concentration in particular that your study is invited. The writer, who has occasion to visit many mines, most of which are under different management, has been inclined to the opinion that improvement has been retarded in many ways and that mining has not as yet been entirely freed from the early-day practices which were forced upon it. Practices resulting in lack of concentration, to which reference will be made, are: The absence of robbing, necessitating the frequent interposition of barrier pillars; lack of system and of proper supervision, resulting in losses of life and coal. These practices could not well be

Jan 1, 1915

By A. Wahab Khair, Negendra P. Reddy

INTRODUCTION The continuous mining machines which were introduced in the 1950's now account for more than half the production of coal from underground mines. Unfortunately, these continuous miners which were designed for increased productivity have also increased the concentration of respirable dust in mines. Inhalation of this respirable dust by miners causes the Coal Worker's Pneumoconiosis (CWP). Concern for CWP increased in the United States following a 1963-65 survey that showed definite x-ray evidence of CWP in 9.8 percent of working miners and in 18.2 percent of nonworking miners in the Appalachian bituminous coal region (Breslin and Niewiadomski, 1982). One of the major objectives of the Federal Coal Mine Health and Safety Act of 1969 was the prevention of CUP. This law initially limited the daily average exposure of coal miners to 3 mg/m3 of respirable dust. However, following the results of a probabilistic model developed by Jacobsen, et. al. in 1971, the limit was reduced to a mass concentration of 2 mg/m3 unless quartz content exceeds 5 percent, a rare occurrence in mines. Based on x-ray categorization prior to death it is believed that the mass concentration in the respirable fraction is a parameter of primary interest for hygenic evaluation of dust exposure. Elorgan, Burgess and Jacobson (1973) suggested that the quantity of inhaled dust, although influential is not the only aspect of exposure which is significant in producing CWP. Miners working in higher rank coal (anthracite) mines are more susceptible to CWP (Morgan, Burgess and Jacobson, 1973). This also confirms the findings of the British (Bennett, Dick and Kaplan, 1979 and Hurley, et. al., 1979) and Germany (Reisner and Rubock, 1977). Based on the cy to toxicological evidence Reisner and Rubock (1979) suggested that when coal properties are similar, increasing quartz and mineral content increases toxicity. David, Ottery and Le ?oux (1975) examined that as the severity of the CWP increased the retention of the coal dust content in the pulmonary region remained the same, while that of quartz content increased significantly . Leiteritz, Baur and Bruckman (1971) studied the various components of coal dust and showed that coal particles comprised a smaller fraction of the mass of fine dust than did particles , of quartz and minerals. It is ironic that quartz and mineral matter both comprise smaller fractions of the higher rank coal dust (Dodgson, et. al., 1971 and Dwiggins, 1981). Results of a recent research revealed that quartz or any other mineral examined had no strong or consistent effect on the incidence or progress of CWP (Attfield,

Jan 1, 1986

By A. Vasenev

The quality and durability of asphalted roads strongly depends on the final step in the road construction process; the profiling and compaction of the fresh spread asphalt. During compaction machine operators continuously make decisions on how to proceed with the compaction accounting for project specific aspects as: ambient conditions, road geometry, roller type, asphalt mixture characteristics and behavior of other machines. In discussions over quality improvement in road construction it is often suggested to robotize rollers. To operate such robots would of course require operational strategies and routines. The reality of this moment is that these operational strategies and routines are not documented. To identify the existing best working practices and, ultimately, to proceed with developing automated robotized compactors, the knowledge of machine operators should at first be explored and described in a formalized way. Unfortunately operators have difficulty verbalizing their expertise. Observation of behavior, as machine movement patterns, could be helpful to extract the operational strategies, but such observations are time and labor consuming. To overcome this burden we developed a Virtual Reality (VR) environment. In this VR environment operators perform compaction virtually, and their operational choices are traced and analysed. This paper describes this VR development and explains how it helps in following machine operators and extracting their (tacit) professional knowledge. The road geometry and the working conditions are visually represented; the operators show - rather than explain - how they would proceed with the compaction process in the given conditions. Movements of virtual machines are documented, analysed, visualised and discussed. This VR approach is expected to contribute to learning, to more formal description of operational strategies; stepping stones towards compaction algorithms for roller robotisation.

Aug 1, 2013

By David J. Hatem, K. Bhattarai

Effective risk management in major subsurface projects involves ways to mitigate adverse impacts to final design and construction approaches due to changed subsurface conditions. An Early Contractor Involvement (ECI) collaborated with Observational Method will be an effective contractual tool to address risk developed due to encountering differing site conditions. Observational Method (OM) can further be supported with artificial intelligence (AI) technologies with automated data-driven decision-making features in risk mitigation and implementation of proper design and construction approaches. This paper presents collaborative applications of ECI, OM, machine learning, and risk baselining in risk management and productivity enhancement in tunneling projects.

Jun 23, 2024

By J. Nielen van der Merwe

During the process of pillar extraction at the Welgedacht Colliery, an unexpected pillar collapse resulted in the entrapment of equipment. The area was visited soon after the event to evaluate the stability of the area for the purposes of extracting the equipment. It was found that the area had stabilised sufficiently to allow work without undue risk to the safety of workers. The equipment was reclaimed successfully. A subsequent investigation into the reasons for the collapse was conducted. It entailed detailed underground and surface subsidence observations and numerical modeling. It was found that none of the perceived negative factors that were present at the time could result in pillar loads that were sufficient to cause the collapse. It was concluded that the local pillar strengths were less than the nationally used value and that they were possibly further reduced by aging.

Jan 1, 1999

By Corrie Pitzer

Safety performance in many companies and even industries has stalled in the last decade. Accidents rates are improving but more slowly and yet, serious accidents and fatality rates are not: in fact, these rates of more serious incidents have plateaued or deteriorating. In more dramatic cases, organizations that had ?exemplary? safety statistics, suddenly had a catastrophic or multi-fatality event occurring. Popular books such as In Search of Excellence of Peters and Waterman or Good to Great of Jim Collins created many delusional ?secrets? or recipes, to achieve great performance and yet, most of those ?great? or ?excellent? companies have now declined in their performance, some dramatically and some have fallen from grace, like Fanny Mae, a company Jim Collins identified as a ?great? one, that had to be bailed out in the latest financial crisis. These organizations share several ?delusions? about managing a business, and often, these delusions are created by academics, consultants and authors of popular books about (safety) management. More damaging however is that safety management is defined by a set of key practices or axioms: a focus on human error, compliance to rules and regulations, creating consistency of systems and actions, reacting to accidents and incidents and on prevention of those, measuring safety with performance metrics and rewarding employees on those measurements. All of these axioms contain the seeds of destruction, and they create conditions and dynamics that precede the disaster - and ironically, they are all 'good things' we do in safety management. For example, a mere focus on safety in the business, and the measurement of it, create a culture of repression of mistakes and incidents, leading to a situation where the organization knows incrementally less and less of risks and risktaking behaviour - until the day it all coincides destructively! This paper discusses seven such safety delusions and how they impact on the views and safety management approaches. They are: ??The delusion of (risk) control, that risks can actually be identified, analyzed and mitigated. ??The delusion of compliance, that mere compliance to rules will safeguard the business ??The delusion of consistency, that standard operating procedures will ensure safe operations ??The delusion of predictability, that accidents and trends tell us everything about the risks of the future ??The delusion of human error, that people are the weakest link and that it can actually be dealt with through discipline and enforcement. ??The delusion of statistical trends, that safety is measurable with statistics ??The delusion of invulnerability, that we have achieved high levels integrity and capability to deal wit risks. Organizations that suffered catastrophes all share some or all of these delusions and this paper traces how these played a role in many disasters, ranging from the Titanic, Challenger, Piper Alpha, Bhopal, BP Deepwater Horizon and many more.

Aug 1, 2013

By Norman O. Lotter, Lori Kormos, Greg J. Wilkie, Peter J. Whittaker, Johannes S. Stickling

"Assessment of opportunities to improve mineral processing performance in existing concentrators and in describing undeveloped orebodies is key to improving the business case of a mining company. This assessment has traditionally been performed using the distinct and separate inputs from Mineral Processing and Mineral Science.More recently, Process Mineralogy has been used to integrate these two disciplines. This trend has been driven by the need to develop and process more challenging ore deposits, and has been assisted by the availability of modern automated instruments. Together with the acquisition of a QemSCAN (Quantitative Evaluation of Materials by Scanning Electron Microscope) from CSIRO in Australia, and with the use of a supporting SEM with EDX / WDX capabilities and an XRD, the development of Process Mineralogy at Falconbridge commenced in 1997.The sampling challenges in presenting a QemSCAN with representative sample material at the polished section level are significant, but have been effectively addressed. The full description of this aspect is beyond the scope of this paper.It is shown that, by use of this approach, the set nature of an orebody can be best exploited with selected flowsheet changes in a concentrator which address the generic characteristics of the orebody. In this way, the flowsheet provides a process that more effectively fits the mineral processing requirements of the ore. This leads to clear and tangible improvements in grade and recovery."

Jan 1, 2002