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By E. A. Sobering

Hydraulic filling or sand filling is a system used to fill underground excavations with a dense pulp. Milltailings are commonly used. The resultant fill, after being placed and de-watered, is known as hydraulic fill. These fills have been effectively used to (a) provide immediate support of the workings place during stoping; (b) .facilitate the recovery of pillars; (c) limit surface damage by subsidence; (d) permit the mining of parallel hanging-wall orebodies; (e) stabilize the ground in mines, thereby reducing the rock burst hazard; (f) control and prevent mine fires; and (g) solve tailings disposal .problems. The various uses of hydraulic filling have been developed during the last ninety years. In 1864 it was employed only to control surface subsidence. Since then, this system has been successfully applied to meet specific ground support problems. Methods of handling mine-fill derived from a source outside the stope include transportation ?Of the material by hand, mechanical, pneumatic, and hydraulic means, or a combination of these methods. The hydraulic method has many advantages not found in the others; a significant advantage is the low compressibility of the material when compared to other mine-fill material. The hydraulic filling operation includes the .preparation and transportation of the pulp. The underground practices in .placing the fill vary from mine to mine. The chief reason, formerly, for using hydraulic fill was the exceptional support it provided, but recently it has proven an important means of reducing mining costs. This is especially true where labour is a large part of an alternative method, or where timber consumption is greatly reduced. The indirect benefits of hydraulic filling are probably as important as the direct benefits, and few important disadvantages exist.

Jan 1, 1956

By J. Fournier

A novel sol ? gel (SG) synthesis procedure utilizing varying ratios of glycine and ethylene glycol to total metal cations has been developed to create high purity nanometer sized La0.65Sr3.5MnO3 powders. X-ray powder diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), and dynamic light scattering (DLS) have confirmed that the crystallite sizes of such powders are ~ 20 nm, and the aggregate particle sizes vary between 100 to 300 nm. Mixing varying weight percents of SG LSM powders with commercially available Praxair LSM in a composite LSM/YSZ functionally graded cathode has been shown, through the use of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), to exhibit enhanced oxygen reduction kinetics vs. at conventional cathode materials.

Jan 1, 2005

By J. Fournier

A novel sol ? gel (SG) synthesis procedure utilizing varying ratios of glycine and ethylene glycol to total metal cations has been developed to create high purity nanometer sized La0.65Sr3.5MnO3 powders. X-ray powder diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), and dynamic light scattering (DLS) have confirmed that the crystallite sizes of such powders are ~ 20 nm, and the aggregate particle sizes vary between 100 to 300 nm. Mixing varying weight percents of SG LSM powders with commercially available Praxair LSM in a composite LSM/YSZ functionally graded cathode has been shown, through the use of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), to exhibit enhanced oxygen reduction kinetics vs. at conventional cathode materials.

Jan 1, 2005

By T S. Cochrane

This paper is based on observations made during a recent visit by the writer to three of the dust research laboratories .in West Germany, each .of which is mainly concerned with studymg the composition and character of the respirable dust produced in mines or at industrial sites. The three institutes are discussed as regards their orgamzat10n and duties, their methods of dust sampling and analysis, and recent trends in research and development. An extensive bibliography completes the paper. Introduction A RECENT trip to Europe to attend international conferences m Austria and m Belgium gave the writer the opportunity to visit a number of research laboratories and mines in Western Europe. The visits to the dust research laboratories in West Germany are the basis of this report. In Germany, cooperative associations formed prior to and since the turn of the 20th Century to promote the safety and welfare of their workers have recognized the effects of airborne dust on the general health of the labour force.

Jan 1, 1964

By J. T. Kalala

The High Pressure Grinding Roll (HPGR) is gaining acceptance in the mineral processing industry and has become a competitive technology in reducing the specific energy consumption in Mineral processing plants. The amount of samples required for HPGR amenability testwork and HPGR wear tests is usually high and often cannot be available at early stage of projects were only a few drill cores are available. Although HPGR was initiated from small scale piston die compression tests, the development of small scale piston die test to predict the performance of HPGR has been slow. The objectives of this paper was to present the designs, operating procedure of piston-die press and operating conditions which have resulted in similar particle size distribution obtained from a piston die test and HPGR Labwal unit starting from the same feed size distribution. Testwork were conducted using a 2 MN piston-die press and a Labwal HPGR unit on major South African ore types, viz, gold, platinum and iron ores. The results obtained show that piston-die test can generate data to predict energy consumption, product size distribution, and even to evaluate the edge effect.

Jan 1, 2012

By F. W. Gray

IN 1922, the writer communicated to the Institute a paper entitled The Development of the Coal Industry in Canada (1), which summarized the considerations set out in a series of papers (2) concerned with coal-mining in Canada which he had presented in 1920 and 1921. This paper contained a forecast by decades, commencing 1920, of Canadian coal production, importation, consumption, and exports, based on anticipated rate of population increase, and continuation of the gradual increase in the per capita rate of coal consumption in Canada that had taken place every year up to 1920. The following comparative statement brings our the differences between the forecast and actual experience:

Jan 1, 1936

By K. J. Heale, G. G. Richards, D. J. Rioux, R. L. Stephens

Slag fuming has remained a key process for the recovery of Zn, Pb, and minor elements in the integrated flow sheet at Teck Cominco's Trail Operations for more than 75 years. Since the start-up of the KIVCETTM process and the #3 slag fuming furnace in 1997, a range of process intensification projects have been completed to improve metals recoveries and throughput based on improved process control, mechanical modifications, and, most recently, the implementation of oxygen enrichment of the blast air. This latter project, initially named 'nitrogen depletion' and now 'nitrogen oxygen performance enhancement' (NOPE), is the primary focus of this paper. NOPE reduces the amount of heat required to heat the inert nitrogen gas, and therefore more of the energy input can be used for reduction. It also frees up boiler capacity because the inert nitrogen gas does not then have to be cooled down. A dynamic METSIMTM model was developed to determine the opportunities to improve the process capacity and heat balance to both assist with justifying the project and to verify the observed furnace behaviour. Several process safety management issues were also addressed and a few key minor mechanical modifications were made to allow the project to proceed to commercial implementation at 25% blast air oxygen enrichment. Short term plant trials have confirmed the model predictions. The first three months of a long term, continuous trial showed a 6% increase in zinc fuming rate from average furnace performance despite the implementation of a KIVCETTM fluxing change to assist with minor element recovery that was expected to negatively impact the zinc fuming rate by 3 to 5%. This encouraging result is also in line with the model predictions.

Jan 1, 2008

By Piotr Litwa

The paper focuses on actions aiming at improvement of work safety in mines, particularly in those extracting hard coal, taking into account the characteristics of natural hazards in Polish underground mining and the reasons of mining disasters connected with those hazards. It refers to conclusions addressed to scientific and research centres, drawn during last decade by Commissions appointed by the President of the State Mining Authority in order to investigate reasons and circumstances of incidents, which till now, could not have been accomplished because of financial reasons. Furthermore, the paper presents basic assumptions of the Strategic Research Project Improvement of work safety in mines, announced by the National Centre for Research and Development at State Mining Authority?s President request.

Aug 1, 2013

By A. A. Paoli

The selection of a mining plant for carrying on development work presents many problems distinct in themselves, and affected by various local factors. In this paper, the writer proposes outlining and discussing in some detail the chief factors governing the economic selection of such plants. This will be followed by an enumeration of the underground and surface plant required for carrying on several hypothetical exploratory and mining operations. Where it is impossible or not convenient to obtain hydro-electric power, and where wood for fuel is scarce, we now find oil engines being used. A 100 h.p. oil engine, such as would be required to operate a three-drill air compressor, consumes approximately five Imperial gallons of fuel-oil per hour at full load. On the basis of a 60 per cent load factor, this gives, for eight hours' operation, a probable actual consumption of twenty-four Imperial gallons.

Jan 1, 1929

By J. L. Gartshore

PRACTICALLY all of Quebec's chrysotile asbestos production derives from twelve mining and milling operations located in the "Eastern Townships" area of the province. The annual output of these twelve operations exceeds one million tons of chrysotile asbestos, valued at over one hundred million dollars, and is shipped to manufacturers spread over all six continental areas of the world. A total of approximately twenty million ton of asbestos ore yearly, or about seventy-five thousand tons a day, is mined. Individually, the operations vary in size from about two thousand tons to thirty thousand tons per day. Removal of waste rock and overburden to develop these ore tonnages varies greatly from one mine to another, but would probably average out at about a one to one ratio.

Jan 1, 1962

By Theodore H. Boggs

The battle of the gold standard is not limited to one country alone, or even to a single group of countries. It is being waged merrily in many important commercial and industrial quarters. Though it is not always a practical issue calling for immediate attention, it is none the less, quite widely, engaging the thought of bankers and other students of finance. The controversy arises, in the last analysis, because of the desire of men to secure a stable currency. There are two ways of restoring a reasonably stable currency system: (1) the re-establishment of the gold standard, or (2) the deliberate and artificial management of a paper currency. Both systems are well known. The gold standard was in use prior to the war in the principal commercial countries. A currency of inconvertible paper has been at times employed in the past in various countries; for example in Britain from 1797 to 1821, and in the United States from 1862 to 1879. The gold standard, as all are aware, implies the selection of gold as the standard of value. The unit of value is a fixed weight of gold and, so long as the standard remains unimpaired, all other means of payment are maintained at a parity with standard gold coins. And gold coins alone constitute the standard money, inasmuch as their value as bullion equals their value as coins. Under the gold standard this would not be true of any other form of money, although all other varieties of money, including bank notes, government notes and silver coins would be freely convertible into gold money. Strictly speaking, the gold standard also implies that the gold money in turn shall itself be freely convertible, through melting, into gold bullion and freely exportable.

Jan 1, 1925

By E. G. Charlesworth, M. J. Robertson

"Abstract - Gold mineralization in the Main Reef Complex at Sheba Gold Mine is hosted within shear zones in a sequence of shales and greywackes of the Fig Tree Group. Competency contrasts between these rocks and a steeply dipping chert unit provided a locus for the development of right lateral steeply dipping shear zones. A set of flatter dipping shear fractures crosscut these zones with their intersections defining a system of en échelon ore shoots.Mineralization is both of vein type and disseminated strata-controlled replacement type. The latter occurs mainly within the wall rocks to the shear zones. Arsenopyrite and pyrite are the major sulfides, with arsenopyrite being confined largely to greywacke beds and pyrite to the more iron-rich shale units. Gold was introduced, together with minor sphalerite, pyrrhotite, chalcopyrite and early arsenopyrite, toward the end stages of a first pyrite phase. The mineralizing fluids were introduced along dilated cleavage planes and, emanating from these, produced a series of replacement fronts. Mineralization was syntectonic to late tectonic and occurred under conditions of progressive deformation, resulting in sulfides which are concentrated in the hinges of shear-related folds and semi­ massive sulfides within tension fractures which are folded, attenuated and fractured .An analysis of the structures shows a sequence of events in which an initial ductile simple-shear event with a steep sense of movement was succeeded by a more brittle strike-slip event. Mineralization is temporally related to the latter. This evolution in structural style was probably related to reactivation of the Sheba Fault as a transcurrent fault during emplacement of large granitoid bodies."

Jan 1, 1994

By László Guczi1

Nanosize model gold particles with varying size were fabricated by deposition of a 10 nm thick gold film onto SiO2/Si(100) substrate by electron beam evaporation followed by modification using low energy Ar+ ion bombardment. The change in particle size were monitored by the Au 5d valence band states determined by ultraviolet photoelectron spectroscopy (UPS). The gold/iron oxide interface was studied by iron oxide deposition on gold. It was found that the energy profile of Au 5d valence band states are strongly redistributed with decreasing the gold particle size mostly affecting at the lowest and at the highest binding energies. The size effect in the UPS spectra can be interpreted by the energy redistribution rather, than by narrowing the 5d states. The iron oxide deposition increases the catalytic activity in CO oxidation whether it is on gold nanoparticles or on a continuous 80 nm thick gold film. The activity enhancement is significantly larger in case of gold nanoparticles. The interface interaction is operative in enlargement of the catalytic activity even if gold particles are not exposed to the surface, but they are located below the iron oxide layer.

Oct 1, 2003

By Yongquan Zhu, Zhengguo Zhu, Zhichun Liu, Chao Kong, Xinqiang Gao

"The aim of the study is to have a good understanding of the change in the seepage field during and after the tunnel excavation in weathering alteration rock. Field tests are used to monitor the changes of the water table and the numerical model is used to analysis the influence of the seepage filed with different operation conditions during and after the tunnel excavation. Results indicate that the depth, diameter and pumpage of precipitation well are the main factors that have a great influence on the drainage effect. Results also indicate that different operation conditions had various effects on the decrease in water yield during tunnel construction and the recovery in groundwater level after construction.INTRODUCTIONAs a potential disease during tunnel construction, Gushing water not only affected construction schedule, increased construction cost, as well as affected tunnel stability and safety during operation, but also decreased ground-water level. What’s more, the fall of water table caused by gushing water in tunnel would have influenced surrounding residents’ living water, agricultural water and ecological environment around tunnel. In recent years, enough emphasis has been paid to the influence on environment due to the construction of tunnel as a result of the reinforcement of people’s environmental protection awareness.As a result of water collection and drainage after excavation, groundwater was discharged into the tunnel, which caused a loss of water resources in the adjacent mountain mass. Furthermore, during tunnel operation, it was difficult for groundwater level to resume its original condition, which caused a bad ecological environment, because drainage system during tunnel construction destroyed its original hydrologic dynamic balance.In order to study whether decreased groundwater level resulting from tunnel construction could be restored during operation to its original condition, this paper gave a field monitoring on tunnel displacement during construction and simultaneously, generalized model of regional hydrogeology was created according to field hydrogeology to carry out a calculation of stable seepage flow and draw comparisons between recovery conditions of various water levels."

Jan 1, 2015

By M. O. Makwarela, M. W. Erwee, K. Bisaka

"Energy efficiency in mining and minerals processing forms part of Mintek’s long-term research strategy which includes a specific programme designed at overcoming the challenges faced by the South African pyrometallurgy industry.The electric smelting industry is currently severely constrained by the global economic downturn as well as by the availability and increasing cost of electricity. Efficient utilisation of electricity through energy recovery systems and improved smelting process flowsheets can significantly contribute towards creating sustainable operations.Apart from efficient engineering design and solid process control, smelting of either cold or hot pre-reduced ores has been shown to decrease furnace electricity consumption by more than 40%. Various methods of solid-state reduction tests have been carried out at Mintek in order to select the most appropriate process option in the context of the South African industry. This paper summarises a subset of the results obtained, specifically on pre-reduction tests done on South African chromite and manganese ore pellets.In this set of tests, it was found that the use of an organic binder, together with B2O3 as flux, promotes manganese ore pre-reduction, but retards the pre-reduction of chromite. By pre-reducing the manganese ore feed, significant cost savings can be achieved in subsequent smelting processes and there is potential to minimise manganese losses as a result of fuming, due to possible lower operating temperatures."

Jan 1, 2016

By H. C. Cooke

THE gold mining industry, in Canada as in other countries, has passed through trying times in the past year. The strains and stresses of war have drawn away much of its man-power, both from the labour and the management. The urgent needs of the war machine have greatly curtailed the amounts of steel and explosives that can be allotted to the mines; and the loss, by enemy action, of supplies of such essential things as rubber, bids fair to reduce operations still further, if not cripple them entirely in time. And, as if these difficulties were not enough, war on the psychological front has been declared on the gold mines. Earnest supporters of the war effort, well-meaning theorists, and perhaps others whose intent is less disinterested, have all combined to clamour against the continuance of gold mining. We have been asked, what is the use of taking gold out of one hole in Canada to put it into another in Kentucky. We have been assured that gold will never again have any value, except for filling teeth. We have been repeatedly adjured to look at Germany, how well it has got along without gold. We have been told that it is unthinkable, when this nation is girding her loins for war, that labour and materials should be diverted to this useless effort. Gold miners should be diverted to the base-metal mines, where they can produce something of real value to the war effort; or to war factories; or, in fact, almost anywhere, so long as they are got out of the gold mines. And, what has made the situation even more disturbing, it has seemed as if all this clamour might be convincing governments. In fact, as you all know, the government of the United States did actually take the step of ordering its gold mines to cease operations. Fortunately, however, for Canada, the facts that no large favourable effects resulted from that action, and that, in Canada, gold mining is a much larger part of the national economy than in the United States, have caused our government, so far at least, to avoid this drastic step. In talking about this, however, let me emphasize that I have no more inside information on the subject than any of you. Like Will Rogers, all I know is what I see in the papers.

Jan 1, 1943

By Y. Héroux, A. Chagnon, M. M. Savard

"Résumé- Le gîte de Pb-Zn de Gays River s'accompagne d'anomalies des propriétés de la matière organique (MO) et des assemblages de minéraux d'argile (AMA). L'association entre la minéralisation, la distribution de la réflectance de la MO et des AMA suggère que ces traceurs peuvent servir à l'exploration des sulfures de métaux de base dans cette région.A l'emplacement du gîte, la réflectance varie considérablement (0,80% à 1,88%), pouvant même afficher une baisse avec l'enfouissement, ce qui est interprété comme une altération chimique de la MO. Les valeurs les plus élevées s'accompagnent localement de quelques textures en mosaïque et délimitent une anomalie thermique au centre sud de la région. Parmi les minéraux des argiles identifiés, l'illite et la chlorite sont terrigènes alors que la smectite, la kaolinite et la corrensite sont authigènes et, à l'instar de l'altération de la MO, résultent des nouveaux équilibres chimiques créés suite à la précipitation des sulfures.Abstract- The Gays River Pb-Zn ore deposit is associated with anomalies defined from the characters of the organic matter (OM) and from the clay minerals assemblages. The relationships be­ tween these anomalies and the mineralization at the mine suggest that these parameters can be used as new guides for the exploration for base-metal sulfides in this area.The vitrinite reflectance (RJ shows a wide range of values (0.8% to 1.88%) and exhibits an anomalous suppressive effect with depth of burial at the mine site, suggesting a chemical alteration of the OM. The highest R, values are associated with mosaic textures and outline a thermal anomaly at the south-center of the studied area. Among the identified clay minerals, illite and chlorite are terrigenous, whereas smectite, kaolinite and corrensite are authigenous and, like the alteration of the OM, are due to the new chemical equilibria resulting from the precipitation of the sulfides."

Jan 1, 1994

By Earl M. Frizzell, Joseph A. Dos Santos

"Conventional belt conveyors offer an economical method for transporting materials at inclines approaching 18 degrees. Sandwich belt conveyors may be used to transport materials at high angles, to 90 degrees, while maintaining the most positive features of conventional conveyors, that is, (1) proven conventional conveyor components. (2) high-speed operation, (3) high-single lifts, (4) continuous cleaning of the smooth surf aced belts, and (5) easy, quick repair by hot or cold vulcanizing. The present discussion deals with the evolution and development of sandwich belt conveyors to satisfy the operational requirements of the open-pit mining and materials-handling industries.A look at the limitation s of conventional shallow angle conveyors reveals the conveying angle at which a cover belt is needed. The relationship between conveying angle and hugging pressure by the cover belt is developed mathematically. A study of past and current developments reveals that the Loop Belt and Beltavator are significant advances in the state-of -the- art. The vertical radius of curvature constraints are discussed in detail and the constraint equations are developed. Criteria for future development is established as a basis for evolutionary developments in sandwich belt high-angle conveyors. The use of intermediate drives in sandwich belt high-angle conveyors is investigated.IntroductionIn connection with U.S. Bureau of Mines funded–study relating to continuous haulage from deep open-pit mines, the authors had occasion to study extensively, the use of high-angle conveyors as a means of hauling mine products continuously from the pit while maintaining optimum mine slopes to minimize total excavation. The many possible high-angle conveying methods investigated included skip hoists, bucket ladders, pocket belts, fin belts, cleated belts, sandwich belts, pipe belts, screw conveyors, slurry pipe lines, and others. The sandwich belt high-angle conveyor appeared to be the most operationally-appropriate and economical solution for the mining industry. The present paper presents the theory, historical development, state-of-the-art, and evolutionary developments in sandwich belt high-angle conveyors."

Jan 1, 1983

By J. H. D. Hargrove, A. F. Snowball

Atmospheric pollution control has become increasingly important in re-cent years with laws and public opinion having required the reduction of contaminants from industrial gas effluents. Treatment methods have advanced to make possible, with proper plant design and operation, a satisfactory removal of these contaminants. Gases from Cominco's metallurgical operations at Trail, approximating 900,000 c.f.m., are treated by baghouses, electrostatic precipitators, cyclones, or wet scrubbers. The tabulated data include gas and dust conditions, plant performance, and some details of plant equipment. Discussion emphasizes the special features, scope of application, and basic design principles of the treatment methods, all based on Cominco experience. Recovery of over 99 per cent of the fume and dust is achieved by the major installations from which effluent gases go to atmosphere. Cooling of gases for baghouse recovery and conditioning for electrostatic precipitation are mentioned. Co3ts are tabulated for some of the installations on the basis of a unit of 1,000 cubic feet of gas. Suggestions are made on the procedure for assessing a smoke treatment problem and for selection of suitable equipment.

Jan 1, 1959

By Magnus Evertsson, Johannes Quist

HPGRs have since introduced in the 1980s (Kellerwessel, 1993; Schönert, 1988), now become integral comminution units at several minerals processing plants around the world. Even though a lot of the initial issues concerning performance, availability and wear have been addressed and solved there are still phenomena and aspects which can be improved and understood further. Schönert and Sander (2002) presented experimental results and a mechanistic model including the internal force dynamics between the rollers and the compacted bed. They derived expressions for the pressure distribution involving most of the influencing terms and effects. However, in order to solve the differential equations several of the terms vanish by assumptions. The Schönert and Sander model reflects the experimental data in many aspects but the predicted shear force distinctly deviates from the experimental results at the angular position of the peak pressure level. This finding suggests that the particle to particle interaction and breakage process in the different zones seen in Figure 1 are complex and difficult to model using analytical models. A numerical modelling approach using DEM does not require the same amount of assumptions and simplifications of boundary conditions. Hence such modelling may provide further knowledge and vital understanding. In this paper the breakage process is simulated in order to investigate the shear slip behaviour and how it relates to different operating variables. A laboratory scale HPGR corresponding to the experimental setup used by Schönert (2002) have been modelled in EDEM (DEM-Solutions). The bonded particle model (BPM) is used for modelling quartz particles (Potyondy, 2004). The breakage model strength parameters are calibrated against interparticle breakage experiments in an Instron 400RD compression device. The contact model parameters are calibrated using calibration methods developed by Quist (2015). The floating roller dynamics are modelled using a spring-damper system. Results present insights regarding the interparticle slip behaviour as well as the frictional tangential force distribution on the rollers. The simulated roller pressure distribution shows good correspondence with previously reported findings in the literature.

Jan 1, 2016