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By David Seymour

Newmont Gold Company (NGC) located in Northeastern Nevada has been processing carbonaceous and sulfide refractory gold ores through a chlorination circuit prior to cyanidation. A "Flash Chlorination" pilot plant was installed in 1987 in an effort to obtain higher chlorine utilization efficiency and increase gold extraction. The Flash Chlorination process oxidizes organic carbon and sulfide sulfur. It also deactivates preg-robbing carbon, making the ore amenable to cyanidation. Significant recovery improvements were observed using this new process. This scheme has also been instrumental in the processing of higher than normal grade ores at economic chlorine levels. The Flash Chlorination pilot plant has been successfully treating carbonaceous ore on a production scale since April 1988. This paper summarizes laboratory and pilot plant optimization test work, using conventional and statistical methods.

Jan 1, 1989

By J. T. Stanley

The identification of crystal phases and crystal chemistry can be critical to understanding the mechanisms of waste material interaction with native soils. Understanding these mechanisms can suggest correct methods for remediation and treatment. A program is outlined and examples are given of the development of effective techniques for rapid phase identification of environmental samples using electron microscopy. The program concentrates on the development of integrated object oriented software to aid rapid searching of online databases and rapid simulation of potential crystal diffraction patterns. Examples come from dried sludge taken from a former hard-chrome plating facility.

Jan 1, 1993

By J. S. Fox

"Pyroclastic rocks are useful guides to volcanic centers due to the tendency of their fragments to increase in size and volume toward the source vent. The felsic rocks of these centers can be the prime hosts of base metal deposits in the Precambrian Shield; their sub-volcanic equivalents are often the focus of porphyry copper mineralization in the Cordillera. Quantitative mapping of pyroclastic rocks has not yet developed into a routine prospecting tool in Canada, however, possibly due to the cumbersome nature of existing manual techniques and their limitation to structurally simple terrains.A rapid pyroclastic mapping method has been developed whereby the field geologist acquires only a down-plunge outcrop photograph, a record of the fragmental deformation ellipsoid and a record of some descriptive features from each station. Mean fragment size and volume percent are obtained later in the laboratory from a photo-enlargement: by means of a digital analyzer. A computer program uses the strain parameters to 'undeform' the field measurements and obtains genetic information from the descriptive data. Results can be superimposed on a geologic map, with values for each station being represented by a dot of a specified diameter corresponding to the size or volume percentile range to which the value belongs.Control traverses were run over the pyroclastic rocks surrounding the Anderson Lake mine and the Flin Flon South main shaft in northern Manitoba. In both locations, the mapping has delineated regular increasing trends in mean size and volume per cent toward the head frame."

Jan 1, 1977

By G. Kazonich

The high costs and environmental problems associated with making iron and steel in the United states is driving the development of new technologies to replace the blast furnace. A prototype reactor incorporating rocket technology was designed and built. This rapid rate reactor was operated successfully and consistently made iron metal. Minus 32s-mesh magnetite particles could be reduced to iron metal in less than 50 ms in a high temperature flow through reactor. Iron product was recovered inside the reactor and in a downstream cyclonic separator. The results of typical operation and how parametric changes affected the reduction of iron ore concentrates are discussed.

Jan 1, 1993

By Gökhan Demirci, Ishak Karakaya

"Energy consumption in electrolytic magnesium cells is well above the theoretical values. However, the mechanism of the back reaction, the main cause of the current losses, has not been fully understood yet. Magnesium dissolution into the melt is generally regarded as the limiting step for the back reaction. Accordingly, present cell designs are made with priority given to fast magnesium removal from the cell. However, experimental data and modeling results in this study indicate that the limiting step for the back reaction between magnesium and chlorine is the chlorine dissolution into the electrolyte when physical contact between electrolysis products was eliminated. Effects of chlorine bubbles on the current efficiency and the cell potential were investigated. Results show that the extent of back reaction is proportional to the chlorine surface area in contact with the electrolyte per unit time, and the cell potential increases with the amount of chlorine bubbles inside the electrolyte.1. IntroductionMagnesium is less dense than the electrolyte in electrolytic magnesium production. Therefore, both electrode products, magnesium and the chlorine gas, move upwards inside the molten salt electrolyte during electrolysis. The upward motion of electrode products promotes the most important current loss mechanism, the ""back reaction"". Separation of the highly reactive species; liquid magnesium and the chlorine gas in the cell, to prevent their recombination is one of the main concerns in cell designs. The employment of large inter-electrode distance or a separation wall in early cell designs; decreased the extent of recombination, but increased the cell voltage and energy consumption. Recent cell designs, on the other hand, make use of lifting action of chlorine gas [1,2] by utilizing smaller inter electrode distances to separate the magnesium and chlorine gas faster. Although energy consumption was reduced, but more physical interactions between electrode products make electrolytic magnesium cells still highly inefficient when energy consumptions are compared with the theoretical values. Today, the most efficient industrial cells utilizing high purity feed operate at 10.5-11.5 kWh kg-1 Mg [3-5] and it is considerably higher than the theoretically attainable value of about 6.0 kWh kg-1 [6]. This large gap demonstrates the necessity of more research on physics and chemistry of magnesium cell electrolysis."

Jan 1, 2011

By Yuanbo Zhang, Zijian Su, Bingbing Liu, Guanghui Li, Manman Lu, Tao Jiang

Acid wastewater containing toxic metal ions has become increasingly important global environmental concern and lead (Pb) is one of the prime toxic heavy metal ions. Humic acid (HA), a kind of natural organic matter, has been proventohaveagreatadsorptioncapacityformetalcations(Pb2+,Cu2+,etc.).Our previous study has verified that HA has excellent adsorbing ability on vanadium titanium-bearing magnetite(VTM) particles. In this study, VTM-HA complex magneticparticles werepreparedfor removing Pb(II)fromacidwastewater,which could be easily recycled by magnetic separation. The effects of pH value, ionic strength and VTM-HA concentration on the removal ratio of Pb(II) were deter- mined by isothermal adsorption tests. The results indicated that Pb(II) adsorption was subject topHand ionic strength. When initial Pb(II) concentration is 100 mg/ L, the residual concentration and removal ratio of Pb(II) reach 0.17 mg/L and 99.83%, respectively, which are much lower than the discharge standard. (cid:1) (cid:1)

Mar 1, 2018

By P F. Hodkiewicz

"Our understanding of mineral resources relies on three basic steps: data capture data interpretation model construction. Until recently, all three of these steps required significant time and manual effort to produce a single resource model for mine planning, typically taking more than a year to progress from drilling to the final block model. Over the past several years, BHP Billiton has been developing innovative workflows in rapid resource modelling projects to significantly reduce these time constraints and make the process more productive by replacing manual activities with automated ones. Rapid resource modelling is the process of combining recently developed off-the-shelf technology with internal technology developments to fundamentally change the way we collect, interpret, model and evaluate geoscience data. Initiatives include automated systems and standardised workflows to make it safer, faster and cheaper to continuously update multidiscipline resource models. Specifically, rapid resource modelling workflows combine: real-time analysis of drill holes and drill samples with downhole tools and hyperspectral scanning systemsautomated interpretation of drill hole intervals based on pattern-recognition algorithmscontinuous modelling workflows using implicit modelling software. This paper outlines technology developments and workflows that provide a more thorough understanding of mineral resources to support faster and more informed strategic, planning and production decisions.CITATION:Hodkiewicz, P F, 2014. Rapid resource modelling – a vision for faster and better mining decisions, in Proceedings Ninth International Mining Geology Conference 2014 , pp 183–188 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By Dipl. -Ing. Mertens

Gentlemen: I am pleased and regard it as a priviledge to give you a report on rapid roadheading with heading machines in the coal mining industry of Western Germany. Importance of Heading Operations in the West German Coal Mining Industry Every year about 770 km of headings are driven In the seams of the West German coal mines, most of them gate roads, the rest rise headings, to open new faces. In thick seams the heading operations are carried out entirely in the coal, in thin seams the country rock has to be ripped. The total length of 770 km corresponds to a rock volume of roughly 9.5 million m3; this figure underlines the importance of the heading operations in the coal mining industry of our country.

Jan 1, 1970

By Luke Meers

Roadway development rates in Australian underground coal mines are failing to keep pace with modern longwall systems and are unlikely to sustain further improvements in longwall productivity into the future unless step change improvements to roadway development equipment and practices are made. Bottlenecks which limit and constrain improved production and impact the safety of operators have been identified through a series of industry surveys, with the manual installation of strata support materials, consumables delivery, coal haulage and monorail installation being highlighted as major areas to improve development performance. This paper looks at research being carried out at the University of Wollongong in designing an integrated system approach for the fully automated handling and installing of development consumables, and the systems required to support these activities. A series of hard automation manipulation devices have been demonstrated in surface trials and the results indicate that rapid roadway development can be achieved.

Aug 1, 2013

By C. Riveros, H. Henein

Bulk Metallic Glasses have a high potential as advanced engineering materials due to their various properties including strength and corrosion resistance, to name a few. This paper investigates amorphous phase formation and rapid solidification characteristics of impulse atomized Co-based alloys in order to understand and control the application properties of the final products. Amorphous fraction and kinetic crystallization properties of the atomized Co-based alloy powders were quantified by means of Differential Scanning Calorimetry. In addition, different but complementary characterization tools were used to analyze microstructures of the powders. These include optical microscopy, X-ray diffraction and micro-hardness tests. While the amorphous fraction within the powders is promoted by high cooling rate and smaller powder size as expected, hardness is found to decrease with the fraction of amorphous phase.

Jan 1, 2015

By Carlos G. Levi

"The principles involved in the rapid solidification of supercooled metal droplets and existing numerical models are reviewed. The limitations of these models for studying alloy solidification are discussed in terms of the effects of alloying elements on the relevant heat transfer, thermodynamic and kinetic parameters. Analysis of the enthalpy-temperature diagram reveals how the extent of rapid solidification is hindered by the addition of solute. A solidification model incorporating thermodynamic and kinetic relationships into a Newtonian heat transfer formulation is used to analyze the thermal history and concurrent solute redistribution during recalescence. IntroductionIt is well acknowledged that microstructural evolution during solidification is intimately associated with the thermal history of the liquid-solid interface. Structural parameters like chemical homogeneity, morphology and size scale of the phases can be related to the interfacial temperature and velocity. These in turn change by the interaction of the interface with the thermal and solutal fields in its neighboring environment.The thermal history of powder solidification can be conveniently described on the enthalpy-temperature diagram for a pure metal shown in Figure 1 and discussed in detail elsewhere [1). A system can conceivably follow any path of decreasing enthalpy in the supercooled region of Figure 1 (~ < 1), starting at the nucleation temperature (oN < 0) on the liquid line, and ending at some point on the solid line. A vertical path represents an isothermal transformation, of which a limiting case is solidification without significant barriers to nucleation and growth, with the interface at the equilibrium temperature TM (path one in Figure 1). A horizontal path represents isenthalpic (or adiabatic) solidification whereby the system could form an amount of solid proportional to the initial supercooling of the liquid without further heat loss to the environment. A liquid that can completely transform to solid under adiabatic conditions is said to be ""hypercooled""."

Jan 1, 1986

By J. R. Carr

A crucial concern when implementing computer algorithms for geostatistical analyses on microcomputers is speed of execution. Kriging, in particular, typically relies on a Gauss elimination algorithm to solve for weights. Because such an algorithm is required for each estimate, the solution for weights can result in very slow program execution speed on a microcomputer. One approach to enhancing the efficiency of Gauss elimination is demonstrated herein. The upper triangle plus diagonal of the intersample covariance matrix is used in a modified banded Gauss elimination algorithm. Results show that such an algorithm yields approximately a two-fold reduction in execution time for kriging when the number of nearest neighbors used for estimation is large.

Jan 1, 1990

By Wenbin Liu

A novel route for rapid synthesis of ultrafine WC-Co cemented carbides with homogeneous binder phase distribution is reported. The composite powder is produced by in situ reduction-carbonization reactions by using WO2.9, Co3O4 and carbon black as raw powders. The reaction equilibrium and phase stability are studied by thermodynamic calculations. The WC-Co composite powder is condensed by spark plasma sintering (SPS) to obtain the cemented carbides bulk. The sintering temperature is lower than that in the conventional sintering methods by 1500C, while the sintering time is remarkably reduced by 3-5 times. The high performances of the hardness and the fracture toughness are obtained. The experimental results confirm that the present processing scheme of in situ reduction-carbonization reactions and subsequent SPS sintering is an efficient way to prepare WC-Co cemented carbides, and is apparently superior to the conventional long-period techniques of preparing composite powder and cemented carbides bulk.

Jan 1, 2008

By Herman D. Mendoza

A rapid recovery/recycling process was introduced utilizing the surface-chemical properties of finely dispersed mercury and alumina (Al2O3) fibers in aqueous environment. The conventional method of amalgamation or .ball milling. involves the mixing of a substantial amount of mercury to collect free gold during the grinding stage. In effect, a portion of the mercury is transformed into minute droplets that readily float and disperse in the amalgamation effluent. The fine droplets of mercury in the dispersion readily attached onto the positively charged macroscopic alumina fibers (i.e. = pH 9.8) at conditions pH 3 to 10. When an effluent from settling procedure after an amalgamation-grinding stage is passed through a column-bed packed with alumina fibers, maximum collection of negatively charged finely dispersed mercury occurred at pH 3 to 6. The collection/attachment efficiency was 99.5%. The collected droplets of mercury, which are left in the column-bed of alumina fibers, were subsequently rinsed with alkaline solution at pH 10 to 11.5. At these conditions, both mercury and alumina fibers carry negative surface potentials and resulted in the partial detachment of mercury from the alumina fibers. The detachment efficiency was only 30-35%. The attachment/detachment mechanisms in this study were analyzed using the DLVO theory.

Jan 1, 2003

By Herman D. Mendoza

"The removal of finely dispersed mercury from the effluent of small-scale gold mining operations and the eventual recycling of the recovered mercury was investigated. The conventional method of amalgamation, or “ball milling”, involves the mixing of a substantial amount of mercury with ore to recover free gold during the grinding stage. During grinding, a portion of the mercury is transformed into minute droplets, which readily float and disperse in the effluent. A kilo of gold ore containing 20-30 g Au/t, when ground with 3 g of mercury, yields 0.005 to 0.050 mg/l of mercury in the effluent, exceeding the concentration of 0.002 mg/l allowed by law for surface water.A rapid recovery/ recycling process was introduced using the surface-chemical properties of finely dispersed mercury in aqueous suspension. It was observed that fine droplets of mercury in an aqueous environment readily attached onto a collector having positive surface potentials for pH 3 to 10. An example of a suitable collector is alumina (Al2O3), which has an iso-electric point of pH 9.8. When an effluent, coming from a settling procedure after an amalgamation-grinding stage, was passed through a column-bed packed with alumina fiber, removal and subsequent collection of finely dispersed mercury occurred under acidic conditions, pH 3-6. Recovery was around 99.5%, yielding an acceptable quality of water safe for disposal into the aquatic environment. The collected droplets of mercury, which are left in the column-bed of alumina fiber, were subsequently treated with a cleansing solution at alkaline conditions pH 10 -12. At these conditions, both mercury and alumina fiber carry negative surface potentials, which results in the eventual detachment of attached mercury from the alumina collector. The effective recovery of attached mercury from the alumina collector by the detachment procedure is only 30-35%. The collected mercury from the cleansing stage can be collected, cleaned and can be used for subsequent amalgamation processes. The attachment and detachment behaviour of finely dispersed mercury onto and from the microscopic collector alumina is shown in Figure 1. The result of attachment and detachment were analyzed using existing interaction energy theories like the Darguin-Landau- Verwey- Overbeek (DLVO) Theory."

Jan 1, 2003

By A. V. Deforest, A. R. Anderson, C. W. MacGregor

ONE of the important problems in the design of structures and machine parts subjected to rapidly applied loads is the determination of the strength and ductility of the material itself under such conditions. Realizing the need for such information, many investigations have been carried out in the past. Most of these experiments have been made using notched bars in bending either with the Charpy or Izod impact machine. While yielding valuable data on the effect of notches in the energy absorption of the material and on the condition of heat-treatment, this form of test does not lend itself readily to a determination of fundamental stress-strain relations. For this and other reasons, more attention has been paid recently to the tension impact test. An extensive literature already exists on the subject and only those investigations somewhat closely related to the present paper will be mentioned. For a more comprehensive list, the reader is referred to the Symposium on Impact Testing of the A.S.T.M., 1938. The work of Mann,1 Clark and Dätwyler,2 Nádai and Manjoine,3 Winlock and Leiter,4 Deutler,5 and Brinkmann,6 however, deserve especial mention. In most of the previous investigations on the subject, when stress-strain relations were obtained under high rates of loading, it was the common procedure to determine stresses based on the original area and strains based on the original length. Stress-strain curves were then constructed by [P OL, plotting So = Ao as a function of eo = Lo] where A o and Lo refer to the original area and gauge length, respectively. At present there exists a paucity of true stress-strain data in the impact problem. The advantages of constructing so-called true stress-strain curves in order to reveal the fundamental physical properties of the material for the tension test were discussed recently by one of the authors&apos; It was shown that the true physical behavior of the material in the tension test could best be represented [by plotting the average true stress, S = P as a function of e = q&apos; = log o = log Log] where P, A, L, S, e, and q&apos; refer to the load, the cross-sectioned area while the load P is applied, the actual gauge length, the average true stress, the true strain and true reduction in area, respectively. Besides giving a better physical representation, the method has certain additional advantages in that the stress-strain curve so plotted becomes a straight line from the maximum load point to fracture. The construction of such- curves, however, while comparatively simple for the slow rates of loading customarily used in the tension test, presents certain difficulties for tensile impact in that both loads and diameters are required throughout the test. The continuous measurement of test-piece

Jan 1, 1941

By A. V. Deforest, A. R. Anderson, C. W. MacGregor

ONE of the important problems in the design of structures and machine parts subjected to rapidly applied loads is the determination of the strength and ductility of the material itself under such conditions. Realizing the need for such information, many investigations have been carried out in the past. Most of these experiments have been made using notched bars in bending either with the Charpy or Izod impact machine. While yielding valuable data on the effect of notches in the energy absorption of the material and on the condition of heat-treatment, this form of test does not lend itself readily to a determination of fundamental stress-strain relations. For this and other reasons, more attention has been paid recently to the tension impact test. An extensive literature already exists on the subject and only those investigations somewhat closely related to the present paper will be mentioned. For a more comprehensive list, the reader is referred to the Symposium on Impact Testing of the A.S.T.M., 1938. The work of Mann,1 Clark and Dätwyler,2 Nádai and Manjoine,3 Winlock and Leiter,4 Deutler,5 and Brinkmann,6 however, deserve especial mention. In most of the previous investigations on the subject, when stress-strain relations were obtained under high rates of loading, it was the common procedure to determine stresses based on the original area and strains based on the original length. Stress-strain curves were then constructed by plotting [So = ooT as a function of eo =o] where A o and Lo refer to the original area and gauge length, respectively. At present there exists a paucity of true stress-strain data in the impact problem. The advantages of constructing so-called true stress-strain curves in order to reveal the fundamental physical properties of the material for the tension test were discussed recently by one of the authors? It was shown that the true physical behavior of the material in the tension test could best be represented by plotting the average true stress, [S = P] as a function of [e = q&apos; = log A-le = log Lo] where P, A, L, S, [e], and q&apos; refer to the load, the cross-sectioned area while the load P is applied, the actual gauge length, the average true stress, the true strain and true reduction in area, respectively. Besides giving a better physical representation, the method has certain additional advantages in that the stress-strain curve so plotted becomes a straight line from the maximum load point to fracture. The construction of such curves, however, while comparatively simple for the slow rates of loading customarily used in the tension test, presents certain difficulties for tensile impact in that both loads and diameters are required throughout the test. The continuous measurement of test-piece

Jan 1, 1941

By G. Bonin, R. P. Preston

"This paper presents a series of case studies where spherical camera photographs were used to generate 3D shaft models using photogrammetric methods. The shaft models were, checked for accuracy by comparing them to overlapping laser scan data, provided survey data or idealized shaft models. Short lengths of model were found to more accurately reproduce the shaft surface, with a best observed accuracy of 8 mm. Longer models encountered errors with accumulated errors as exhibited by slight deviations from vertical or slightly conical model shape. At present, the models are considered acceptable for general documentation and gross change detection. INTRODUCTION Shaft inspections are required by mining regulations in many jurisdictions and are commonly completed by trained mine personnel via visual inspections. This can be time consuming and prone to errors due to lapses in attention and the rapid travel rate required to inspect an entire shaft in a reasonable amount of time. Similarly, because of the time requirements, there can be impacts on other aspects of mining as a result of occupying the shaft for inspections. Spherical cameras with supplemental light systems offer a modern addition or alternative to conventional inspections. These cameras can be lowered relatively quickly to collect high definition, fully illuminated videos of the shaft that can be reviewed in detail later while the shaft returns to service (Gillis et.al., 2019). The use of cameras offers a further opportunity for valuable survey data generation from the same original data stream. The video data can be processed into three-dimensional (3D) models using Structure-from-Motion (Westoby et al., 2012) based photogrammetric methods. Depending on the quality of the source video and availability of survey control (required for all photogrammetry models) these models can be very accurate. Shaft surveying can be conducted with traditional theodolite methods but such surveys are time consuming and limited in their data density. Similarly, scans can be completed using conventional terrestrial laser scanners, but this requires a significant number of distinct setups to provide sufficient overlap between scans. Work is being conducted both on the laser scanning (SLAM, Durrant-Whyte & Bailey, 2006) and photogrammetry fronts towards kinetic scanning (Benecke, 2017) systems. The major advancement which is permitting these kinetic systems is Inertial Measurement Units (IMUs) which can provide localization in GPS denied environments and reduce errors associated with the open traverse format associated with shaft scanning."

Jan 1, 2019

By J. Botha

There are many underground mining software tools available to plan and schedule the development of underground mines. A shortfall of these tools is the optimization of the underground equipment and strategy in order to maximize the development rate. This paper will illustrate how the SimMine® software was used to maximize underground development at Petra Diamonds&apos; Cullinan Diamond Mine. It will also determine the effect of various development strategies and equipment capacities on the underground development rate and pinpoint potential bottlenecks in the mine development cycle.

Jan 1, 2010

By Eugene P. Pfleider

The mining industry of the World, and particularly of the United States, has made a complete reversal from underground to surface mining methods since the turn of the 20th Century. This has occurred even as average ore grades were decreasing and strip ratios rising. In the early 1900&apos;s there were over 100 underground mines producing from the three iron ranges of Minnesota -- today there are hone. Practically all of our coal prior to 1930 was mined underground; today over one-third is from surface operations and that percentage is increasing. Although world mining has hot changed to surface techniques as rapidly as has the U. S. Industry, the shift is escalating and will approach our figures shortly. A comparison of World and U. S. production figures are shown in Table 1, taken from the AIME Surface Mining volume, and the trend rates for the U. S. are depicted in Fig. 1.

Jan 1, 1968